Detection of bruises on golden delicious apples using spatial-frequency-domain imaging

Spatial frequency domain imaging (SFDI), a novel non-contact optical imaging technology developed for biomedical applications, is applied to the detection of bruising on Golden Delicious apples. Quantitative absorption and scattering image maps from 650 to 980 rim are obtained for two levels of bruising severity. While not obviously distinguishable by eye, using SFDI the severity of these bruises, which have been created using a controlled impact device, are distinguishable from each other and from the surrounding non-bruised region. The average scattering and absorption spectra is calculated for the two levels of bruising and compared to the adjacent non-bruised regions. There is a considerable difference in the average reduced scattering coefficients between the bruise and non-bruised regions for the two levels of bruising from 650 to 980 nm.