Fig. 1. Schematic model of auto sharpness detection based on SFV theory

Fig. 2. Rectangular-type spatial filer sampling process

Fig. 3. Schematic model of a typical rectangular-type spatial filter

Fig. 4. Behavior of a sinc function

Fig. 5. Power spectra for the sinusoidal and rectangular transmittance functions h₁（x）and h₂（x）， respectively

Fig. 6. Schematic diagrams of three typical filter windows

Fig. 7. Power spectral normalized by values at μ= ν = 0， for rectangular transmittance function restricted by three types of windows

Fig. 8. Experimental imaging setup

Fig. 9. Experimental acquisition of images

Fig. 10. Three evaluation function curves for three types of windows