1. An information processing method comprising: an image sensing step of sensing an image representing physical space; an orientation acquiring step of acquiring orientation information of an image sensing apparatus; an index detecting step of detecting an index from the sensed image; a first calculation step of calculating the first reliability of the detection result based on the image of the detected index in the sensed image; a second calculation step of calculating the second reliability of the detection result using the orientation information; an identification step of identifying the detected index based on the first reliability and the second reliability.