Abstract:It is challenging to identify the features of subsurface fresh bruises of fruits and vegetables by traditional uniform imaging techniques due to the mild symptoms. Owing to the capability of depth-varying and signal-enhanced characterization, spatial-frequency domain imaging was used to detect the fresh bruising (within 30 minutes) of 10 kinds of fruits and vegetables (carrot, Fuji apple, cucumber, golden delicious apple, fruit cucumber, delicious apple, mango, yellow peach, rose plum, and honey peach). Through the procedures of image acquisition, image demodulation, whiteboard correction and inverse estimation, optical properties of the fruits and vegetables were obtained. The results indicated that there were great differences of optical properties between non-bruised and bruised samples, with decreased values of reduced scattering coefficients for the bruised ones, which visually realized the non-destructive detection of early bruising. The novel method proposed in this paper is promising for non-destructive detection of early bruising of fruits and vegetables.