Assessment of Internal and External Quality of Fruits and Vegetables

In this chapter, advances in the most important imaging techniques that can be applied to fruit and vegetable inspection are addressed. The review begins with the external inspection, dominated by the use of computer vision, which analyses morphological features and surface attributes. Then, inspection goes through the pericarp and reaches the closest inner layers by the application of hyperspectral imaging, which provides complementary information by analysing both external and internal attributes. At this location, the microscale inspection is achieved by optical coherence tomography, which performs high resolution imaging of the microstructure. Two techniques are finally reviewed as being capable of evaluating the most internal regions, providing cross-sectional images of the complete sample at both macro- and microscale. X-ray imaging is based on the contrast arising from the differences in the atomic number, density and thickness of the internal structures and tissues, revealing morphological and structural aspects. For the magnetic resonance imaging, the image contrast can be weighted in several resonance parameters, which broadens the field of applications. Therefore, in addition to morphological and structural features, the chemical composition and tissue characteristics of different nature can be studied.