图像处理

Question

I want to change the value of the pixels in an image, for which i need to store the image as a matrix. How can i perform this job? Please guide.

Answer 1

BufferedImage image = ImageIO.read(..);
image.setRGB(x, y, rgb);

Check the documentation of BufferedImage

Answer 2

Using image.setRGB is extremely slow.

You can use Catalano Framework

Example:

FastBitmap fb = new FastBitmap(bufferedImage);

int x = fb.getRed(0,0);

//If you prefer to retrieve the matrix you can do too.
int[][][] image = new int[fb.getHeight][fb.getWidth][3];
fb.toArrayRGB(image);

Answer 3

Firstly read the image into a BufferedImage.

BufferedImage image = ImageIO.read(new File("..."));

Then create matrix like structure in the 2D array like this and set RGB:

for(int i = 0; i < image.getWidth(); i++){
   for(int j = 0; j < image.getHeight(); j++){
     image.setRGB(i, j, rgb);  
   } 
}

Answer 4

• Image is 2d representation of data (pixel info)

• 2D means x&y directions. In case of image, these directions are generally treated as rows & columns

• To change the pixel value, we have to get its location in these rows and columns

• Getting pixel location is like that class teacher addressing the unknown student with his sitting position (ex:2nd bench 3rd person)

• Like this we have to address the pixel by its rows and column location