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Help requested in eradicating FOR loops [message #57539]

Fri, 14 December 2007 08:06

dplatten
Messages: 32
Registered: December 2007

Member

Dear IDL users,

I would really appreciate some help in removing a nested FOR loop.

FOR x=0, image_width-1 DO BEGIN
FOR y=0, image_height-1 DO BEGIN
; Write the current pixel value
results[(x*mtf_region_height)+y, 1] = image[x,y]
; Calculate the distance of the current pixel from the
line defined
by the
; two points (x1, y1) and (x2, y2).
results[(x*image_height)+y, 0] = ( (y1-y2)*x + (x2-
x1)*y + (x1*y2 -
x2*y1) ) / SQRT( (x2-x1)^2 + (y2-y1)^2 )
ENDFOR
ENDFOR

'image' is a 2d image array
I want to work out the distance of each pixel from a line that is
defined by the two points (x1, y1), (x2, y2) and store this distance,
together with the pixel value in a 'results' array. The 'results'
array has the dimensions [(image_height*image_width), 2].

The above bit of code works but is a bit slow.

Any advice would be much appreciated.

Thanks,

David
Northampton, UK

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[Message index]

		Help requested in eradicating FOR loops By: dplatten on Fri, 14 December 2007 08:06
		Re: Help requested in eradicating FOR loops By: Jean H. on Wed, 19 December 2007 19:02
		Re: Help requested in eradicating FOR loops By: Kenneth Bowman on Wed, 19 December 2007 13:45
		Re: Help requested in eradicating FOR loops By: Jean H. on Wed, 19 December 2007 08:18
		Re: Help requested in eradicating FOR loops By: dplatten on Wed, 19 December 2007 07:57
		Re: Help requested in eradicating FOR loops By: Spon on Tue, 18 December 2007 05:23

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