ConvexAnalyzer.java

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package theba.core.math;

import java.awt.Point;
import java.awt.Polygon;

import theba.core.ImageFunctions;

public class ConvexAnalyzer {

        public static double getSolidity(short[] data, int width, int height) {
                Polygon pout = getConvexRegion(data, width, height);

                int cnt = 0;
                int convcnt = 0;

                for (int xx = 0; xx < width; xx++) {
                        for (int yy = 0; yy < height; yy++) {
                                if (data[xx + yy * width] != 0) {
                                        cnt++;
                                }
                                if (pout.contains(xx, yy))
                                        convcnt++;
                        }
                }

                if (convcnt == 0)
                        return 0;
                return (cnt / (double) convcnt);
        }

        public static Polygon getConvexRegion(short[] data, int width, int height) {

                int counter = 0;

                int i, j, k = 0, m;

                for (j = 0; j < width; j++) {
                        for (i = 0; i < height; i++) {
                                if (data[j + i * width] != 0)
                                        counter++;
                        }
                }

                int[] x = new int[counter + 1];
                int[] y = new int[counter + 1];

                for (j = 0; j < width; j++) {
                        for (i = 0; i < height; i++) {
                                if (data[j + i * width] != 0) {
                                        x[k] = i;
                                        y[k] = j;
                                        k++;
                                }
                        }
                }

                // cnvx hull
                int n = counter, min = 0, ney = 0, h, h2, dx, dy, temp, ax, ay;
                double minangle, th, t, v, zxmi = 0;

                for (i = 1; i < n; i++) {
                        if (y[i] < y[min])
                                min = i;
                }

                temp = x[0];
                x[0] = x[min];
                x[min] = temp;
                temp = y[0];
                y[0] = y[min];
                y[min] = temp;
                min = 0;

                for (i = 1; i < n; i++) {
                        if (y[i] == y[0]) {
                                ney++;
                                if (x[i] < x[min])
                                        min = i;
                        }
                }
                temp = x[0];
                x[0] = x[min];
                x[min] = temp;
                temp = y[0];
                y[0] = y[min];
                y[min] = temp;

                min = 0;
                m = -1;
                x[n] = x[min];
                y[n] = y[min];
                if (ney > 0)
                        minangle = -1;
                else
                        minangle = 0;

                while (min != n + 0) {
                        m = m + 1;
                        temp = x[m];
                        x[m] = x[min];
                        x[min] = temp;
                        temp = y[m];
                        y[m] = y[min];
                        y[min] = temp;

                        min = n;
                        v = minangle;
                        minangle = 360.0;
                        h2 = 0;

                        for (i = m + 1; i < n + 1; i++) {
                                dx = x[i] - x[m];
                                ax = Math.abs(dx);
                                dy = y[i] - y[m];
                                ay = Math.abs(dy);

                                if (dx == 0 && dy == 0)
                                        t = 0.0;
                                else
                                        t = (double) dy / (double) (ax + ay);

                                if (dx < 0)
                                        t = 2.0 - t;
                                else {
                                        if (dy < 0)
                                                t = 4.0 + t;
                                }
                                th = t * 90.0;

                                if (th > v) {
                                        if (th < minangle) {
                                                min = i;
                                                minangle = th;
                                                h2 = dx * dx + dy * dy;
                                        } else {
                                                if (th == minangle) {
                                                        h = dx * dx + dy * dy;
                                                        if (h > h2) {
                                                                min = i;
                                                                h2 = h;
                                                        }
                                                }
                                        }
                                }
                        }

                        zxmi = zxmi + Math.sqrt(h2);
                }
                m++;

                int[] hx = new int[m];// ROI polygon array
                int[] hy = new int[m];

                for (i = 0; i < m; i++) {
                        hx[i] = x[i]; // copy to new polygon array
                        hy[i] = y[i];
                }

                // We flip x and y to avoid the coordinates being turned
                Polygon pout = new Polygon(hy, hx, hx.length); // new output

                return pout;

        }

        public static double getConvexity(short[] data, int width, int height) {
                Polygon pout = getConvexRegion(data, width, height);
                int cnt = 0;
                int convcnt = 0;

                for (int xx = 0; xx < width; xx++) {
                        for (int yy = 0; yy < height; yy++) {
                                if (data[xx + yy * width] != 0) {
                                        cnt++;
                                }
                                if (pout.contains(xx, yy))
                                        convcnt++;
                        }
                }

                Point start = null;
                for (int xx = 0; xx < width; xx++) {
                        for (int yy = 0; yy < height; yy++) {
                                if (data[xx + yy * width] != 0) {
                                        start = new Point(xx, yy);
                                        xx = width;
                                        yy = height;
                                }
                        }

                }

                for (int xx = 0; xx < width; xx++) {
                        for (int yy = 0; yy < height; yy++) {
                                if (data[xx + yy * width] != 0)
                                        data[xx + yy * width] = (short) 150;
                        }
                }

                if (start == null) {
                        System.out.println("No region found!");
                        return 0.0;
                }

                int count1 = ImageFunctions.countOutlinePixels(data, start.x, start.y, width, height, (short) 100);
                short[] data2 = new short[data.length];
                for (int xx = 0; xx < width; xx++) {
                        for (int yy = 0; yy < height; yy++) {
                                if (pout.contains(xx, yy))
                                        data2[xx + yy * width] = (short) 0x150;
                                else
                                        data2[xx + yy * width] = 0;
                        }
                }

                int count2 = ImageFunctions.countOutlinePixels(data2, start.x, start.y,
                                width, height, (short) 100);

                return (count2 / (double) count1);
                
        }

}