Edge enhancement of remote sensing image data in the DCT domain

Edge enhancement is an important image processing method for remote sensing image data. Many images are compressed by JPEG standard which uses Discrete Cosine Transform (DCT). Since most coefficients in the DCT domain are small and can be quantized to zero, manipulating data in the DCT domain is an efficient way to save the computer resources. In this paper, new and fast algorithms for edge enhancement of remote sensing image data in the DCT domain are developed and implemented in three steps: high pass filtering, adding back full or part of gray levels to the original image, and contrast stretching. Experimental results show that the quality of images generated by the new algorithms are comparable with that of images generated by the corresponding methods in the spatial domain. (C) 1999 Elsevier Science B.V. All rights reserved.