Detecting citrus fruits with highlight on tree based on fusion of multi-map

Artificial vision systems are powerful tools for the automatic guiding of fruit harvesting robots, a novel method based on chromatic aberration map and luminance map is developed to identify citrus fruits with highlight within a tree canopy. Twenty images of citrus-grove scene under direct sunlight are taken, the color properties of target objects are analyzed. First, parts of citrus fruits from background are segmented from background by thresholding the CAM (chromatic aberration map), then the highlight region of citrus fruits could be detected correctly from the tree canopy by thresholding the LM (luminance map), at last the citrus fruits can be detected integrally by fusing the segmented results of CAM and LM. The results showed that the fruits under direct sunlight can be segmented wholly using this algorithm, the detection accuracy by fusion method is up to 86.81%, and the false alarm rate of fusion method is 2.25%.