Bruce and I both worked with Jeff Chien from Adobe who was primary engineer (along with a few others) when they developed Smart Sharpen. Bruce's problem was that while deconvolution algorithms may have a lot of promise when the optical defects can be known and an algorithm specifically designed to remove a known defect, it's not clear that "general" deconvolution algorithms can be derived without knowing the exact aberration it will be used against.
That was Jeff's problem with Smart Sharpen...he actually showed us a 50 pass iteration that could effectively remove an applied gaussian blur, but he first needed to know the EXACT PSF that could attack the specific blur. Once known, multiple passes could essentially rebuild a soft image into a sharp image with little or only small defects...
Using deconvolution algorithms for removing specific camera shake is another area of interest because you can actually measure the shake involved and the line of bias and then go about removing that camera shake from the image. But, again, this is neither easy nor quick.
Smart Sharpen has both a Lens Blur as well as a Motion Blur mode...but there are no parameters to adjust the Lens Blur mode and you can't combine modes without separate runs...
Jeff, you have summed up the situation with deconvolution algorithms quite well. When the PSF is unknown, blind deconvolution methods, which are being developed, can produce an approximate PSF. The ImagesPlus astronomical program that Roger Clark uses offers the adaptive Richardson-Lucy algorithm with noise amplification control. Its Point spread functions include: Choose box, Gauss, binomial, or custom function. Having a MIT PhD is astrophysics helps in choosing an approximate PSF, bit the process is a bit difficult for most of us.
Focus Magic uses a PSF for defocus, where a point source is spread out into a disk. One can identify point sources in the image and choose an appropriate pixel value for the deconvolution as shown in their tutorial. Motion blur and defocus can be handled simultaneously.
Bruce had determined, after Smart Sharpen shipped, that there was no compelling reason to adapt PKS to incorporate it...he actually was more interested in DxO and used that earlier last year and was pleased because it offered a method of fixing a lot of lens defects all in one fell swoop. But I'm not sure if he thought of fixing lens defects in the same light as doing capture sharpening. He would run images through DxO and output a linear DNG and then run through Camera Raw for tone & color and finally used PKS for capture sharpening through to output sharpening.
But his time with DxO was rather short and came after finishing his first edition of RW Image Sharpening.
Bruce did sum up his impression of smart sharpening in his sharpening book and he found few advantages for it. He stated that the Gaussian PSF gave about the same results as USM, and recommended the lens blur PSF for general use and the motion blur PSF for removal of that defect. However, smart sharpening was in its first iteration and may have improved with CS3. Also, did Bruce have enough time with the algorithm to learn how to use it to best advantage?. After all, he had been using USM for years and had worked out how to use it with edge masks and layers modulated by opacity and the blend if sliders and what radius and amount would give the intended results.
About half of the book is dedicated to capture sharpening, which uses USM. For smart sharpen, we have about one page of documentation in the PSCS3 manual. I doubt that many of us know how to optimally use smart sharpen. Should it be used with a mask or blend if options? When should one use the more accurate function? Should it be used in conjunction with USM?
All of this research is all very interesting, but to put something in a shipping product that can have a useful impact given the wide range of shooting conditions and lenses that photographers use is another thing. And correcting for very specific lens defects is very complicated as the potential matrix of defects is large–particularly zoom lenses whose defects vary along the focal length make something like DxO seem like a more logical solution. But, again, that still doesn't mean it's a "capture sharpener" per se...
That is true for a shipping product when PK was introduced, but as this and other threads show, some people are interested in deconvolution algorithms and are beginning to use them for capture sharpening. Your own work with Adobe in incorporating capture sharpening in to ACR has diminished the role of PK in capture sharpening, and the other algorithms discussed may diminish its use further. However, its role in output sharpening remains. Would you agree?
I'm not familiar with DxO. I know that it offers correction for various lens defects, but does it use deconvolution? Certainly, correction for light fall off and chromatic aberration do not use deconvolution, but deconvolution could be used to correct for spherical aberration and astigmatism.