Color-Separated Aimer and Illuminator for Barcode Readers
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Solution Overview
Problem
Existing barcode readers face challenges in accurately decoding symbols due to interference from aimer illumination, which disrupts image capture and reduces response speed, especially with 2D symbols of poor quality or high density, as they require time-sharing between aiming and symbol capture processes.
Innovation Solution
The use of different colors or frequency bands for aimer patterns and image capture illumination, achieved through color blocking filters or software processing, allows for concurrent aiming and symbol capture without interference, enabling continuous aimer illumination while capturing images without degrading signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the aimer illumination is used to indicate the scanner's field of view, then the scanner alignment is facilitated, but the aimer pattern becomes visible noise in the captured symbol image, disrupting symbol interpretation
Solution Approach 1:
The patent applies color changes by using different wavelength ranges for aimer illumination and symbol illumination. The aimer uses a first wavelength range (e.g., red or green) while the symbol illumination uses a second wavelength range (e.g., blue or violet), allowing the image sensor to distinguish between aimer patterns and symbol features through color filtering, thus eliminating aimer-induced noise in captured images
Solution Approach 2:
The patent introduces an intermediary color blocking filter that selectively blocks the first wavelength range (aimer wavelength) while allowing the second wavelength range (symbol illumination wavelength) to pass through to the image sensor. This filter acts as a mediator that separates the harmful aimer light from the useful symbol illumination, preventing aimer patterns from appearing as noise in the captured image
2Ease of operation
If the aimer is turned on continuously to provide constant alignment indication, then the alignment visibility is improved, but the response speed of the imager barcode reader decreases due to time-sharing requirements
Solution Approach 1:
The patent enables continuous aimer illumination by separating the aimer wavelength from the symbol illumination wavelength using color blocking filters. This allows the aimer to remain constantly on for continuous alignment indication without needing to share time with the imaging process, as the filter prevents aimer light from interfering with symbol capture, thereby maintaining both continuous visibility and fast response speed
3Reliability
If the aimer intensity is reduced to minimize interference with image capture, then the image capture quality is improved, but the alignment indication becomes less visible
Solution Approach 1:
The patent uses color changes by assigning different wavelength ranges to aimer and symbol illumination. The image sensor is configured with color blocking filters that are highly sensitive to the second wavelength range (symbol illumination) while blocking the first wavelength range (aimer). This allows the aimer to maintain high intensity for good visibility while the filter ensures only symbol illumination reaches the sensor, achieving both high aimer visibility and high image capture quality
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 allows for high-performance symbol decoding with continuous aimer illumination, improving response speed and accuracy, especially for 2D symbols, by effectively separating aimer patterns from image capture illumination.
Implementation Method 1
the image sensor then becomes effectively color-blind to the aimer color through the use of a color blocking filter
Implementation Method 2
an imaging element, the imager, having a spectral response only to a second wavelength
Data Source
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AI summary
A scanner for machine-readable symbols, such as barcodes and two-dimensional matrix symbols, employs at least two different light frequencies (colors). The first frequency supports accurate aiming of the scanner at a symbol. The second frequency supports illumination of a machine-readable symbol so that the reflected illumination light can be read at the second frequency by the scanner's optical imaging element. Employing two different light frequencies enables both aiming and scanning to occur simultaneously, while the aiming process does not interfere with the scanning process. It enables the aiming frequency to be used for additional purposes, such as providing signaling to a user of the scanner. In an embodiment, two distinct light sources are used in the scanner to provide the different light frequencies. In an embodiment, various color filters are employed to separate and distinguish light frequencies. In an embodiment, signal processing may be employed to digitally distinguish multiple separate frequencies in light reflected from the symbol.