I am trying to figure out which type of sensor (and which model too, I suppose) would work the bet for detecting small objects (Lego bricks) on a white colour board by an autonomous robotic arm that will be approximately 5-10 cm from the ground(tip of sensor to board). What I don't know is whether a given sensor will be able to detect the brick, and be fairly accurate about it's position.
Any help would be greatly appreciated.