docs: public static void RGB_to_PLU8(Picture input, Planar<GrayU8> output) {
  		if( input.getColor() != ColorSpace.RGB )
  			throw new RuntimeException("Unexpected input color space!");
  		if( output.getNumBands() != 3 )
  			throw new RuntimeException("Unexpected number of bands in output image!");
  
  		output.reshape(input.getWidth(),input.getHeight());
  
  		int dataIn[] = input.getData()[0];
  
  		GrayU8 out0 = output.getBand(0);
  		GrayU8 out1 = output.getBand(1);
  		GrayU8 out2 = output.getBand(2);
  
  		int indexIn = 0;
  		int indexOut = 0;
  		for (int i = 0; i < output.height; i++) {
  			for (int j = 0; j < output.width; j++, indexOut++ ) {
  				int r = dataIn[indexIn++];
  				int g = dataIn[indexIn++];
  				int b = dataIn[indexIn++];
  
  				out2.data[indexOut] = (byte)r;
  				out1.data[indexOut] = (byte)g;
  				out0.data[indexOut] = (byte)b;
  			}
  		}
  	}