How to change the contrast and brightness of an image stored as pixel values

Question

I have an image that is stored as an array of pixel values. I want to be able to apply a brightness or contrast filter to this image. Is there any simple way, or algorithm,

Answer 1

My suggestion would be to use the built-in methods of Java to adjust the brightness and contrast, rather than trying to adjust the pixel values yourself. It seems pretty easy by doing something like this...

float brightenFactor = 1.2f

PlanarImage img=JAI.create("fileload","C:\\aimages\\blue_water.jpg");
BufferedImage image = img.getAsBufferedImage();

RescaleOp op = new RescaleOp(brightenFactor, 0, null);
image = op.filter(image, image);

The float number is a percentage of the brightness. In my example it would increase the brightness to 120% of the existing value (ie. 20% brighter than the original image)

See this link for a similar question... Adjust brightness and contrast of BufferedImage in Java

See this link for an example application... http://www.java2s.com/Code/Java/Advanced-Graphics/BrightnessIncreaseDemo.htm