Xref: utzoo comp.compression:46 sci.astro:12181 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uwm.edu!psuvax1!psuvm!wvnvm!u5f97 From: U5F97@wvnvm.wvnet.edu (Jeff Brooks) Newsgroups: comp.compression,sci.astro Subject: Re: Astronomical data compression Message-ID: <91084.134536U5F97@wvnvm.wvnet.edu> Date: 25 Mar 91 18:45:36 GMT References: <1991Mar23.013557.28151@nntp-server.caltech.edu> Organization: West Virginia Network Lines: 18 The topic of astronomical image data compression is near and dear to my heart. I did an internship at NRAO (Socorro) in 1985 looking at techniques for transmitting image data from a Cray in LA to the VLA over a low speed phone line. We looked at iterative schemes for sending the images in progressive detail based on an initial "model". The initial model could be flat sky, a fitted model from image deconvolution or maximum entropy methods, whatever. You could either transmit the image at low spatial resolution and double the spatial resolution at each step, or increase the datum resolution. We implemented the former under AIPS (Atronomical Image Processing System); there were a lot of improvements to make, but it gave a very quick look at the overall image while allowing the image to be sent eventually at up to full spatial resolution. Jeffrey A. Brooks (304) 293-5192 IBM Systems Group u5f97@wvnvm.wvnet.edu West Virginia Network for Educational Telecomputing Morgantown, West Virginia 26505