Thanks, that's what I _thought_ it meant! ;-) Visual acuity, or, the amount of visible detail in a photo would be practical terms for it. Now I have a new term to banter about. You're explanations are very good, even though complex for a novice. Have you taught mathmatics somewhere?
Don On 6/15/06, Godfrey DiGiorgi <[EMAIL PROTECTED]> wrote: > > On Jun 15, 2006, at 4:29 PM, Don Sanderson wrote: > > Godfrey that's a great explanation, I understood most of it! > > Could you simply define "spatial resolution" for me? > > Thank you for the compliment, Don. While the subject matter is rich > in details and can be quite complex to understand in implementation, > I believe that the basic concepts are not all that difficult when > explained clearly. Much less so for me than understanding the > mechanics of chemistry ... I'm a Mathematician, not a Chemist. ;-) :-) > > ... > Spatial resolution in this context is the [x,y] pixel coordinate > position of the photosites relative to the subject target that they > recorded. Larger shifts in relative pixel position usually only occur > with resampling (aka: resizing of the pixel grid for different > resolutions) because you're interpolating discrete pixel positions in > the [x,y] grid to new positions [x',y'] through some typically Real- > valued function, which causes round off error. > > JPEG compression, when set to high compression/low quality, can > create artifacts due to the way the algorithm works on [NxN] blocks > of pixels. These artifacts influence spatial resolution not so much > through intentionally moving pixels relative to one another but by > changing the tonal values to where the original pixel data altered > spatially. > > Chroma interpolation can affect spatial resolution in a similar way > but by a different mechanism. (As an aside, This is one reason the > Fovean folks make such a big deal of how each photosite in a Fovean > chip captures all three colors ... they claimed gains in spatial > resolution for the same [x,y] grid. However, in practical terms, the > spatial resolution degradation caused by chroma interpolation is > pretty minimal. What the Fovean sensor theoretically provides is more > accurate RGB tonal capture, but this has not worked out quite as well > in practical terms as the hype would lead you to believe.) > > Godfrey > > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
