Bio-photonic detection method for morphological analysis of anthracnose disease and physiological disorders of Diospyros kaki

The pathological and physiological defects in various types of fruits lead to large amounts of economical waste. It is well recognized that internal fruit defects due to pathological infections and physiological disorders can be effectively visualized at an initial stage of the disease using a well-known bio-photonic detection method called optical coherence tomography (OCT). This work investigates the use of OCT for identifying the morphological variations of anthracnose (bitter rot) disease infected and physiologically disordered Diospyros kaki (Asian Persimmon) fruits. An experiment was conducted using fruit samples that were carefully selected from persimmon orchards. Depth-resolved images with a high axial resolution were acquired using 850-nm-based spectral-domain OCT (SD-OCT) system. The obtained exemplary high-resolution two-dimensional and volumetric three-dimensional images revealed complementary morphological differences between healthy and defected samples. Moreover, the obtained depth-profile analysis results confirmed the disappearance of the healthy cell layers among the healthy-infected boundary regions. Thus, the proposed method has the potential to increase the diagnostic accuracy of the OCT technique used in agricultural plantations.