Impact of Band-ratio Enhanced Awifs Image to Crop Classification Accuracy

Multispectral satellite images have been utilized in the National Agricultural Statistics Service (NASS) for crop cover classification and crop acreage estimation since the 1970's. Though ancillary data is utilized to enhance the classification accuracy, there are few applications that maximize the utilization of the feature information of the given multispectral images. Every multispectral image band directly provides the specific spectral response to a given land cover category. The different combinations of band ratios or vegetation indices enhance spectral characteristics of some crops while suppressing others. Therefore, various vegetation indices and image ratios of Landsat images have been extensively studied and applied to identify various land cover and land use characteristics in the past. However, NASS began using the ResourceSat-1 AWIFS sensor for operational crop classification and acreage estimation in 2006. The AWIFS’ bands are different from those of Landsat, and there is sparse literature published about research and applications of the spectral characteristics of AWIFS image band ratio and vegetation indices. In this paper, the impact of using band ratio and vegetation indices of the AWIFS images to the crop classification accuracy is empirically investigated via supervised classification. The classification results with respect to the additional vegetation index and band ratio are presented and compared in terms of the overall and crop only classification accuracy. The research indicates that appropriately used vegetation indices and image ratios can potentially improve crop classification accuracy though the gain may not be huge. It is concluded that further research is needed.