摘要 |
Method and apparatus for grading articles, particularly lemons, according to their surface color. The apparatus measures each lemon's reflectance in infrared, red and green wavelength bands, and computes the ratio of the red and infrared measurements and the ratio of the red and green measurements. If the red/infrared ratio is less than a prescribed crossover threshold, the apparatus compares the red/infrared ratio to a first set of thresholds, to grade the lemon into either a very dark green, dark green or light green color grade. Conversely, if the red/infrared color ratio is greater than the crossover threshold, the apparatus compares the red/green ratio to a second set of thresholds, to grade the lemon into either a silver, tree-ripe or bronzy color grade.
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