Merge pull request #26485 from gursimarsingh:fixed_edge_detection_and_segmentation_sample

Added cap.isOpened() check to edge detection and segmentation sample

samples/dnn/edge_detection.cpp

@@ -171,6 +171,11 @@ int main(int argc, char** argv) {
     else
         cap.open(0);
 
+    if (!cap.isOpened()) {
+        cerr << "Error: Video could not be opened." << endl;
+        return -1;
+    }
+
     namedWindow("Input", WINDOW_AUTOSIZE);
     namedWindow("Output", WINDOW_AUTOSIZE);
     moveWindow("Output", 200, 0);

samples/dnn/segmentation.cpp

@@ -229,6 +229,12 @@ int main(int argc, char **argv)
         cap.open(findFile(parser.get<String>("input")));
     else
         cap.open(parser.get<int>("device"));
+
+    if (!cap.isOpened()) {
+        cerr << "Error: Video could not be opened." << endl;
+        return -1;
+    }
+
     //! [Open a video file or an image file or a camera stream]
     // Process frames.
     Mat frame, blob;

samples/dnn/segmentation.py

@@ -110,6 +110,10 @@ def main(func_args=None):
     cv.namedWindow(winName, cv.WINDOW_AUTOSIZE)
 
     cap = cv.VideoCapture(cv.samples.findFile(args.input) if args.input else 0)
+    if not cap.isOpened():
+        print("Failed to open the input video")
+        exit(-1)
+
     legend = None
     while cv.waitKey(1) < 0:
         hasFrame, frame = cap.read()