用Java在灰度图像中写入像素数据 [英] Write pixel data in a grayscale image in java

问题描述

我正在开发一个图像处理项目，在该项目中，我必须填充破裂绘画的数字化图像.我必须将彩色图像转换为灰度图像，对灰度图像的2D数组执行一些计算，然后将其写回灰度图像.的代码是:

I am developing a project on image processing where I have to fill the digitized images of cracked paintings. I have to convert a color image to grayscale, performing some calculations on the 2D Array of the gray image and writing it back as gray image. The code for this is:

BufferedImage colorImage=ImageIO.read(new File(strImagePath));

            BufferedImage image = new BufferedImage(colorImage.getWidth(),colorImage.getHeight(),BufferedImage.TYPE_BYTE_GRAY);
            Graphics g = image.getGraphics();
            g.drawImage(colorImage, 0, 0, null);
            g.dispose();

            ImageIO.write(image,"PNG",new File("Image.PNG"));

            BufferedImage imgOriginal=ImageIO.read(new File("Image.PNG"));

            int width=image.getWidth();
            int height=image.getHeight();

            BufferedImage im=new BufferedImage(width,height,BufferedImage.TYPE_BYTE_GRAY);

            int arrOriginal[][]=new int[height][width];


            for(int i=0;i<height;i++)
                for(int j=0;j<width;j++)
                    arrOriginal[i][j]=imgOriginal.getRGB(j,i)& 0xFF;

            for(int i=0;i<height;i++)
                for(int j=0;j<width;j++)
                    im.setRGB(j,i,arrOriginal[i][j]);

            ImageIO.write(im,"PNG",new File("Image1.PNG"));

但是输出的图像要暗得多，我没有找回原始图像(我还没有做任何更改).

But the output image is very much darker, I am not getting the original image back (I have not done any changes yet).

我认为setRGB()语句中应该有一些更改，但是我不知道是什么.

I think there should be some changes in setRGB() statement but I don't know what.

要写回图像，我也尝试过:

To write image back, I have also tried:

`

BufferedImage im = new BufferedImage(width,height,BufferedImage.TYPE_BYTE_GRAY);
 WritableRaster raster = im.getRaster();
 for(int i=0;i<height;i++)
     for(int j=0;j<width;j++)
         raster.setSample(j,i,0,arrOriginal[i][j]); 

`

但是它也不会给我原始图像.

But it also don't give me original image back.

任何人都可以为我提供此问题的解决方案吗? 预先感谢.

Can anyone provide me the solution of this problem? Thanks in advance.

推荐答案

我对基于Java的图像处理一无所知，但是总体上我对图像处理了解很多，所以我看看是否可以给你任何想法.如果我错了，请不要射击我-我只是在提出一个主意.

I don't know anything about Java-based image processing, but I do know quite a lot about image processing in general, so I will see if I can give you any ideas. Please don't shoot me if I am wrong - I am just suggesting an idea.

在灰度图像中，红色，绿色和蓝色值都相同，即Red = Green = Blue.因此，当您调用getRGB并使用0xff进行与"运算时，您可能只得到蓝色分量，但这没关系，因为红色和绿色是相同的-因为它是灰度的.

In a greyscale image, the red, green and blue values are all the same, i.e. Red=Green=Blue. So, when you call getRGB and do the AND with 0xff, you are probably getting the blue component only, but that is ok as the red and green are the same - because it's greyscale.

我怀疑问题在于，当您将其写回以创建新的输出图像时，您仅设置了蓝色分量，而不是红色和绿色，它们应该仍然相同.尝试写回

I suspect the problem is that when you write it back to create your new output image, you are only setting the blue component and not the red and green - which should still be the same. Try writing back

original pixel + (original pixel << 8 ) + (original pixel <<16)

这样，您不仅可以设置蓝色组件，还可以设置红色和绿色组件.

so that you set not only the Blue, but also the Red and Green components.

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