00000nam 2200000zi 4500 9.953870 CaOODSP 20250916153120 m o d f cr |n||||||||| 250807e19941212bccad obt f000 0 eng d CaOODSP eng rda CaOODSP n-cn--- DR52-11/22-1994E-PDF Heard, Garry John, 1955- author. Block truncation compression of sonar images / Garry J. Heard. Victoria, B.C. : Defence Research Establishment Pacific = Centre de recherches pour la défense pacifique : Research and Development Branch, Department of National Defence, December 12, 1994. 1 online resource (12 pages, 10 unnumbered pages) : illustrations, chart. text txt rdacontent computer c rdamedia online resource cr rdacarrier Technical memorandum ; 94-146 Digitized edition from print [produced by Defence Research and Development Canada]. Includes bibliographical references (page 12). "This paper describes the Block Truncation Compression algorithm and applies it to the problem of storing sonar lofargram and frequency-azimuth (FRAZ) images. Four simulation test cases are presented that demonstrate the algorithm's capabilities, and two real data examples are shown that illustrate the use of the method with actual lofargram and FRAZ images. Only qualitative comparisons of the original and restored images are given, as the technique greatly changes the picture details, but maintains the original image's appearance. This compression algorithm has desirable features such as data independence, minimal computation, and fixed compress/decompress processing times that suit it ideally to real-time applications. Compression ratios of 4:1 are achieved with the basic implementation of the algorithm"--Abstract (page 1). Sonar Military applications Canada. Data compression (Computer science) Sonar Applications militaires Canada. Données--Compression (Informatique) Defence Research Establishment Pacific, issuing body. Canada. Department of National Defence. Research and Development Branch, issuing body. Technical memorandum (Defence Research Establishment Pacific) 94-146. (CaOODSP)9.936067 PDF 1.61 MB https://publications.gc.ca/collections/collection_2025/rddc-drdc/DR52-11-22-1994-eng.pdf