我如何编写图像边缘检测算法？

Question

我现在正在编写程序，我需要将当前像素与下面的像素进行比较，并在颜色距离大于边缘距离时将当前像素颜色设置为黑色。

代码：

public void edgeDetection(int edgeDist) {
    Picture swan = new Picture("swan.jpg");
    Pixel leftPixel = null;
    Pixel rightPixel = null;
    Pixel[][] pixels = this.getPixels2D();
    Color rightColor = null;
    Color botColor = null;
    Pixel botPixel = null;
    Pixel topPixel = null;
    Color topColor = null;
    for (int row = 1; row < pixels.length; row++) {
        for (int col = 0; col < pixels[0].length - 1; col++) {
            leftPixel = pixels[row][col];
            rightPixel = pixels[row][col + 1];
            rightColor = rightPixel.getColor(); 
            for(int i = row + 1; i < pixels.length ; i++) {
                topPixel = pixels[i][col];
                botPixel = pixels[row][col];
                botColor = botPixel.getColor();
                topColor = topPixel.getColor();
                if(topPixel.colorDistance(botColor) > edgeDist) {
                    topPixel.setColor(Color.BLACK);
                }
                else
                    leftPixel.setColor(Color.WHITE);

                if (leftPixel.colorDistance(rightColor) > edgeDist) {
                    leftPixel.setColor(Color.GREEN);    

                }

                else
                    leftPixel.setColor(Color.WHITE);    


            }
        }
    }
}

Answer 1

我最终弄清楚了。我删除了多余的循环，并重新整理了一些东西，它奏效了。代码：

public void edgeDetection(int edgeDist) {
    Pixel leftPixel = null;
    Pixel rightPixel = null;
    Pixel[][] pixels = this.getPixels2D();
    Color rightColor = null;
    Color botColor = null;
    Pixel botPixel = null;
    Pixel topPixel = null;
    for (int row = 0; row < pixels.length - 1 ; row++) {
        for (int col = 0; col < pixels[0].length - 1; col++) {
            leftPixel = pixels[row][col];
            rightPixel = pixels[row][col + 1];
            rightColor = rightPixel.getColor(); 

                topPixel = pixels[row][col];
                botPixel = pixels[row + 1][col];
                botColor = botPixel.getColor();
                if (leftPixel.colorDistance(rightColor) > edgeDist) {
                    leftPixel.setColor(Color.BLACK);
                }
                else if(topPixel.colorDistance(botColor) > edgeDist) {
                    topPixel.setColor(Color.BLACK);
                }
                else
                    topPixel.setColor(Color.WHITE);

        }               
    }
}