Informatika (Mar 2018)
ADAPTIVE COMPRESSING OF THE HIGH DYNAMIC RANGE OF DIGITAL RADAR SATELLITE IMAGES
Abstract
Transformation of a digital radar image with a wide dynamic range of luminance values (up to 216 tones) for visualization on a standard monitor is considered. The monitor has 28 gray value range or any of three basic colors in the RGB system. Linear quantization of the luminance values of the original image generates a nearly black image with small light blobs, since most of the original values are less than 255–512 and are reduced by 256 times. To solve the problem, it is proposed to use a nonlinear logarithmic transformation with a parameter calculated from the original images. On real data received from the TerraSAR-X satellite in the geoTIFF format, comparative studies with other compression algorithms for a wide dynamic range of image brightness are performed. It is shown that the proposed solution allows creating a visually better image in comparison with the known algorithms.
