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Re: Mapping image into a polar-square coordinate [message #61187 is a reply to message #61184]

Wed, 09 July 2008 07:47

pgrigis
Messages: 436
Registered: September 2007

Senior Member

seems like my previous post got lost...
anyway I am suggesting to use interpolation (i.e. BILINEAR)
to convert from cartesian to polar coordinates.
That should be pretty fast.

Ciao,
Paolo

cmejiapr...@gmail.com wrote:
> Hi programmers,
>
> I have an image and I want to map an annulus of it (matrix 981X 981)
> onto a rectangular axes whose columns are the angle, and the rows are
> the radius to the central pixel. I tried:
>
> ;data has the image
> xx1 = findgen(4096,10)*0.
> for i=0,1023 do begin
> roll=i*360./4096.
> SB=rot(data,-roll,1,490.5,490.5,cubic=-0.5,missing=-1,/pivot )
> xx1[i,*]=SB[50:59,490]
> for j=0,9 do xx1[i+2048,j]=SB[930-j,490]
> xx1[i+3072,*]=SB[490,50:59]
> for j=0,9 do xx1[i+1024,j]=SB[490,930-j]
> endfor
>
> But it takes too long to run, i need something faster. Any advise?
> Thanks

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[Message index]

		Re: Mapping image into a polar-square coordinate By: Camilo Mejia on Wed, 09 July 2008 13:00
		Re: Mapping image into a polar-square coordinate By: jschwab@gmail.com on Wed, 09 July 2008 12:43
		Re: Mapping image into a polar-square coordinate By: Camilo Mejia on Wed, 09 July 2008 12:01
		Re: Mapping image into a polar-square coordinate By: pgrigis on Wed, 09 July 2008 07:47
		Re: Mapping image into a polar-square coordinate By: pgrigis on Wed, 09 July 2008 06:29

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