fix histogram calculation and add some tests for simpleWB

modules/xphoto/src/simple_color_balance.cpp

@@ -39,7 +39,6 @@
 
 #include <algorithm>
 #include <iostream>
-#include <iterator>
 #include <vector>
 
 #include "opencv2/core.hpp"
@@ -59,74 +58,56 @@ void balanceWhiteSimple(std::vector<Mat_<T> > &src, Mat &dst, const float inputM
     const float s1 = p; // low quantile
     const float s2 = p; // high quantile
 
-    int depth = 2; // depth of histogram tree
-    if (src[0].depth() != CV_8U)
-        ++depth;
-    int bins = 16; // number of bins at each histogram level
+    int nElements = src[0].depth() == CV_8U ? 256 : 4096;
 
-    int nElements = int(pow((float)bins, (float)depth));
-    // number of elements in histogram tree
+    float minValue0 = inputMin;
+    float maxValue0 = inputMax;
 
-    for (size_t i = 0; i < src.size(); ++i)
+    // deal with cv::calcHist (exclusive upper bound)
+    if (src[0].depth() == CV_32F || src[0].depth() == CV_64F) // floating
     {
-        std::vector<int> hist(nElements, 0);
-
-        typename Mat_<T>::iterator beginIt = src[i].begin();
-        typename Mat_<T>::iterator endIt = src[i].end();
-
-        for (typename Mat_<T>::iterator it = beginIt; it != endIt; ++it)
-        // histogram filling
+        maxValue0 += MIN((inputMax - inputMin) / (nElements - 1), 1);
+        if (inputMax == inputMin) // single value
+            maxValue0 += 1;
+    }
+    else // integer
     {
-            int pos = 0;
-            float minValue = inputMin - 0.5f;
-            float maxValue = inputMax + 0.5f;
-            T val = *it;
+        maxValue0 += 1;
+    }
 
-            float interval = float(maxValue - minValue) / bins;
+    float interval = (maxValue0 - minValue0) / float(nElements);
 
-            for (int j = 0; j < depth; ++j)
+    for (size_t i = 0; i < src.size(); ++i)
     {
-                int currentBin = int((val - minValue + 1e-4f) / interval);
-                ++hist[pos + currentBin];
-
-                pos = (pos + currentBin) * bins;
+        float minValue = minValue0;
+        float maxValue = maxValue0;
 
-                minValue = minValue + currentBin * interval;
-                maxValue = minValue + interval;
+        Mat img = src[i].reshape(1);
+        Mat hist;
+        int channels[] = {0};
+        int histSize[] = {nElements};
+        float inputRange[] = {minValue, maxValue};
+        const float *ranges[] = {inputRange};
 
-                interval /= bins;
-            }
-        }
+        calcHist(&img, 1, channels, Mat(), hist, 1, histSize, ranges, true, false);
 
         int total = int(src[i].total());
 
-        int p1 = 0, p2 = bins - 1;
+        int p1 = 0, p2 = nElements - 1;
         int n1 = 0, n2 = total;
 
-        float minValue = inputMin - 0.5f;
-        float maxValue = inputMax + 0.5f;
-
-        float interval = (maxValue - minValue) / float(bins);
-
-        for (int j = 0; j < depth; ++j)
         // searching for s1 and s2
+        while (n1 + hist.at<float>(p1) < s1 * total / 100.0f)
         {
-            while (n1 + hist[p1] < s1 * total / 100.0f)
-            {
-                n1 += hist[p1++];
+            n1 += saturate_cast<int>(hist.at<float>(p1++));
             minValue += interval;
         }
-            p1 *= bins;
 
-            while (n2 - hist[p2] > (100.0f - s2) * total / 100.0f)
+        while (n2 - hist.at<float>(p2) > (100.0f - s2) * total / 100.0f)
         {
-                n2 -= hist[p2--];
+            n2 -= saturate_cast<int>(hist.at<float>(p2--));
             maxValue -= interval;
         }
-            p2 = (p2 + 1) * bins - 1;
-
-            interval /= bins;
-        }
 
         src[i] = (outputMax - outputMin) * (src[i] - minValue) / (maxValue - minValue) + outputMin;
     }

modules/xphoto/test/simple_color_balance.cpp

@@ -5,33 +5,140 @@
 
 namespace opencv_test { namespace {
 
-    TEST(xphoto_simplecolorbalance, regression)
+    TEST(xphoto_simplecolorbalance, uchar_max_value)
     {
-        cv::String dir = cvtest::TS::ptr()->get_data_path() + "cv/xphoto/simple_white_balance/";
-        int nTests = 8;
-        cv::Ptr<cv::xphoto::WhiteBalancer> wb = cv::xphoto::createSimpleWB();
+        const uchar oldMax = 120, newMax = 255;
 
-        for (int i = 0; i < nTests; ++i)
+        Mat test = Mat::zeros(3,3,CV_8UC1);
+        test.at<uchar>(0, 0) = oldMax;
+        test.at<uchar>(0, 1) = oldMax / 2;
+        test.at<uchar>(0, 2) = oldMax / 4;
+
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(0);
+        wb->setInputMax(oldMax);
+        wb->setOutputMin(0);
+        wb->setOutputMax(newMax);
+
+        wb->balanceWhite(test, test);
+
+        double minDst, maxDst;
+        cv::minMaxIdx(test, &minDst, &maxDst);
+
+        ASSERT_NEAR(maxDst, newMax, 1e-4);
+    }
+
+    TEST(xphoto_simplecolorbalance, uchar_min_value)
+    {
+        const uchar oldMin = 120, newMin = 0;
+
+        Mat test = Mat::zeros(1,3,CV_8UC1);
+        test.at<uchar>(0, 0) = oldMin;
+        test.at<uchar>(0, 1) = (256 + oldMin) / 2;
+        test.at<uchar>(0, 2) = 255;
+
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(oldMin);
+        wb->setInputMax(255);
+        wb->setOutputMin(newMin);
+        wb->setOutputMax(255);
+
+        wb->balanceWhite(test, test);
+
+        double minDst, maxDst;
+        cv::minMaxIdx(test, &minDst, &maxDst);
+
+        ASSERT_NEAR(minDst, newMin, 1e-4);
+    }
+
+    TEST(xphoto_simplecolorbalance, uchar_equal_range)
     {
-            cv::String srcName = dir + cv::format( "sources/%02d.png", i + 1);
-            cv::Mat src = cv::imread( srcName, 1 );
-            ASSERT_TRUE(!src.empty());
+        const int N = 4;
+        uchar data[N] = {0, 1, 16, 255};
+        Mat test = Mat(1, N, CV_8UC1, data);
+        Mat result = Mat(1, N, CV_8UC1, data);
 
-            cv::String previousResultName = dir + cv::format( "results/%02d.jpg", i + 1 );
-            cv::Mat previousResult = cv::imread( previousResultName, 1 );
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(0);
+        wb->setInputMax(255);
+        wb->setOutputMin(0);
+        wb->setOutputMax(255);
+
+        wb->balanceWhite(test, test);
+
+        double err;
+        cv::minMaxIdx(cv::abs(test - result), NULL, &err);
+        ASSERT_LE(err, 1e-4);
+    }
 
-            cv::Mat currentResult;
-            wb->balanceWhite(src, currentResult);
+    TEST(xphoto_simplecolorbalance, uchar_single_value)
+    {
+        const int N = 4;
+        uchar data0[N] = {51, 51, 51, 51};
+        uchar data1[N] = {33, 33, 33, 33};
+        Mat test = Mat(1, N, CV_8UC1, data0);
+        Mat result = Mat(1, N, CV_8UC1, data1);
+
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(51);
+        wb->setInputMax(51);
+        wb->setOutputMin(33);
+        wb->setOutputMax(200);
 
-            double psnr = cv::PSNR(currentResult, previousResult);
+        wb->balanceWhite(test, test);
 
-            EXPECT_GE( psnr, 30 );
+        double err;
+        cv::minMaxIdx(cv::abs(test - result), NULL, &err);
+        ASSERT_LE(err, 1e-4);
     }
+
+    TEST(xphoto_simplecolorbalance, uchar_p)
+    {
+        const int N = 5;
+        uchar data0[N] = {10, 55, 102, 188, 233};
+        uchar data1[N] = {0, 1, 90, 254, 255};
+        Mat test = Mat(1, N, CV_8UC1, data0);
+        Mat result = Mat(1, N, CV_8UC1, data1);
+
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(10);
+        wb->setInputMax(233);
+        wb->setOutputMin(0);
+        wb->setOutputMax(255);
+        wb->setP(21);
+
+        wb->balanceWhite(test, test);
+
+        double err;
+        cv::minMaxIdx(cv::abs(test - result), NULL, &err);
+        ASSERT_LE(err, 1e-4);
     }
 
-    TEST(xphoto_simplecolorbalance, max_value)
+    TEST(xphoto_simplecolorbalance, uchar_c3)
     {
-        const float oldMax = 24000., newMax = 65536.;
+        const int N = 15;
+        uchar data0[N] = {10, 55, 102, 55, 102, 188, 102, 188, 233, 188, 233, 10, 233, 10, 55};
+        uchar data1[N] = {0, 1, 90, 1, 90, 254, 90, 254, 255, 254, 255, 0, 255, 0, 1};
+        Mat test = Mat(1, N / 3, CV_8UC3, data0);
+        Mat result = Mat(1, N / 3, CV_8UC3, data1);
+
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(10);
+        wb->setInputMax(233);
+        wb->setOutputMin(0);
+        wb->setOutputMax(255);
+        wb->setP(21);
+
+        wb->balanceWhite(test, test);
+
+        double err;
+        cv::minMaxIdx(cv::abs(test - result), NULL, &err);
+        ASSERT_LE(err, 1e-4);
+    }
+
+    TEST(xphoto_simplecolorbalance, float_max_value)
+    {
+        const float oldMax = 24000.f, newMax = 65536.f;
 
         Mat test = Mat::zeros(3,3,CV_32FC1);
         test.at<float>(0, 0) = oldMax;
@@ -55,5 +162,112 @@ namespace opencv_test { namespace {
         ASSERT_NEAR(maxDst, newMax, newMax*1e-4);
     }
 
+    TEST(xphoto_simplecolorbalance, float_min_value)
+    {
+        const float oldMin = 24000.f, newMin = 0.f;
+
+        Mat test = Mat::zeros(1,3,CV_32FC1);
+        test.at<float>(0, 0) = oldMin;
+        test.at<float>(0, 1) = (65536.f + oldMin) / 2;
+        test.at<float>(0, 2) = 65536.f;
+
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(oldMin);
+        wb->setInputMax(65536.f);
+        wb->setOutputMin(newMin);
+        wb->setOutputMax(65536.f);
+
+        wb->balanceWhite(test, test);
+
+        double minDst, maxDst;
+        cv::minMaxIdx(test, &minDst, &maxDst);
+
+        ASSERT_NEAR(minDst, newMin, 65536*1e-4);
+    }
+
+    TEST(xphoto_simplecolorbalance, float_equal_range)
+    {
+        const int N = 5;
+        float data[N] = {0.f, 1.f, 16.2f, 256.3f, 4096.f};
+        Mat test = Mat(1, N, CV_32FC1, data);
+        Mat result = Mat(1, N, CV_32FC1, data);
+
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(0);
+        wb->setInputMax(4096);
+        wb->setOutputMin(0);
+        wb->setOutputMax(4096);
+
+        wb->balanceWhite(test, test);
+
+        double err;
+        cv::minMaxIdx(cv::abs(test - result), NULL, &err);
+        ASSERT_LE(err, 1e-4);
+    }
+
+    TEST(xphoto_simplecolorbalance, float_single_value)
+    {
+        const int N = 4;
+        float data0[N] = {24000.5f, 24000.5f, 24000.5f, 24000.5f};
+        float data1[N] = {52000.25f, 52000.25f, 52000.25f, 52000.25f};
+        Mat test = Mat(1, N, CV_32FC1, data0);
+        Mat result = Mat(1, N, CV_32FC1, data1);
+
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(24000.5f);
+        wb->setInputMax(24000.5f);
+        wb->setOutputMin(52000.25f);
+        wb->setOutputMax(65536.f);
+
+        wb->balanceWhite(test, test);
+
+        double err;
+        cv::minMaxIdx(cv::abs(test - result), NULL, &err);
+        ASSERT_LE(err, 65536*1e-4);
+    }
+
+    TEST(xphoto_simplecolorbalance, float_p)
+    {
+        const int N = 5;
+        float data0[N] = {16000.f, 20000.5f, 24000.f, 36000.5f, 48000.f};
+        float data1[N] = {-16381.952f, 0.f, 16381.952f, 65536.f, 114685.952f};
+        Mat test = Mat(1, N, CV_32FC1, data0);
+        Mat result = Mat(1, N, CV_32FC1, data1);
+
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(16000.f);
+        wb->setInputMax(48000.f);
+        wb->setOutputMin(0.f);
+        wb->setOutputMax(65536.f);
+        wb->setP(21);
+
+        wb->balanceWhite(test, test);
+
+        double err;
+        cv::minMaxIdx(cv::abs(test - result), NULL, &err);
+        ASSERT_LE(err, 65536*1e-4);
+    }
+
+    TEST(xphoto_simplecolorbalance, float_c3)
+    {
+        const int N = 15;
+        float data0[N] = {16000.f, 20000.5f, 24000.f, 20000.5f, 24000.f, 36000.5f, 24000.f, 36000.5f, 48000.f, 36000.5f, 48000.f, 16000.f, 48000.f, 16000.f, 20000.5f};
+        float data1[N] = {-16381.952f, 0.f, 16381.952f, 0.f, 16381.952f, 65536.f, 16381.952f, 65536.f, 114685.952f, 65536.f, 114685.952f, -16381.952f, 114685.952f, -16381.952f, 0.f};
+        Mat test = Mat(1, N / 3, CV_32FC3, data0);
+        Mat result = Mat(1, N / 3, CV_32FC3, data1);
+
+        cv::Ptr<cv::xphoto::SimpleWB> wb = cv::xphoto::createSimpleWB();
+        wb->setInputMin(16000.f);
+        wb->setInputMax(48000.f);
+        wb->setOutputMin(0.f);
+        wb->setOutputMax(65536.f);
+        wb->setP(21);
+
+        wb->balanceWhite(test, test);
+
+        double err;
+        cv::minMaxIdx(cv::abs(test - result), NULL, &err);
+        ASSERT_LE(err, 65536*1e-4);
+    }
 
 }} // namespace