Re: Re[3]: filmscanners: Film Scanners and what they see.

[Bill Ross]

        > > ...
        > >
        > > Aliasing isn't relevant to this question.
        >
        > But, er, what you just described *is* aliasing.
        >
        
        Uh no, it is not aliasing.  Not even in the slightest.   The 
        physical cell simply acts as low pass filter due to its size 
        and geometry.  Mathematically it is the 2 dimensional convolution 
        of the cell's structure with an idealised point sampler.  NONE 
        of this causes ANY aliasing to occur but the damage (in
        terms of softness) has already been done.

My attempt to tease this out:

Both phenomena depend on the use of a grid. But while aliasing
is exemplified by forcing a pixel to be all one color (a binary
sort if thing), the low pass effect has to do with diffraction 
effects, physics on order of the wavelength of light. It seems
to me that the two effects might even cancel a little if the 
diffusion provided some antialiasing.

Is this close to right?

Bill Ross