an x - ray computed tomography system , method , and computer product that generates an x - ray beam with an x - ray generator and detects with an x - ray detector at least one characteristic of the x - ray beam generated by the x - ray generator , after the x - ray beam has passed through an object , the system including a converting unit configured to obtain analog projection data outputted by the x - ray detector and to convert the analog projection data to digital projection data , and a processing unit configured to obtain the digital projection data from the converting unit , to detect overflow digital projection data that overflows a measuring range of the computed tomography system , and to correct the overflow digital projection data of the digital projection data by using a curve fitting function .