OpenCV Computer Vision with Java

Pixel manipulation

Pixel manipulation is often required for one to access pixels in an image. There are several ways to do this and each one has its advantages and disadvantages. A straightforward method to do this is the put(row, col, value) method. For instance, in order to fill our preceding matrix with values {1, 2, 3}, we will use the following code:

for(int i=0;i<image.rows();i++){
  for(int j=0;j<image.cols();j++){ 
    image.put(i, j, new byte[]{1,2,3});
  }
}

Tip

Note that in the array of bytes {1, 2, 3}, for our matrix, 1 stands for the blue channel, 2 for the green, and 3 for the red channel, as OpenCV stores its matrix internally in the BGR (blue, green, and red) format.

It is okay to access pixels this way for small matrices. The only problem ...