java BufferedImage - 获取灰度颜色模型图片中像素的值
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BufferedImage - getting the value of a pixel in grayscale color model picture
提问by Kajzer
I have an BufferedImagetransformed to grayscale using this code. I usually got the pixel values by BufferedImage.getRGB(i,j)and the gor each value for R, G, and B. But how do I get the value of a pixel in a grayscale image?
我BufferedImage使用此代码转换为灰度。我通常得到BufferedImage.getRGB(i,j)R、G 和 B的像素值和 gor 每个值。但是如何获得灰度图像中的像素值？
EDIT: sorry, forgot abou the conversion.
编辑：对不起，忘了转换。
static BufferedImage toGray(BufferedImage origPic) {
BufferedImage pic = new BufferedImage(origPic.getWidth(), origPic.getHeight(), BufferedImage.TYPE_BYTE_GRAY);
Graphics g = pic.getGraphics();
g.drawImage(origPic, 0, 0, null);
g.dispose();
return pic;
}
回答by Alya'a Gamal
if you have RGB image so you can get the (Red , green , blue , Gray) values like that:
如果你有 RGB 图像，那么你可以获得这样的 (Red , green , blue , Gray) 值：
BufferedImage img;//////read the image
int rgb = img.getRGB(x, y);
int r = (rgb >> 16) & 0xFF;
int g = (rgb >> 8) & 0xFF;
int b = (rgb & 0xFF);
and the gray is the average for (r , g , b), like this:
灰色是 (r , g , b) 的平均值，如下所示：
int gray = (r + g + b) / 3;
but if you convert RGB image(24bit) to gray image (8bit) :
但是如果您将 RGB 图像（24 位）转换为灰度图像（8 位）：
int gray= img.getRGB(x, y)& 0xFF;/////////will be the gray value
