This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
You might start by looking at the java.awt.image package. If that won't do it for you, the Java Advanced Imaging API may have what you need (there is an on-line tutorial/book for this). You can also look at ImageJ.