A New Vegetation Enhancement/Extraction Technique for IKONOS and QuickBird Imagery

Most image fusion techniques are designed for multispectral (MS) images with natural color responses. If there is an unnatural spectral response, the fused image will be unsuitable for visualization. To enhance the vegetation content in such cases, applying the normalized difference vegetation index (NDVI) to tune the color of MS images is a feasible approach. However, the NDVI is usually used to generate lower resolution vegetation maps, and particularly, the threshold needs to be chosen manually for various scenes. In order to avert this drawback, using VI with a fixed threshold, a method is developed for IKONOS and QuickBird images in this letter, which integrates a fast technique of intensity-hue-saturation fusion. For MS images with unnatural color responses on vegetation areas, experimental results demonstrate that the proposed method can effectively enhance and extract vegetation information from the IKONOS and QuickBird images.