JavaScript bindings for dnn module

3rdparty/protobuf/src/google/protobuf/stubs/port.h

@@ -224,8 +224,7 @@ static const uint64 kuint64max = GOOGLE_ULONGLONG(0xFFFFFFFFFFFFFFFF);
 
 #if defined(__clang__) && defined(__has_cpp_attribute) \
     && !defined(GOOGLE_PROTOBUF_OS_APPLE)
-# if defined(GOOGLE_PROTOBUF_OS_NACL) || defined(EMSCRIPTEN) || \
-     __has_cpp_attribute(clang::fallthrough)
+# if defined(GOOGLE_PROTOBUF_OS_NACL) || __has_cpp_attribute(clang::fallthrough)
 #  define GOOGLE_FALLTHROUGH_INTENDED [[clang::fallthrough]]
 # endif
 #endif

doc/tutorials/dnn/dnn_javascript/dnn_javascript.markdown

+# How to run deep networks in browser {#tutorial_dnn_javascript}
+
+## Introduction
+This tutorial will show us how to run deep learning models using OpenCV.js right
+in a browser. Tutorial refers a sample of face detection and face recognition
+models pipeline.
+
+## Face detection
+Face detection network gets BGR image as input and produces set of bounding boxes
+that might contain faces. All that we need is just select the boxes with a strong
+confidence.
+
+## Face recognition
+Network is called OpenFace (project https://github.com/cmusatyalab/openface).
+Face recognition model receives RGB face image of size `96x96`. Then it returns
+`128`-dimensional unit vector that represents input face as a point on the unit
+multidimensional sphere. So difference between two faces is an angle between two
+output vectors.
+
+## Sample
+All the sample is an HTML page that has JavaScript code to use OpenCV.js functionality.
+You may see an insertion of this page below. Press `Start` button to begin a demo.
+Press `Add a person` to name a person that is recognized as an unknown one.
+Next we'll discuss main parts of the code.
+
+@htmlinclude js_face_recognition.html
+
+-# Run face detection network to detect faces on input image.
+@snippet dnn/js_face_recognition.html Run face detection model
+You may play with input blob sizes to balance detection quality and efficiency.
+The bigger input blob the smaller faces may be detected.
+
+-# Run face recognition network to receive `128`-dimensional unit feature vector by input face image.
+@snippet dnn/js_face_recognition.html Get 128 floating points feature vector
+
+-# Perform a recognition.
+@snippet dnn/js_face_recognition.html Recognize
+Match a new feature vector with registered ones. Return a name of the best matched person.
+
+-# The main loop.
+@snippet dnn/js_face_recognition.html Define frames processing
+A main loop of our application receives a frames from a camera and makes a recognition
+of an every detected face on the frame. We start this function ones when OpenCV.js was
+initialized and deep learning models were downloaded.

doc/tutorials/dnn/table_of_content_dnn.markdown

@@ -25,6 +25,14 @@ Deep Neural Networks (dnn module) {#tutorial_table_of_content_dnn}
 
     In this tutorial we describe the ways to schedule your networks using Halide backend in OpenCV deep learning module.
 
+-   @subpage tutorial_dnn_android
+
+    *Compatibility:* \> OpenCV 3.3
+
+    *Author:* Dmitry Kurtaev
+
+    This tutorial will show you how to run deep learning model using OpenCV on Android device.
+
 -   @subpage tutorial_dnn_yolo
 
     *Compatibility:* \> OpenCV 3.3.1
@@ -32,3 +40,11 @@ Deep Neural Networks (dnn module) {#tutorial_table_of_content_dnn}
     *Author:* Alessandro de Oliveira Faria
 
     In this tutorial you will learn how to use opencv_dnn module using yolo_object_detection with device capture, video file or image.
+
+-   @subpage tutorial_dnn_javascript
+
+    *Compatibility:* \> OpenCV 3.3.1
+
+    *Author:* Dmitry Kurtaev
+
+    In this tutorial we'll run deep learning models in browser using OpenCV.js.

modules/dnn/CMakeLists.txt

@@ -15,7 +15,7 @@ set(the_description "Deep neural network module. It allows to load models from d
 
 ocv_add_dispatched_file("layers/layers_common" AVX AVX2)
 
-ocv_add_module(dnn opencv_core opencv_imgproc WRAP python matlab java)
+ocv_add_module(dnn opencv_core opencv_imgproc WRAP python matlab java js)
 ocv_warnings_disable(CMAKE_CXX_FLAGS -Wno-shadow -Wno-parentheses -Wmaybe-uninitialized -Wsign-promo
                                      -Wmissing-declarations -Wmissing-prototypes
 )

modules/dnn/include/opencv2/dnn/all_layers.hpp

@@ -221,11 +221,6 @@ CV__DNN_EXPERIMENTAL_NS_BEGIN
     class CV_EXPORTS LRNLayer : public Layer
     {
     public:
-        enum Type
-        {
-            CHANNEL_NRM,
-            SPATIAL_NRM
-        };
         int type;
 
         int size;
@@ -238,14 +233,6 @@ CV__DNN_EXPERIMENTAL_NS_BEGIN
     class CV_EXPORTS PoolingLayer : public Layer
     {
     public:
-        enum Type
-        {
-            MAX,
-            AVE,
-            STOCHASTIC,
-            ROI
-        };
-
         int type;
         Size kernel, stride, pad;
         bool globalPooling;
@@ -474,13 +461,6 @@ CV__DNN_EXPERIMENTAL_NS_BEGIN
     class CV_EXPORTS EltwiseLayer : public Layer
     {
     public:
-        enum EltwiseOp
-        {
-            PROD = 0,
-            SUM = 1,
-            MAX = 2,
-        };
-
         static Ptr<EltwiseLayer> create(const LayerParams &params);
     };
 

modules/dnn/include/opencv2/dnn/dnn.hpp

@@ -423,7 +423,7 @@ CV__DNN_EXPERIMENTAL_NS_BEGIN
          *  @param outputBlobs contains all output blobs for each layer specified in @p outBlobNames.
          *  @param outBlobNames names for layers which outputs are needed to get
          */
-        CV_WRAP void forward(std::vector<std::vector<Mat> >& outputBlobs,
+        void forward(std::vector<std::vector<Mat> >& outputBlobs,
                      const std::vector<String>& outBlobNames);
 
         //TODO:
@@ -467,7 +467,7 @@ CV__DNN_EXPERIMENTAL_NS_BEGIN
          *  @note If updating blob is not empty then @p blob must have the same shape,
          *  because network reshaping is not implemented yet.
          */
-        CV_WRAP void setInput(const Mat &blob, const String& name = "");
+        CV_WRAP void setInput(InputArray blob, const String& name = "");
 
         /** @brief Sets the new value for the learned param of the layer.
          *  @param layer name or id of the layer.
@@ -733,7 +733,7 @@ CV__DNN_EXPERIMENTAL_NS_BEGIN
      *  If @p crop is false, direct resize without cropping and preserving aspect ratio is performed.
      *  @returns 4-dimansional Mat with NCHW dimensions order.
      */
-    CV_EXPORTS_W Mat blobFromImage(const Mat& image, double scalefactor=1.0, const Size& size = Size(),
+    CV_EXPORTS_W Mat blobFromImage(InputArray image, double scalefactor=1.0, const Size& size = Size(),
                                    const Scalar& mean = Scalar(), bool swapRB=true, bool crop=true);
     /** @brief Creates 4-dimensional blob from series of images. Optionally resizes and
      *  crops @p images from center, subtract @p mean values, scales values by @p scalefactor,

modules/dnn/src/dnn.cpp

@@ -84,11 +84,11 @@ static String toString(const T &v)
     return ss.str();
 }
 
-Mat blobFromImage(const Mat& image, double scalefactor, const Size& size,
+Mat blobFromImage(InputArray image, double scalefactor, const Size& size,
                   const Scalar& mean, bool swapRB, bool crop)
 {
     CV_TRACE_FUNCTION();
-    std::vector<Mat> images(1, image);
+    std::vector<Mat> images(1, image.getMat());
     return blobFromImages(images, scalefactor, size, mean, swapRB, crop);
 }
 
@@ -1910,7 +1910,7 @@ void Net::setInputsNames(const std::vector<String> &inputBlobNames)
     impl->netInputLayer->setNames(inputBlobNames);
 }
 
-void Net::setInput(const Mat &blob_, const String& name)
+void Net::setInput(InputArray blob, const String& name)
 {
     CV_TRACE_FUNCTION();
     CV_TRACE_ARG_VALUE(name, "name", name.c_str());
@@ -1930,6 +1930,7 @@ void Net::setInput(const Mat &blob_, const String& name)
         ld.umat_outputBlobs.resize( std::max(pin.oid+1, (int)ld.requiredOutputs.size()) );
     ld.outputBlobsWrappers.resize(ld.outputBlobs.size());
     MatShape prevShape = shape(ld.outputBlobs[pin.oid]);
+    Mat blob_ = blob.getMat();
     bool oldShape = prevShape == shape(blob_);
     if (oldShape)
     {

modules/dnn/src/layers/eltwise_layer.cpp

@@ -52,22 +52,27 @@ namespace dnn
 class EltwiseLayerImpl : public EltwiseLayer
 {
 public:
-    EltwiseOp op;
+    enum EltwiseOp
+    {
+        PROD = 0,
+        SUM = 1,
+        MAX = 2,
+    } op;
     std::vector<float> coeffs;
 
     EltwiseLayerImpl(const LayerParams& params)
     {
         setParamsFrom(params);
-        op = EltwiseLayer::SUM;
+        op = SUM;
         if (params.has("operation"))
         {
             String operation = params.get<String>("operation").toLowerCase();
             if (operation == "prod")
-                op = EltwiseLayer::PROD;
+                op = PROD;
             else if (operation == "sum")
-                op = EltwiseLayer::SUM;
+                op = SUM;
             else if (operation == "max")
-                op = EltwiseLayer::MAX;
+                op = MAX;
             else
                 CV_Error(cv::Error::StsBadArg, "Unknown operaticon type \"" + operation + "\"");
         }
@@ -122,7 +127,7 @@ public:
         int channels;
         size_t planeSize;
 
-        EltwiseInvoker() : srcs(0), nsrcs(0), dst(0), coeffs(0), op(EltwiseLayer::PROD), nstripes(0), activ(0), channels(0), planeSize(0)  {}
+        EltwiseInvoker() : srcs(0), nsrcs(0), dst(0), coeffs(0), op(PROD), nstripes(0), activ(0), channels(0), planeSize(0)  {}
 
         static void run(const Mat** srcs, int nsrcs, Mat& dst,
                         const std::vector<float>& coeffs, EltwiseOp op,
@@ -150,7 +155,7 @@ public:
             CV_Assert(dst.total() == dst.size[0] * p.channels * p.planeSize);
 
             bool simpleCoeffs = true;
-            if( op == EltwiseLayer::SUM && !coeffs.empty() )
+            if( op == SUM && !coeffs.empty() )
             {
                 CV_Assert( coeffs.size() == (size_t)nsrcs );
 
@@ -192,7 +197,7 @@ public:
                     const float* srcptr0 = srcs[0]->ptr<float>() + globalDelta;
                     float* dstptr = dstptr0 + globalDelta;
 
-                    if( op == EltwiseLayer::PROD )
+                    if( op == PROD )
                     {
                         for( k = 1; k < n; k++ )
                         {
@@ -204,7 +209,7 @@ public:
                             srcptr0 = (const float*)dstptr;
                         }
                     }
-                    else if( op == EltwiseLayer::MAX )
+                    else if( op == MAX )
                     {
                         for( k = 1; k < n; k++ )
                         {

modules/dnn/src/layers/lrn_layer.cpp

@@ -67,9 +67,9 @@ public:
         type = -1;
         String nrmType = params.get<String>("norm_region", "ACROSS_CHANNELS");
         if (nrmType == "ACROSS_CHANNELS")
-            type = LRNLayer::CHANNEL_NRM;
+            type = CHANNEL_NRM;
         else if (nrmType == "WITHIN_CHANNEL")
-            type = LRNLayer::SPATIAL_NRM;
+            type = SPATIAL_NRM;
         else
             CV_Error(Error::StsBadArg, "Unknown region type \"" + nrmType + "\"");
 
@@ -397,6 +397,13 @@ public:
         }
         return flops;
     }
+
+private:
+    enum Type
+    {
+        CHANNEL_NRM,
+        SPATIAL_NRM
+    };
 };
 
 Ptr<LRNLayer> LRNLayer::create(const LayerParams& params)

modules/dnn/src/layers/pooling_layer.cpp

@@ -63,7 +63,7 @@ class PoolingLayerImpl : public PoolingLayer
 public:
     PoolingLayerImpl(const LayerParams& params)
     {
-        type = PoolingLayer::MAX;
+        type = MAX;
         computeMaxIdx = true;
         globalPooling = false;
 
@@ -71,11 +71,11 @@ public:
         {
             String pool = params.get<String>("pool").toLowerCase();
             if (pool == "max")
-                type = PoolingLayer::MAX;
+                type = MAX;
             else if (pool == "ave")
-                type = PoolingLayer::AVE;
+                type = AVE;
             else if (pool == "stochastic")
-                type = PoolingLayer::STOCHASTIC;
+                type = STOCHASTIC;
             else
                 CV_Error(Error::StsBadArg, "Unknown pooling type \"" + pool + "\"");
             getPoolingKernelParams(params, kernel.height, kernel.width, globalPooling,
@@ -83,7 +83,7 @@ public:
         }
         else if (params.has("pooled_w") || params.has("pooled_h") || params.has("spatial_scale"))
         {
-            type = PoolingLayer::ROI;
+            type = ROI;
         }
         setParamsFrom(params);
         ceilMode = params.get<bool>("ceil_mode", true);
@@ -115,8 +115,7 @@ public:
     {
         return backendId == DNN_BACKEND_DEFAULT ||
                backendId == DNN_BACKEND_HALIDE && haveHalide() &&
-               (type == PoolingLayer::MAX ||
-                type == PoolingLayer::AVE && !pad.width && !pad.height);
+               (type == MAX || type == AVE && !pad.width && !pad.height);
     }
 
 #ifdef HAVE_OPENCL
@@ -200,9 +199,9 @@ public:
 
     virtual Ptr<BackendNode> initHalide(const std::vector<Ptr<BackendWrapper> > &inputs)
     {
-        if (type == PoolingLayer::MAX)
+        if (type == MAX)
             return initMaxPoolingHalide(inputs);
-        else if (type == PoolingLayer::AVE)
+        else if (type == AVE)
             return initAvePoolingHalide(inputs);
         else
             return Ptr<BackendNode>();
@@ -221,7 +220,7 @@ public:
         float spatialScale;
 
         PoolingInvoker() : src(0), rois(0), dst(0), mask(0), nstripes(0),
-                           computeMaxIdx(0), poolingType(PoolingLayer::MAX), spatialScale(0) {}
+                           computeMaxIdx(0), poolingType(MAX), spatialScale(0) {}
 
         static void run(const Mat& src, const Mat& rois, Mat& dst, Mat& mask, Size kernel,
                         Size stride, Size pad, int poolingType, float spatialScale,
@@ -698,7 +697,7 @@ public:
             out.height = 1;
             out.width = 1;
         }
-        else if (type == PoolingLayer::ROI)
+        else if (type == ROI)
         {
             out.height = pooledSize.height;
             out.width = pooledSize.width;
@@ -757,6 +756,14 @@ public:
         }
         return flops;
     }
+private:
+    enum Type
+    {
+        MAX,
+        AVE,
+        STOCHASTIC,
+        ROI
+    };
 };
 
 Ptr<PoolingLayer> PoolingLayer::create(const LayerParams& params)

modules/js/src/core_bindings.cpp

@@ -73,11 +73,13 @@
 #include "opencv2/video/tracking.hpp"
 #include "opencv2/video/background_segm.hpp"
 #include "opencv2/objdetect.hpp"
+#include "opencv2/dnn.hpp"
 
 #include <emscripten/bind.h>
 
 using namespace emscripten;
 using namespace cv;
+using namespace dnn;
 
 namespace binding_utils
 {
@@ -339,12 +341,12 @@ EMSCRIPTEN_BINDINGS(binding_utils)
         .constructor<int, int, int, const Scalar&>()
         .constructor(&binding_utils::createMat, allow_raw_pointers())
 
-        .class_function("eye", select_overload<Mat(int, int, int)>(&binding_utils::matEye))
         .class_function("eye", select_overload<Mat(Size, int)>(&binding_utils::matEye))
-        .class_function("ones", select_overload<Mat(int, int, int)>(&binding_utils::matOnes))
+        .class_function("eye", select_overload<Mat(int, int, int)>(&binding_utils::matEye))
         .class_function("ones", select_overload<Mat(Size, int)>(&binding_utils::matOnes))
-        .class_function("zeros", select_overload<Mat(int, int, int)>(&binding_utils::matZeros))
+        .class_function("ones", select_overload<Mat(int, int, int)>(&binding_utils::matOnes))
         .class_function("zeros", select_overload<Mat(Size, int)>(&binding_utils::matZeros))
+        .class_function("zeros", select_overload<Mat(int, int, int)>(&binding_utils::matZeros))
 
         .property("rows", &cv::Mat::rows)
         .property("cols", &cv::Mat::cols)

modules/js/src/embindgen.py

@@ -125,6 +125,9 @@ video = {'': ['CamShift', 'calcOpticalFlowFarneback', 'calcOpticalFlowPyrLK', 'c
          'BackgroundSubtractorMOG2': ['BackgroundSubtractorMOG2', 'apply'],
          'BackgroundSubtractor': ['apply', 'getBackgroundImage']}
 
+dnn = {'dnn_Net': ['setInput', 'forward'],
+       '': ['readNetFromCaffe', 'readNetFromTensorflow', 'readNetFromTorch', 'readNetFromDarknet', 'blobFromImage']}
+
 def makeWhiteList(module_list):
     wl = {}
     for m in module_list:
@@ -135,7 +138,7 @@ def makeWhiteList(module_list):
                 wl[k] = m[k]
     return wl
 
-white_list = makeWhiteList([core, imgproc, objdetect, video])
+white_list = makeWhiteList([core, imgproc, objdetect, video, dnn])
 
 # Features to be exported
 export_enums = False

platforms/js/build_js.py

@@ -134,7 +134,7 @@ class Builder:
                "-DBUILD_ZLIB=ON",
                "-DBUILD_opencv_apps=OFF",
                "-DBUILD_opencv_calib3d=OFF",
-               "-DBUILD_opencv_dnn=OFF",
+               "-DBUILD_opencv_dnn=ON",
                "-DBUILD_opencv_features2d=OFF",
                "-DBUILD_opencv_flann=OFF",
                "-DBUILD_opencv_ml=OFF",

samples/dnn/js_face_recognition.html

+<!DOCTYPE html>
+
+<html>
+
+<head>
+  <script async src="../../opencv.js" type="text/javascript"></script>
+  <script src="../../utils.js" type="text/javascript"></script>
+
+<script type='text/javascript'>
+var netDet = undefined, netRecogn = undefined;
+var persons = {};
+
+//! [Run face detection model]
+function detectFaces(img) {
+  var blob = cv.blobFromImage(img, 1, {width: 128, height: 96}, [104, 177, 123, 0], false, false);
+  netDet.setInput(blob);
+  var out = netDet.forward();
+
+  var faces = [];
+  for (var i = 0, n = out.data32F.length; i < n; i += 7) {
+    var confidence = out.data32F[i + 2];
+    var left = out.data32F[i + 3] * img.cols;
+    var top = out.data32F[i + 4] * img.rows;
+    var right = out.data32F[i + 5] * img.cols;
+    var bottom = out.data32F[i + 6] * img.rows;
+    left = Math.min(Math.max(0, left), img.cols - 1);
+    right = Math.min(Math.max(0, right), img.cols - 1);
+    bottom = Math.min(Math.max(0, bottom), img.rows - 1);
+    top = Math.min(Math.max(0, top), img.rows - 1);
+
+    if (confidence > 0.5 && left < right && top < bottom) {
+      faces.push({x: left, y: top, width: right - left, height: bottom - top})
+    }
+  }
+  blob.delete();
+  out.delete();
+  return faces;
+};
+//! [Run face detection model]
+
+//! [Get 128 floating points feature vector]
+function face2vec(face) {
+  var blob = cv.blobFromImage(face, 1.0 / 255, {width: 96, height: 96}, [0, 0, 0, 0], true, false)
+  netRecogn.setInput(blob);
+  var vec = netRecogn.forward();
+  blob.delete();
+  return vec;
+};
+//! [Get 128 floating points feature vector]
+
+//! [Recognize]
+function recognize(face) {
+  var vec = face2vec(face);
+
+  var bestMatchName = 'unknown';
+  var bestMatchScore = 0.5;  // Actually, the minimum is -1 but we use it as a threshold.
+  for (name in persons) {
+    var personVec = persons[name];
+    var score = vec.dot(personVec);
+    if (score > bestMatchScore) {
+      bestMatchScore = score;
+      bestMatchName = name;
+    }
+  }
+  vec.delete();
+  return bestMatchName;
+};
+//! [Recognize]
+
+function loadModels(callback) {
+  var utils = new Utils('');
+  var proto = 'https://raw.githubusercontent.com/opencv/opencv/master/samples/dnn/face_detector/deploy.prototxt';
+  var weights = 'https://raw.githubusercontent.com/opencv/opencv_3rdparty/dnn_samples_face_detector_20170830/res10_300x300_ssd_iter_140000.caffemodel';
+  var recognModel = 'https://raw.githubusercontent.com/pyannote/pyannote-data/master/openface.nn4.small2.v1.t7';
+  utils.createFileFromUrl('face_detector.prototxt', proto, () => {
+    document.getElementById('status').innerHTML = 'Downloading face_detector.caffemodel';
+    utils.createFileFromUrl('face_detector.caffemodel', weights, () => {
+      document.getElementById('status').innerHTML = 'Downloading OpenFace model';
+      utils.createFileFromUrl('face_recognition.t7', recognModel, () => {
+        document.getElementById('status').innerHTML = '';
+        netDet = cv.readNetFromCaffe('face_detector.prototxt', 'face_detector.caffemodel');
+        netRecogn = cv.readNetFromTorch('face_recognition.t7');
+        callback();
+      });
+    });
+  });
+};
+
+function main() {
+  // Create a camera object.
+  var output = document.getElementById('output');
+  var camera = document.createElement("video");
+  camera.setAttribute("width", output.width);
+  camera.setAttribute("height", output.height);
+
+  // Get a permission from user to use a camera.
+  navigator.mediaDevices.getUserMedia({video: true, audio: false})
+    .then(function(stream) {
+      camera.srcObject = stream;
+      camera.onloadedmetadata = function(e) {
+        camera.play();
+      };
+  });
+
+  //! [Open a camera stream]
+  var cap = new cv.VideoCapture(camera);
+  var frame = new cv.Mat(camera.height, camera.width, cv.CV_8UC4);
+  var frameBGR = new cv.Mat(camera.height, camera.width, cv.CV_8UC3);
+  //! [Open a camera stream]
+
+  //! [Add a person]
+  document.getElementById('addPersonButton').onclick = function() {
+    var rects = detectFaces(frameBGR);
+    if (rects.length > 0) {
+      var face = frameBGR.roi(rects[0]);
+
+      var name = prompt('Say your name:');
+      var cell = document.getElementById("targetNames").insertCell(0);
+      cell.innerHTML = name;
+
+      persons[name] = face2vec(face).clone();
+
+      var canvas = document.createElement("canvas");
+      canvas.setAttribute("width", 96);
+      canvas.setAttribute("height", 96);
+      var cell = document.getElementById("targetImgs").insertCell(0);
+      cell.appendChild(canvas);
+
+      var faceResized = new cv.Mat(canvas.height, canvas.width, cv.CV_8UC3);
+      cv.resize(face, faceResized, {width: canvas.width, height: canvas.height});
+      cv.cvtColor(faceResized, faceResized, cv.COLOR_BGR2RGB);
+      cv.imshow(canvas, faceResized);
+      faceResized.delete();
+    }
+  };
+  //! [Add a person]
+
+  //! [Define frames processing]
+  var isRunning = false;
+  const FPS = 30;  // Target number of frames processed per second.
+  function captureFrame() {
+    var begin = Date.now();
+    cap.read(frame);  // Read a frame from camera
+    cv.cvtColor(frame, frameBGR, cv.COLOR_RGBA2BGR);
+
+    var faces = detectFaces(frameBGR);
+    faces.forEach(function(rect) {
+      cv.rectangle(frame, {x: rect.x, y: rect.y}, {x: rect.x + rect.width, y: rect.y + rect.height}, [0, 255, 0, 255]);
+
+      var face = frameBGR.roi(rect);
+      var name = recognize(face);
+      cv.putText(frame, name, {x: rect.x, y: rect.y}, cv.FONT_HERSHEY_SIMPLEX, 1.0, [0, 255, 0, 255]);
+    });
+
+    cv.imshow(output, frame);
+
+    // Loop this function.
+    if (isRunning) {
+      var delay = 1000 / FPS - (Date.now() - begin);
+      setTimeout(captureFrame, delay);
+    }
+  };
+  //! [Define frames processing]
+
+  document.getElementById('startStopButton').onclick = function toggle() {
+    if (isRunning) {
+      isRunning = false;
+      document.getElementById('startStopButton').innerHTML = 'Start';
+      document.getElementById('addPersonButton').disabled = true;
+    } else {
+      function run() {
+        isRunning = true;
+        captureFrame();
+        document.getElementById('startStopButton').innerHTML = 'Stop';
+        document.getElementById('startStopButton').disabled = false;
+        document.getElementById('addPersonButton').disabled = false;
+      }
+      if (netDet == undefined || netRecogn == undefined) {
+        document.getElementById('startStopButton').disabled = true;
+        loadModels(run);  // Load models and run a pipeline;
+      } else {
+        run();
+      }
+    }
+  };
+
+  document.getElementById('startStopButton').disabled = false;
+};
+</script>
+
+</head>
+
+<body onload="main()">
+  <button id="startStopButton" type="button" disabled="true">Start</button>
+  <div id="status"></div>
+  <canvas id="output" width=640 height=480 style="max-width: 100%"></canvas>
+
+  <table>
+    <tr id="targetImgs"></tr>
+    <tr id="targetNames"></tr>
+  </table>
+  <button id="addPersonButton" type="button" disabled="true">Add a person</button>
+</body>
+
+</html>