| Re: Slow with large images... [message #16275 is a reply to message #16181] |
Fri, 09 July 1999 00:00  |
Whizziez
Messages: 1
Registered: July 1999
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Junior Member |
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If you like, and to add more memory is a problem to you, you might also
skipping image's pixels line. For example, you only use the odd / even
pixel's line number, or use every tenth, so it will be a bargain for less
available memory.
Mark Rivers <rivers@cars3.uchicago.edu> wrote in message
news:FEK0Ix.2yv@midway.uchicago.edu...
> In article <3779F9F6.B35319AE@stud.uni-bayreuth.de>, Juergen Baier
<Juergen.Baier@stud.uni-bayreuth.de> writes:
>> Hello everybody!
>>
>> Has anyone experience in efficient manipulation of large images (e.g.
>> 4500x3000 Pixels)? I slipped into having to write an application for
>> analyzing x-ray-images, where i do have to rotate them, overlay them or
>> compare intensities of different areas. I do use use lonarr() for
>> storing the data and it works, but is poorely slow. I do only have the
>> books delivered with idl, so i hope that there exists some more detailed
>> description of this chapter...
>
> I imagine your problem is not enough physical memory in the machine you
are
> using. Your images are 54MB each. When you do operations on these you
> probably need memory to store at least 2 of them. Thus, you need to have
128MB
> available to IDL. Your problem could either be physical memory or the
amount
> of virtual memory allowed to your process if you are using Unix or VMS.
>
> I routinely use IDL manipulate 3-D arrays as large as 1GB in size. As
long as
> I have 1GB of memory available IDL performs just fine on these huge
arrays,
> scaling in time just as expected from smaller arrays.
>
> ____________________________________________________________
> Mark Rivers (773) 702-2279 (office)
> CARS (773) 702-9951 (secretary)
> Univ. of Chicago (773) 702-5454 (FAX)
> 5640 S. Ellis Ave. (708) 922-0499 (home)
> Chicago, IL 60637 rivers@cars.uchicago.edu (e-mail)
>
> or:
> Argonne National Laboratory (630) 252-0422 (office)
> Building 434A (630) 252-0405 (lab)
> 9700 South Cass Avenue (630) 252-1713 (beamline)
> Argonne, IL 60439 (630) 252-0443 (FAX)
>
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