Patent ID: 7643154

Claim:
An optical image measurement device, comprising: a light source configured to emit a low-coherence light; an interference-light generator configured to generate an interference light, by splitting the emitted low-coherence light into a signal light heading toward a measurement object and a reference light heading toward a reference object, and superimposing the signal light passed through the measurement object and the reference light passed through the reference object; a changer configured to change a difference in optical path length between the signal light and the reference light; a detector configured to detect the generated interference light; an image forming part configured to form an image of the measurement object within a predetermined frame based on the result of the detection by the detector; an analyzer configured to analyze the formed image, and specify a position within the predetermined frame of a partial image of the formed image corresponding to a predetermined depth position of the measurement object; and a controller configured to control the changer based on the specified position to change the difference in optical path length so that, in a newly formed image by the image forming part, the partial image is placed in a specific position within the predetermined frame, thereby placing the newly formed image in a predetermined position, wherein regarding the formed image, the analyzer finds the position of the partial image within the predetermined frame, and calculates displacement between the found position and the specific position; and the controller controls to change the difference in optical path length by a distance corresponding to the displacement, thereby placing the partial image of the newly formed image in the specific position.