Inpainting floating point values with Telea's algorithm gives unexpected results

modules/photo/src/inpaint.cpp

@@ -46,6 +46,7 @@
 // */
 
 #include <queue>
+#include <type_traits>
 
 #include "precomp.hpp"
 #include "opencv2/imgproc/imgproc_c.h"
@@ -55,6 +56,16 @@
 #define CV_MAT_ELEM_PTR_FAST( mat, row, col, pix_size )  \
      ((mat).data.ptr + (size_t)(mat).step*(row) + (pix_size)*(col))
 
+template<typename T>
+typename std::enable_if<std::is_floating_point<T>::value, T>::type round_cast(float val) {
+   return cv::saturate_cast<T>(val);
+}
+
+template<typename T>
+typename std::enable_if<!std::is_floating_point<T>::value, T>::type round_cast(float val) {
+   return cv::saturate_cast<T>(val + 0.5);
+}
+
 inline float
 min4( float a, float b, float c, float d )
 {
@@ -339,8 +350,8 @@ icvTeleaInpaintFMM(const CvMat *f, CvMat *t, CvMat *out, int range, CvPriorityQu
                   }
                }
                for (color=0; color<=2; color++) {
-                  sat = (float)((Ia[color]/s[color]+(Jx[color]+Jy[color])/(sqrt(Jx[color]*Jx[color]+Jy[color]*Jy[color])+1.0e-20f)+0.5f));
-                  CV_MAT_3COLOR_ELEM(*out,uchar,i-1,j-1,color) = cv::saturate_cast<uchar>(sat);
+                  sat = (float)(Ia[color]/s[color]+(Jx[color]+Jy[color])/(sqrt(Jx[color]*Jx[color]+Jy[color]*Jy[color])+1.0e-20f));
+                  CV_MAT_3COLOR_ELEM(*out,uchar,i-1,j-1,color) = round_cast<uchar>(sat);
                }
 
                CV_MAT_ELEM(*f,uchar,i,j) = BAND;
@@ -449,9 +460,9 @@ icvTeleaInpaintFMM(const CvMat *f, CvMat *t, CvMat *out, int range, CvPriorityQu
                         }
                      }
                   }
-                  sat = (float)((Ia/s+(Jx+Jy)/(sqrt(Jx*Jx+Jy*Jy)+1.0e-20f)+0.5f));
+                  sat = (float)(Ia/s+(Jx+Jy)/(sqrt(Jx*Jx+Jy*Jy)+1.0e-20f));
                   {
-                  CV_MAT_ELEM(*out,data_type,i-1,j-1) = cv::saturate_cast<data_type>(sat);
+                  CV_MAT_ELEM(*out,data_type,i-1,j-1) = round_cast<data_type>(sat);
                   }
                }
 

modules/photo/test/test_inpaint.cpp

@@ -116,9 +116,9 @@ void CV_InpaintTest::run( int )
 
 TEST(Photo_Inpaint, regression) { CV_InpaintTest test; test.safe_run(); }
 
-typedef testing::TestWithParam<tuple<int> > formats;
+typedef testing::TestWithParam<tuple<perf::MatType> > formats;
 
-TEST_P(formats, 1c)
+TEST_P(formats, basic)
 {
     const int type = get<0>(GetParam());
     Mat src(100, 100, type);
@@ -126,18 +126,18 @@ TEST_P(formats, 1c)
     Mat ref = src.clone();
     Mat dst, mask = Mat::zeros(src.size(), CV_8U);
 
-    circle(src, Point(50, 50), 5, Scalar(200), 6);
-    circle(mask, Point(50, 50), 5, Scalar(200), 6);
+    circle(src, Point(50, 50), 5, Scalar::all(200), 6);
+    circle(mask, Point(50, 50), 5, Scalar::all(200), 6);
     inpaint(src, mask, dst, 10, INPAINT_NS);
 
     Mat dst2;
     inpaint(src, mask, dst2, 10, INPAINT_TELEA);
 
-    ASSERT_LE(cv::norm(dst, ref, NORM_INF), 3.);
-    ASSERT_LE(cv::norm(dst2, ref, NORM_INF), 3.);
+    ASSERT_EQ(cv::norm(dst, ref, NORM_INF), 0.);
+    ASSERT_EQ(cv::norm(dst2, ref, NORM_INF), 0.);
 }
 
-INSTANTIATE_TEST_CASE_P(Photo_Inpaint, formats, testing::Values(CV_32F, CV_16U, CV_8U));
+INSTANTIATE_TEST_CASE_P(Photo_Inpaint, formats, testing::Values(CV_32FC1, CV_16UC1, CV_8UC1, CV_8UC3));
 
 TEST(Photo_InpaintBorders, regression)
 {