On the Sampling Strategy for Evaluation of Spectral Spectral-Spatial Spatial Methods in Hyperspectral Image Classification
Abstract: Spectral-spatial spatial processing has been increasingly explored in remote sensing hyperspectral image classification. While extensive studies have focused on developing methods to improve the classification accuracy, experimental setting and design for method evaluation have drawn little attention. In the scope of supervised classification, we find that traditional experimental designs for spectral processing are often improperly used in the spectral spectral-spatial spatial processing context, leading to unfair or biased performance evaluation. This is especially the case when training and testing samples are random randomly ly drawn from the same image - a practice that has been commonly adopted in the experiments. Under such setting, the dependence caused by overlap between the training and testing samples may be artificially enhanced by some spatial information processing methods, ethods, such as spatial filtering and morphological operation. Such enhancement of dependence in return amplifies the classification accuracy, leading to an improper evaluation of spectral spectral-spatial spatial classification techniques. Therefore, the widely adopted pi pixel-based based random sampling strategy is not always suitable to evaluate spectral spectral-spatial spatial classification algorithms, because it is difficult to determine whether the improvement of classification accuracy is caused by incorporating spatial information into cl classifier assifier or by increasing the overlap between training and testing samples. To tackle this problem, we propose