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Originally Posted by Dennis
Hi Mike
That is one of the best Janssen images I have seen. I like the "information panel" very much although I'm not too sure of the mixed fonts. You seem to have used 3 styles and I think with fonts, less is usually better.
How do you perform the metres per pixel calcs?
Cheers
Dennis
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I'm guessing you were just asking this question out of interest, Dennis. I imagine you know what I'm about to say...
To calculate the resolution per pixel (Maths Warning! Maths Warning!) the simplest way is to apply similar triangles...
Therefore:
Pixel size (in mm)....... Distance per pixel (in kilometres)
------------------- = --------------------------------
Focal length (in mm) ..Distance to subject (in kilometres)
(Edit: oh, what a mess! So much for writing equations!)
Actually the kms and mms don't specifically matter, just as long as the sam units are used on top and bottom of the same side of the equation.
Rearranging:
Resolution (i.e. distance per pixel) = (Distance to subject) x (Pixel size) /(Focal length)
FYI in case someone didn't know.
Al.