Mechatronic components in apple sorting machines with computer vision

A mechatronic system is a special application of mechanical engineering with a more focus on automation using emerging technologies such as computer sciences, electronics, and control instead of entirely mechanical elements. In recent years, mechatronics plays an important role in automated food industry. Apple is one of horticultural products that contain valuable nutrient. External appearance of apple is one of the important factors affecting the market price and customer satisfaction. By now, various machines have been developed for automated sorting of fruit and vegetables but still major grading and sorting operations are manually preformed in the packing houses. Computer vision provides an automated, non-destructive, cost-effective and objective technique to satisfy these needs. In this study, various components of the computer vision inspection systems for quality evaluation of apple are reviewed. Recently, infrared (IR) imaging, multispectral imaging (MSI) and hyperspectral imaging (HSI) systems are also being used as advanced techniques, which could acquire high quality spatial and spectral information for online quality and safety inspection of agricultural products. Therefore, the current article includes various research conducted in these domains as well. Finally, different pattern recognition techniques for apple defect detection and the stem-calyx region identification are discussed.