[Imgcif-l] High speed image compression

[Justin Anderson]

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 at 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 at rayonix.com
>> 1880 Oak Ave. #120
>> Evanston, IL, USA 60201
>> PH:+1.847.869.1548
>> FX:+1.847.869.1587
>>
>>
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>>
>
>