Physical properties measurements of okra fruits using image processing to predict of visual maturity index

Abstract

Okra is a vegetable widely grown in the tropics, sub-tropics and warmer areas of the temperate zones. Fruitquality plays an important role in marketability and it is mainly related to the characteristic pod length and diameter. Thiswork was intended to classify okra pods, according to their length and diameter by determining, the measure and image dimensions,to compare accuracy image measuring of dimensions, in order to quality attributes and to know harvest maturity index. The investigation on various main dimensions using to measure methods (Line and rectangle) by image processing  of okra pods revealed the following.

• The length, diameter, weight, volume, and density ranged from (2.63 to 5.50 cm), (1.43 to 2.11 cm), (2.12 to 9.72 g), (4.24 to 19.24 cm3) and (0.17 to 0.66 g/cm3), respectively of okra pods
• The relationship between the measure and image of the diameter of okra pods has a high correlation (R² = 0.9117). So, it can establish the standards for grades of Egyptian okra, according to image processing of the diameter of okra pods. Therefore, the standard grading according to image diameter as follows: The “very small” group includes okra pods less than 1.22 cm (<1.22 cm) in diameter; the “small”  group includes okra pods not less than 1.22 cm or more than 1.77 cm (1.22 to 1.77 cm); the “medium” class includes okra pods more than 1.77 cm and not ore than 2.52 cm (1.77 to 2.52 cm) in diameter; and the “large” group includes okra pods more than 2.52 cm (> 2.52 cm).
• The relationship between the measure and image of the length of okra pods has a high correlation (R² = 0.9783). So, it can establish the standards for grades of Egyptian okra, according to image processing of the length of okra pods. Therefore, the standard grading according to image length as follows: The “very small” group includes okra pods less than 2.42 cm (<2.42 cm) in length; the “small”  group includes okra pods not less than 2.42 cm or more than 4.08 cm (2.42 to 4.08 cm); the “medium” class includes okra pods more than 4.08 cm and not more than 6.10 cm (4.08 cm to 6.10 cm) in length; and the “large” group includes okra pods more than 6.10 (> 6.10 cm).
• The relationship between the measure and image of the L/D ratio of okra pods has a high correlation (R² = 0.9678).  So, it can establish the standards for grades of Egyptian okra, according to image processing of the L/D ratio of okra pods. Therefore, the standard grading according to image processing as follows: the “very small” group includes okra pods less than 1.98 (<1.98) in L/D ratio; the “small”  group includes okra pods not less than 1.98 or more than 2.28 (1.98 to 2.28); the “medium” class includes okra pods more than 2.28 and not ore than 2.55 (2.28 to 2.55) in length; and the “large” group includes okra pods more than 2.55 (> 2.55).

·    The difference percentage between color values, which measuried by line and rectangle pixel methods. The minimum values were of 9.09, 7.22 and 6.67 %, and for maximum values  were about 1.69, 2.94, and 6.67 %, and for average values were 6.89, 5.24 and 6.79 % for Red (R) and Green (G) and Blue (B) values, respectively. Therefore, According to measure of color and size of okra fruits, the measurements considering visual means as aMaturity index of okra fruits.