Indicia Reading Terminal Specular Reflection Mitigation
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Solution Overview
Problem
Indicia reading terminals face challenges in decoding bar codes and OCR characters due to specular reflection, which causes image degradation and saturation issues, leading to unsuccessful decoding.
Innovation Solution
The terminal captures and processes frames with varying imaging attributes, including different illumination profiles and source attributes, to minimize specular reflection effects by alternating between frames with distinct imaging attributes, ensuring successful decoding even under conditions of saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the terminal uses a single image sensor to capture frames, then the device complexity is reduced, but specular reflection causes image degradation and saturation leading to decoding failures
Solution Approach 1:
The patent applies dynamics by making the imaging attributes variable rather than fixed. The terminal dynamically changes illumination profiles (e.g., switching between different LED banks with different colors or intensities) and exposure parameters between successive frames. This dynamic adjustment allows the system to adapt to specular reflection conditions in real-time, improving decoding reliability without requiring multiple physical image sensors.
Solution Approach 2:
The patent implements parameter changes by modifying imaging attributes such as illumination profile, exposure time, and gain between frames. By changing these parameters, the terminal captures the same target under different lighting and exposure conditions, which helps overcome specular reflection issues. For example, switching between warm white and cool white LED illumination can alter how specular reflections appear, enabling successful decoding of barcodes that would otherwise be obscured.
2Reliability
If the terminal captures multiple frames with varying imaging attributes, then decoding reliability under specular reflection is improved, but the processing time and energy consumption increase
Solution Approach 1:
The patent applies periodic action by capturing multiple frames with alternating illumination profiles in a systematic sequence. Instead of randomly changing parameters, the terminal follows a periodic pattern of switching between different illumination conditions (e.g., alternating between LED bank 1 and LED bank 2). This structured approach ensures comprehensive coverage of different lighting scenarios while maintaining efficient processing rhythm, reducing overall decoding time compared to unstructured repeated attempts.
Solution Approach 2:
The patent implements preliminary action by pre-configuring multiple illumination profiles and exposure settings before actual decoding begins. The terminal prepares a sequence of imaging attribute combinations in advance, allowing it to quickly switch between them during frame capture without extensive real-time computation. This pre-preparation reduces processing delays and enables faster response when encountering specular reflection challenges.
3Object-affected harmful factors
If the terminal alternates between frames with distinct imaging attributes, then specular reflection effects are minimized, but the device complexity and control requirements increase
Solution Approach 1:
The patent applies self-service by implementing automatic selection and switching of illumination profiles based on real-time decoding feedback. The terminal monitors decoding success rates under different illumination conditions and automatically adjusts which profiles to use next, without requiring manual intervention or complex external control systems. This self-managing approach handles the complexity of coordinating multiple imaging attributes internally, reducing the burden on external control while still achieving effective specular reflection mitigation.
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 approach significantly increases the likelihood of successful decoding by avoiding a sequence of undecodable frames and reducing specular reflection-related errors, enhancing the terminal's performance in data collection applications.
Implementation Method 1
Indicia reading terminals face challenges in decoding bar codes and OCR characters due to specular reflection, which causes image degradation and saturation issues
Data Source
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AI summary
There is described a decodable indicia reading terminal which in one embodiment can capture and process a certain (e.g., a first) and a subsequent (e.g., a second) frame of image data, wherein the certain and the subsequent frames have different imaging attributes. In one embodiment the attributes between certain and subsequent frames are differentiated in that the certain frame represents light incident on pixels of a first image sensor (111) and the subsequent frame of image data represents light incident on pixels of a second image sensor (211) spaced apart from the first image sensor. Additionally, or in the alternative, the attributes between certain and subsequent frames can be differentiated in that the first frame represents light incident on an image sensor under a first illumination profile and the subsequent frame represents light incident on pixels of an image sensor under a second illumination profile. In one embodiment imaging attributes of a frame subject to decoding are maintained constant for each frame subject to processing during a time that a trigger signal remains active. In one embodiment the certain and subsequent frames can be processed to yield partial decoding results and the partial decoding results can be combined to form a complete decoding result.