Re: Viewing angle

[T3D <jeremy.hinton@xxxxxxxxx>]

     John B asks 'Where'd the +1 come from?' 
     in:
        > (linear resolution proportional to (theta+1)^-1)
     
 Maybe it could be described as a curve fit... it is part of a 
 computational formula I use, where the '+1' basically stops the 
 function from heading for infinity where theta (visual angle from 
 fovea) is zero. So it doesnt have to be 1, but it has to be soemthing 
 if your program is going to be well-behaved!.
 
 With the right constants, the curve fits fairly well to Osterbergs 
 1935 cone receptor count data. (more recently replicated by Curcio et 
 al)... but I cant remember the constants without looking it up.
 
 Cheers
 
 Jeremy.


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