edu.sust.cse.util.Histogram.java Source code

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Here is the source code for edu.sust.cse.util.Histogram.java

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package edu.sust.cse.util;

import java.util.ArrayList;
import java.util.Vector;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.MatOfFloat;
import org.opencv.core.MatOfInt;
import org.opencv.core.Point;
import org.opencv.core.Scalar;
import org.opencv.imgproc.Imgproc;

/**
 *
 * @author Biswajit Debnath
 */
public class Histogram {

    public static Mat getHistogram(Mat image) {

        try {
            Mat src = new Mat(image.height(), image.width(), CvType.CV_8UC2);
            Imgproc.cvtColor(image, src, Imgproc.COLOR_RGB2GRAY);
            ArrayList<Mat> bgr_planes = new ArrayList<>();
            Core.split(src, bgr_planes);

            MatOfInt histSize = new MatOfInt(256);

            final MatOfFloat histRange = new MatOfFloat(0f, 256f);

            boolean accumulate = false;

            Mat b_hist = new Mat();

            Imgproc.calcHist(bgr_planes, new MatOfInt(0), new Mat(), b_hist, histSize, histRange, accumulate);

            int hist_w = 512;
            int hist_h = 600;
            long bin_w;
            bin_w = Math.round((double) (hist_w / 256));

            Mat histImage = new Mat(hist_h, hist_w, CvType.CV_8UC1);

            Core.normalize(b_hist, b_hist, 3, histImage.rows(), Core.NORM_MINMAX);

            for (int i = 1; i < 256; i++) {

                Core.line(histImage, new Point(bin_w * (i - 1), hist_h - Math.round(b_hist.get(i - 1, 0)[0])),
                        new Point(bin_w * (i), hist_h - Math.round(Math.round(b_hist.get(i, 0)[0]))),
                        new Scalar(255, 0, 0), 2, 8, 0);

            }

            return histImage;
        } catch (Exception ex) {
            System.out.println("[HISTOGRAM][ERROR][" + ex.getMessage() + "]");
            return null;
        }
    }

}