Apparatus for measuring three-dimensional position of object

A position measuring apparatus comprising:

• an image acquirer configured to acquire a plurality of sets of images at a plurality of respective time instants, each set of images being simultaneously captured at a respective one of the plurality of time instants from different perspectives so as to include the same captured area;
• a correspondence point detector configured to detect, for each set of images at a respective one of the time instants, correspondence points from the respective images of the set, the correspondence points being points on respective image planes representing the same three-dimensional position;
• a projection point calculator configured to calculate a projection point of each of the correspondence points detected at the respective time instants onto each of a plurality of common planes set at different depthwise positions in a world coordinate system using preset camera parameters, the camera parameters representing a correspondence relationship to acquire non-linear mapping from each image plane to each common plane for each of all combinations of one of the image planes for each set of images captured at a respective one of the time instants and the plurality of common planes;
• and
• a reconstruction point calculator configured to calculate a point at which distances to a plurality of rays each connecting the projection points of the correspondence point on a respective one of the image planes onto the plurality of common planes are minimized, as a reconstruction point representing a three-dimensional position of the correspondence point.