Hello,
I want my program to input an image (attachment) 
and output a string like :
- Question 1: box 2 checked
- Question 2: box 1 checked
- Question 3: box 3 checked
- Question 4: box 2 checked
Etc ... (as many question as I have per image)
I can simply locate empty boxes with this program:
import java.util.ArrayList; import java.util.List; import org.opencv.core.Core; import org.opencv.core.CvType; import org.opencv.core.Mat; import org.opencv.core.MatOfPoint; import org.opencv.core.Point; import org.opencv.core.Rect; import org.opencv.core.Scalar; import org.opencv.core.Size; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc;public class test { public static void main(String[] args) { // Load the library of openCv System.loadLibrary(Core.NATIVE_LIBRARY_NAME); // Consider the image for processing Mat image = Imgcodecs.imread("C:/attachement.jpg", Imgproc.COLOR_BGR2GRAY); Mat imageHSV = new Mat(image.size(), CvType.CV_8UC4); Mat imageBlurr = new Mat(image.size(),CvType.CV_8UC4); Mat imageA = new Mat(image.size(), CvType.CV_32F); Imgproc.cvtColor(image, imageHSV, Imgproc.COLOR_BGR2GRAY); Imgproc.GaussianBlur(imageHSV, imageBlurr, new Size(5,5), 0); Imgproc.adaptiveThreshold(imageBlurr, imageA, 255,Imgproc.ADAPTIVE_THRESH_MEAN_C, Imgproc.THRESH_BINARY,7, 5); List<matofpoint> contours = new ArrayList<matofpoint>();
Imgproc.findContours(imageA, contours, new Mat(), Imgproc.RETR_LIST,Imgproc.CHAIN_APPROX_SIMPLE); for(int i=0; i< contours.size();i++) { if (Imgproc.contourArea(contours.get(i)) > 50 ) { Rect rect = Imgproc.boundingRect(contours.get(i)); if ((rect.height > 35 && rect.height < 60) && (rect.width > 35 && rect.width < 60)) { Imgproc.rectangle(image, new Point(rect.x,rect.y), new Point(rect.x+rect.width,rect.y+rect.height),new Scalar(0,0,255)); } } } Imgcodecs.imwrite("C:/Users/Benreghai/Downloads/tof/output.png",image); } }
Here is the output of my program: (image attached) 
Thank you for your help !
