| 摘要 |
<p>PROBLEM TO BE SOLVED: To properly and easily grade a Shiitake mushroom.SOLUTION: A grading apparatus using a computer includes: means for calculating a direction of a gradient vectorθrelating to a luminance component of a pixel to be processed from a pixel constituting a Shiitake mushroom image, to obtain a gradient direction image; means for calculating a directional difference of the gradient vector from the gradient direction image, to obtain a directional difference image; means for determining whether the directional difference is equal to or less than a predetermined threshold, to discriminate a lamella part 1 and a non-lamella part 3 from the directional difference image; and means for comparing the area of a lamella area 1A including the lamella part 1 with the area of a Shiitake mushroom image 7 detected in advance, to calculate the proportion of the lamella area on the basis of the ratio between them. A Shiitake mushroom is graded by a numeric value of the proportion of the calculated lamella area. The directional difference is formed of a difference q1 to be obtained by a difference between a direction of the gradient vectorγand a lineβcrossing a vector lineθfrom a center O of the Shiitake mushroom at each of pixel points at a predetermined angle.</p> |
