Comparison of multispectral indexes extracted from hyperspectral images for the assessment of fruit ripening

• Published in: Journal of food engineering Vol. 104; no. 4; pp. 612 - 620
• Main Authors: Lleó, L., Roger, J.M., Herrero-Langreo, A., Diezma-Iglesias, B., Barreiro, P.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-06-2011; [New York, NY]: Elsevier Science Pub. Co; Elsevier
• Subjects: Artificial vision; Biological and medical sciences; Convexity; Environmental Sciences; Evolution; Food engineering; Food industries; Fruit and vegetable industries; Fruits; Fundamental and applied biological sciences. Psychology; General aspects; Hyperspectral imaging; Non-destructive assessment; Peach; Peaches; Quality; Reflectivity; Ripeness; Ripening; Vision; Wavelengths; Ripeness; Non-destructive assessment; Vision; Quality; Peach; Hyperspectral imaging; Ripening; Fruit; Extract; Index; Imagery; Comparative study
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2011.01.028

The present research is focused on the application of artificial vision to assess the ripening of red skinned soft-flesh peach (‘Richlady’). Artificial vision allows a spatially detailed determination of the ripening stage of the fruit. The considered optical indexes (Ind
1 and Ind
2, proposed in the present research, and Ind
3 and I
AD, proposed by other authors) are based on the combination of wavelengths close to the chlorophyll absorption peak at 680
nm. Ind
1 corresponds approximately to the depth of the absorption peak, and Ind
2 corresponds to the relative absorption peak. An artificial image of each index was obtained by computing the corresponding reflectance images, which were acquired with a hyperspectral camera. All indexes were able to correct convexity (except for the just-harvested peaches and for Ind
1). Ind
2 is the preferred index; it showed the highest discriminating power between ripening stages and no influence of convexity. Ind
2 also allowed the differentiation of ripening regions within the fruits, and it showed the evolution of those regions during ripening.