Merge pull request #3357 from briansp2020:master

samples/cpp/stereo_match.cpp

@@ -159,7 +159,18 @@ int main(int argc, char** argv)
     Mat img1 = imread(img1_filename, color_mode);
     Mat img2 = imread(img2_filename, color_mode);
 
-    if( scale != 1.f )
+    if (img1.empty())
+    {
+        printf("Command-line parameter error: could not load the first input image file\n");
+        return -1;
+    }
+    if (img2.empty())
+    {
+        printf("Command-line parameter error: could not load the second input image file\n");
+        return -1;
+    }
+
+    if (scale != 1.f)
     {
         Mat temp1, temp2;
         int method = scale < 1 ? INTER_AREA : INTER_CUBIC;