本研究已研製成功一部選別柑橘類水果顏色、大小之光電選別機。整套選別系統包括五個由微處理機控制之進料、大小偵測、顏色偵測、出料、主控等模組化子系統。大小選別是計數水果通過偵測處所遮擋的LED(發光二極体)點數,以此作為該水果之投影面積値,並以「及閘」邏輯電路及發光二極体掃描程序成功地克服光線散射之問題。顏色選別則以880及650 nm波長之光源照射於行進中的水果表皮,分別取樣100點的平均反射率,組合成IVRF型顏色指標(R880-R650)/R880,顏色等級之區分即由此決定。並列式出料原理提供了不受選別速度影響之並列式選別訊號管理模式。本研究以檸檬為試驗樣品,其大小選別、顏色選別、大小及顏色綜合選別之平均選別精度各為94.7%,95.3%,及91.6%,選別速度為每分鐘每條線24至48個水果。
An electro-optical sorter was developed for color and size sorting of citrus fruits. The system includes five microprocessor controlled systems: feeding, size detection, color detection, discharging and master control. The grading of size is accomplished by detecting the number of LED light beams blocked by the projected area of fruit, in which an AND gate logical circuit and LED scanning algorithm were designed to successfully avoid the light diffusion problem. The color grading is conducted by using the dual wavelength IVRF quality index, (R880-R650)/R880, at light wavelengths of 880 and 650 nm. The parallel discharging algorithm provides a parallel management of grading signals, and is independent of sorting speeds. Lemons were used for experiments, the averaged accuracy in size sorting, color sorting and combined sorting is 94.7%, 95.3% and 91.6% respectively with the sorting capacity of 24 to 48 fruits per minute per line.