How to read in a JPG image into a 3 matrices: red, green, blue?

What is 开发者_如何转开发the process to read in a JPG image into a 3 matrices (intensities): red, green, blue?

you could search for a relevant class in the java api
this might help: http://download.oracle.com/javase/6/docs/api/java/awt/image/ColorModel.html