Real-time distance measurement using a modified camera

In this paper we propose a real-time method which can measure distance using a modified camera. The camera's image sensor is inclined by a certain angle. Thus, the image projected on the sensor is defocused differently at different areas. The area where the image is focused best is just at projection plane. The position of the projection plane can be obtained after finding out this area. The distance between the projection plane and the lens of the camera is image distance. Object distance can be obtained by applying image distance to lens formula. This method is proved to be effective and a single distance measurement can be performed within 3.21ms.