tailieunhanh - Báo cáo hóa học: " Virtually Lossless Compression of Astrophysical Images Cinzia Lastri"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Virtually Lossless Compression of Astrophysical Images Cinzia Lastri | EURASIP Journal on Applied Signal Processing 2005 15 2521-2535 2005 Cinzia Lastri et al. Virtually Lossless Compression of Astrophysical Images Cinzia Lastri Institute of Applied Physics Nello Carrara Italian National Research Council IFAC-CNR 64 via Panciatichi 50127 Florence Italy Email Bruno Aiazzi Institute of Applied Physics Nello Carrara Italian National Research Council IFAC-CNR 64 via Panciatichi 50127 Florence Italy Email Luciano Alparone Department of Electronics and Telecommunications DET University of Florence 3 via di Santa Marta 50139 Florence Italy Email alparone@ Stefano Baronti Institute of Applied Physics Nello Carrara Italian National Research Council IFAC-CNR 64 via Panciatichi 50127 Florence Italy Email Received 10 June 2004 Revised 31 January 2005 We describe an image compression strategy potentially capable of preserving the scientific quality of astrophysical data simultaneously allowing a consistent bandwidth reduction to be achieved. Unlike strictly lossless techniques by which moderate compression ratios are attainable and conventional lossy techniques in which the mean square error of the decoded data is globally controlled by users near-lossless methods are capable of locally constraining the maximum absolute error based on user s requirements. An advanced lossless near-lossless differential pulse code modulation DPCM scheme recently introduced by the authors and relying on a causal spatial prediction is adjusted to the specific characteristics of astrophysical image data high radiometric resolution generally low noise etc. . The background noise is preliminarily estimated to drive the quantization stage for high quality which is the primary concern in most of astrophysical applications. Extensive experimental results of lossless near-lossless and lossy compression of astrophysical images acquired by the Hubble space telescope show the advantages of the .