1. An image processing apparatus for acquiring, on a per access unit basis, a value of at least one parameter indicating characteristics of image blur taking place during the image pickup of a moving image by a predetermined image pickup device, a plurality of access units forming the moving image picked up by the image pickup device, or acquiring the parameter value from the outside, the image processing apparatus comprising a corrector for correcting a pixel value of each of a plurality of pixels forming each access unit to be processed, based on at least one of the parameter values corresponding to the access unit to be processed, the corrector comprising: acquisition means for setting, as a target pixel, one of the plurality of pixels forming the access unit to be processed, and acquiring input pixel values of n pixels centered on the target pixel and consecutively arranged in a first direction, n being an integer equal to or more than 3; first mean value calculating means for determining a calculation range of input pixel values of k pixels arranged further in the first direction than the target pixel from among the input pixel values acquired by the acquisition means based the parameter value corresponding to the target pixel, and calculating, as a mean pixel value in the first direction, the mean value of the input pixel values falling within the calculation range, k being an integer less than n/2; second mean value calculating means for determining a calculation range of input pixel values of k pixels arranged further in a second direction, opposed to the first direction, than the target pixel from among the input pixel values acquired by the acquisition means based the parameter value corresponding to the target pixel, and calculating, as a mean pixel value in the second direction, the mean value of the input pixel values falling within the calculation range; correction value determination means for determining a correction value correcting the input pixel value of the target pixel based on the relationship of the first direction mean pixel value calculated by the first mean value calculating means, the input pixel value of the target pixel, the second direction mean pixel value calculated by the second mean value calculating means; and first adding means for adding the correction value determined by the correction value determination means to the input pixel value of the target pixel, and outputting the resulting sum as an output pixel value of the target pixel.