Bitmap alteredBitmap = Bitmap.createBitmap(bmp.getWidth(), bmp
.getHeight(), bmp.getConfig());
Canvas canvas = new Canvas(alteredBitmap);
Paint paint = new Paint();
ColorMatrix cm = new ColorMatrix();
// Increase Contrast, Slightly Reduce Brightness
float contrast = 3;
float brightness = -5;
cm.set(new float[] { contrast, 0, 0, 0, brightness, 0,
contrast, 0, 0, brightness, 0, 0, contrast, 0,
brightness, 0, 0, 0, 1, 0 });
paint.setColorFilter(new ColorMatrixColorFilter(cm));
Matrix matrix = new Matrix();
canvas.drawBitmap(bmp, matrix, paint);