src/org/nutz/img/Images.java
public static BufferedImage channelImage(Object srcIm, int channel) {
        BufferedImage srcImage = read(srcIm);
        BufferedImage rcImage = new BufferedImage(srcImage.getWidth(),
                                                  srcImage.getHeight(),
                                                  srcImage.getType());
        for (int i = 0; i < srcImage.getWidth(); i++) {
            for (int j = 0; j < srcImage.getHeight(); j++) {
                int r = Colors.getRGB(srcImage, i, j)[channel];
                rcImage.setRGB(i, j, new Color(r, r, r).getRGB());
            }
        }
        return rcImage;
    }
public static BufferedImage channelImage(Object srcIm, int channel) {
        BufferedImage srcImage = read(srcIm);
        BufferedImage rcImage = new BufferedImage(srcImage.getWidth(),
                                                  srcImage.getHeight(),
                                                  srcImage.getType());
        for (int i = 0; i < srcImage.getWidth(); i++) {
            for (int j = 0; j < srcImage.getHeight(); j++) {
                int r = Colors.getRGB(srcImage, i, j)[channel];
                rcImage.setRGB(i, j, new Color(r, r, r).getRGB());
            }
        }
        return rcImage;
    }
获取三原色通道图片

@param srcIm
源图片
@param channel
通道编号，0:red 1:green 2:blue
@return 单一通道图片