Image processing method, image processing apparatus and image capturing apparatus

An image processing apparatus for obtaining image data undergoing a distortion correction process by using plural pieces of pixel data acquired when an image capturing element including a plurality of pixels receives the light via an optical system, the apparatus comprising:

• an image processing unit calculating coordinates of the respective pixels on the virtual projection plane in the world coordinate system on the basis of the datum plane, of which a position and a size are set, always having a fixed positional relationship with a virtual projection plane, converting the calculated coordinates into a camera coordinate system by using a distortion correction coefficient, and calculating the image data on the virtual projection plane on the basis of the coordinates in the camera coordinate system with the conversion being done and the plural pieces of pixel data;
• and
• a storage unit retaining a two-dimensional LUT stored, datum plane system coordinates xdydzd with the datum plane as a basis being set, with zd coordinates in a direction perpendicular to the datum plane with respect to xd- and yd-coordinates on the datum plane and based on a shape of the virtual projection plane,
• wherein the image processing unit calculates the coordinates of the respective pixels on the virtual projection plane in the world coordinate system on the basis of the two-dimensional LUT.

An image capturing apparatus comprising:

• an optical system;
• an image capturing element including a plurality of pixels;
• a setting unit setting a position and a size of the datum plane always having a fixed positional relationship with the virtual projection plane in the world coordinate system;
• an image processing unit calculating coordinates of the respective pixels on the virtual projection plane in the world coordinate system on the basis of the datum plane set by the setting unit, converting the calculated coordinates into a camera coordinate system by using a distortion correction coefficient of the optical system, and calculating the image data on the virtual projection plane on the basis of the coordinates in the camera coordinate system with the conversion being done and the pixel data obtained from the plurality of pixels;
• and
• a storage unit retaining a two-dimensional LUT stored, datum plane system coordinates xdydzd with the datum plane as a basis being set, with zd coordinates in a direction perpendicular to the datum plane with respect to Xd- and yd-coordinates on the datum plane and based on a shape of the virtual projection plane,
• wherein the image processing unit calculates the coordinates of the respective pixels on the virtual projection plane in the world coordinate system on the basis of the two-dimensional LUT.