Patent ID: 9715604
Date: 2017-07-25
CPC Classifications: G06K

Claim:
1. An RFID tag reading device comprising: response requesting unit configured to output a response request signal to a wireless tag; response reception unit configured to extract an ID of the wireless tag and detecting a signal collision of a response from the wireless tag, based on a response signal output from the wireless tag in response to the response request signal; reading result acquisition unit configured to acquire a read tag number indicating the number of wireless tags from which the corresponding ID has been successfully read; collision occurrence status acquisition unit configured to count the number of time slots in which the signal collision has occurred, and for calculating the number of collisions; and reading result complementing unit configured to estimate the number of readable wireless tags based on the read tag number and the number of collisions; wherein the wireless tag outputs the response signal having a higher signal strength in a state where no article is placed at a location corresponding to the wireless tag, than in a state where an article is placed at the location corresponding to the wireless tag.