In the measurement in Figure 9, to reduce the affection, we placed the mobile device in such a way as to set the optical axis of the mobile device camera through the center of the two position detection patterns placed in the lower. As a result, it was able to meet the requirement. From the above results, to achieve accurate synchronization, we found out that appropriate correction of the distortion is needed in the case of the time marker captured at arbitrary position and that we can draw out sufficient accuracy without the correction if we place the mobile device at appropriate position.