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Re: Array resize with arbitrary arithmetic [message #52944 is a reply to message #52943]

Mon, 12 March 2007 14:50

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

rpertaub@gmail.com writes:

> I have this 640x240 array. I need to change it to a 320x240 array.
> However, in first array, consecutive 2 pixels hold information for 1
> pixel in second array and I need to do a certain bit of arithmetic to
> obtain that. This should not be too difficult, except I keep getting
> errors and I am not sure why:
> This is what I do:
>
> pro compress_image
>
> image=read_bmp('9 March 2007\775u.bmp') ; 640x240 array
>
> comp_image=make_array(76800,/long) ;1x76800 array that I can
> reform to 320x240array later
>
> temp=0
>
> for j=0,239 DO BEGIN
> for i=0,319 DO BEGIN
>
> comp_image[0,temp]= image[2*i,j]*256 + image[2*i+1,j] ;
> arithmetic necessary
> temp=temp+1
> endfor
>
> endfor
>
>
> end

Seems to me the way to do this might be like this:

image=read_bmp('9 March 2007\775u.bmp') ; 640x240 array
temp = Rebin(image, 2, 320, 240)
temp = Total(Temporary(temp), 1)

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.")

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[Message index]

		Re: Array resize with arbitrary arithmetic By: David Fanning on Mon, 12 March 2007 15:15
		Re: Array resize with arbitrary arithmetic By: David Fanning on Mon, 12 March 2007 14:52
		Re: Array resize with arbitrary arithmetic By: David Fanning on Mon, 12 March 2007 14:50
		Re: Array resize with arbitrary arithmetic By: Dick Jackson on Tue, 13 March 2007 20:26

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