Counting Regions of Interest in a Picture

Question

I need to count the number of strips (as labeled) in the following photo:

I have hundreds of photos that I need to analyze and I am curious if there is a way to automatically isolate the regions of interest and perform a simple count for each photo. I have little experience with image analysis and any advice to get me started would be greatly appreciated.

Answer 1

Please run the below code i have worked for you. Its approx close enough and tune it. Good Luck..!

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
#include "tchar.h"
using namespace cv;
using namespace std;

#define INPUT_FILE              "u.jpg"
#define OUTPUT_FOLDER_PATH      string("")

int _tmain(int argc, _TCHAR* argv[])
{
    Mat large = imread(INPUT_FILE);
    Mat rgb;
    // downsample and use it for processing
    pyrDown(large, rgb);
    Mat small;
    cvtColor(rgb, small, CV_BGR2GRAY);
    // morphological gradient
    Mat grad;
    Mat morphKernel = getStructuringElement(MORPH_ELLIPSE, Size(2, 2));
    Mat morphKernel1 = getStructuringElement(MORPH_ELLIPSE, Size(1, 1));
    morphologyEx(small, grad, MORPH_GRADIENT, morphKernel);
    // binarize
    Mat bw;
    threshold(grad, bw, 5.0, 50.0, THRESH_BINARY | THRESH_OTSU);
    // connect horizontally oriented regions
    Mat connected;
    morphKernel = getStructuringElement(MORPH_RECT, Size(5, 1));
    morphologyEx(bw, connected, MORPH_CLOSE, morphKernel);
    morphologyEx(bw, connected, MORPH_OPEN, morphKernel1);
    // find contours
    Mat mask = Mat::zeros(bw.size(), CV_8UC1);
    vector<vector<Point>> contours;
    vector<Vec4i> hierarchy;
    findContours(connected, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE, Point(0, 0));
    // filter contours
    int y=0;
    for(int idx = 0; idx >= 0; idx = hierarchy[idx][0])
    {
        Rect rect = boundingRect(contours[idx]);
        Mat maskROI(mask, rect);
        maskROI = Scalar(0, 0, 0);
        // fill the contour
        drawContours(mask, contours, idx, Scalar(255, 255, 255), CV_FILLED);

        double a=contourArea( contours[idx],false);

            if(a> 75)

        {
            rectangle(rgb, rect, Scalar(0, 255, 0), 2);
            y++;
        }
        imshow("Result1",rgb);
    }
    cout<<" The number of elements"<<y<< endl; 
    imshow("Result",mask);
    imwrite(OUTPUT_FOLDER_PATH + string("rgb.jpg"), rgb);
    waitKey(0);
    return 0;
}