Image processing apparatus and information processing method for improving resolution of direction exhibiting degraded resolution

Abstract

An image processing apparatus includes an acquisition unit configured to acquire a first finite spatial filter having image resolution anisotropy, and a calculation unit configured to compute a second spatial filter by convolving a finite filter with respect to the first spatial filter, the finite filter having a sum of elements being 0 and at least two of the elements being non-0.

What is claimed is: 
     
       1. An image processing apparatus, comprising:
 ana first acquisition unit configured to acquire a first finite spatial filter having image resolution anisotropyby making a spatial filter finite, so that the first finite spatial filter is limited to a finite number of elements less than or equal to an element number of the spatial filter being calculated from an inverse function of a function representing image blurring and used to improve anisotropy of a resolution of an image in which an imagethe resolution varies as a function of separation and direction relative to a center of an image; and 
 a calculationa second acquisition unit configured to computeacquire a second spatial filter by convolving a finite high-pass filter with respect to the first finite spatial filter, the finite high-pass filter having a sum of elements being 0 and at least two of the elements being non-0, the second spatial filter being smaller than the first finite spatial filter and the finite high-pass filterimproving the resolution differing in different directions and reducing a moiré pattern for the first finite spatial filter, the moiré pattern being generated by a correction causing deterioration in high frequency components in the different directions. 
 
     
     
       2. The image processing apparatus as claimed in  claim 1 , wherein
 the finite high-pass filter is a high-pass filter having all the elements being non-0 coefficients. 
 
     
     
       3. The image processing apparatus as claimed in  claim 1 , wherein
 the calculation unit computes a third spatial filter by subtracting the second spatial filter from a filter having a central element being 1 and elements other than the central element being 0. 
 
     
     
       4. The image processing apparatus as claimed in  claim 1 , further comprising:
 a filter processor configured to perform a filter process on an input image utilizing the second spatial filter and subtract a filter-processed image from the input image to generate a corrected image. 
 
     
     
       5. The image processing apparatus as claimed in  claim 3 , further comprising:
 a filter processor configured to perform a filter process on an input image utilizing the second spatial filter to generate a corrected image. 
 
     
     
       6. An image pickup apparatus, comprising:
 the image processing apparatus as claimed in  claim 1 ; and 
 an image pickup unit. 
 
     
     
       7. A non-transitory computer-readable storage medium that stores a program which, when executed by a processor, causes a computer to perform a process comprising:
 acquiring a first finite spatial filter having image resolution anisotropy by making a spatial filter finite, so that the first finite spatial filter is limited to a finite number of elements less than or equal to an element number of the spatial filter being calculated from an inverse function of a function representing image blurring and used to improve anisotropy of a resolution of an image in which an image the resolution varies as a function of separation and direction relative to a center of an image; and 
 computingacquiring a second spatial filter by convolving a finite high-pass filter with respect to the first finite spatial filter, the finite high-pass filter having a sum of elements being 0 and at least two of the elements being non-0, the second spatial filter being smaller than the first finite spatial filter and the finite high-pass filter improving the resolution differing in different directions and reducing a moiré pattern for the first finite spatial filter, the moiré pattern being generated by a correction causing deterioration in high frequency components in the different directions. 
 
     
     
       8. An information processing method executed by a computer, the information processing method comprising:
 acquiring a first finite spatial filter having image resolution anisotropy by making a spatial filter finite, so that the first finite spatial filter is limited to a finite number of elements less than or equal to an element number of the spatial filter being calculated from an inverse function of a function representing image blurring and used to improve anisotropy of a resolution of an image in which an image the resolution varies as a function of separation and direction relative to a center of an image; and 
 computingacquiring a second spatial filter by convolving a finite high-pass filter with respect to the first finite spatial filter, the finite high-pass filter having a sum of elements being 0 and at least two of the elements being non-0, the second spatial filter being smaller than the first finite spatial filter and the finite high-pass filterimproving the resolution differing in different directions and reducing a moiré pattern for the first finite spatial filter, the moiré pattern being generated by a correction causing deterioration in high frequency components in the different directions.