Implementation aspects of multistage adaptive filtering of MM-band SLAR images

• Main Authors: Tsymbal, O.V., Lukin, W., Zelensky, A.A., Astola, J.T.
• Format: Conference Proceeding
• Language: English
• Subjects: Adaptive filters; Degradation; Design methodology; Filtering; Hardware; Image processing; Image retrieval; Information retrieval; Pipelines; Radar imaging
• DOI: 10.1109/MSMW.2004.1345840

MM-band images formed by side-look aperture radars (SLARs) contain a lot of useful information concerning properties and characteristics of the sensed terrain. But they are commonly degraded by multiplicative noise. Sometimes, in case of image transferring from the imaging system carrier via communication line, impulse bursts can also take place. Thus, in order to improve useful information retrieval, the image preprocessing is required, and quite often it has to be performed in real time or, at least, rather quickly. For the considered application and noise properties, one approach to image processing can be the use of multistage procedures. At the first stage, the multiplicative noise variance can be evaluated (this stage is optional and can be skipped if statistical characteristics of noise are a priori known). Then we propose to apply the specially designed method for detection and removal of impulse bursts. Finally, the three-state texture/detail preserving hard-switching locally adaptive filtering (LAF) of pre-processed image is to be performed that serves suppression of remained multiplicative noise. The main goal of this article is to concentrate on fast hardware-software realization of the proposed multistage filtering procedure. Since we ought to provide the ability to operate in real time it is reasonable to use specialized hardware units that implement basic algorithm blocks. Thus, the pipeline architecture is the best choice for providing optimal computation load of the hardware units used for ensuring the highest overall processing speed for the proposed multistage filter. On the other side, such approaches will be also efficient in the case of multiprocessor software realization.