Glare Reduction in Graphical Code Readers via Dynamic Illumination Control
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Solution Overview
Problem
Graphical code readers face challenges in reducing glare, which leads to uneven illumination and decreased contrast in images, especially when capturing codes on reflective surfaces, due to undesirable reflections and specular reflections.
Innovation Solution
A graphical code reader is equipped with an illumination controller that uses multiple sets of light sources with unique characteristics to identify and correct glare by sequencing their activation based on image sensor exposure, employing techniques like rolling shutter methods to adjust light source activation dynamically and deactivate sources causing glare.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple sets of light sources are used to illuminate the target area, then illumination coverage is improved, but glare and specular reflections increase
Solution Approach 1:
The light sources are divided into multiple sets, each set being controllable independently. The illumination controller selectively activates specific sets based on the target area characteristics and camera field of view, thereby providing adequate illumination coverage while avoiding activation of light sources that would cause glare in the captured image.
Solution Approach 2:
The system dynamically controls the activation of different light source sets based on real-time conditions. The illumination controller adjusts which light sources are active according to the target area position, camera angle, and detected glare conditions, optimizing illumination while minimizing harmful reflections.
2Illumination intensity
If light sources are activated to illuminate reflective surfaces, then image brightness is improved, but contrast decreases due to glare
Solution Approach 1:
Different sets of light sources are positioned to provide localized illumination with specific angular characteristics. By selecting appropriate light source sets based on the target area and camera position, the system achieves adequate brightness in the image while avoiding the specific illumination angles that produce glare and maintain image contrast.
3Stability of the object's composition
If all light sources are activated simultaneously, then illumination uniformity is improved, but glare correction becomes more difficult
Solution Approach 1:
The illumination controller activates different sets of light sources in a sequential or selective manner rather than simultaneously. By periodically or selectively switching between different light source configurations, the system achieves adequate illumination uniformity while simplifying glare correction, as each active set can be optimized for specific conditions without the complexity of managing all sources simultaneously.
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 effectively reduces glare in captured images, ensuring even illumination and improved contrast, allowing for accurate decoding of graphical codes even on reflective surfaces.
Implementation Method 1
Light is reflected from the graphical code toward the graphical code reader
Implementation Method 2
Pixels within the image sensor are read electronically to provide a two-dimensional array of image data
Data Source
AI summary
A method for glare reduction may be implemented by a graphical code reader. The method may include illuminating a target area using a plurality of light sources. The method may also include capturing images of the target area using at least one image sensor. The method may also include determining that glare is present in at least one captured image. The method may also include determining glare information that indicates which of the light sources are responsible for the glare. The method may further include taking corrective action to reduce the glare in subsequent images based on the glare information that is determined.