Java SE (Java Platform, Standard Edition)

I am developing an application in java that allow to opacify/blur an image and in a second time to remove the opacify/blur on the image in such way to obtain the original image. My problem is that I can insert opacify/blur on the image but I can�t remove the opacify/blur on the image. To opacify/blur the image I used the class �ConvolveOp�. Someone can help me please? THANKS to everybody.

This is the piece of my program that allow to blur/opacify an image:

public void blur() {
float elements []= {0, 0.2f, 0, 0.2f, 0.2f, 0.2f, 0, 0.2f, 0};
convolve(elements);
}
private void convolve(float[] elements) {
Kernel kernel = new Kernel(3, 3, elements);
ConvolveOp op = new ConvolveOp(kernel,ConvolveOp.EDGE_NO_OP,null);
filter(op);
}