| dc.description.abstract | An objective grading method using a Computer Vision System (CVS) for mangoes is proposed. Red
peel was selected using two types of color space values at chroma = 22 and hue angle = 52˚. Eighteen
out of 25 fully-ripened fruits were graded as “excellent,” determined by the share of red area
per fruit being in the range of 80% - 100%. In contrast, all green-mature fruits were graded as
“fair,” where the share of red area per fruit was <30%. If the threshold for the share of the red area
on the peel is set between 10% (maximal green-mature fruits) and 18% (minimal fully-ripened
fruits), automatic removal of green-mature fruits on a grading line is feasible. CVS was effective for
nondestructively assuming anthocyanin concentration. A linear relationship between the natural
logarithm of the concentration and hue angle was observed (y = −0.0542x + 7.83), with a correlation
coefficient accuracy of 0.94 and root mean square error of 1.31 mg∙kg−1. This result may be
effective for the visualization of anthocyanin distribution on mango skin. The threshold for red
peel can be in the range of 131 - 186 mg∙kg−1. This suggests that the pigment concentration is usable
as a universal threshold. This value is unaffected by conditions for image acquisition or color
measurement (e.g., light source, sensor, filter, and optical geometry), unlike color space values as
hue angle. | en_US |
