Rolling angle measurement for carrots using computer vision and improved cyclic shift method

Abstract

This paper proposed a method to measure the rolling angle for carrots. An imaging system was designed to capture the image of the cross-section located on the root–stem junction. The outer profile curve (OPC) of the cross-section was extracted and transformed into polar coordinates with the centroid serving as the origin. And a one-to-one correspondence between its polar angle and polar radius was established. Then an improved cyclic shift method (ICSM) was proposed. The ICSM was developed based on the consistent angular spacing between any two points on OPC throughout the rolling process. This addressed the issue of low efficiency. Furthermore, the additional requirements for calculation were pointed out. Finally, an experiment was conducted to measure the rolling angle of 60 carrot samples. The results show that the proposed method exhibits high accuracy and high efficiency. It provides an effective tool for full-surface image acquisition of carrots.