Hi,
what is the maximum possible range of color sensors available in market?
A camera with a high quality tele lens and the software to analyze the frames can go a very long distance, but as with anything light and sound, the target has to be larger the farther away it is - double the distance and you need 4 times the area.
A better way to address this, is to define your needs and then look for solutions, not the (sadly very common) other way round.
So, what do you really need in terms of distance?
