An efficient shape analysis method for shrimp quality evaluation

Two grading criteria used in determining shrimp product quality and value by the shrimp industry are: 1. Presence or percentage of black spot, measured as a percentage of the total body surface. 2. Shape quality referring to whole shrimp and broken pieces. Black spots (melanoma) on the shrimp surface are evidence of aging shrimp and are considered defects that must be removed from the main production line. Shape quality is measured as the size and the completeness of the body. Broken shrimp pieces are considered a product defect and also must be removed from the main production line. Black spot detection is a simple task for a well-designed machine vision system, which provides consistent and controlled lighting. Shape analysis, on the other hand, is a challenging task because it involves contour extraction and shape analysis. In this paper, a simple, fast, and accurate shape analysis method using Turn Angle Cross-correlation is developed for shrimp quality evaluation. Our analysis results validate that the performance of the proposed shape analysis method is suitable for real-time inspection for commercial applications.