| 摘要 |
PROBLEM TO BE SOLVED: To provide a portable terminal device capable of reliably giving warning to a user who uses the portable terminal device during walking.SOLUTION: A portable terminal device includes: a camera 15 having an automatic focus function; and a control part 21 for performing prescribed control. The control part 21 sets a focal length Df_s acquired from the camera 15 as a first focal length, sets a focal length Df_p acquired from the camera 15 as a second focal length after passing a prescribed time from acquiring the first focus length Df_s, and performs a warning process if the absolute value of the difference between the focal lengths Df_s and Df_p becomes larger than a prescribed threshold value Dth. |
