“…18 -20 The visual characteristics obtained by computer vision-based image analysis systems include colour, shine, surface roughness, bumpiness, view area and height. 20,21 The system commonly is mainly composed of the illuminant, a digital camera, digitizer and software to analysis the pictures, 22 and two processes -image acquisition and image processing -are usually carried out. Image processing is considered the most important part of a computer vision-based image analysis system with data analysis, 23,24 and it consists of three steps: (i) pre-processing (pixel pre-processing or local pre-processing) improves the quality of the image by removing noise; (ii) when performing image intermediate processing, an image is partitioned into several parts by segmentation techniques (thresholding-based segmentation, region-based segmentation, gradient-based segmentation, classification-based segmentation and so on), to acquire precise data; (iii) high-level processing builds a predictive model from those features to describe the region of interest.…”