弗洛伊德-斯坦伯格抖动程序错误。java

Question

嘿，我试图创建一个程序，它使用的抖动算法生成一个抖动版本的图像。

我的程序代码如下。

但我相信，在"calculateErr“乘法的舍入和除法中，我遇到了一个错误。我用来测试的图像是这个猫--一个：Cat图像

出于某种原因，它最终看起来像这个抖动猫像

对于我所做的错事，任何解决办法都将不胜感激。

import java.awt.*;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

public class Dithering extends Canvas {
    public BufferedImage ditheredIMG = new BufferedImage(481,480,
            BufferedImage.TYPE_BYTE_GRAY);

public void paint(Graphics g) {
    BufferedImage i = null;
    try {
        i = displayImage(g);
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
    getPixels(g, i);
    g.drawImage(ditheredIMG,480,0,this);



}
public static void main(String[] args) {
    Dithering d = new Dithering();
    JFrame f =new JFrame();
    f.add(d);
    f.setSize( 960,481);
    f.setVisible(true);
}


public BufferedImage displayImage(Graphics g) throws IOException {
    final File file = new File("Cat.jpg");
    final BufferedImage i = ImageIO.read(file);
    g.drawImage(i, 0,0,this);
    return i;
}

public void getPixels(Graphics g, BufferedImage i) {
    for (int y = 1; y < i.getHeight()-1; y++){
        for (int x = 1; x < i.getWidth()-1; x++) {
            int pixelValue = i.getRGB(x, y);
            int  red   = (pixelValue & 0x00ff0000) >> 16;
            int  green = (pixelValue & 0x0000ff00) >> 8;
            int  blue  =  pixelValue & 0x000000ff;
            int newRed = quantisePixel(red);
            int newGreen = quantisePixel(green);
            int newBlue = quantisePixel(blue);
            int newPixel = (newRed << 16) | (newGreen << 8) | newBlue;

            ditheredIMG.setRGB(x+1,y, (int) (calculateErr(pixelValue, newPixel) * (7/16.0)));
            ditheredIMG.setRGB(x-1,y+1, (int) (calculateErr(pixelValue, newPixel) * (3/16.0)));
            ditheredIMG.setRGB(x,y+1, (int) (calculateErr(pixelValue, newPixel) * (5/16.0)));
            ditheredIMG.setRGB(x+1,y+1, (int) (calculateErr(pixelValue, newPixel)* (1/16.0)));
       
        }
    }
}

public int calculateErr(int oldVal, int newVal){
    return oldVal-newVal;
}

public static int quantisePixel(int val){
    if(val > 127){
        return 255;
    } else{
        return 0;
    }

}

}

Answer 1

嘿，这是更新的版本，但我不确定它是否正确工作，如果有人能告诉我，它是或不是，这将是非常感谢。我已经改变了它，所以现在它应该是正确地更新周围的像素，但是在我看来，它看起来和没有更新邻居完全一样。

import java.awt.*;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import static java.lang.Math.abs;

public class Dithering extends Canvas {
public BufferedImage ditheredIMG = new BufferedImage(481,480,
        BufferedImage.TYPE_BYTE_GRAY);

public void paint(Graphics g) {
    BufferedImage i = null;
    try {
        i = displayImage(g);
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
    getPixels(g, i);
    g.drawImage(ditheredIMG,480,0,this);



}
public static void main(String[] args) {
    Dithering d = new Dithering();
    JFrame f =new JFrame();
    f.add(d);
    f.setSize( 960,481);
    f.setVisible(true);
}


public BufferedImage displayImage(Graphics g) throws IOException {
    final File file = new File("Cat.jpg");
    final BufferedImage i = ImageIO.read(file);
    g.drawImage(i, 0,0,this);
    return i;
}

public void getPixels(Graphics g, BufferedImage i) {
    for (int y = 1; y < i.getHeight()-1; y++){
        for (int x = 1; x < i.getWidth()-1; x++) {
            int pixelValue = i.getRGB(x, y);
            int  red   = (pixelValue & 0x00ff0000) >> 16;
            int  green = (pixelValue & 0x0000ff00) >> 8;
            int  blue  =  pixelValue & 0x000000ff;
            int newRed = quantisePixel(red);
            int newGreen = quantisePixel(green);
            int newBlue = quantisePixel(blue);
            int newPixel = (newRed << 16) | (newGreen << 8) | newBlue;
            ditheredIMG.setRGB(x,y,newPixel);

            int newPixelValue = i.getRGB(x+1,y);
            ditheredIMG.setRGB(x+1,y,      (int) (newPixelValue + calculateErr(pixelValue, newPixel) * (7/16.0)));
            newPixelValue = i.getRGB(x-1,y+1);
            ditheredIMG.setRGB(x-1,y+1, (int) (newPixelValue + calculateErr(pixelValue, newPixel) * (3/16.0)));
            newPixelValue = i.getRGB(x,y+1);
            ditheredIMG.setRGB(x,y+1,      (int) (newPixelValue + calculateErr(pixelValue, newPixel) * (5/16.0)));
            newPixelValue = i.getRGB(x+1,y+1);
            ditheredIMG.setRGB(x+1,y+1, (int) (newPixelValue + calculateErr(pixelValue, newPixel)* (1/16.0)));


        }
    }
}

public int calculateErr(int oldVal, int newVal){
    return oldVal-newVal;
}

public static int quantisePixel(int val){
    if(val > 127){
        return 255;
    } else{
        return 0;
    }

}

}