An Improved Intensity-Hue-Saturation for A High-Resolution Image Fusion Technique Minimizing Color Distortion

International audienceAmong the existing pan-sharpening methods, the Intensity-Hue-Saturation (IHS) technique is the most widely used one for its efficiency and high spatial resolution. When the IHS method is used for IKONOS or QuickBird imagery, there is a significant color distortion, due mainly to the range of wavelengths in the panchromatic (Pan) image. Based on the fact that the grey values of Pan in the green vegetated regions are far larger than the grey values of intensity (I), we propose to adjust spatially the I image, in the vegetated area only, in order to get grey values in the same range as those of the Pan image. We use the Normalized Difference Vegetation Index (NDVI) to identify the vegetation area and enhance the green (G) band by using the red (R) and the NIR bands. We obtain an intensity image with grey values comparable to the Pan's grey values. Hence the color distortion in the fused image is reduced. Visual and statistical analyses prove that the concept of the proposed method is promising, and it significantly improves the fusion quality compared to conventional IHS techniques