Patent ID: 7724353

Claim:
A method comprising: determining whether a luminance received by at least one light receiving element of a plurality of light receiving elements of an apparatus is equal to or higher than a predetermined value; determining whether luminances received by the at least one light receiving element that has received the luminance are equal to or higher than the predetermined value change in a time-series manner; acquiring information relating to a size of a light source from the time-series change when it is determined that the luminances change in the time-series manner; detecting a size of a light receiving region based on a ratio of the at least one light receiving element that has received the luminances that change in the time-series manner to the plurality of light receiving elements; and calculating a distance from the apparatus to the light source based on the size of the light receiving region and the acquired information relating to the size of the light source; wherein the information relating to the size of the light source is contained in the luminances that change in the time-series manner provided by the light source.