Merge remote-tracking branch 'upstream/3.4' into merge-3.4

cmake/OpenCVUtils.cmake

@@ -1624,7 +1624,7 @@ endif()
 
 macro(ocv_git_describe var_name path)
   if(GIT_FOUND)
-    execute_process(COMMAND "${GIT_EXECUTABLE}" describe --tags --tags --exact-match --dirty
+    execute_process(COMMAND "${GIT_EXECUTABLE}" describe --tags --exact-match --dirty
       WORKING_DIRECTORY "${path}"
       OUTPUT_VARIABLE ${var_name}
       RESULT_VARIABLE GIT_RESULT

doc/tutorials/imgproc/imgtrans/distance_transformation/distance_transform.markdown

@@ -16,42 +16,152 @@ Theory
 Code
 ----
 
+@add_toggle_cpp
 This tutorial code's is shown lines below. You can also download it from
-    [here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp).
+[here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp).
 @include samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp
+@end_toggle
+
+@add_toggle_java
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java)
+@include samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java
+@end_toggle
+
+@add_toggle_python
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/master/samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py)
+@include samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py
+@end_toggle
 
 Explanation / Result
 --------------------
 
--#  Load the source image and check if it is loaded without any problem, then show it:
-    @snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp load_image
-    ![](images/source.jpeg)
+-   Load the source image and check if it is loaded without any problem, then show it:
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp load_image
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java load_image
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py load_image
+@end_toggle
+
+![](images/source.jpeg)
+
+-   Then if we have an image with a white background, it is good to transform it to black. This will help us to discriminate the foreground objects easier when we will apply the Distance Transform:
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp black_bg
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java black_bg
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py black_bg
+@end_toggle
+
+![](images/black_bg.jpeg)
+
+-   Afterwards we will sharpen our image in order to acute the edges of the foreground objects. We will apply a laplacian filter with a quite strong filter (an approximation of second derivative):
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp sharp
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java sharp
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py sharp
+@end_toggle
+
+![](images/laplace.jpeg)
+![](images/sharp.jpeg)
+
+-   Now we transform our new sharpened source image to a grayscale and a binary one, respectively:
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp bin
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java bin
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py bin
+@end_toggle
+
+![](images/bin.jpeg)
+
+-   We are ready now to apply the Distance Transform on the binary image. Moreover, we normalize the output image in order to be able visualize and threshold the result:
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp dist
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java dist
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py dist
+@end_toggle
+
+![](images/dist_transf.jpeg)
+
+-   We threshold the *dist* image and then perform some morphology operation (i.e. dilation) in order to extract the peaks from the above image:
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp peaks
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java peaks
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py peaks
+@end_toggle
+
+![](images/peaks.jpeg)
+
+-   From each blob then we create a seed/marker for the watershed algorithm with the help of the @ref cv::findContours function:
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp seeds
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java seeds
+@end_toggle
 
--#  Then if we have an image with a white background, it is good to transform it to black. This will help us to discriminate the foreground objects easier when we will apply the Distance Transform:
-    @snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp black_bg
-    ![](images/black_bg.jpeg)
+@add_toggle_python
+@snippet samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py seeds
+@end_toggle
 
--#  Afterwards we will sharpen our image in order to acute the edges of the foreground objects. We will apply a laplacian filter with a quite strong filter (an approximation of second derivative):
-    @snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp sharp
-    ![](images/laplace.jpeg)
-    ![](images/sharp.jpeg)
+![](images/markers.jpeg)
 
--#  Now we transform our new sharpened source image to a grayscale and a binary one, respectively:
-    @snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp bin
-    ![](images/bin.jpeg)
+-   Finally, we can apply the watershed algorithm, and visualize the result:
 
--#  We are ready now to apply the Distance Transform on the binary image. Moreover, we normalize the output image in order to be able visualize and threshold the result:
-    @snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp dist
-    ![](images/dist_transf.jpeg)
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp watershed
+@end_toggle
 
--#  We threshold the *dist* image and then perform some morphology operation (i.e. dilation) in order to extract the peaks from the above image:
-    @snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp peaks
-    ![](images/peaks.jpeg)
+@add_toggle_java
+@snippet samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java watershed
+@end_toggle
 
--#  From each blob then we create a seed/marker for the watershed algorithm with the help of the @ref cv::findContours function:
-    @snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp seeds
-    ![](images/markers.jpeg)
+@add_toggle_python
+@snippet samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py watershed
+@end_toggle
 
--#  Finally, we can apply the watershed algorithm, and visualize the result:
-    @snippet samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp watershed
-    ![](images/final.jpeg)
+![](images/final.jpeg)
\ No newline at end of file

doc/tutorials/imgproc/table_of_content_imgproc.markdown

@@ -285,6 +285,8 @@ In this section you will learn about the image processing (manipulation) functio
 
 -   @subpage tutorial_distance_transform
 
+    *Languages:* C++, Java, Python
+
     *Compatibility:* \> OpenCV 2.0
 
     *Author:* Theodore Tsesmelis

modules/calib3d/include/opencv2/calib3d.hpp

@@ -1985,6 +1985,31 @@ CV_EXPORTS_W int decomposeHomographyMat(InputArray H,
                                         OutputArrayOfArrays translations,
                                         OutputArrayOfArrays normals);
 
+/** @brief Filters homography decompositions based on additional information.
+
+@param rotations Vector of rotation matrices.
+@param normals Vector of plane normal matrices.
+@param beforePoints Vector of (rectified) visible reference points before the homography is applied
+@param afterPoints Vector of (rectified) visible reference points after the homography is applied
+@param possibleSolutions Vector of int indices representing the viable solution set after filtering
+@param pointsMask optional Mat/Vector of 8u type representing the mask for the inliers as given by the findHomography function
+
+This function is intended to filter the output of the decomposeHomographyMat based on additional
+information as described in @cite Malis . The summary of the method: the decomposeHomographyMat function
+returns 2 unique solutions and their "opposites" for a total of 4 solutions. If we have access to the
+sets of points visible in the camera frame before and after the homography transformation is applied,
+we can determine which are the true potential solutions and which are the opposites by verifying which
+homographies are consistent with all visible reference points being in front of the camera. The inputs
+are left unchanged; the filtered solution set is returned as indices into the existing one.
+
+*/
+CV_EXPORTS_W void filterHomographyDecompByVisibleRefpoints(InputArrayOfArrays rotations,
+                                                           InputArrayOfArrays normals,
+                                                           InputArray beforePoints,
+                                                           InputArray afterPoints,
+                                                           OutputArray possibleSolutions,
+                                                           InputArray pointsMask = noArray());
+
 /** @brief The base class for stereo correspondence algorithms.
  */
 class CV_EXPORTS_W StereoMatcher : public Algorithm

modules/calib3d/src/homography_decomp.cpp

 /*M///////////////////////////////////////////////////////////////////////////////////////
- //
- // This is a homography decomposition implementation contributed to OpenCV
- // by Samson Yilma. It implements the homography decomposition algorithm
- // described in the research report:
- // Malis, E and Vargas, M, "Deeper understanding of the homography decomposition
- // for vision-based control", Research Report 6303, INRIA (2007)
- //
- //  IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
- //
- //  By downloading, copying, installing or using the software you agree to this license.
- //  If you do not agree to this license, do not download, install,
- //  copy or use the software.
- //
- //
- //                           License Agreement
- //                For Open Source Computer Vision Library
- //
- // Copyright (C) 2014, Samson Yilma (samson_yilma@yahoo.com), all rights reserved.
- //
- // Third party copyrights are property of their respective owners.
- //
- // Redistribution and use in source and binary forms, with or without modification,
- // are permitted provided that the following conditions are met:
- //
- //   * Redistribution's of source code must retain the above copyright notice,
- //     this list of conditions and the following disclaimer.
- //
- //   * Redistribution's in binary form must reproduce the above copyright notice,
- //     this list of conditions and the following disclaimer in the documentation
- //     and/or other materials provided with the distribution.
- //
- //   * The name of the copyright holders may not be used to endorse or promote products
- //     derived from this software without specific prior written permission.
- //
- // This software is provided by the copyright holders and contributors "as is" and
- // any express or implied warranties, including, but not limited to, the implied
- // warranties of merchantability and fitness for a particular purpose are disclaimed.
- // In no event shall the Intel Corporation or contributors be liable for any direct,
- // indirect, incidental, special, exemplary, or consequential damages
- // (including, but not limited to, procurement of substitute goods or services;
- // loss of use, data, or profits; or business interruption) however caused
- // and on any theory of liability, whether in contract, strict liability,
- // or tort (including negligence or otherwise) arising in any way out of
- // the use of this software, even if advised of the possibility of such damage.
- //
- //M*/
+//
+// This is a homography decomposition implementation contributed to OpenCV
+// by Samson Yilma. It implements the homography decomposition algorithm
+// described in the research report:
+// Malis, E and Vargas, M, "Deeper understanding of the homography decomposition
+// for vision-based control", Research Report 6303, INRIA (2007)
+//
+//  IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
+//
+//  By downloading, copying, installing or using the software you agree to this license.
+//  If you do not agree to this license, do not download, install,
+//  copy or use the software.
+//
+//
+//                           License Agreement
+//                For Open Source Computer Vision Library
+//
+// Copyright (C) 2014, Samson Yilma (samson_yilma@yahoo.com), all rights reserved.
+// Copyright (C) 2018, Intel Corporation, all rights reserved.
+//
+// Third party copyrights are property of their respective owners.
+//
+// Redistribution and use in source and binary forms, with or without modification,
+// are permitted provided that the following conditions are met:
+//
+//   * Redistribution's of source code must retain the above copyright notice,
+//     this list of conditions and the following disclaimer.
+//
+//   * Redistribution's in binary form must reproduce the above copyright notice,
+//     this list of conditions and the following disclaimer in the documentation
+//     and/or other materials provided with the distribution.
+//
+//   * The name of the copyright holders may not be used to endorse or promote products
+//     derived from this software without specific prior written permission.
+//
+// This software is provided by the copyright holders and contributors "as is" and
+// any express or implied warranties, including, but not limited to, the implied
+// warranties of merchantability and fitness for a particular purpose are disclaimed.
+// In no event shall the Intel Corporation or contributors be liable for any direct,
+// indirect, incidental, special, exemplary, or consequential damages
+// (including, but not limited to, procurement of substitute goods or services;
+// loss of use, data, or profits; or business interruption) however caused
+// and on any theory of liability, whether in contract, strict liability,
+// or tort (including negligence or otherwise) arising in any way out of
+// the use of this software, even if advised of the possibility of such damage.
+//
+//M*/
 
 #include "precomp.hpp"
 #include <memory>
@@ -489,4 +490,67 @@ int decomposeHomographyMat(InputArray _H,
     return nsols;
 }
 
+void filterHomographyDecompByVisibleRefpoints(InputArrayOfArrays _rotations,
+                                              InputArrayOfArrays _normals,
+                                              InputArray _beforeRectifiedPoints,
+                                              InputArray _afterRectifiedPoints,
+                                              OutputArray _possibleSolutions,
+                                              InputArray _pointsMask)
+{
+    CV_Assert(_beforeRectifiedPoints.type() == CV_32FC2 && _afterRectifiedPoints.type() == CV_32FC2);
+    CV_Assert(_pointsMask.empty() || _pointsMask.type() == CV_8U);
+
+    Mat beforeRectifiedPoints = _beforeRectifiedPoints.getMat();
+    Mat afterRectifiedPoints = _afterRectifiedPoints.getMat();
+    Mat pointsMask = _pointsMask.getMat();
+    int nsolutions = (int)_rotations.total();
+    int npoints = (int)beforeRectifiedPoints.total();
+    CV_Assert(pointsMask.empty() || pointsMask.checkVector(1, CV_8U) == npoints);
+    const uchar* pointsMaskPtr = pointsMask.data;
+
+    std::vector<uchar> solutionMask(nsolutions, (uchar)1);
+    std::vector<Mat> normals(nsolutions);
+    std::vector<Mat> rotnorm(nsolutions);
+    Mat R;
+
+    for( int i = 0; i < nsolutions; i++ )
+    {
+        _normals.getMat(i).convertTo(normals[i], CV_64F);
+        CV_Assert(normals[i].total() == 3);
+        _rotations.getMat(i).convertTo(R, CV_64F);
+        rotnorm[i] = R*normals[i];
+        CV_Assert(rotnorm[i].total() == 3);
+    }
+
+    for( int j = 0; j < npoints; j++ )
+    {
+        if( !pointsMaskPtr || pointsMaskPtr[j] )
+        {
+            Point2f prevPoint = beforeRectifiedPoints.at<Point2f>(j);
+            Point2f currPoint = afterRectifiedPoints.at<Point2f>(j);
+
+            for( int i = 0; i < nsolutions; i++ )
+            {
+                if( !solutionMask[i] )
+                    continue;
+
+                const double* normal_i = normals[i].ptr<double>();
+                const double* rotnorm_i = rotnorm[i].ptr<double>();
+                double prevNormDot = normal_i[0]*prevPoint.x + normal_i[1]*prevPoint.y + normal_i[2];
+                double currNormDot = rotnorm_i[0]*currPoint.x + rotnorm_i[1]*currPoint.y + rotnorm_i[2];
+
+                if (prevNormDot <= 0 || currNormDot <= 0)
+                    solutionMask[i] = (uchar)0;
+            }
+        }
+    }
+
+    std::vector<int> possibleSolutions;
+    for( int i = 0; i < nsolutions; i++ )
+        if( solutionMask[i] )
+            possibleSolutions.push_back(i);
+
+    Mat(possibleSolutions).copyTo(_possibleSolutions);
+}
+
 } //namespace cv

modules/dnn/CMakeLists.txt

@@ -12,7 +12,8 @@ ocv_add_dispatched_file_force_all("layers/layers_common" AVX AVX2 AVX512_SKX)
 
 ocv_add_module(dnn opencv_core opencv_imgproc WRAP python matlab java js)
 
-ocv_option(OPENCV_DNN_OPENCL "Build with OpenCL support" HAVE_OPENCL)
+ocv_option(OPENCV_DNN_OPENCL "Build with OpenCL support" HAVE_OPENCL AND NOT APPLE)
+
 if(OPENCV_DNN_OPENCL AND HAVE_OPENCL)
   add_definitions(-DCV_OCL4DNN=1)
 else()

modules/dnn/src/dnn.cpp

@@ -1446,7 +1446,7 @@ struct Net::Impl
             // TODO: OpenCL target support more fusion styles.
             if ( preferableBackend == DNN_BACKEND_OPENCV && IS_DNN_OPENCL_TARGET(preferableTarget) &&
                  (!cv::ocl::useOpenCL() || (ld.layerInstance->type != "Convolution" &&
-                 ld.layerInstance->type != "MVN")) )
+                 ld.layerInstance->type != "MVN" && ld.layerInstance->type != "Pooling")) )
                 continue;
 
             Ptr<Layer>& currLayer = ld.layerInstance;
@@ -1993,11 +1993,17 @@ Net Net::readFromModelOptimizer(const String& xml, const String& bin)
     backendNode->net = Ptr<InfEngineBackendNet>(new InfEngineBackendNet(ieNet));
     for (auto& it : ieNet.getOutputsInfo())
     {
+        Ptr<Layer> cvLayer(new InfEngineBackendLayer(it.second));
+        InferenceEngine::CNNLayerPtr ieLayer = ieNet.getLayerByName(it.first.c_str());
+        CV_Assert(ieLayer);
+
         LayerParams lp;
         int lid = cvNet.addLayer(it.first, "", lp);
 
         LayerData& ld = cvNet.impl->layers[lid];
-        ld.layerInstance = Ptr<Layer>(new InfEngineBackendLayer(it.second));
+        cvLayer->name = it.first;
+        cvLayer->type = ieLayer->type;
+        ld.layerInstance = cvLayer;
         ld.backendNodes[DNN_BACKEND_INFERENCE_ENGINE] = backendNode;
 
         for (int i = 0; i < inputsNames.size(); ++i)

modules/dnn/src/layers/pooling_layer.cpp

@@ -165,6 +165,7 @@ public:
                                 (type == AVE ? LIBDNN_POOLING_METHOD_AVE :
                                                LIBDNN_POOLING_METHOD_STO);
             config.avePoolPaddedArea = avePoolPaddedArea;
+            config.computeMaxIdx = computeMaxIdx;
             config.use_half = use_half;
             poolOp = Ptr<OCL4DNNPool<float> >(new OCL4DNNPool<float>(config));
         }

modules/dnn/src/ocl4dnn/include/ocl4dnn.hpp

@@ -352,6 +352,7 @@ struct OCL4DNNPoolConfig
         pool_method(LIBDNN_POOLING_METHOD_MAX),
         global_pooling(false),
         avePoolPaddedArea(true),
+        computeMaxIdx(true),
         use_half(false)
     {}
     MatShape in_shape;
@@ -365,6 +366,7 @@ struct OCL4DNNPoolConfig
     ocl4dnnPoolingMethod_t pool_method; // = LIBDNN_POOLING_METHOD_MAX;
     bool global_pooling; // = false;
     bool avePoolPaddedArea;
+    bool computeMaxIdx;
     bool use_half;
 };
 
@@ -399,6 +401,7 @@ class OCL4DNNPool
         int32_t pooled_height_;
         int32_t pooled_width_;
         bool avePoolPaddedArea;
+        bool computeMaxIdx;
         bool use_half;
 };
 

modules/dnn/src/ocl4dnn/src/ocl4dnn_pool.cpp

@@ -56,6 +56,7 @@ OCL4DNNPool<Dtype>::OCL4DNNPool(OCL4DNNPoolConfig config)
     channels_ = config.channels;
     pool_method_ = config.pool_method;
     avePoolPaddedArea = config.avePoolPaddedArea;
+    computeMaxIdx = config.computeMaxIdx;
     use_half = config.use_half;
 
     for (int i = 0; i < spatial_dims; ++i)
@@ -97,7 +98,7 @@ bool OCL4DNNPool<Dtype>::Forward(const UMat& bottom,
                                  UMat& top_mask)
 {
     bool ret = true;
-    size_t global[] = { 128 * 128 };
+    size_t global[] = { (size_t)count_ };
     size_t local[] = { 128 };
 
     // support 2D case
@@ -105,8 +106,7 @@ bool OCL4DNNPool<Dtype>::Forward(const UMat& bottom,
     {
     case LIBDNN_POOLING_METHOD_MAX:
         {
-            bool haveMask = !top_mask.empty();
-            String kname = haveMask ? "max_pool_forward_mask" : "max_pool_forward";
+            String kname = computeMaxIdx ? "max_pool_forward_mask" : "max_pool_forward";
             kname += (use_half) ? "_half" : "_float";
             ocl::Kernel oclk_max_pool_forward(
                 kname.c_str(),
@@ -118,7 +118,7 @@ bool OCL4DNNPool<Dtype>::Forward(const UMat& bottom,
                        kernel_w_, kernel_h_,
                        stride_w_, stride_h_,
                        pad_w_, pad_h_,
-                       haveMask ? " -D HAVE_MASK=1" : ""
+                       computeMaxIdx ? " -D HAVE_MASK=1" : ""
                 ));
 
             if (oclk_max_pool_forward.empty())

modules/dnn/src/opencl/ocl4dnn_pooling.cl

@@ -65,28 +65,33 @@ __kernel void
 #endif
 )
 {
-  for (int index = get_global_id(0); index < nthreads;
-      index += get_global_size(0))
-  {
+  int index = get_global_id(0);
+  if (index >= nthreads)
+    return;
+
   const int pw = index % pooled_width;
-    const int ph = (index / pooled_width) % pooled_height;
-    const int c = (index / pooled_width / pooled_height) % channels;
-    const int n = index / pooled_width / pooled_height / channels;
+  const int xx = index / pooled_width;
+  const int ph = xx % pooled_height;
+  const int ch = xx / pooled_height;
   int hstart = ph * STRIDE_H - PAD_H;
   int wstart = pw * STRIDE_W - PAD_W;
-    const int hend = min(hstart + KERNEL_H, height);
-    const int wend = min(wstart + KERNEL_W, width);
-    hstart = max(hstart, (int)0);
-    wstart = max(wstart, (int)0);
   Dtype maxval = -FLT_MAX;
   int maxidx = -1;
-    __global const Dtype* bottom_slice = bottom_data
-        + (n * channels + c) * height * width;
-    for (int h = hstart; h < hend; ++h) {
-      for (int w = wstart; w < wend; ++w) {
-        if (bottom_slice[h * width + w] > maxval) {
-          maxidx = h * width + w;
-          maxval = bottom_slice[maxidx];
+  int in_offset = ch * height * width;
+  for (int h = 0; h < KERNEL_H; ++h)
+  {
+    int off_y = hstart + h;
+    if (off_y >= 0 && off_y < height)
+    {
+      for (int w = 0; w < KERNEL_W; ++w)
+      {
+        int off_x = wstart + w;
+        if (off_x >= 0 && off_x < width)
+        {
+          Dtype val = bottom_data[in_offset + off_y * width + off_x];
+          maxidx = (val > maxval) ? (off_y * width + off_x) : maxidx;
+          maxval = fmax(val, maxval);
+        }
       }
     }
   }
@@ -94,7 +99,6 @@ __kernel void
 #ifdef HAVE_MASK
   mask[index] = maxidx;
 #endif
-  }
 }
 
 #elif defined KERNEL_AVE_POOL
@@ -105,14 +109,14 @@ __kernel void TEMPLATE(ave_pool_forward, Dtype)(
     const int pooled_height, const int pooled_width,
     __global Dtype* top_data)
 {
-  for (int index = get_global_id(0); index < nthreads;
-      index += get_global_size(0))
-  {
-    {
+  int index = get_global_id(0);
+  if (index >= nthreads)
+    return;
+
   const int pw = index % pooled_width;
-      const int ph = (index / pooled_width) % pooled_height;
-      const int c = (index / pooled_width / pooled_height) % channels;
-      const int n = index / pooled_width / pooled_height / channels;
+  const int xx = index / pooled_width;
+  const int ph = xx % pooled_height;
+  const int ch = xx / pooled_height;
   int hstart = ph * STRIDE_H - PAD_H;
   int wstart = pw * STRIDE_W - PAD_W;
   int hend = min(hstart + KERNEL_H, height + PAD_H);
@@ -132,16 +136,15 @@ __kernel void TEMPLATE(ave_pool_forward, Dtype)(
   pool_size = (hend - hstart) * (wend - wstart);
 #endif
   Dtype aveval = 0;
-      __global const Dtype* bottom_slice = bottom_data
-          + (n * channels + c) * height * width;
-      for (int h = hstart; h < hend; ++h) {
-        for (int w = wstart; w < wend; ++w) {
-          aveval += bottom_slice[h * width + w];
+  int in_offset = ch * height * width;
+  for (int h = hstart; h < hend; ++h)
+  {
+    for (int w = wstart; w < wend; ++w)
+    {
+      aveval += bottom_data[in_offset + h * width + w];
     }
   }
   top_data[index] = aveval / pool_size;
-    }
-  }
 }
 
 #elif defined KERNEL_STO_POOL

modules/dnn/test/test_backends.cpp

@@ -182,11 +182,9 @@ TEST_P(DNNTestNetwork, MobileNet_SSD_Caffe)
         throw SkipTestException("");
     Mat sample = imread(findDataFile("dnn/street.png", false));
     Mat inp = blobFromImage(sample, 1.0f / 127.5, Size(300, 300), Scalar(127.5, 127.5, 127.5), false);
-    float l1 = (backend == DNN_BACKEND_OPENCV && target == DNN_TARGET_OPENCL_FP16) ? 0.0007 : 0.0;
-    float lInf = (backend == DNN_BACKEND_OPENCV && target == DNN_TARGET_OPENCL_FP16) ? 0.011 : 0.0;
-
+    float diffScores = (target == DNN_TARGET_OPENCL_FP16) ? 6e-3 : 0.0;
     processNet("dnn/MobileNetSSD_deploy.caffemodel", "dnn/MobileNetSSD_deploy.prototxt",
-               inp, "detection_out", "", l1, lInf);
+               inp, "detection_out", "", diffScores);
 }
 
 TEST_P(DNNTestNetwork, MobileNet_SSD_v1_TensorFlow)

modules/dnn/test/test_common.hpp

@@ -157,7 +157,8 @@ static inline bool checkMyriadTarget()
     net.addLayerToPrev("testLayer", "Identity", lp);
     net.setPreferableBackend(cv::dnn::DNN_BACKEND_INFERENCE_ENGINE);
     net.setPreferableTarget(cv::dnn::DNN_TARGET_MYRIAD);
-    net.setInput(cv::Mat::zeros(1, 1, CV_32FC1));
+    static int inpDims[] = {1, 2, 3, 4};
+    net.setInput(cv::Mat(4, &inpDims[0], CV_32FC1, cv::Scalar(0)));
     try
     {
         net.forward();

modules/dnn/test/test_darknet_importer.cpp

@@ -143,7 +143,7 @@ TEST_P(Test_Darknet_nets, YoloVoc)
     classIds[0] = 6;  confidences[0] = 0.750469f; boxes[0] = Rect2d(0.577374, 0.127391, 0.325575, 0.173418);  // a car
     classIds[1] = 1;  confidences[1] = 0.780879f; boxes[1] = Rect2d(0.270762, 0.264102, 0.461713, 0.48131); // a bicycle
     classIds[2] = 11; confidences[2] = 0.901615f; boxes[2] = Rect2d(0.1386, 0.338509, 0.282737, 0.60028);  // a dog
-    double scoreDiff = (targetId == DNN_TARGET_OPENCL_FP16 || targetId == DNN_TARGET_MYRIAD) ? 7e-3 : 8e-5;
+    double scoreDiff = (targetId == DNN_TARGET_OPENCL_FP16 || targetId == DNN_TARGET_MYRIAD) ? 1e-2 : 8e-5;
     double iouDiff = (targetId == DNN_TARGET_OPENCL_FP16 || targetId == DNN_TARGET_MYRIAD) ? 0.013 : 3e-5;
     testDarknetModel("yolo-voc.cfg", "yolo-voc.weights", outNames,
                      classIds, confidences, boxes, backendId, targetId, scoreDiff, iouDiff);

modules/dnn/test/test_layers.cpp

@@ -925,6 +925,10 @@ TEST(Layer_Test_Convolution_DLDT, Accuracy)
     Mat out = net.forward();
 
     normAssert(outDefault, out);
+
+    std::vector<int> outLayers = net.getUnconnectedOutLayers();
+    ASSERT_EQ(net.getLayer(outLayers[0])->name, "output_merge");
+    ASSERT_EQ(net.getLayer(outLayers[0])->type, "Concat");
 }
 
 // 1. Create a .prototxt file with the following network:
@@ -1183,6 +1187,7 @@ TEST(Layer_Test_PoolingIndices, Accuracy)
             }
         }
     }
+    net.setPreferableBackend(DNN_BACKEND_OPENCV);
     net.setInput(blobFromImage(inp));
 
     std::vector<Mat> outputs;

modules/dnn/test/test_tf_importer.cpp

@@ -127,6 +127,7 @@ TEST_P(Test_TensorFlow_layers, conv)
     runTensorFlowNet("atrous_conv2d_same", targetId);
     runTensorFlowNet("depthwise_conv2d", targetId);
     runTensorFlowNet("keras_atrous_conv2d_same", targetId);
+    runTensorFlowNet("conv_pool_nchw", targetId);
 }
 
 TEST_P(Test_TensorFlow_layers, padding)
@@ -142,9 +143,10 @@ TEST_P(Test_TensorFlow_layers, eltwise_add_mul)
     runTensorFlowNet("eltwise_add_mul", GetParam());
 }
 
-TEST_P(Test_TensorFlow_layers, pad_and_concat)
+TEST_P(Test_TensorFlow_layers, concat)
 {
     runTensorFlowNet("pad_and_concat", GetParam());
+    runTensorFlowNet("concat_axis_1", GetParam());
 }
 
 TEST_P(Test_TensorFlow_layers, batch_norm)
@@ -440,4 +442,20 @@ TEST(Test_TensorFlow, resize_bilinear)
     runTensorFlowNet("resize_bilinear_factor");
 }
 
+TEST(Test_TensorFlow, two_inputs)
+{
+    Net net = readNet(path("two_inputs_net.pbtxt"));
+    net.setPreferableBackend(DNN_BACKEND_OPENCV);
+
+    Mat firstInput(2, 3, CV_32FC1), secondInput(2, 3, CV_32FC1);
+    randu(firstInput, -1, 1);
+    randu(secondInput, -1, 1);
+
+    net.setInput(firstInput, "first_input");
+    net.setInput(secondInput, "second_input");
+    Mat out = net.forward();
+
+    normAssert(out, firstInput + secondInput);
+}
+
 }

modules/imgcodecs/src/grfmt_sunras.cpp

@@ -175,8 +175,6 @@ bool  SunRasterDecoder::readData( Mat& img )
 
     AutoBuffer<uchar> _src(src_pitch + 32);
     uchar* src = _src;
-    AutoBuffer<uchar> _bgr(m_width*3 + 32);
-    uchar* bgr = _bgr;
 
     if( !color && m_maptype == RMT_EQUAL_RGB )
         CvtPaletteToGray( m_palette, gray_palette, 1 << m_bpp );
@@ -340,16 +338,18 @@ bad_decoding_end:
         case 24:
             for( y = 0; y < m_height; y++, data += step )
             {
-                m_strm.getBytes( color ? data : bgr, src_pitch );
+                m_strm.getBytes(src, src_pitch );
 
                 if( color )
                 {
                     if( m_type == RAS_FORMAT_RGB )
-                        icvCvt_RGB2BGR_8u_C3R( data, 0, data, 0, cvSize(m_width,1) );
+                        icvCvt_RGB2BGR_8u_C3R(src, 0, data, 0, cvSize(m_width,1) );
+                    else
+                        memcpy(data, src, std::min(step, (size_t)src_pitch));
                 }
                 else
                 {
-                    icvCvt_BGR2Gray_8u_C3C1R( bgr, 0, data, 0, cvSize(m_width,1),
+                    icvCvt_BGR2Gray_8u_C3C1R(src, 0, data, 0, cvSize(m_width,1),
                                               m_type == RAS_FORMAT_RGB ? 2 : 0 );
                 }
             }

modules/objdetect/include/opencv2/objdetect.hpp

@@ -670,6 +670,14 @@ public:
     void groupRectangles(std::vector<cv::Rect>& rectList, std::vector<double>& weights, int groupThreshold, double eps) const;
 };
 
+/** @brief Detect QR code in image and return minimum area of quadrangle that describes QR code.
+    @param in  Matrix of the type CV_8UC1 containing an image where QR code are detected.
+    @param points Output vector of vertices of a quadrangle of minimal area that describes QR code.
+    @param eps_x Epsilon neighborhood, which allows you to determine the horizontal pattern of the scheme 1:1:3:1:1 according to QR code standard.
+    @param eps_y Epsilon neighborhood, which allows you to determine the vertical pattern of the scheme 1:1:3:1:1 according to QR code standard.
+    */
+CV_EXPORTS bool detectQRCode(InputArray in, std::vector<Point> &points, double eps_x = 0.2, double eps_y = 0.1);
+
 //! @} objdetect
 
 }

modules/objdetect/test/test_qrcode.cpp

+/*M///////////////////////////////////////////////////////////////////////////////////////
+//
+//  IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
+//
+//  By downloading, copying, installing or using the software you agree to this license.
+//  If you do not agree to this license, do not download, install,
+//  copy or use the software.
+//
+//
+//                        Intel License Agreement
+//                For Open Source Computer Vision Library
+//
+// Copyright (C) 2000, Intel Corporation, all rights reserved.
+// Third party copyrights are property of their respective owners.
+//
+// Redistribution and use in source and binary forms, with or without modification,
+// are permitted provided that the following conditions are met:
+//
+//   * Redistribution's of source code must retain the above copyright notice,
+//     this list of conditions and the following disclaimer.
+//
+//   * Redistribution's in binary form must reproduce the above copyright notice,
+//     this list of conditions and the following disclaimer in the documentation
+//     and/or other materials provided with the distribution.
+//
+//   * The name of Intel Corporation may not be used to endorse or promote products
+//     derived from this software without specific prior written permission.
+//
+// This software is provided by the copyright holders and contributors "as is" and
+// any express or implied warranties, including, but not limited to, the implied
+// warranties of merchantability and fitness for a particular purpose are disclaimed.
+// In no event shall the Intel Corporation or contributors be liable for any direct,
+// indirect, incidental, special, exemplary, or consequential damages
+// (including, but not limited to, procurement of substitute goods or services;
+// loss of use, data, or profits; or business interruption) however caused
+// and on any theory of liability, whether in contract, strict liability,
+// or tort (including negligence or otherwise) arising in any way out of
+// the use of this software, even if advised of the possibility of such damage.
+//
+//M*/
+
+#include "test_precomp.hpp"
+
+namespace opencv_test { namespace {
+
+TEST(Objdetect_QRCode, regression)
+{
+    String root = cvtest::TS::ptr()->get_data_path() + "qrcode/";
+    // String cascades[] =
+    // {
+        // root + "haarcascade_frontalface_alt.xml",
+        // root + "lbpcascade_frontalface.xml",
+        // String()
+    // };
+
+    // vector<Rect> objects;
+    // RNG rng((uint64)-1);
+
+    // for( int i = 0; !cascades[i].empty(); i++ )
+    // {
+        // printf("%d. %s\n", i, cascades[i].c_str());
+        // CascadeClassifier cascade(cascades[i]);
+        // for( int j = 0; j < 100; j++ )
+        // {
+            // int width = rng.uniform(1, 100);
+            // int height = rng.uniform(1, 100);
+            // Mat img(height, width, CV_8U);
+            // randu(img, 0, 256);
+            // cascade.detectMultiScale(img, objects);
+        // }
+    // }
+}
+
+}} // namespace

modules/video/include/opencv2/video/tracking.hpp

@@ -250,7 +250,9 @@ when fullAffine=false.
 @sa
 estimateAffine2D, estimateAffinePartial2D, getAffineTransform, getPerspectiveTransform, findHomography
  */
-CV_EXPORTS_W Mat estimateRigidTransform( InputArray src, InputArray dst, bool fullAffine );
+CV_EXPORTS_W Mat estimateRigidTransform( InputArray src, InputArray dst, bool fullAffine);
+CV_EXPORTS_W Mat estimateRigidTransform( InputArray src, InputArray dst, bool fullAffine, int ransacMaxIters, double ransacGoodRatio,
+                                         int ransacSize0);
 
 
 enum

modules/video/src/lkpyramid.cpp

@@ -1402,7 +1402,7 @@ namespace cv
 {
 
 static void
-getRTMatrix( const Point2f* a, const Point2f* b,
+getRTMatrix( const std::vector<Point2f> a, const std::vector<Point2f> b,
              int count, Mat& M, bool fullAffine )
 {
     CV_Assert( M.isContinuous() );
@@ -1478,6 +1478,12 @@ getRTMatrix( const Point2f* a, const Point2f* b,
 }
 
 cv::Mat cv::estimateRigidTransform( InputArray src1, InputArray src2, bool fullAffine )
+{
+    return estimateRigidTransform(src1, src2, fullAffine, 500, 0.5, 3);
+}
+
+cv::Mat cv::estimateRigidTransform( InputArray src1, InputArray src2, bool fullAffine, int ransacMaxIters, double ransacGoodRatio,
+                                    const int ransacSize0)
 {
     CV_INSTRUMENT_REGION()
 
@@ -1485,9 +1491,6 @@ cv::Mat cv::estimateRigidTransform( InputArray src1, InputArray src2, bool fullA
 
     const int COUNT = 15;
     const int WIDTH = 160, HEIGHT = 120;
-    const int RANSAC_MAX_ITERS = 500;
-    const int RANSAC_SIZE0 = 3;
-    const double RANSAC_GOOD_RATIO = 0.5;
 
     std::vector<Point2f> pA, pB;
     std::vector<int> good_idx;
@@ -1499,6 +1502,12 @@ cv::Mat cv::estimateRigidTransform( InputArray src1, InputArray src2, bool fullA
     RNG rng((uint64)-1);
     int good_count = 0;
 
+    if( ransacSize0 < 3 )
+        CV_Error( Error::StsBadArg, "ransacSize0 should have value bigger than 2.");
+
+    if( ransacGoodRatio > 1 || ransacGoodRatio < 0)
+        CV_Error( Error::StsBadArg, "ransacGoodRatio should have value between 0 and 1");
+
     if( A.size() != B.size() )
         CV_Error( Error::StsUnmatchedSizes, "Both input images must have the same size" );
 
@@ -1587,23 +1596,23 @@ cv::Mat cv::estimateRigidTransform( InputArray src1, InputArray src2, bool fullA
 
     good_idx.resize(count);
 
-    if( count < RANSAC_SIZE0 )
+    if( count < ransacSize0 )
         return Mat();
 
     Rect brect = boundingRect(pB);
 
+    std::vector<Point2f> a(ransacSize0);
+    std::vector<Point2f> b(ransacSize0);
+
     // RANSAC stuff:
     // 1. find the consensus
-    for( k = 0; k < RANSAC_MAX_ITERS; k++ )
+    for( k = 0; k < ransacMaxIters; k++ )
     {
-        int idx[RANSAC_SIZE0];
-        Point2f a[RANSAC_SIZE0];
-        Point2f b[RANSAC_SIZE0];
-
-        // choose random 3 non-coplanar points from A & B
-        for( i = 0; i < RANSAC_SIZE0; i++ )
+        std::vector<int> idx(ransacSize0);
+        // choose random 3 non-complanar points from A & B
+        for( i = 0; i < ransacSize0; i++ )
         {
-            for( k1 = 0; k1 < RANSAC_MAX_ITERS; k1++ )
+            for( k1 = 0; k1 < ransacMaxIters; k1++ )
             {
                 idx[i] = rng.uniform(0, count);
 
@@ -1623,7 +1632,7 @@ cv::Mat cv::estimateRigidTransform( InputArray src1, InputArray src2, bool fullA
                 if( j < i )
                     continue;
 
-                if( i+1 == RANSAC_SIZE0 )
+                if( i+1 == ransacSize0 )
                 {
                     // additional check for non-complanar vectors
                     a[0] = pA[idx[0]];
@@ -1647,11 +1656,11 @@ cv::Mat cv::estimateRigidTransform( InputArray src1, InputArray src2, bool fullA
                 break;
             }
 
-            if( k1 >= RANSAC_MAX_ITERS )
+            if( k1 >= ransacMaxIters )
                 break;
         }
 
-        if( i < RANSAC_SIZE0 )
+        if( i < ransacSize0 )
             continue;
 
         // estimate the transformation using 3 points
@@ -1665,11 +1674,11 @@ cv::Mat cv::estimateRigidTransform( InputArray src1, InputArray src2, bool fullA
                 good_idx[good_count++] = i;
         }
 
-        if( good_count >= count*RANSAC_GOOD_RATIO )
+        if( good_count >= count*ransacGoodRatio )
             break;
     }
 
-    if( k >= RANSAC_MAX_ITERS )
+    if( k >= ransacMaxIters )
         return Mat();
 
     if( good_count < count )
@@ -1682,7 +1691,7 @@ cv::Mat cv::estimateRigidTransform( InputArray src1, InputArray src2, bool fullA
         }
     }
 
-    getRTMatrix( &pA[0], &pB[0], good_count, M, fullAffine );
+    getRTMatrix( pA, pB, good_count, M, fullAffine );
     M.at<double>(0, 2) /= scale;
     M.at<double>(1, 2) /= scale;
 

samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp

 /**
- * @function Watershed_and_Distance_Transform.cpp
  * @brief Sample code showing how to segment overlapping objects using Laplacian filtering, in addition to Watershed and Distance Transformation
  * @author OpenCV Team
  */
@@ -12,39 +11,43 @@
 using namespace std;
 using namespace cv;
 
-int main()
+int main(int argc, char *argv[])
 {
-//! [load_image]
+    //! [load_image]
     // Load the image
-    Mat src = imread("../data/cards.png");
-
-    // Check if everything was fine
-    if (!src.data)
+    CommandLineParser parser( argc, argv, "{@input | ../data/cards.png | input image}" );
+    Mat src = imread( parser.get<String>( "@input" ) );
+    if( src.empty() )
+    {
+        cout << "Could not open or find the image!\n" << endl;
+        cout << "Usage: " << argv[0] << " <Input image>" << endl;
         return -1;
+    }
 
     // Show source image
     imshow("Source Image", src);
-//! [load_image]
+    //! [load_image]
 
-//! [black_bg]
+    //! [black_bg]
     // Change the background from white to black, since that will help later to extract
     // better results during the use of Distance Transform
-    for( int x = 0; x < src.rows; x++ ) {
-      for( int y = 0; y < src.cols; y++ ) {
-          if ( src.at<Vec3b>(x, y) == Vec3b(255,255,255) ) {
-            src.at<Vec3b>(x, y)[0] = 0;
-            src.at<Vec3b>(x, y)[1] = 0;
-            src.at<Vec3b>(x, y)[2] = 0;
+    for ( int i = 0; i < src.rows; i++ ) {
+        for ( int j = 0; j < src.cols; j++ ) {
+            if ( src.at<Vec3b>(i, j) == Vec3b(255,255,255) )
+            {
+                src.at<Vec3b>(i, j)[0] = 0;
+                src.at<Vec3b>(i, j)[1] = 0;
+                src.at<Vec3b>(i, j)[2] = 0;
             }
         }
     }
 
     // Show output image
     imshow("Black Background Image", src);
-//! [black_bg]
+    //! [black_bg]
 
-//! [sharp]
-    // Create a kernel that we will use for accuting/sharpening our image
+    //! [sharp]
+    // Create a kernel that we will use to sharpen our image
     Mat kernel = (Mat_<float>(3,3) <<
                   1,  1, 1,
                   1, -8, 1,
@@ -57,8 +60,8 @@ int main()
     // BUT a 8bits unsigned int (the one we are working with) can contain values from 0 to 255
     // so the possible negative number will be truncated
     Mat imgLaplacian;
-    Mat sharp = src; // copy source image to another temporary one
-    filter2D(sharp, imgLaplacian, CV_32F, kernel);
+    filter2D(src, imgLaplacian, CV_32F, kernel);
+    Mat sharp;
     src.convertTo(sharp, CV_32F);
     Mat imgResult = sharp - imgLaplacian;
 
@@ -68,41 +71,39 @@ int main()
 
     // imshow( "Laplace Filtered Image", imgLaplacian );
     imshow( "New Sharped Image", imgResult );
-//! [sharp]
-
-    src = imgResult; // copy back
+    //! [sharp]
 
-//! [bin]
+    //! [bin]
     // Create binary image from source image
     Mat bw;
-    cvtColor(src, bw, COLOR_BGR2GRAY);
+    cvtColor(imgResult, bw, COLOR_BGR2GRAY);
     threshold(bw, bw, 40, 255, THRESH_BINARY | THRESH_OTSU);
     imshow("Binary Image", bw);
-//! [bin]
+    //! [bin]
 
-//! [dist]
+    //! [dist]
     // Perform the distance transform algorithm
     Mat dist;
     distanceTransform(bw, dist, DIST_L2, 3);
 
     // Normalize the distance image for range = {0.0, 1.0}
     // so we can visualize and threshold it
-    normalize(dist, dist, 0, 1., NORM_MINMAX);
+    normalize(dist, dist, 0, 1.0, NORM_MINMAX);
     imshow("Distance Transform Image", dist);
-//! [dist]
+    //! [dist]
 
-//! [peaks]
+    //! [peaks]
     // Threshold to obtain the peaks
     // This will be the markers for the foreground objects
-    threshold(dist, dist, .4, 1., THRESH_BINARY);
+    threshold(dist, dist, 0.4, 1.0, THRESH_BINARY);
 
     // Dilate a bit the dist image
-    Mat kernel1 = Mat::ones(3, 3, CV_8UC1);
+    Mat kernel1 = Mat::ones(3, 3, CV_8U);
     dilate(dist, dist, kernel1);
     imshow("Peaks", dist);
-//! [peaks]
+    //! [peaks]
 
-//! [seeds]
+    //! [seeds]
     // Create the CV_8U version of the distance image
     // It is needed for findContours()
     Mat dist_8u;
@@ -113,34 +114,36 @@ int main()
     findContours(dist_8u, contours, RETR_EXTERNAL, CHAIN_APPROX_SIMPLE);
 
     // Create the marker image for the watershed algorithm
-    Mat markers = Mat::zeros(dist.size(), CV_32SC1);
+    Mat markers = Mat::zeros(dist.size(), CV_32S);
 
     // Draw the foreground markers
     for (size_t i = 0; i < contours.size(); i++)
-        drawContours(markers, contours, static_cast<int>(i), Scalar::all(static_cast<int>(i)+1), -1);
+    {
+        drawContours(markers, contours, static_cast<int>(i), Scalar(static_cast<int>(i)+1), -1);
+    }
 
     // Draw the background marker
-    circle(markers, Point(5,5), 3, CV_RGB(255,255,255), -1);
+    circle(markers, Point(5,5), 3, Scalar(255), -1);
     imshow("Markers", markers*10000);
-//! [seeds]
+    //! [seeds]
 
-//! [watershed]
+    //! [watershed]
     // Perform the watershed algorithm
-    watershed(src, markers);
+    watershed(imgResult, markers);
 
-    Mat mark = Mat::zeros(markers.size(), CV_8UC1);
-    markers.convertTo(mark, CV_8UC1);
+    Mat mark;
+    markers.convertTo(mark, CV_8U);
     bitwise_not(mark, mark);
-//    imshow("Markers_v2", mark); // uncomment this if you want to see how the mark
+    //    imshow("Markers_v2", mark); // uncomment this if you want to see how the mark
     // image looks like at that point
 
     // Generate random colors
     vector<Vec3b> colors;
     for (size_t i = 0; i < contours.size(); i++)
     {
-        int b = theRNG().uniform(0, 255);
-        int g = theRNG().uniform(0, 255);
-        int r = theRNG().uniform(0, 255);
+        int b = theRNG().uniform(0, 256);
+        int g = theRNG().uniform(0, 256);
+        int r = theRNG().uniform(0, 256);
 
         colors.push_back(Vec3b((uchar)b, (uchar)g, (uchar)r));
     }
@@ -155,16 +158,16 @@ int main()
         {
             int index = markers.at<int>(i,j);
             if (index > 0 && index <= static_cast<int>(contours.size()))
+            {
                 dst.at<Vec3b>(i,j) = colors[index-1];
-            else
-                dst.at<Vec3b>(i,j) = Vec3b(0,0,0);
+            }
         }
     }
 
     // Visualize the final image
     imshow("Final Result", dst);
-//! [watershed]
+    //! [watershed]
 
-    waitKey(0);
+    waitKey();
     return 0;
 }

samples/dnn/object_detection.cpp

@@ -22,6 +22,7 @@ const char* keys =
     "{ height      | -1 | Preprocess input image by resizing to a specific height. }"
     "{ rgb         |    | Indicate that model works with RGB input images instead BGR ones. }"
     "{ thr         | .5 | Confidence threshold. }"
+    "{ thr         | .4 | Non-maximum suppression threshold. }"
     "{ backend     |  0 | Choose one of computation backends: "
                          "0: automatically (by default), "
                          "1: Halide language (http://halide-lang.org/), "
@@ -37,7 +38,7 @@ const char* keys =
 using namespace cv;
 using namespace dnn;
 
-float confThreshold;
+float confThreshold, nmsThreshold;
 std::vector<std::string> classes;
 
 void postprocess(Mat& frame, const std::vector<Mat>& out, Net& net);
@@ -59,6 +60,7 @@ int main(int argc, char** argv)
     }
 
     confThreshold = parser.get<float>("thr");
+    nmsThreshold = parser.get<float>("nms");
     float scale = parser.get<float>("scale");
     Scalar mean = parser.get<Scalar>("mean");
     bool swapRB = parser.get<bool>("rgb");
@@ -144,6 +146,9 @@ void postprocess(Mat& frame, const std::vector<Mat>& outs, Net& net)
     static std::vector<int> outLayers = net.getUnconnectedOutLayers();
     static std::string outLayerType = net.getLayer(outLayers[0])->type;
 
+    std::vector<int> classIds;
+    std::vector<float> confidences;
+    std::vector<Rect> boxes;
     if (net.getLayer(0)->outputNameToIndex("im_info") != -1)  // Faster-RCNN or R-FCN
     {
         // Network produces output blob with a shape 1x1xNx7 where N is a number of
@@ -160,8 +165,11 @@ void postprocess(Mat& frame, const std::vector<Mat>& outs, Net& net)
                 int top = (int)data[i + 4];
                 int right = (int)data[i + 5];
                 int bottom = (int)data[i + 6];
-                int classId = (int)(data[i + 1]) - 1;  // Skip 0th background class id.
-                drawPred(classId, confidence, left, top, right, bottom, frame);
+                int width = right - left + 1;
+                int height = bottom - top + 1;
+                classIds.push_back((int)(data[i + 1]) - 1);  // Skip 0th background class id.
+                boxes.push_back(Rect(left, top, width, height));
+                confidences.push_back(confidence);
             }
         }
     }
@@ -181,16 +189,16 @@ void postprocess(Mat& frame, const std::vector<Mat>& outs, Net& net)
                 int top = (int)(data[i + 4] * frame.rows);
                 int right = (int)(data[i + 5] * frame.cols);
                 int bottom = (int)(data[i + 6] * frame.rows);
-                int classId = (int)(data[i + 1]) - 1;  // Skip 0th background class id.
-                drawPred(classId, confidence, left, top, right, bottom, frame);
+                int width = right - left + 1;
+                int height = bottom - top + 1;
+                classIds.push_back((int)(data[i + 1]) - 1);  // Skip 0th background class id.
+                boxes.push_back(Rect(left, top, width, height));
+                confidences.push_back(confidence);
             }
         }
     }
     else if (outLayerType == "Region")
     {
-        std::vector<int> classIds;
-        std::vector<float> confidences;
-        std::vector<Rect> boxes;
         for (size_t i = 0; i < outs.size(); ++i)
         {
             // Network produces output blob with a shape NxC where N is a number of
@@ -218,8 +226,12 @@ void postprocess(Mat& frame, const std::vector<Mat>& outs, Net& net)
                 }
             }
         }
+    }
+    else
+        CV_Error(Error::StsNotImplemented, "Unknown output layer type: " + outLayerType);
+
     std::vector<int> indices;
-        NMSBoxes(boxes, confidences, confThreshold, 0.4f, indices);
+    NMSBoxes(boxes, confidences, confThreshold, nmsThreshold, indices);
     for (size_t i = 0; i < indices.size(); ++i)
     {
         int idx = indices[i];
@@ -227,9 +239,6 @@ void postprocess(Mat& frame, const std::vector<Mat>& outs, Net& net)
         drawPred(classIds[idx], confidences[idx], box.x, box.y,
                  box.x + box.width, box.y + box.height, frame);
     }
-    }
-    else
-        CV_Error(Error::StsNotImplemented, "Unknown output layer type: " + outLayerType);
 }
 
 void drawPred(int classId, float conf, int left, int top, int right, int bottom, Mat& frame)

samples/dnn/object_detection.py

@@ -31,6 +31,7 @@ parser.add_argument('--height', type=int,
 parser.add_argument('--rgb', action='store_true',
                     help='Indicate that model works with RGB input images instead BGR ones.')
 parser.add_argument('--thr', type=float, default=0.5, help='Confidence threshold')
+parser.add_argument('--nms', type=float, default=0.4, help='Non-maximum suppression threshold')
 parser.add_argument('--backend', choices=backends, default=cv.dnn.DNN_BACKEND_DEFAULT, type=int,
                     help="Choose one of computation backends: "
                          "%d: automatically (by default), "
@@ -57,6 +58,7 @@ net.setPreferableBackend(args.backend)
 net.setPreferableTarget(args.target)
 
 confThreshold = args.thr
+nmsThreshold = args.nms
 
 def getOutputsNames(net):
     layersNames = net.getLayerNames()
@@ -86,12 +88,14 @@ def postprocess(frame, outs):
     lastLayerId = net.getLayerId(layerNames[-1])
     lastLayer = net.getLayer(lastLayerId)
 
+    classIds = []
+    confidences = []
+    boxes = []
     if net.getLayer(0).outputNameToIndex('im_info') != -1:  # Faster-RCNN or R-FCN
         # Network produces output blob with a shape 1x1xNx7 where N is a number of
         # detections and an every detection is a vector of values
         # [batchId, classId, confidence, left, top, right, bottom]
-        assert(len(outs) == 1)
-        out = outs[0]
+        for out in outs:
             for detection in out[0, 0]:
                 confidence = detection[2]
                 if confidence > confThreshold:
@@ -99,14 +103,16 @@ def postprocess(frame, outs):
                     top = int(detection[4])
                     right = int(detection[5])
                     bottom = int(detection[6])
-                classId = int(detection[1]) - 1  # Skip background label
-                drawPred(classId, confidence, left, top, right, bottom)
+                    width = right - left + 1
+                    height = bottom - top + 1
+                    classIds.append(int(detection[1]) - 1)  # Skip background label
+                    confidences.append(float(confidence))
+                    boxes.append([left, top, width, height])
     elif lastLayer.type == 'DetectionOutput':
         # Network produces output blob with a shape 1x1xNx7 where N is a number of
         # detections and an every detection is a vector of values
         # [batchId, classId, confidence, left, top, right, bottom]
-        assert(len(outs) == 1)
-        out = outs[0]
+        for out in outs:
             for detection in out[0, 0]:
                 confidence = detection[2]
                 if confidence > confThreshold:
@@ -114,8 +120,11 @@ def postprocess(frame, outs):
                     top = int(detection[4] * frameHeight)
                     right = int(detection[5] * frameWidth)
                     bottom = int(detection[6] * frameHeight)
-                classId = int(detection[1]) - 1  # Skip background label
-                drawPred(classId, confidence, left, top, right, bottom)
+                    width = right - left + 1
+                    height = bottom - top + 1
+                    classIds.append(int(detection[1]) - 1)  # Skip background label
+                    confidences.append(float(confidence))
+                    boxes.append([left, top, width, height])
     elif lastLayer.type == 'Region':
         # Network produces output blob with a shape NxC where N is a number of
         # detected objects and C is a number of classes + 4 where the first 4
@@ -138,7 +147,11 @@ def postprocess(frame, outs):
                     classIds.append(classId)
                     confidences.append(float(confidence))
                     boxes.append([left, top, width, height])
-        indices = cv.dnn.NMSBoxes(boxes, confidences, confThreshold, 0.4)
+    else:
+        print('Unknown output layer type: ' + lastLayer.type)
+        exit()
+
+    indices = cv.dnn.NMSBoxes(boxes, confidences, confThreshold, nmsThreshold)
     for i in indices:
         i = i[0]
         box = boxes[i]

samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java

+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import org.opencv.core.Core;
+import org.opencv.core.CvType;
+import org.opencv.core.Mat;
+import org.opencv.core.MatOfPoint;
+import org.opencv.core.Point;
+import org.opencv.core.Scalar;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
+
+/**
+ *
+ * @brief Sample code showing how to segment overlapping objects using Laplacian filtering, in addition to Watershed
+ * and Distance Transformation
+ *
+ */
+class ImageSegmentation {
+    public void run(String[] args) {
+        //! [load_image]
+        // Load the image
+        String filename = args.length > 0 ? args[0] : "../data/cards.png";
+        Mat srcOriginal = Imgcodecs.imread(filename);
+        if (srcOriginal.empty()) {
+            System.err.println("Cannot read image: " + filename);
+            System.exit(0);
+        }
+
+        // Show source image
+        HighGui.imshow("Source Image", srcOriginal);
+        //! [load_image]
+
+        //! [black_bg]
+        // Change the background from white to black, since that will help later to
+        // extract
+        // better results during the use of Distance Transform
+        Mat src = srcOriginal.clone();
+        byte[] srcData = new byte[(int) (src.total() * src.channels())];
+        src.get(0, 0, srcData);
+        for (int i = 0; i < src.rows(); i++) {
+            for (int j = 0; j < src.cols(); j++) {
+                if (srcData[(i * src.cols() + j) * 3] == (byte) 255 && srcData[(i * src.cols() + j) * 3 + 1] == (byte) 255
+                        && srcData[(i * src.cols() + j) * 3 + 2] == (byte) 255) {
+                    srcData[(i * src.cols() + j) * 3] = 0;
+                    srcData[(i * src.cols() + j) * 3 + 1] = 0;
+                    srcData[(i * src.cols() + j) * 3 + 2] = 0;
+                }
+            }
+        }
+        src.put(0, 0, srcData);
+
+        // Show output image
+        HighGui.imshow("Black Background Image", src);
+        //! [black_bg]
+
+        //! [sharp]
+        // Create a kernel that we will use to sharpen our image
+        Mat kernel = new Mat(3, 3, CvType.CV_32F);
+        // an approximation of second derivative, a quite strong kernel
+        float[] kernelData = new float[(int) (kernel.total() * kernel.channels())];
+        kernelData[0] = 1; kernelData[1] = 1; kernelData[2] = 1;
+        kernelData[3] = 1; kernelData[4] = -8; kernelData[5] = 1;
+        kernelData[6] = 1; kernelData[7] = 1; kernelData[8] = 1;
+        kernel.put(0, 0, kernelData);
+
+        // do the laplacian filtering as it is
+        // well, we need to convert everything in something more deeper then CV_8U
+        // because the kernel has some negative values,
+        // and we can expect in general to have a Laplacian image with negative values
+        // BUT a 8bits unsigned int (the one we are working with) can contain values
+        // from 0 to 255
+        // so the possible negative number will be truncated
+        Mat imgLaplacian = new Mat();
+        Imgproc.filter2D(src, imgLaplacian, CvType.CV_32F, kernel);
+        Mat sharp = new Mat();
+        src.convertTo(sharp, CvType.CV_32F);
+        Mat imgResult = new Mat();
+        Core.subtract(sharp, imgLaplacian, imgResult);
+
+        // convert back to 8bits gray scale
+        imgResult.convertTo(imgResult, CvType.CV_8UC3);
+        imgLaplacian.convertTo(imgLaplacian, CvType.CV_8UC3);
+
+        // imshow( "Laplace Filtered Image", imgLaplacian );
+        HighGui.imshow("New Sharped Image", imgResult);
+        //! [sharp]
+
+        //! [bin]
+        // Create binary image from source image
+        Mat bw = new Mat();
+        Imgproc.cvtColor(imgResult, bw, Imgproc.COLOR_BGR2GRAY);
+        Imgproc.threshold(bw, bw, 40, 255, Imgproc.THRESH_BINARY | Imgproc.THRESH_OTSU);
+        HighGui.imshow("Binary Image", bw);
+        //! [bin]
+
+        //! [dist]
+        // Perform the distance transform algorithm
+        Mat dist = new Mat();
+        Imgproc.distanceTransform(bw, dist, Imgproc.DIST_L2, 3);
+
+        // Normalize the distance image for range = {0.0, 1.0}
+        // so we can visualize and threshold it
+        Core.normalize(dist, dist, 0, 1., Core.NORM_MINMAX);
+        Mat distDisplayScaled = dist.mul(dist, 255);
+        Mat distDisplay = new Mat();
+        distDisplayScaled.convertTo(distDisplay, CvType.CV_8U);
+        HighGui.imshow("Distance Transform Image", distDisplay);
+        //! [dist]
+
+        //! [peaks]
+        // Threshold to obtain the peaks
+        // This will be the markers for the foreground objects
+        Imgproc.threshold(dist, dist, .4, 1., Imgproc.THRESH_BINARY);
+
+        // Dilate a bit the dist image
+        Mat kernel1 = Mat.ones(3, 3, CvType.CV_8U);
+        Imgproc.dilate(dist, dist, kernel1);
+        Mat distDisplay2 = new Mat();
+        dist.convertTo(distDisplay2, CvType.CV_8U);
+        distDisplay2 = distDisplay2.mul(distDisplay2, 255);
+        HighGui.imshow("Peaks", distDisplay2);
+        //! [peaks]
+
+        //! [seeds]
+        // Create the CV_8U version of the distance image
+        // It is needed for findContours()
+        Mat dist_8u = new Mat();
+        dist.convertTo(dist_8u, CvType.CV_8U);
+
+        // Find total markers
+        List<MatOfPoint> contours = new ArrayList<>();
+        Mat hierarchy = new Mat();
+        Imgproc.findContours(dist_8u, contours, hierarchy, Imgproc.RETR_EXTERNAL, Imgproc.CHAIN_APPROX_SIMPLE);
+
+        // Create the marker image for the watershed algorithm
+        Mat markers = Mat.zeros(dist.size(), CvType.CV_32S);
+
+        // Draw the foreground markers
+        for (int i = 0; i < contours.size(); i++) {
+            Imgproc.drawContours(markers, contours, i, new Scalar(i + 1), -1);
+        }
+
+        // Draw the background marker
+        Imgproc.circle(markers, new Point(5, 5), 3, new Scalar(255, 255, 255), -1);
+        Mat markersScaled = markers.mul(markers, 10000);
+        Mat markersDisplay = new Mat();
+        markersScaled.convertTo(markersDisplay, CvType.CV_8U);
+        HighGui.imshow("Markers", markersDisplay);
+        //! [seeds]
+
+        //! [watershed]
+        // Perform the watershed algorithm
+        Imgproc.watershed(imgResult, markers);
+
+        Mat mark = Mat.zeros(markers.size(), CvType.CV_8U);
+        markers.convertTo(mark, CvType.CV_8UC1);
+        Core.bitwise_not(mark, mark);
+        // imshow("Markers_v2", mark); // uncomment this if you want to see how the mark
+        // image looks like at that point
+
+        // Generate random colors
+        Random rng = new Random(12345);
+        List<Scalar> colors = new ArrayList<>(contours.size());
+        for (int i = 0; i < contours.size(); i++) {
+            int b = rng.nextInt(256);
+            int g = rng.nextInt(256);
+            int r = rng.nextInt(256);
+
+            colors.add(new Scalar(b, g, r));
+        }
+
+        // Create the result image
+        Mat dst = Mat.zeros(markers.size(), CvType.CV_8UC3);
+        byte[] dstData = new byte[(int) (dst.total() * dst.channels())];
+        dst.get(0, 0, dstData);
+
+        // Fill labeled objects with random colors
+        int[] markersData = new int[(int) (markers.total() * markers.channels())];
+        markers.get(0, 0, markersData);
+        for (int i = 0; i < markers.rows(); i++) {
+            for (int j = 0; j < markers.cols(); j++) {
+                int index = markersData[i * markers.cols() + j];
+                if (index > 0 && index <= contours.size()) {
+                    dstData[(i * dst.cols() + j) * 3 + 0] = (byte) colors.get(index - 1).val[0];
+                    dstData[(i * dst.cols() + j) * 3 + 1] = (byte) colors.get(index - 1).val[1];
+                    dstData[(i * dst.cols() + j) * 3 + 2] = (byte) colors.get(index - 1).val[2];
+                } else {
+                    dstData[(i * dst.cols() + j) * 3 + 0] = 0;
+                    dstData[(i * dst.cols() + j) * 3 + 1] = 0;
+                    dstData[(i * dst.cols() + j) * 3 + 2] = 0;
+                }
+            }
+        }
+        dst.put(0, 0, dstData);
+
+        // Visualize the final image
+        HighGui.imshow("Final Result", dst);
+        //! [watershed]
+
+        HighGui.waitKey();
+        System.exit(0);
+    }
+}
+
+public class ImageSegmentationDemo {
+    public static void main(String[] args) {
+        // Load the native OpenCV library
+        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
+
+        new ImageSegmentation().run(args);
+    }
+}

samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py

+from __future__ import print_function
+import cv2 as cv
+import numpy as np
+import argparse
+import random as rng
+
+rng.seed(12345)
+
+## [load_image]
+# Load the image
+parser = argparse.ArgumentParser(description='Code for Image Segmentation with Distance Transform and Watershed Algorithm.\
+    Sample code showing how to segment overlapping objects using Laplacian filtering, \
+    in addition to Watershed and Distance Transformation')
+parser.add_argument('--input', help='Path to input image.', default='../data/cards.png')
+args = parser.parse_args()
+
+src = cv.imread(args.input)
+if src is None:
+    print('Could not open or find the image:', args.input)
+    exit(0)
+
+# Show source image
+cv.imshow('Source Image', src)
+## [load_image]
+
+## [black_bg]
+# Change the background from white to black, since that will help later to extract
+# better results during the use of Distance Transform
+src[np.all(src == 255, axis=2)] = 0
+
+# Show output image
+cv.imshow('Black Background Image', src)
+## [black_bg]
+
+## [sharp]
+# Create a kernel that we will use to sharpen our image
+# an approximation of second derivative, a quite strong kernel
+kernel = np.array([[1, 1, 1], [1, -8, 1], [1, 1, 1]], dtype=np.float32)
+
+# do the laplacian filtering as it is
+# well, we need to convert everything in something more deeper then CV_8U
+# because the kernel has some negative values,
+# and we can expect in general to have a Laplacian image with negative values
+# BUT a 8bits unsigned int (the one we are working with) can contain values from 0 to 255
+# so the possible negative number will be truncated
+imgLaplacian = cv.filter2D(src, cv.CV_32F, kernel)
+sharp = np.float32(src)
+imgResult = sharp - imgLaplacian
+
+# convert back to 8bits gray scale
+imgResult = np.clip(imgResult, 0, 255)
+imgResult = imgResult.astype('uint8')
+imgLaplacian = np.clip(imgLaplacian, 0, 255)
+imgLaplacian = np.uint8(imgLaplacian)
+
+#cv.imshow('Laplace Filtered Image', imgLaplacian)
+cv.imshow('New Sharped Image', imgResult)
+## [sharp]
+
+## [bin]
+# Create binary image from source image
+bw = cv.cvtColor(imgResult, cv.COLOR_BGR2GRAY)
+_, bw = cv.threshold(bw, 40, 255, cv.THRESH_BINARY | cv.THRESH_OTSU)
+cv.imshow('Binary Image', bw)
+## [bin]
+
+## [dist]
+# Perform the distance transform algorithm
+dist = cv.distanceTransform(bw, cv.DIST_L2, 3)
+
+# Normalize the distance image for range = {0.0, 1.0}
+# so we can visualize and threshold it
+cv.normalize(dist, dist, 0, 1.0, cv.NORM_MINMAX)
+cv.imshow('Distance Transform Image', dist)
+## [dist]
+
+## [peaks]
+# Threshold to obtain the peaks
+# This will be the markers for the foreground objects
+_, dist = cv.threshold(dist, 0.4, 1.0, cv.THRESH_BINARY)
+
+# Dilate a bit the dist image
+kernel1 = np.ones((3,3), dtype=np.uint8)
+dist = cv.dilate(dist, kernel1)
+cv.imshow('Peaks', dist)
+## [peaks]
+
+## [seeds]
+# Create the CV_8U version of the distance image
+# It is needed for findContours()
+dist_8u = dist.astype('uint8')
+
+# Find total markers
+_, contours, _ = cv.findContours(dist_8u, cv.RETR_EXTERNAL, cv.CHAIN_APPROX_SIMPLE)
+
+# Create the marker image for the watershed algorithm
+markers = np.zeros(dist.shape, dtype=np.int32)
+
+# Draw the foreground markers
+for i in range(len(contours)):
+    cv.drawContours(markers, contours, i, (i+1), -1)
+
+# Draw the background marker
+cv.circle(markers, (5,5), 3, (255,255,255), -1)
+cv.imshow('Markers', markers*10000)
+## [seeds]
+
+## [watershed]
+# Perform the watershed algorithm
+cv.watershed(imgResult, markers)
+
+#mark = np.zeros(markers.shape, dtype=np.uint8)
+mark = markers.astype('uint8')
+mark = cv.bitwise_not(mark)
+# uncomment this if you want to see how the mark
+# image looks like at that point
+#cv.imshow('Markers_v2', mark)
+
+# Generate random colors
+colors = []
+for contour in contours:
+    colors.append((rng.randint(0,256), rng.randint(0,256), rng.randint(0,256)))
+
+# Create the result image
+dst = np.zeros((markers.shape[0], markers.shape[1], 3), dtype=np.uint8)
+
+# Fill labeled objects with random colors
+for i in range(markers.shape[0]):
+    for j in range(markers.shape[1]):
+        index = markers[i,j]
+        if index > 0 and index <= len(contours):
+            dst[i,j,:] = colors[index-1]
+
+# Visualize the final image
+cv.imshow('Final Result', dst)
+## [watershed]
+
+cv.waitKey()

samples/python/tutorial_code/features2D/feature_flann_matcher/SURF_FLANN_matching_Demo.py

@@ -28,10 +28,9 @@ knn_matches = matcher.knnMatch(descriptors1, descriptors2, 2)
 #-- Filter matches using the Lowe's ratio test
 ratio_thresh = 0.7
 good_matches = []
-for matches in knn_matches:
-    if len(matches) > 1:
-        if matches[0].distance / matches[1].distance <= ratio_thresh:
-            good_matches.append(matches[0])
+for m,n in knn_matches:
+    if m.distance / n.distance <= ratio_thresh:
+        good_matches.append(m)
 
 #-- Draw matches
 img_matches = np.empty((max(img1.shape[0], img2.shape[0]), img1.shape[1]+img2.shape[1], 3), dtype=np.uint8)

samples/python/tutorial_code/features2D/feature_homography/SURF_FLANN_matching_homography_Demo.py

@@ -28,10 +28,9 @@ knn_matches = matcher.knnMatch(descriptors_obj, descriptors_scene, 2)
 #-- Filter matches using the Lowe's ratio test
 ratio_thresh = 0.75
 good_matches = []
-for matches in knn_matches:
-    if len(matches) > 1:
-        if matches[0].distance / matches[1].distance <= ratio_thresh:
-            good_matches.append(matches[0])
+for m,n in knn_matches:
+    if m.distance / n.distance <= ratio_thresh:
+        good_matches.append(m)
 
 #-- Draw matches
 img_matches = np.empty((max(img_object.shape[0], img_scene.shape[0]), img_object.shape[1]+img_scene.shape[1], 3), dtype=np.uint8)