Merge pull request #4204 from gladilov-gleb:minMaxLocBugFix

modules/core/src/stat.cpp

@@ -1097,8 +1097,8 @@ void cv::minMaxIdx(InputArray _src, double* minVal,
 
     size_t minidx = 0, maxidx = 0;
     int iminval = INT_MAX, imaxval = INT_MIN;
-    float fminval = FLT_MAX, fmaxval = -FLT_MAX;
-    double dminval = DBL_MAX, dmaxval = -DBL_MAX;
+    float  fminval = std::numeric_limits<float>::infinity(),  fmaxval = -fminval;
+    double dminval = std::numeric_limits<double>::infinity(), dmaxval = -dminval;
     size_t startidx = 1;
     int *minval = &iminval, *maxval = &imaxval;
     int planeSize = (int)it.size*cn;
@@ -1111,6 +1111,14 @@ void cv::minMaxIdx(InputArray _src, double* minVal,
     for( size_t i = 0; i < it.nplanes; i++, ++it, startidx += planeSize )
         func( ptrs[0], ptrs[1], minval, maxval, &minidx, &maxidx, planeSize, startidx );
 
+    if (!src.empty() && mask.empty())
+    {
+        if( minidx == 0 )
+             minidx = 1;
+         if( maxidx == 0 )
+             maxidx = 1;
+    }
+
     if( minidx == 0 )
         dminval = dmaxval = 0;
     else if( depth == CV_32F )

modules/core/test/test_arithm.cpp

@@ -1792,3 +1792,21 @@ INSTANTIATE_TEST_CASE_P(Arithm, SubtractOutputMatNotEmpty, testing::Combine(
     testing::Values(perf::MatType(CV_8UC1), CV_8UC3, CV_8UC4, CV_16SC1, CV_16SC3),
     testing::Values(-1, CV_16S, CV_32S, CV_32F),
     testing::Bool()));
+
+TEST(MinMaxLoc, Mat_IntMax_Without_Mask)
+{
+    Mat_<int> mat(50, 50);
+    int iMaxVal = numeric_limits<int>::max();
+    mat.setTo(iMaxVal);
+
+    double min, max;
+    Point minLoc, maxLoc;
+
+    minMaxLoc(mat, &min, &max, &minLoc, &maxLoc, Mat());
+
+    ASSERT_EQ(iMaxVal, min);
+    ASSERT_EQ(iMaxVal, max);
+
+    ASSERT_EQ(Point(0, 0), minLoc);
+    ASSERT_EQ(Point(0, 0), maxLoc);
+}

modules/ts/src/ts_func.cpp

@@ -977,12 +977,12 @@ minMaxLoc_(const _Tp* src, size_t total, size_t startidx,
         for( size_t i = 0; i < total; i++ )
         {
             _Tp val = src[i];
-            if( minval > val )
+            if( minval > val || !minpos )
             {
                 minval = val;
                 minpos = startidx + i;
             }
-            if( maxval < val )
+            if( maxval < val || !maxpos )
             {
                 maxval = val;
                 maxpos = startidx + i;
@@ -994,12 +994,12 @@ minMaxLoc_(const _Tp* src, size_t total, size_t startidx,
         for( size_t i = 0; i < total; i++ )
         {
             _Tp val = src[i];
-            if( minval > val && mask[i] )
+            if( (minval > val || !minpos) && mask[i] )
             {
                 minval = val;
                 minpos = startidx + i;
             }
-            if( maxval < val && mask[i] )
+            if( (maxval < val || !maxpos) && mask[i] )
             {
                 maxval = val;
                 maxpos = startidx + i;
@@ -1046,8 +1046,8 @@ void minMaxLoc(const Mat& src, double* _minval, double* _maxval,
     size_t startidx = 1, total = planes[0].total();
     size_t i, nplanes = it.nplanes;
     int depth = src.depth();
-    double maxval = depth < CV_32F ? INT_MIN : depth == CV_32F ? -FLT_MAX : -DBL_MAX;
-    double minval = depth < CV_32F ? INT_MAX : depth == CV_32F ? FLT_MAX : DBL_MAX;
+    double minval = 0;
+    double maxval = 0;
     size_t maxidx = 0, minidx = 0;
 
     for( i = 0; i < nplanes; i++, ++it, startidx += total )
@@ -1090,9 +1090,6 @@ void minMaxLoc(const Mat& src, double* _minval, double* _maxval,
         }
     }
 
-    if( minidx == 0 )
-        minval = maxval = 0;
-
     if( _maxval )
         *_maxval = maxval;
     if( _minval )