Yes, that could be problematic, hence I incorporated the LED in my proposal image. As we are working with standard paper, we know its color (as it appears to t

Yes, that could be problematic, hence I incorporated the LED in my proposal image. As we are working with standard paper, we know its color (as it appears to the camera in neutral light). We could have a calibration step, where the multicolored LEDs are tuned to get the right contrast and color balance. Though, I have no idea how well it will work in practice.