Image-based lime size grading using the comparison ratio of the pixel radius and the actual size of lime fruit

Lime is a commercially important fruit in Thailand whose sale price depends on the fruit’s size; hence, farmers must grade limes by size before distribution. However, as lime grading machines are very expensive and each province has different limits, often performed manually, which time-consuming error-prone. Agricultural production systems for automatic selection use image processing techniques extracting key features. Therefore, this study proposes to extract features of develop analytical methods them. This method can reduce time cost, increase accuracy flexibility selecting sizes according province’s criteria. To verify our method, we classified criteria from four provinces sample data an experiment. The focal feature was radius or diameter conditions were defined maximum comparison ratio pixels measured actual centimeters. average 99.59%, outperformed that mechanical grading. 1.70 seconds per individual fruit.