I think you would have to create a PixelGrabber which returns an array of ints made from the image. Once you have that, I think you could use this method to convert the ints to binary:
Integer.toBinaryString(int);
Here is an example of a Pixel Grabber that creates a screen shot and throws it into an array of ints.
private int[] capture() throws InterruptedException {
dim = Toolkit.getDefaultToolkit().getScreenSize();
Image tmp = robot.createScreenCapture(new Rectangle(dim.width,dim.height)).getScaledInstance(800,600,BufferedImage.SCALE_SMOOTH);
int pix[] = new int[IMG_WIDTH*IMG_HEIGHT];
PixelGrabber pg = new PixelGrabber(tmp,0,0,IMG_WIDTH,IMG_HEIGHT,pix,0,IMG_WIDTH);
pg.grabPixels();
return pix;
}