白と暗いピクセルの境界に存在する境界点を見つけることを提案します。その後、それらのポイントをデジタル化できます。DELTAそのためには、スキップするポイントと結果リストに追加するポイントを定義する必要があります。
DELTA = 3, Number of points = 223
DELTA = 5, Number of points = 136
DELTA = 10, Number of points = 70
以下に、画像を印刷してポイントを探すソースコードを示します。これを読んで、問題を解決する方法を見つけていただければ幸いです。
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Program {
public static void main(String[] args) throws IOException {
BufferedImage image = ImageIO.read(new File("/home/michal/Desktop/FkXG1.png"));
PathFinder pathFinder = new PathFinder(10);
List<Point> borderPoints = pathFinder.findBorderPoints(image);
System.out.println(Arrays.toString(borderPoints.toArray()));
System.out.println(borderPoints.size());
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new ImageBorderPanel(image, borderPoints));
frame.pack();
frame.setMinimumSize(new Dimension(image.getWidth(), image.getHeight()));
frame.setVisible(true);
}
}
class PathFinder {
private int maxDelta = 3;
public PathFinder(int delta) {
this.maxDelta = delta;
}
public List<Point> findBorderPoints(BufferedImage image) {
int width = image.getWidth();
int[][] imageInBytes = convertTo2DWithoutUsingGetRGB(image);
int[] borderPoints = findBorderPoints(width, imageInBytes);
List<Integer> indexes = dwindlePoints(width, borderPoints);
List<Point> points = new ArrayList<Point>(indexes.size());
for (Integer index : indexes) {
points.add(new Point(index, borderPoints[index]));
}
return points;
}
private List<Integer> dwindlePoints(int width, int[] borderPoints) {
List<Integer> indexes = new ArrayList<Integer>(width);
indexes.add(borderPoints[0]);
int delta = 0;
for (int index = 1; index < width; index++) {
delta += Math.abs(borderPoints[index - 1] - borderPoints[index]);
if (delta >= maxDelta) {
indexes.add(index);
delta = 0;
}
}
return indexes;
}
private int[] findBorderPoints(int width, int[][] imageInBytes) {
int[] borderPoints = new int[width];
int black = Color.BLACK.getRGB();
for (int y = 0; y < imageInBytes.length; y++) {
int maxX = imageInBytes[y].length;
for (int x = 0; x < maxX; x++) {
int color = imageInBytes[y][x];
if (color == black && borderPoints[x] == 0) {
borderPoints[x] = y;
}
}
}
return borderPoints;
}
private int[][] convertTo2DWithoutUsingGetRGB(BufferedImage image) {
final byte[] pixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
final int width = image.getWidth();
final int height = image.getHeight();
final boolean hasAlphaChannel = image.getAlphaRaster() != null;
int[][] result = new int[height][width];
if (hasAlphaChannel) {
final int pixelLength = 4;
for (int pixel = 0, row = 0, col = 0; pixel < pixels.length; pixel += pixelLength) {
int argb = 0;
argb += (((int) pixels[pixel] & 0xff) << 24); // alpha
argb += ((int) pixels[pixel + 1] & 0xff); // blue
argb += (((int) pixels[pixel + 2] & 0xff) << 8); // green
argb += (((int) pixels[pixel + 3] & 0xff) << 16); // red
result[row][col] = argb;
col++;
if (col == width) {
col = 0;
row++;
}
}
} else {
final int pixelLength = 3;
for (int pixel = 0, row = 0, col = 0; pixel < pixels.length; pixel += pixelLength) {
int argb = 0;
argb += -16777216; // 255 alpha
argb += ((int) pixels[pixel] & 0xff); // blue
argb += (((int) pixels[pixel + 1] & 0xff) << 8); // green
argb += (((int) pixels[pixel + 2] & 0xff) << 16); // red
result[row][col] = argb;
col++;
if (col == width) {
col = 0;
row++;
}
}
}
return result;
}
}
class ImageBorderPanel extends JPanel {
private static final long serialVersionUID = 1L;
private BufferedImage image;
private List<Point> borderPoints;
public ImageBorderPanel(BufferedImage image, List<Point> borderPoints) {
this.image = image;
this.borderPoints = borderPoints;
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, null);
Graphics2D graphics2d = (Graphics2D) g;
g.setColor(Color.YELLOW);
for (Point point : borderPoints) {
graphics2d.fillRect(point.x, point.y, 3, 3);
}
}
}
私のソースコードでは、この質問の例を使用しました:
