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Re: Mapping image into a polar-square coordinate [message #61184 is a reply to message #61183]

Wed, 09 July 2008 12:01

Camilo Mejia
Messages: 4
Registered: July 2008

Junior Member

On Jul 9, 7:47 am, pgri...@gmail.com wrote:
> 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

yeah, but i dont know how to extract a rectangular matrix which rows
are radius and columns are angles

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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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