Device and method for position measurement

Abstract

A position measurement device is provided that can precisely measure the photographing position or posture of a photographing device or the coordinates of an object based on sequentially changing photographed images. A position measuring deviceof the invention comprises: an image acquisition sectionfor acquiring a series of photographed images changing continuously or little by little along with position displacement relative to an object to be photographed; a positional relationship measurement sectionfor measuring position displacement and posture change of the image acquisition section; a feature extraction sectionfor extracting feature points from the photographed images obtained with the image acquisition section; a feature point tracking sectionfor tracking the feature points by searching corresponding points corresponding to the feature points on a plurality of the photographed images; an image selection sectionfor selecting an image to be processed from the series of photographed images based on a measurement result made with the positional relationship measurement section; and a position measurement sectionfor measuring the photographing position and the photographing posture of the image acquisition sectionbased on the image to be processed selected with the image selection section