Example about BLOB with a new image in data folder

samples/cpp/exampleBLOB.cpp

+#include <opencv2/opencv.hpp>
+#include <vector>
+#include <map>
+#include <iostream>
+
+using namespace std;
+using namespace cv;
+
+
+static void help()
+{
+    cout << "\n This program demonstrates how to use BLOB and MSER to detect region \n"
+        "Usage: \n"
+        "  ./BLOB_MSER <image1(../data/forme2.jpg as default)>\n"
+        "Press a key when image window is active to change descriptor";
+}
+
+
+String Legende(SimpleBlobDetector::Params &pAct)
+{
+    String s = "";
+    if (pAct.filterByArea)
+    {
+        String inf = static_cast<ostringstream*>(&(ostringstream() << pAct.minArea))->str();
+        String sup = static_cast<ostringstream*>(&(ostringstream() << pAct.maxArea))->str();
+        s = " Area range [" + inf + " to  " + sup + "]";
+    }
+    if (pAct.filterByCircularity)
+    {
+        String inf = static_cast<ostringstream*>(&(ostringstream() << pAct.minCircularity))->str();
+        String sup = static_cast<ostringstream*>(&(ostringstream() << pAct.maxCircularity))->str();
+        if (s.length() == 0)
+            s = " Circularity range [" + inf + " to  " + sup + "]";
+        else
+            s += " AND Circularity range [" + inf + " to  " + sup + "]";
+    }
+    if (pAct.filterByColor)
+    {
+        String inf = static_cast<ostringstream*>(&(ostringstream() << (int)pAct.blobColor))->str();
+        if (s.length() == 0)
+            s = " Blob color " + inf;
+        else
+            s += " AND Blob color " + inf;
+    }
+    if (pAct.filterByConvexity)
+    {
+        String inf = static_cast<ostringstream*>(&(ostringstream() << pAct.minConvexity))->str();
+        String sup = static_cast<ostringstream*>(&(ostringstream() << pAct.maxConvexity))->str();
+        if (s.length() == 0)
+            s = " Convexity range[" + inf + " to  " + sup + "]";
+        else
+            s += " AND  Convexity range[" + inf + " to  " + sup + "]";
+    }
+    if (pAct.filterByInertia)
+    {
+        String inf = static_cast<ostringstream*>(&(ostringstream() << pAct.minInertiaRatio))->str();
+        String sup = static_cast<ostringstream*>(&(ostringstream() << pAct.maxInertiaRatio))->str();
+        if (s.length() == 0)
+            s = " Inertia ratio range [" + inf + " to  " + sup + "]";
+        else
+            s += " AND  Inertia ratio range [" + inf + " to  " + sup + "]";
+    }
+    return s;
+}
+
+
+
+int main(int argc, char *argv[])
+{
+    vector<String> fileName;
+    Mat img(600, 800, CV_8UC1);
+    if (argc == 1)
+    {
+        fileName.push_back("../data/example_blob.bmp");
+    }
+    else if (argc == 2)
+    {
+        fileName.push_back(argv[1]);
+    }
+    else
+    {
+        help();
+        return(0);
+    }
+    img = imread(fileName[0], IMREAD_UNCHANGED);
+    if (img.rows*img.cols <= 0)
+    {
+        cout << "Image " << fileName[0] << " is empty or cannot be found\n";
+        return(0);
+    }
+
+    SimpleBlobDetector::Params pDefaultBLOB;
+    // This is default parameters for SimpleBlobDetector
+    pDefaultBLOB.thresholdStep = 10;
+    pDefaultBLOB.minThreshold = 10;
+    pDefaultBLOB.maxThreshold = 220;
+    pDefaultBLOB.minRepeatability = 2;
+    pDefaultBLOB.minDistBetweenBlobs = 10;
+    pDefaultBLOB.filterByColor = false;
+    pDefaultBLOB.blobColor = 0;
+    pDefaultBLOB.filterByArea = false;
+    pDefaultBLOB.minArea = 25;
+    pDefaultBLOB.maxArea = 5000;
+    pDefaultBLOB.filterByCircularity = false;
+    pDefaultBLOB.minCircularity = 0.9f;
+    pDefaultBLOB.maxCircularity = std::numeric_limits<float>::max();
+    pDefaultBLOB.filterByInertia = false;
+    pDefaultBLOB.minInertiaRatio = 0.1f;
+    pDefaultBLOB.maxInertiaRatio = std::numeric_limits<float>::max();
+    pDefaultBLOB.filterByConvexity = false;
+    pDefaultBLOB.minConvexity = 0.95f;
+    pDefaultBLOB.maxConvexity = std::numeric_limits<float>::max();
+    // Descriptor array (BLOB or MSER)
+    vector<String> typeDesc;
+    // Param array for BLOB
+    vector<SimpleBlobDetector::Params> pBLOB;
+    vector<SimpleBlobDetector::Params>::iterator itBLOB;
+    // Param array for MSER
+
+    // Color palette
+    vector< Vec3b >  palette;
+    for (int i = 0; i<65536; i++)
+    {
+        palette.push_back(Vec3b((uchar)rand(), (uchar)rand(), (uchar)rand()));
+    }
+    help();
+
+    typeDesc.push_back("BLOB");
+    pBLOB.push_back(pDefaultBLOB);
+    pBLOB.back().filterByColor = true;
+    pBLOB.back().blobColor = 0;
+
+    // This descriptor are going to be detect and compute BLOBS with 5 differents 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
+    pBLOB.push_back(pDefaultBLOB);
+    pBLOB.back().filterByArea = true;
+    pBLOB.back().minArea = 1;
+    pBLOB.back().maxArea = float(img.rows*img.cols);
+    // Param for second BLOB detector we want area between 500 and 2900 pixels
+    typeDesc.push_back("BLOB");
+    pBLOB.push_back(pDefaultBLOB);
+    pBLOB.back().filterByArea = true;
+    pBLOB.back().minArea = 500;
+    pBLOB.back().maxArea = 2900;
+    // Param for third BLOB detector we want only circular object
+    typeDesc.push_back("BLOB");
+    pBLOB.push_back(pDefaultBLOB);
+    pBLOB.back().filterByCircularity = true;
+    // Param for Fourth BLOB detector we want ratio inertia
+    typeDesc.push_back("BLOB");
+    pBLOB.push_back(pDefaultBLOB);
+    pBLOB.back().filterByInertia = true;
+    pBLOB.back().minInertiaRatio = 0;
+    pBLOB.back().maxInertiaRatio = (float)0.2;
+    // Param for Fourth BLOB detector we want ratio inertia
+    typeDesc.push_back("BLOB");
+    pBLOB.push_back(pDefaultBLOB);
+    pBLOB.back().filterByConvexity = true;
+    pBLOB.back().minConvexity = 0.;
+    pBLOB.back().maxConvexity = (float)0.9;
+
+    itBLOB = pBLOB.begin();
+    vector<double> desMethCmp;
+    Ptr<Feature2D> b;
+    String label;
+    // Descriptor loop
+    vector<String>::iterator itDesc;
+    for (itDesc = typeDesc.begin(); itDesc != typeDesc.end(); itDesc++)
+    {
+        vector<KeyPoint> keyImg1;
+        if (*itDesc == "BLOB")
+        {
+            b = SimpleBlobDetector::create(*itBLOB);
+            label = Legende(*itBLOB);
+            itBLOB++;
+        }
+        try 
+        {
+            // We can detect keypoint with detect method
+            vector<KeyPoint>  keyImg;
+            vector<Rect>  zone;
+            vector<vector <Point>>  region;
+            Mat     desc, result(img.rows, img.cols, CV_8UC3);
+            if (b.dynamicCast<SimpleBlobDetector>() != NULL)
+            {
+                Ptr<SimpleBlobDetector> sbd = b.dynamicCast<SimpleBlobDetector>();
+                sbd->detect(img, keyImg, Mat());
+                drawKeypoints(img, keyImg, result);
+                int i = 0;
+                for (vector<KeyPoint>::iterator k = keyImg.begin(); k != keyImg.end(); k++, i++)
+                    circle(result, k->pt, (int)k->size, palette[i % 65536]);
+            }
+            namedWindow(*itDesc + label, WINDOW_AUTOSIZE);
+            imshow(*itDesc + label, result);
+            imshow("Original", img);
+            waitKey();
+        }
+        catch (Exception& e)
+        {
+            cout << "Feature : " << *itDesc << "\n";
+            cout << e.msg << endl;
+        }
+    }
+    return 0;
+}
+
+
+
+