Method and system for recovering a code image including blurring

Abstract

Error-function determining means makes use of a blur function serving as a function representing the degree of blurring of a blurred input image and a geometrical-deformation matrix serving as a matrix for restricting an operation to lay out a 2-dimensional code shown by the input image on cells each serving as a configuration unit of the 2-dimensional code in order to determine an error function serving as a function satisfying a relation that, the smaller the error between the input image and an image obtained by adding geometrical deformations and blurs to a recovered image obtained from a recovering process, the more the approach to a result determined in advance. Pixel-value restricting means determines pixel-value restriction information prescribing a restriction condition for a restriction imposed on a predetermined pixel value obtained from discretization of pixel values of the 2-dimensional code to be recovered. Objective-function determining means makes use of the error function and the pixel-value restriction information as a basis for determining an objective function serving as a function satisfying a relation that, the closer the recovered image to the true image, the more the approach to a result determined in advance. Objective-function optimizing means determines a recovered image optimizing the objective function.