Abstract
Underwater forward-looking imaging sonar (FLS) is widely used on stationary and moving platforms to overcome underwater visibility problems. The SONAR images are perturbed by a multiplicative noise called speckle, due to the coherent nature of the scattering phenomenon. Speckle reduction filters are necessary to optimize the images' exploitation procedures. The results of speckle filters may vary from one sensor and one wavelength to another; therefore, no generic de-speckling algorithm exists. Several studies have been carried out on speckle noise suppression on sidescan sonar, but the problem of speckle noise suppression for FLS has not yet been covered. A comparison of the most used classical speckle suppression filters as well as advanced wavelet-based ones was carried out. The Frost filter was found to be the most adequate for FLS data, but also the most computationally complex and not suitable for real-time processing. Two novel architectures for real-time and low-power field-programmable gate array (FPGA) implementation of the Frost speckle filter for underwater imaging sonar are presented. The proposed architectures have superior performance and power efficiency compared to standard software implementation.
Original language | English |
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Article number | 5981406 |
Pages (from-to) | 646-657 |
Number of pages | 12 |
Journal | IEEE Journal of Oceanic Engineering |
Volume | 36 |
Issue number | 4 |
DOIs | |
State | Published - 1 Oct 2011 |
Keywords
- Adaptive filters
- field-programmable gate array (FPGA)
- sonar
- speckle
ASJC Scopus subject areas
- Ocean Engineering
- Mechanical Engineering
- Electrical and Electronic Engineering