Correct handling when IPP is enabled

modules/imgproc/src/histogram.cpp

@@ -821,6 +821,10 @@ static bool ipp_calchist(const Mat &image, Mat &hist, int histSize, const float*
         return false;
 #endif
 
+    // IPP_DISABLE_HISTOGRAM - https://github.com/opencv/opencv/issues/11544
+    if (uniform && (ranges[0][1] - ranges[0][0]) != histSize)
+        return false;
+
     Mat ihist = hist;
     if(accumulate)
         ihist.create(1, &histSize, CV_32S);

modules/imgproc/test/test_histograms.cpp

@@ -1918,5 +1918,35 @@ TEST(Imgproc_Hist_CalcBackProject, accuracy) { CV_CalcBackProjectTest test; test
 TEST(Imgproc_Hist_CalcBackProjectPatch, accuracy) { CV_CalcBackProjectPatchTest test; test.safe_run(); }
 TEST(Imgproc_Hist_BayesianProb, accuracy) { CV_BayesianProbTest test; test.safe_run(); }
 
+TEST(Imgproc_Hist_Calc, calcHist_regression_11544)
+{
+    cv::Mat1w m = cv::Mat1w::zeros(10, 10);
+    int n_images = 1;
+    int channels[] = { 0 };
+    cv::Mat mask;
+    cv::MatND hist1, hist2;
+    cv::MatND hist1_opt, hist2_opt;
+    int dims = 1;
+    int hist_size[] = { 1000 };
+    float range1[] = { 0, 900 };
+    float range2[] = { 0, 1000 };
+    const float* ranges1[] = { range1 };
+    const float* ranges2[] = { range2 };
+
+    setUseOptimized(false);
+    cv::calcHist(&m, n_images, channels, mask, hist1, dims, hist_size, ranges1);
+    cv::calcHist(&m, n_images, channels, mask, hist2, dims, hist_size, ranges2);
+
+    setUseOptimized(true);
+    cv::calcHist(&m, n_images, channels, mask, hist1_opt, dims, hist_size, ranges1);
+    cv::calcHist(&m, n_images, channels, mask, hist2_opt, dims, hist_size, ranges2);
+
+    for(int i = 0; i < 1000; i++)
+    {
+        EXPECT_EQ(hist1.at<float>(i, 0), hist1_opt.at<float>(i, 0)) << i;
+        EXPECT_EQ(hist2.at<float>(i, 0), hist2_opt.at<float>(i, 0)) << i;
+    }
+}
+
 }} // namespace
 /* End Of File */