Camera based step detection on mobile phones

This paper presents an extension to an indoor positioning system leveraging the camera which is built into current mobile phones to detect steps. Current indoor positioning systems on mobile phones based on pedestrian dead reckoning (PDR) often rely on step length and step frequency estimation. Usually the accelerometer is used to determine these values. Depending on the attitude of the device or the smoothness of the movement sometimes steps are not correctly detected. We propose to use the camera as additional sensor element to detect the forward section of both feet appear and disappear in the camera image and detect the steps based on this information. A comparison to an accelerometer based approach is provided.