Shelf Item Retrieval Detection With Light Curtains and Weight Sensing
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Solution Overview
Problem
Conventional micro markets face challenges in accurately tracking customer interactions with inventory items and determining the number of items retrieved without relying on costly individual sensors at each location, as well as ensuring honest customer scanning and preventing theft, while maintaining a cost-effective and non-intrusive monitoring system.
Innovation Solution
A system combining hand tracking and weight sensing techniques to monitor inventory items, using a curtain of IR light or digital cameras to track hand interactions and weight changes to determine item location and removal without individual sensors at each location, allowing for cost-effective and reliable inventory management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual sensors are installed at each inventory location to track item retrieval, then measurement precision of item location and quantity is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent combines multiple sensing functions into two monitoring systems: (1) a light curtain or camera system that tracks hand movement and item location, and (2) a weight monitoring system that detects item removal. This merging eliminates the need for individual sensors at each shelf location while maintaining tracking precision.
Solution Approach 2:
The light curtain/camera system serves multiple functions: detecting hand presence, determining item location (X-Y coordinates), and triggering weight monitoring. The weight system universally monitors all shelves simultaneously. This multi-functionality reduces the overall sensor count while improving measurement capabilities.
2Reliability
If comprehensive monitoring systems are implemented to prevent theft and ensure honest scanning, then reliability of inventory tracking is improved, but device complexity and cost increase
Solution Approach 1:
The system implements continuous feedback loops where the light curtain detects hand movement, determines item location, triggers weight monitoring, and compares expected vs. actual weight changes. This feedback mechanism ensures reliable theft prevention by cross-validating optical detection with weight measurement, maintaining high reliability without excessive complexity.
Solution Approach 2:
The patent replaces complex mechanical sensor arrays with optical fields (light curtain) and electronic weight sensing. This substitution maintains or improves reliability while reducing mechanical complexity and enabling more elegant theft detection through non-contact optical monitoring combined with electronic weight verification.
3Device complexity
If cost-effective monitoring solutions are used with minimal sensors, then device complexity is reduced, but measurement precision of item location and quantity may deteriorate
Solution Approach 1:
The light curtain creates a multi-dimensional optical field that precisely locates hand position in X-Y coordinates without requiring individual sensors at each location. The weight system adds a temporal dimension by measuring weight before and after interaction. This dimensional approach maintains measurement precision while using minimal sensors.
Solution Approach 2:
The light curtain acts as an intermediary that translates hand movement into precise location data, while the weight system serves as an intermediary that converts physical item removal into measurable weight changes. These intermediary systems enable accurate measurement without direct contact sensors at each inventory position.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively resolves item location and number of items removed with minimal sensors, providing accurate inventory tracking and reducing costs, suitable for various applications including micro markets, home pantries, and other inventory setups.
Implementation Method 1
A first sensing subsystem may be a curtain of light across the plane over all the inventory item locations with light detectors that can sense a perturbation, disruption, or blockage of light in at least two directions relative the curtain
Implementation Method 2
A second sensing subsystem may be a weight sensor that can sense a change of weight of the support and any inventory items on it
Data Source
AI summary
A system, method, and apparatus for generating an automatic detection solution of location and number of one or more user-selectable items retrieved by a user from at least one support (e.g., shelf or rack or drawer) in a interaction with an inventory of items. In one example, the interaction is a transaction from a micro market during a pre-determined user-interaction session. In some embodiments, at least one support is configured to store one or more user-selectable items along the front-to-back depth at each of a plurality of pre-determined solution detection areas along the side-to-side width of the shelf or rack. A weight sensor is installed at each support and configured to sense and report at least a weight of any user-selectable items on the support via a digital weight signal (and in some cases a total weight of the support and any items on the support). An item interaction detector is installed at or near the front plane of the one or more supports and is configured to sense and report user-interaction with any solution detection area of any support via a digital solution detection area signal. A programmable controller is configured to receive the digital solution detection area signal and any weight difference in comparing the digital weight signal before and after each user-interaction with a solution detection area, and automatically generate or store the automatic position solution of location and number of one or more user-selectable items retrieved from each solution detection area in the user-interaction by correlation of the solution detection area with digital weight signal before and after the user-interaction. The item interaction detector and weight sensor combination can be installed an operated in analogous manners in other contexts. A food pantry is one. A drawer is another.