Image Processing in Java

Hi guys, I'm relatively new to java and to image processing and I'm hoping someone on here can help me with the problem I'm having.

What I've done so far is make a simple application which opens the webcam and can take and save a picture. Ive then loaded the image pixel data into a 2d array. How then do I do what is known as 'fast fourier transform' on it from here? Has anyone done anything like this before?

Thanks very much for any help

Have you tried googling for it? There are libraries available which perform FFT already (most notably, FFTW which has Java wrappers).

Yeah the tutorials assume you have the real and imaginary part of the image, whereas I just have one 2d array of the pixel values.

Also, a quick question though its somewhat off the java topic, if you wanted to get say, the face from an image and you have 2 images where the faces are different sizes, any ideas how to scale these so they are the same size for fft?

ps i am using the fft to then get the magnitude of the images so i can compare them

So why not set the imaginary parts to 0?

You can scale an image by using a BufferedImage, then using an affine transformation. See: java - How to scale a BufferedImage - Stack Overflow

Thanks for the buffered image link, but with regard the imaginary parts of the image is this not specific to the image each time? As I'm going to be comparing the images to find out who's in the picture won't the imaginary part have to be that for the image?