Satake Smart Sensitivity offers new possibilities for optical sorting
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by Nobuyoshi “Nick� Ikeda, Assistant Manager, Technical Division, Satake Corporation, Japan
lectric Sorting Machine Company (ESM), a Michigan based company later acquired by Satake, developed the world’s first optical sorter approximately 90 years ago. Since then, optical sorters have been used in various industries such as rice milling, flour milling, tree nuts processing, etc. Optical sorter performance has improved year on year by adopting various new technologies available. Among the technological innovations contributing to the improvement, image processing technology is a feature that has tended to be overlooked. However, the effective utilisation of information from modern optics such as higher than 2K pixel
Figure 1: Accepts and rejects signals in 1D, 2D and 3D space
Figure 2: Overlapping accepts and defects signals and sensitivity
Figure 3: Finding the optimum angle for sensitivity in the 3D space
80 | January 2020 - Milling and Grain
high-resolution cameras, IR cameras, and full-color cameras, is one of the key features directly affecting sorting performance by helping determine both good product and defects - often referred to as accepts and rejects respectively. The more information the optical sorter receives from the optics, the more the sorting parameters and criteria can be set, and as a result, the better the sorting performance it can achieve. On the other hand, it may create more confusion to the human operators to adjust or set the equipment due to multiple complex parameters. Satake Smart Sensitivity (3S) developed by Satake in 2011, is an innovative solution to the above problems and offers not only hassle-free equipment adjustment and setting but also provides better sorting performance than optical sorters with traditional image-processing technology. Normally, the adjustment of the optical sorter is done by setting a sensitivity to tell the equipment what it needs to separate. The adjustment process is like drawing a border between the information signal of the good products and the defective product, the accepts and rejects respectively. If the information signals from the camera are one or two, the signal is mapped in 2D, therefore, the operator is able to determine the best position of the sensitivity needed to remove the defects easily. However, in the current mainstream optical sorter, equipped with a full-color camera, the image obtained from the camera is represented by a combination of three types of information signals, red, green, and blue (See Figure 1). The operator has to find the most effective angle of the border in the 3D space in order to determine the best position for the sensitivity parameters. In other words, the operator needs to rotate the 3D space in which the signal group of accepts and rejects are mapped in all directions. This is an extremely difficult task compared to the traditional image processing of optical sorters in 2D space. Satake Smart Sensitivity (3S) has a function to automatically