Hyperspectral band selection for detecting different blueberry fruit maturity stages

• Outdoor hyperspectral images of blueberry bushes were taken and analyzed.
• Hyperspectral image was shown to be able to separate fruit stages and background.
• PWCD, HDR and NG measure were used for band selection.
• Selected bands performed well in classifying fruit stages and background.

Hyperspectral imagery divides spectrum into many bands with very narrow bandwidth. It is more capable to detect or classify objects, where visible information is not sufficient for the task. However, hyperspectral image contains a large amount of redundant information, which eliminates its discriminability. Band selection is used to both reduce the dimensionality of hyperspectral images and save useful bands for further application. This study explores the feasibility of hyperspectral imaging for the task of classifying blueberry fruit growth stages and background. Three information theory based band selection methods using Kullback–Leibler divergence: pair-wise class discriminability, hierarchical dimensionality reduction and non-Gaussianity measures were applied. Three classifiers, K-nearest neighbor, support vector machine and AdaBoost were used to test the performance of the selected bands by the three methods. The selected bands achieved classification accuracies of 88% and higher. Therefore, the band selection methods are very useful in reducing the volume of the hyperspectral data, and constructing a multispectral imaging system for detecting blueberry fruit maturity stages.