Two new methods are presented for recovering the focused image of an object from only two blurred images recorded with different camera parameter settings.The camera parameters include lens position, focal length, and aperture diameter.First a blur parameter is estimated using one of our two recently proposed depth-fromdefocus methods.Then one of the two blurred images is deconvolved to recover the focused image.The first method is based on a recently proposed Spatial Domain Convolution/Deconvolution Transform.This method requires only the knowledge of of the camera's point spread function (PSF).It does not require information about the actual form of the camera's PSF.The second method, in contrast to the first, requires full knowledge of the form of the PSF.As part of the second method, we present a calibration procedure for estimating the camera's PSF for different values of the blur parameter .In the second method, the focused image is obtained through deconvolution in the Fourier Domain using the Wiener filter.For both methods, results of experiments on actual defocused images recorded by a CCD camera are given.The first method requires much less computation than the second method.The first method gives satisfactory results for up to medium levels of blur and the second method gives good results for up to relatively high levels of blur.

Two new methods are presented for recovering the focused image of an object from only two blurred images recorded with different camera parameter settings. First a blur parameter /spl sigma/ is estimated using one of our two recently proposed depth-from-defocus methods. Then one of the two blurred images is deconvolved to recover the focused image. The first method requires only the knowledge of /spl sigma/ of the camera's point spread function (PSF). It is based on a new spatial domain convolution/deconvolution transform. The second method requires full knowledge of the form of the PSF and is estimated using step edges. The focused image is obtained through deconvolution in the Fourier Domain using the Wiener filter. For both methods, results of experiments on actual defocused images recorded by a CCD camera are presented. The first method requires less computation and gives satisfactory results for up to medium levels of blur. The second method gives good results for up to relatively high levels of blur.>

A method for determining depth (range) from image defocus and rapid autofocusing of a camera named DFD1F, is presented. It requires only two images in theory, but three images in the present implementation. DFD1F is based on computing only one-dimensional Fourier coefficients as opposed to two-dimensional Fourier coefficients for a related prior method, thus providing not only computational advantage but also robustness in practical applications. DFD1F is independent of the form of the modulation transfer function of the camera. DFD1F has been successfully implemented and tested on an actual camera system named SPARCS. SPARCS can determine the distance of an object placed in front of it at any distance in the range of 0.5 m to infinity, and can successfully focus the object by moving the lens with a root-mean-square error of less than 6% in terms of lens position.>