docs: public static BufferedImage colorizeGradient(ImageGray derivX, ImageGray derivY, double maxAbsValue,
  												 BufferedImage output){
  		if( derivX instanceof GrayS16) {
  			return colorizeGradient((GrayS16)derivX,(GrayS16)derivY,(int)maxAbsValue, output);
  		} else if( derivX instanceof GrayF32) {
  			return colorizeGradient((GrayF32)derivX,(GrayF32)derivY,(float)maxAbsValue, output);
  		} else {
  			throw new IllegalArgumentException("Image type not supported");
  		}
  	}