| Re: Slow with large images... [message #16181] |
Thu, 08 July 1999 00:00  |
rivers
Messages: 228
Registered: March 1991
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Senior Member |
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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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| 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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