Handheld Optical Reader Multi-Angle Illumination for Reflective Symbols
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Solution Overview
Problem
Handheld optical information reading devices face difficulties in reading symbols on workpieces with high surface reflectance, as specular reflection reduces the brightness difference between symbols and the surface, making it challenging to extract the symbol contour, and existing optimization methods are cumbersome and inconvenient for users.
Innovation Solution
The device includes a housing with a grip, an image capture device, an illuminator with multiple lighting devices around the optical axis, and an image processor that captures and synthesizes images from different illumination directions to create an outline-emphasized image of the symbol, allowing for stable reading of symbols even on specularly reflective surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lighting direction is optimized to emphasize brightness difference, then symbol reading accuracy is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The patent applies dynamics by making the illumination direction changeable through rotation of the illumination unit relative to the optical axis. This allows the system to adapt to different workpiece surface conditions (specular vs. diffuse reflection) by dynamically adjusting the illumination angle, thereby maintaining high reading accuracy without requiring complex fixed lighting structures for each condition.
Solution Approach 2:
The patent changes the illumination direction parameter (angle relative to optical axis) to optimize symbol reading under different surface conditions. By varying this parameter, the system can emphasize brightness differences between symbol and background on specular surfaces, improving measurement precision without adding structural complexity.
2Measurement precision
If lighting direction is optimized to emphasize brightness difference, then symbol reading accuracy is improved, but ease of operation worsens
Solution Approach 1:
The system performs self-service by automatically selecting and adjusting the illumination direction based on the detected workpiece surface characteristics. The control unit automatically manages the rotation and positioning of the illumination unit, eliminating the need for users to manually optimize lighting conditions, thereby maintaining high reading accuracy while preserving ease of operation.
3Measurement precision
If handheld device is held in particular orientation, then symbol reading accuracy is improved, but ease of operation worsens
Solution Approach 1:
The patent applies dynamics by enabling the illumination unit to rotate and adjust its direction independently of the device housing orientation. This dynamic adjustment capability allows the system to maintain optimal illumination angles for accurate symbol reading regardless of how the user holds the device, thereby improving ease of operation while preserving measurement precision.
4Measurement precision
If multiple lighting devices are used to irradiate from different directions, then outline extraction is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the illumination function into multiple lighting devices arranged at different positions and angles around the optical axis. This segmentation allows each lighting device to contribute to emphasizing different portions of the symbol outline, improving extraction accuracy while keeping each individual lighting component relatively simple.
Solution Approach 2:
The patent combines multiple lighting devices into a single integrated illuminator unit that can be rotated as one assembly. This merging approach allows the system to achieve multi-directional illumination benefits while managing complexity through unified control and coordinated operation of the lighting array.
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 enables stable and efficient reading of symbols by emphasizing the outline of the symbol through multi-angle illumination, improving user convenience and reducing the need for complex lighting optimizations.
Implementation Method 1
The illuminator includes a plurality of lighting devices arranged around the periphery of an optical axis of the image capture device
Implementation Method 2
light irradiated on a surface of a workpiece will be specularly reflected when handheld optical information reading devices read such a DPM symbol
Implementation Method 3
brightness difference in reflected light between the protruding/recessed part of symbols and the other part of the surface of the workpiece
Data Source
AI summary
A handheld optical information reading device is provided which comprises a housing, a grip arranged on the housing, an image capture device, an illuminator, an illumination controller, an imaging controller, an image processor, and a reader. The image capture device captures an image including a symbol. The illuminator includes lighting devices around the periphery of an optical axis of the image capture device. The illumination controller controls the illuminator to selectively successively light up the lighting devices based on a predetermined order whereby irradiating a symbol with light in different illumination directions with respect to the optical axis. The imaging controller controls the image capture device to capture images of the symbol every when the lighting devices are selectively successively lighted up. The image processor creates an outline image of the symbol based on the captured images. The reader reads the symbol based on the created outline image.