Patent ID: 7719597

Claim:
A distortion correction device that performs distortion correction on an inputted image signal by converting an input coordinate position, the input coordinate position being a coordinate position of the inputted image signal, the distortion correction device comprising: a distortion data memory that stores distortion data, the distortion data being discrete points on an image height-distortion curve representing a relationship between image height, which is a distance from the optical axis of the optical lens to an imaging position, and distortion, which shows correlation between an output coordinate position, the output coordinate position being a coordinate position of an outputted image signal, and the input coordinate position corresponding to the output coordinate position; a distortion calculator that reads, out of the distortion data being the discrete points stored in the distortion data memory, a predetermined number of distortion data among the distortion data near an image height at the output coordinate position, that then calculates an approximation formula for approximating the image height-distortion curve near the image height at the output coordinate position, and that then substitute the image height at the output coordinate position in the approximation formula, the distortion calculator thereby calculating the distortion at the output coordinate position; and a coordinate calculator that calculates the input coordinate position based on the output coordinate position and the distortion calculated by the distortion calculator as corresponding to the output coordinate position, wherein as data of the output coordinate position, data of the input coordinate position obtained for the output coordinate position are outputted.