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Re: linear-space image converted to log-space [message #58840 is a reply to message #58839]

Sat, 23 February 2008 15:32

Vince Hradil
Messages: 574
Registered: December 1999

Senior Member

On Feb 23, 4:45 pm, jkj <ke...@vexona.com> wrote:
> Hi,
>
> I have a need to reproduce an image like this:
>
> http://diamondhead.org/linear_logspace.png
>
> beginning with data like this:
>
> http://diamondhead.org/linear_linearspace.png
>
> Using logarithmic scaling, the first image (produced by a custom
> graphics package) expands lower frequency components while contracting
> the higher frequency components. To do this in object graphics, I
> believe I will have to reconstruct the image data so that the lower
> frequency [the bottom] information is replicated according to a log
> scaling scheme.
>
> I can think of some [tortured] ways to do this but keep thinking there
> must be some sophisticated way to handle this in IDL. Any thoughts
> would be appreciated.
>
> Thanks,
> -Kevin

Is it not just image = alog10(image), with the proper use of finite()
and where() to trap errors?

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[Message index]

		Re: linear-space image converted to log-space By: jkj on Sat, 23 February 2008 20:46
		Re: linear-space image converted to log-space By: jkj on Sat, 23 February 2008 19:33
		Re: linear-space image converted to log-space By: ben.bighair on Sat, 23 February 2008 18:26
		Re: linear-space image converted to log-space By: jkj on Sat, 23 February 2008 18:04
		Re: linear-space image converted to log-space By: Vince Hradil on Sat, 23 February 2008 15:32

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