| 摘要 |
An apparatus is provided for detecting a shopping cart used to bring items to a checkout location, and inspecting its bottom tray for the presence of items. The apparatus includes a cart-detector to detect the presence of the cart at a pre-determined location; and an item-detector to detect the presence of items placed on the lower tray of the cart. The cart detector includes an arrangement of three optical sensors and corresponding retro-reflective targets; and finite state-machine processing logic to discriminate a specific sequence of sensor responses. The item detector includes an optical line generator to project a structured illumination pattern on any items placed on the lower tray of the shopping cart as well as on the opposite wall of the checkout lane; an area-imaging sensor and associated optics and digitizing means to capture the reflected pattern in digital form; a pattern-analysis means to analyze the captured pattern; and a means for transmitting the result of the pattern analysis, for example, to a system that can alert the attendant and/or the customer, or to a means that prevents further progress of the car through the checkout lane. |
