UI LED Synchronization for Vision Camera Reflections
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Solution Overview
Problem
In slot scanner designs, the placement of a user interface (UI) light emitting diode (LED) behind the scan window causes internal reflections, which are exacerbated in horizontal scanners, leading to erroneous reflections picked up by vision cameras, damaging the UI LED and affecting object recognition.
Innovation Solution
The synchronization of the UI light emitter with the imaging assemblies' exposure times ensures that the UI light is only active during non-exposure periods, preventing overlap and minimizing internal reflections, achieved through timing signals and processor-controlled operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the UI LED is placed behind the scan window, then the UI light remains visible through the scan window even when the slot scanner is recessed, but internal reflections occur that are picked up by vision cameras
Solution Approach 1:
The UI LED is operated in a periodic manner, being activated only during specific time intervals (when the vision camera sensor is not capturing images) and remaining inactive during other intervals (when the sensor is exposed). This temporal modulation allows the UI light to be visible to users while preventing its reflection from being captured by the vision camera sensor, thus resolving the contradiction between UI visibility and reflection elimination.
2Ease of operation
If the UI LED is placed outside the scan window protruding through sheetmetal, then the UI light is visible, but the UI LED is damaged and scuffed by products being dragged across the platter
Solution Approach 1:
The UI LED is extracted from its vulnerable position outside the scan window and relocated to a protected position behind the scan window. This extraction removes the UI LED from the path of products being dragged across the platter, eliminating the mechanical damage risk while preserving UI visibility through the optically transmissive scan window.
3Measurement precision
If the vision camera uses a wide viewing angle to detect scan avoidance and improve object recognition, then detection capability is improved, but reflections of the UI source propagate farther along into the field of view
Solution Approach 1:
The UI LED operates periodically with synchronized on/off cycles that are coordinated with the vision camera sensor's exposure timing. The UI LED is activated only when the sensor is in its non-exposure state, ensuring that even with a wide viewing angle, the UI light reflection does not coincide with sensor capture windows, thereby eliminating reflection interference while maintaining wide-angle detection capability.
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 allows for a visible UI in slot scanners while avoiding internal reflections, ensuring accurate object recognition and protecting the UI LED from damage.
Implementation Method 1
an illumination assembly mounted within the housing and configured to generate an illumination through the optically transmissive window during at least one of the exposure-on times
Implementation Method 2
a housing having an optically transmissive window
Implementation Method 3
vision cameras will see internal reflections off the scan window. Namely, vision cameras can pick up reflections of the user interface source in the scan window
Data Source
AI summary
An imaging device includes a housing having an optically transmissive window, a first imaging assembly, a second imaging assembly, and illumination emitter for generating a user interface visual indicator. The illumination emitter may be a light emitting diode or other light source. To prevent internal reflection of the user interface visual indicator off the window and appearing in captured images from the imaging assemblies, the imaging device synchronizes emitter-on times and sensor exposure-on times to prevent substantial overlap therebetween, thereby allowing for more accurate image captures, including color image captures of the imaging device.