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Re: Fractional Pixels Origin? [message #47549 is a reply to message #47548]

Thu, 16 February 2006 16:02

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Wayne Landsman writes:

> I'll say that the FITS convention is that [0,0] locates
> the center of the pixel. (This differs from most other
> image processing standards where [0.,0.] defines the lower
> lefthand corner.)

Then, JD Smith writes:

> FITS does indeed use [0.0,0.0]. I'd urge those of you making the
> choice for your programs to save the world confusion, and adopt the
> "natural" choice: pixels centered on [a.5,b.5].

I'm confused. :-(

I thought Wayne was saying that the center of the first
pixel was at [0,0], which would mean the pixel spanned
the distance (on my ruler) of -0.5 to 0.5. JD seems to
contradict this.

I'm not sure when (if ever) I am going to *use* fractional
pixels, but I would like to understand it. :-)

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/

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[Message index]

		Re: Fractional Pixels Origin? By: David Fanning on Thu, 16 February 2006 21:15
		Re: Fractional Pixels Origin? By: Greg Hennessy on Thu, 16 February 2006 20:20
		Re: Fractional Pixels Origin? By: David Fanning on Thu, 16 February 2006 16:02
		Re: Fractional Pixels Origin? By: JD Smith on Thu, 16 February 2006 14:48
		Re: Fractional Pixels Origin? By: rm on Thu, 16 February 2006 06:24
		Re: Fractional Pixels Origin? By: Craig Markwardt on Wed, 15 February 2006 14:28
		Re: Fractional Pixels Origin? By: Wayne Landsman on Wed, 15 February 2006 13:31
		Re: Fractional Pixels Origin? By: David Fanning on Wed, 15 February 2006 13:03
		Re: Fractional Pixels Origin? By: JD Smith on Fri, 17 February 2006 13:25
		Re: Fractional Pixels Origin? By: mmiller3 on Fri, 17 February 2006 05:36
		Re: Fractional Pixels Origin? By: Greg Hennessy on Fri, 17 February 2006 05:06
		Re: Fractional Pixels Origin? By: Wayne Landsman on Thu, 16 February 2006 23:50

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