samples: use findFile() in "cpp"

samples/cpp/detect_blob.cpp

@@ -14,7 +14,7 @@ static void help()
 {
     cout << "\n This program demonstrates how to use BLOB to detect and filter region \n"
         "Usage: \n"
-        "  ./detect_blob <image1(../data/detect_blob.png as default)>\n"
+        "  ./detect_blob <image1(detect_blob.png as default)>\n"
         "Press a key when image window is active to change descriptor";
 }
 
@@ -70,20 +70,19 @@ static String Legende(SimpleBlobDetector::Params &pAct)
 
 int main(int argc, char *argv[])
 {
-    vector<String> fileName;
-    Mat img(600, 800, CV_8UC1);
-    cv::CommandLineParser parser(argc, argv, "{@input |../data/detect_blob.png| }{h help | | }");
+    String fileName;
+    cv::CommandLineParser parser(argc, argv, "{@input |detect_blob.png| }{h help | | }");
     if (parser.has("h"))
     {
         help();
         return 0;
     }
-    fileName.push_back(parser.get<string>("@input"));
-    img = imread(fileName[0], IMREAD_COLOR);
-    if (img.rows*img.cols <= 0)
+    fileName = parser.get<string>("@input");
+    Mat img = imread(samples::findFile(fileName), IMREAD_COLOR);
+    if (img.empty())
     {
-        cout << "Image " << fileName[0] << " is empty or cannot be found\n";
-        return(0);
+        cout << "Image " << fileName << " is empty or cannot be found\n";
+        return 1;
     }
 
     SimpleBlobDetector::Params pDefaultBLOB;
@@ -116,14 +115,17 @@ int main(int argc, char *argv[])
     vector< Vec3b >  palette;
     for (int i = 0; i<65536; i++)
     {
-        palette.push_back(Vec3b((uchar)rand(), (uchar)rand(), (uchar)rand()));
+        uchar c1 = (uchar)rand();
+        uchar c2 = (uchar)rand();
+        uchar c3 = (uchar)rand();
+        palette.push_back(Vec3b(c1, c2, c3));
     }
     help();
 
 
     // These descriptors are going to be detecting and computing BLOBS with 6 different params
     // Param for first BLOB detector we want all
-    typeDesc.push_back("BLOB");    // see http://docs.opencv.org/trunk/d0/d7a/classcv_1_1SimpleBlobDetector.html
+    typeDesc.push_back("BLOB");    // see http://docs.opencv.org/3.4/d0/d7a/classcv_1_1SimpleBlobDetector.html
     pBLOB.push_back(pDefaultBLOB);
     pBLOB.back().filterByArea = true;
     pBLOB.back().minArea = 1;
@@ -150,7 +152,7 @@ int main(int argc, char *argv[])
     pBLOB.back().filterByConvexity = true;
     pBLOB.back().minConvexity = 0.;
     pBLOB.back().maxConvexity = (float)0.9;
-    // Param for six BLOB detector we want blob with gravity center color equal to 0 bug #4321 must be fixed
+    // Param for six BLOB detector we want blob with gravity center color equal to 0
     typeDesc.push_back("BLOB");
     pBLOB.push_back(pDefaultBLOB);
     pBLOB.back().filterByColor = true;