Computer-Vision-Based Fruit Grading System Increases Throughput 6-Fold

Published on November 2, 2023 by TIS Marketing.

Traditionally, orchard owners have relied on manual labor for the grading and sorting of citrus fruit. The task is labor-intensive and tedious for humans which results in mistakes and reduced throughput. When faced with this problem, an orchard owner with a rapidly growing business in Kaohsiung, Taiwan partnered with Hitspectra, an intelligent inspection and vision system integrator. Hitspectra helped the citrus grower rapidly increase inspection and sorting efficiency with an innovative computer-vision-based inspection system. Using software that they developed in-house, Hitspectra integrated The Imaging Source's 5 MP USB 3 cameras into the orchard's existing sorting system to create a robust inspection and grading system that has increased overall efficiency by 6-fold.

Grading and sorting lemons: Hitspectra's integration of a computer-vision-based inspection and sorting system has rapidly increased efficiency and accuracy for an orchard operator in Taiwan.

Deep Learning Approach Increases Inspection Scope

Early automated fruit sorting used rule-based inspection to grade, for example, fruit color and size. Deep learning methodologies have developed to enable vision solutions for applications whose inspection criteria are not readily quantified or defined, allowing for a wider range of important inspection and sorting criteria: blemishes, rot, mold, and other defects. Hitspectra was able to integrate the new inspection station into an existing weight screening machine at the orchard's sorting facility. The industrial color cameras capture images from multiple angels of each lemon as it proceeds along the conveyor. The image data is then segmented, fused, and analyzed against the training data for shape, size, color, and surface defects. Based on the training data, the system then sorts the lemons as "OK" or "NOK".

AI approach provides additional inspection possibilities: Image data is segmented, fused, and analyzed against the training data for shape, size, color, and surface defects.

Vision System Maximizes Throughput With Less Labor

Prior to the integration of Hitspectra's vision solution, three employees processed around 400 kilograms of lemons per hour. The new system allows one employee to process 800 kilograms per hour, increasing throughput by an astounding 6-fold. The accuracy rate of the AI-based system has increased to 90% and Hitspectra expects to see additional improvements after additional updates and training data. Hitspectra's manager commented: "With the successful introduction of automated visual inspection [in agricultural applications], manual labor can be reduced, and the inspection screening criteria can be quantified and standardized."

The Imaging Source's 5 MP USB 3 industrial cameras are USB3 Vision compliant and are easily integrated into new and existing systems.

Enhanced Image Quality with Compact USB 3 Industrial Cameras

The Imaging Source's industrial color cameras offer HDR imaging functionality, ensuring high-quality image data for precise surface imperfection detection and critical feature grading in sorting applications. Their compact design and adherence to the USB3 Vision standard facilitate seamless integration into both new and existing systems, ensuring hassle-free setup. The 5-megapixel resolution provides the ideal amount of image data, effortlessly capturing multiple detailed images from various angles without straining the system's computational resources, thus efficiently keeping the system operating within the desired cycle time.