Color Enhancement of Remote Sensing Imagery Using IHS (Intense, Hue, Saturation) Transformations and Decorrelation Stretch Methods

摘要

Two digital color image processing methods for providing color contrast stretch and improvement of visual interpretation of remote sensing imagery are presented and compared. The first methodology is based on the transformation of the image represented in RGB coordinates to perception independent IHS (intensity, hue, saturation) coordinates. In IHS space it is possible to process each component independently, therefore achieving better control over the color. Examples of such process include linear operations and hue shifts. After the color enhancement, high pass filtering operation can be performed to enhance spatial detail. The second methodology is the well known decorrelation method, where a decorrelating spectral rotation is performed, followed by a standard deviation equalization among channels and finally a rotation back to the original coordinate system. Several experiments with LANDSAT TM images were made. The results proved to be valuable and different enhancement procedures were suitable for different observations.