Device and associated methodology for measuring three-dimensional positions based on retrieved points from one view angle and positions and postures from another view angle

While a view angle is switched between wide and narrow view angles, images with the wide view angle and images with the narrow view angle are alternately taken. Based on images taken with the narrow view angle, movements of corresponding points in images in correspondence between the narrow-angle images are detected. Based on the images taken with the wide view angle, a translational vector and a rotation matrix that represent changes in the position and posture between the wide-angle images are calculated. By linearly interpolating the translational vector and the rotation matrix between the wide-angle images, a translational vector and a rotation matrix that represent changes in the position and posture between the narrow-angle images are estimated. Based on movements of corresponding points in the images and the translational vector and the rotational matrix between the narrow-angle images, three-dimensional coordinates of the corresponding points on the measurement object are highly accurately measured.