Patent ID: 8811746

Claim:
A mobile unit position detecting apparatus, comprising: an image capturing device for sequentially or intermittently shooting, with the image capturing device, a target installed in a vicinity of a route on which a mobile unit can move, and for detecting a position of the mobile unit based on the target in a shot image; target position extracting unit configured to identify image data that matches image data of the target in the image from among image data of a plurality of targets by making a comparison between the image data of the plurality of targets and the image data of the target, which are recorded in a recording unit, and the image data of the target in the image, and to obtain position data that is recorded in the recording unit, is associated with the identified image data and indicates a position when the mobile unit approaches the target at a predetermined distance; target position outputting unit configured to output the position data if determining whetherthat the target in the image changes to a shape, recorded in the recording unit, of the target in the image when the mobile unit approaches the target at the predetermined distance; the recording unit configured to record a target ID, assigned to the target, for identifying the target, target setting data including the image data of the target shot in advance for each target in association with the target ID, a threshold value obtained by calculating an aspect ratio based on the shape of the target in the image when the mobile unit approaches the target at the predetermined distance, and position data, that indicates a position for which the threshold value is calculated, wherein: the target position extracting unit comprises a target detecting unit configured to generate target data by extracting the target from the image shot by the image capturing device, to extract from the recording unit target setting data that best matches the target data, and to obtain a target ID corresponding to the extracted target setting data, and a target position information converting unit configured to detect the position data associated with the target ID from the recording unit after obtaining the target ID obtained by the target detecting unit; and the target position outputting unit comprises an aspect ratio calculating unit configured to track the target in the image shot by the image capturing device, and to calculate an aspect ratio of the target being tracked in the image, a comparing unit configured to output an enable signal if the aspect ratio is equal to or lower than the threshold value, and an FF unit configured to obtain position data from the target position information converting unit, to output the position data upon receipt of the enable signal and to update a current position of the mobile unit based on the position data.