A Harvesting Robot for Small Fruit in Bunches Based on 3-D Stereoscopic Vision

This paper describes the concept of a harvesting robotic system for small and delicate fruit that may grow in bunches. The main component of the robot is the vision system that, unlike traditional vision methods, is able to distinguish and locate each individual fruit in a bunch. It combines a passive and an active 3-D reconstruction technique: stereoscopic vision and structured lighting. It is composed of two stereoscopic cameras and a matrix of laser diodes, which is used to project a reticule of luminous spots when a bunch is detected in order that the stereoscopic camera system can perform a 3-D reconstruction of their position. A prototype of a harvesting robot based on it has been developed and tested with real strawberry crops in hydroponic greenhouses. Some experimental results of these tests are included.