Weigh Platter Assembly with Parallax Off-Platter Detection
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Solution Overview
Problem
Weigh platters in barcode readers often fail to accurately measure objects that extend off the platter, leading to incorrect weight measurements and pricing due to variations in shape and size.
Innovation Solution
The implementation of off-platter detection assemblies with offset light sources and sensors along the lateral edge of the weigh platter, which emit a focused light beam and use position-sensitive sensors to detect objects extending beyond the platter, limiting the field of view to the platter's edges to prevent false detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a weigh platter is used to measure produce or products, then weight measurement is achieved, but measurement precision deteriorates when objects extend off the platter
Solution Approach 1:
The patent introduces an intermediary detection system consisting of light sources and position-sensitive sensors that act as mediators between the weigh platter and the control system. These sensors detect the presence and position of objects extending off the platter by detecting reflected light, providing intermediate information that enables the control system to identify and correct measurement errors before final pricing is determined.
Solution Approach 2:
The patent implements a feedback mechanism where position-sensitive sensors continuously monitor object position on the weigh platter. When objects are detected extending off the platter, the system provides feedback signals to the control system, which then adjusts or invalidates the weight measurement accordingly. This closed-loop feedback ensures measurement accuracy by continuously verifying object placement during the weighing process.
2Reliability
If the field of view of sensors is expanded to detect off-platter objects, then off-platter detection capability is improved, but false detections from external objects increase
Solution Approach 1:
The patent applies local quality by creating distinct detection zones with different functional characteristics. The field of view is divided into a first region (over the weigh platter) and a second region (beyond the platter edges). Position-sensitive sensors are configured with specific detection thresholds and acceptance criteria that vary by region, allowing the system to be more sensitive to objects in the first region while being more selective about objects in the second region, thereby reducing false detections.
Solution Approach 2:
The patent utilizes parameter changes by varying the detection criteria based on object position. The control system adjusts detection parameters such as light intensity thresholds, sensor sensitivity, and acceptance angles depending on whether objects are detected in the first region (on platter) or second region (off platter). This dynamic parameter adjustment enables the system to maintain high detection accuracy across different spatial zones.
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
This solution ensures accurate weight measurements by identifying when objects are off the platter and preventing incorrect pricing, enhancing the reliability of weigh platter assemblies in various environments, including bright conditions with multiple light sources.
Implementation Method 1
a light source and a position-sensitive sensor offset from one another... emit a focused light beam and use position-sensitive sensors to detect objects
Data Source
AI summary
A weigh platter assembly includes a weigh platter and an off-platter detection assembly having a light emission assembly, a light detection assembly, and a controller. The light emission assembly has a light source to emit a light along a lateral edge of the weigh platter. The light detection assembly detects at least a portion of the light reflected from an object extending across the light beam and includes a sensor offset from the light source and an aperture positioned in front of the sensor and configured to limit a field of view of the sensor along the lateral edge. The controller is configured to provide a first signal in response to a first value received from the sensor and to provide a second signal, different from the first signal, in response to a second value.