CLOSE RANGE PHOTOGRAMMETRY – STRUCTURED LIGHT APPROACH FOR MACHINE VISION AIDED HARVESTING

The following paper describes a novel data acquisition system for machine vision aided harvesting, which can also be used to provide data for various different applications. The system consists of two cameras and a projector. The basis for the operation is to project a pattern of structured light onto a target. By synchronous operation of the projector and the cameras, a dataset of imaged patterns can be produced. These images are formed of feature points, which can be used as input data for known photogrammetric measurement algorithms. (Luhman, 2006) As an arbitrary pattern can be projected, imaged and extracted from the background, the use of automatic feature point search is made feasible. The system is designed to work under challenging Finnish forestry conditions and is able to detect the projected pattern even in bright ambient sunlight by using spectral filtering and pulsed operation. In ideal conditions, this can be compared to using a flashlight in a dark corridor, offering the user a total control over the lighting.