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Re: [Imgcif-l] High speed image compression
- To: The Crystallographic Binary File and its imgCIF application to image data <imgcif-l@iucr.org>
- Subject: Re: [Imgcif-l] High speed image compression
- From: "Herbert J. Bernstein" <yaya@bernstein-plus-sons.com>
- Date: Thu, 28 Jul 2011 21:42:31 -0400
- In-Reply-To: <4E31E452.3050905@rayonix.com>
- References: <4E31AE8C.8040405@rayonix.com><CAMkkSyn+uC4VxZpaqAhQb=ENzJYEgj+N5CCs+bPt2-JS+S_otQ@mail.gmail.com><4E31E452.3050905@rayonix.com>
Have you considered using cstdio and fwrite to write in large blocks? That should take you close to the minimum time. -- Herbert At 5:36 PM -0500 7/28/11, Justin Anderson wrote: >Thanks Nicholas. > >I only made a couple small changes to Graeme's code. 1: to load an >image from a file and write to file and 2: to pass the data vectors >by reference. The last change seems to have sped things up a little >but it's still taking 110 - 130 ms to compress which is too slow. >We are not as concerned with decompression speed as that will not >need to occur in real-time. > >I put on our FTP here: >ftp://ftp.rayonix.com/pub/del_in_30_days/byte_offset.tgz. > >Thanks, > >Justin > >On 7/28/11 2:06 PM, Nicholas Sauter wrote: >>Justin, >> >>Just some comments based on our experience...first, I haven't tried the >>compression extensively, just the decompression. But I've found Graeme's >>decompression code to be significantly faster than the CBF library, first >>because it is buffer-based instead of file-based, and also because it >>hard-codes some assumptions about data depth. >> >>I'd be happy to examine this in more detail if there is some way to share >>your code example... >> >>Nick >> >>On Thu, Jul 28, 2011 at 11:46 AM, Justin Anderson<justin@rayonix.com>wrote: >> >>>Hello all, >>> >>>I have run Graeme's byte offset code on a 4k x 4k (2 byte depth) Gaussian >>>noise image and found it to compress the image in around 150 ms (64-bit >>>RHEL, Pentium D 3.46GHz). Using CBF library with byte offset compression, I >>>find the compression takes around 125 ms. >>> >>>This will be too slow to keep up with our high speed CCD cameras. We are >>>considering parallelizing the byte offset routine by operating on each line >>>of the image individually. Note that this would mean that a given >>>compressed image would be stored differently than via the whole image >>>algorithm. >>> >>>Has anyone been thinking about this already or does anyone have any >>>thoughts? >>> >>>Regards, >>> >>>Justin >>> >>>-- >>>Justin Anderson >>>Software Engineer >>>Rayonix, LLC >>>justin@rayonix.com >>>1880 Oak Ave. #120 >>>Evanston, IL, USA 60201 >>>PH:+1.847.869.1548 >>>FX:+1.847.869.1587 >>> >>> >>>_______________________________________________ >>>imgcif-l mailing list >>>imgcif-l@iucr.org >>>http://scripts.iucr.org/mailman/listinfo/imgcif-l >>> >> >> > > >_______________________________________________ >imgcif-l mailing list >imgcif-l@iucr.org >http://scripts.iucr.org/mailman/listinfo/imgcif-l -- ===================================================== Herbert J. Bernstein, Professor of Computer Science Dowling College, Kramer Science Center, KSC 121 Idle Hour Blvd, Oakdale, NY, 11769 +1-631-244-3035 yaya@dowling.edu ===================================================== _______________________________________________ imgcif-l mailing list imgcif-l@iucr.org http://scripts.iucr.org/mailman/listinfo/imgcif-l
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- [Imgcif-l] High speed image compression (Justin Anderson)
- Re: [Imgcif-l] High speed image compression (Nicholas Sauter)
- Re: [Imgcif-l] High speed image compression (Justin Anderson)
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