Abstract: In view of the limitations of traditional simple threshold algorithms under the complicated background， a ripe strawberry image segmentation algorithm based on RGB color similarity （CS\|BASED RSIS） was proposed. Firstly， ripe strawberry regions were extracted， which determined the main color of ripe strawberry. Then， the CS\|BASED RSIS algorithm traveled all pixels in the image for segmentation， calculated the color ratio and similarity of each pixel point relative to the main color， and threshold classification on color similarity were carried out. Finally， the image was processed with the multiple expansion and removing small objects and the segmentation result was output. Experimental results showed that， in three kinds of complex environment， i.e.， no adhesion and no occlusion， no adhesion and occlusion， adhesion and occlusion， the CS\|BASED RSIS algorithm not only could achieve better segmentation effect compared with the OTSU image segmentation algorithm， etc， but also could save time， its average segmentation time was only 0965 s， and the CS\|BASED RSIS algorithm could meet the real\|time requirement of ripe strawberry mechanization picking.

Key words: image segmentation, color similarity, ripe strawberry