comp.lang.idl-pvwave archive: archive » Cannot understand a part of the IDL routine!! pls help!!

Home » Public Forums » archive » Cannot understand a part of the IDL routine!! pls help!!

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: Cannot understand a part of the IDL routine!! pls help!! [message #71054 is a reply to message #70925]

Mon, 24 May 2010 11:26

Brian Daniel
Messages: 80
Registered: July 2009

Member

On 24 May, 08:16, Jeremy Bailin <astroco...@gmail.com> wrote:
> On May 23, 11:07 am, David Fanning <n...@dfanning.com> wrote:
>
>
>
>
>
>> bala murugan writes:
>>> The following is a part of the IDL routine for region grow. The
>>> following three lines of code is used to define the pixels that is the
>>> ROI pixels.
>>> x = FINDGEN(16*16) MOD 16 + 276
>>> y = LINDGEN(16*16) / 16 + 254
>>> roiPixels = x + y * imgDims[0]
>
>>> The question is how does it define the ROI pixels?
>>> I dont see how it does........ Somebody please help me by giving a
>>> simple and clear description.
>
>> What is happening here is the IDL is turning one-dimensional
>> image indices into two-dimensional image indices. Before
>> the advent of the function Array_Indices, we always had
>> to do this by hand. This code was obviously written in
>> those long-ago dark days.
>
>> Here is an article that explains this process in some
>> detail:
>
>> http://www.dfanning.com/tips/where_to_2d.html
>
>> Cheers,
>
>> David
>
>> --
>> David Fanning, Ph.D.
>> Fanning Software Consulting, Inc.
>> Coyote's Guide to IDL Programming:http://www.dfanning.com/
>> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
>
> Incidentally, is there an in-built routine that I've missed that does
> the reverse mapping (multi-D to 1D)? I know I've written my own and I
> suspect others have too, but it seems like there ought to be a built-
> in version.
>
> -Jeremy.- Hide quoted text -
>
> - Show quoted text -

reform does the trick. For example:
image = indgen(20,30,3)
help, image
IMAGE INT = Array[20, 30, 3]
image_vector = reform(image,20*30*3)
help, image_vector
IMAGE_VECTOR INT = Array[1800]

-Brian

Report message to a moderator

[Message index]

		Cannot understand a part of the IDL routine!! pls help!! By: bala murugan on Fri, 21 May 2010 14:33
		Re: Cannot understand a part of the IDL routine!! pls help!! By: Brian Daniel on Tue, 25 May 2010 12:16
		Re: Cannot understand a part of the IDL routine!! pls help!! By: Brian Daniel on Tue, 25 May 2010 12:13
		Re: Cannot understand a part of the IDL routine!! pls help!! By: Jeremy Bailin on Wed, 26 May 2010 05:51
		Re: Cannot understand a part of the IDL routine!! pls help!! By: Jeremy Bailin on Tue, 25 May 2010 06:23
		Re: Cannot understand a part of the IDL routine!! pls help!! By: Brian Daniel on Mon, 24 May 2010 11:26
		Re: Cannot understand a part of the IDL routine!! pls help!! By: Jeremy Bailin on Mon, 24 May 2010 05:16
		Re: Cannot understand a part of the IDL routine!! pls help!! By: David Fanning on Sun, 23 May 2010 09:07

Previous Topic:	Re: Matching data in different time resolution
Next Topic:	running an IDL .pro from outside IDL e.g. from a .bat file

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 15:17:11 PDT 2025

Total time taken to generate the page: 0.00426 seconds