Dual Camera Bar Code Reader with Fold Mirrors
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Solution Overview
Problem
Imaging-based bar code readers face challenges in simultaneously achieving high resolution for high-density 2D bar codes and decoding moving 1D/2D bar codes without distortion, as the characteristics required for each type of imaging are often at odds with each other, and existing systems struggle to handle both stationary and portable scanning modes effectively.
Innovation Solution
A dual camera assembly is employed within a housing, featuring a first camera with a global shutter for minimizing blurring when imaging moving 1D bar codes and a second camera with a rolling shutter for high-resolution imaging of high-density 2D bar codes, using fold mirrors to ensure congruent fields of view and allowing for both stationary and portable scanning modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single imaging system is used, then it can be simple in structure, but it cannot simultaneously achieve high resolution for stationary high-density 2D bar codes and minimize distortion for moving 1D bar codes
Solution Approach 1:
The imaging system is segmented into two separate camera assemblies: a first camera with a rolling shutter optimized for high-resolution imaging of stationary high-density 2D bar codes, and a second camera with a global shutter optimized for capturing moving 1D bar codes with minimal distortion. Each camera is specialized for a specific function, allowing the system to handle both bar code types effectively without requiring a single complex camera to do everything.
Solution Approach 2:
The bar code reader system achieves multi-functionality by integrating two cameras with different shutter mechanisms. The system can universally read both stationary high-density 2D bar codes and moving 1D bar codes by selecting the appropriate camera based on the bar code type and motion state, making the reader adaptable to various scanning scenarios.
2Manufacturing precision
If a rolling shutter is used, then high resolution imaging of stationary high-density 2D bar codes is achieved, but distortion occurs when imaging moving bar codes
Solution Approach 1:
Different quality characteristics are applied locally to different cameras: the first camera uses a rolling shutter with high spatial resolution optimized for stationary targets, while the second camera uses a global shutter optimized for capturing moving targets. Each camera's shutter mechanism is matched to its specific function, allowing high resolution for stationary codes and reliability for moving codes without compromise.
Solution Approach 2:
The system introduces a control mechanism that acts as an intermediary to select which camera to use based on the bar code type and motion detection. This mediator determines whether to use the rolling shutter camera for high-resolution stationary code imaging or the global shutter camera for moving code capture, ensuring the appropriate imaging mode is applied in each scenario.
3Reliability
If a global shutter is used, then successful decoding of moving bar codes is achieved, but resolution is insufficient for high-density 2D bar codes
Solution Approach 1:
Different quality characteristics are applied locally to different cameras: the first camera uses a rolling shutter with high spatial resolution optimized for stationary high-density 2D bar codes, while the second camera uses a global shutter optimized for capturing moving 1D bar codes. Each camera's shutter mechanism is matched to its specific function, allowing high resolution for stationary codes and reliability for moving codes without compromise.
Solution Approach 2:
The imaging system is segmented into two separate camera assemblies: a first camera with a rolling shutter optimized for high-resolution imaging of stationary high-density 2D bar codes, and a second camera with a global shutter optimized for capturing moving 1D bar codes with minimal distortion. Each camera is specialized for a specific function, allowing the system to handle both bar code types effectively.
4Quantity of substance
If bar code density is increased to encode more data, then more information is stored in limited area, but imaging resolution requirements increase making decoding more difficult
Solution Approach 1:
The dual-camera system provides universal imaging capability that handles both high-density 2D bar codes requiring high resolution and standard-density 1D bar codes. The system can adaptively select the appropriate camera based on the detected bar code type, ensuring sufficient resolution for decoding high-density codes while maintaining the ability to read standard-density codes.
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
The dual camera assembly enables successful imaging and decoding of both high-density 2D and moving 1D/2D bar codes, providing clear images and minimizing distortion, while allowing the device to be used in both hands-free and portable modes without requiring special user training.
Implementation Method 1
The first camera assembly includes a two dimensional sensor array having a global shutter pixel structure for imaging a target bar code swiped through the first field of view
Implementation Method 2
The second camera assembly includes a two dimensional sensor array having a rolling shutter pixel readout structure for high resolution imaging of a target bar code comprising a high density one or two dimensional bar code
Implementation Method 3
a fold mirror and positioned within the bar code reader housing to intersect and direct the field of view of at least one of the first and second camera assemblies such that the first and second fields of view pass through the exit window and are substantially congruent exterior of the housing
Implementation Method 4
Light reflected from the target bar code is focused through a system of one or more lens of the imaging system onto the pixel array
Data Source
AI summary
An imaging system (20) for an imaging-base bar code reader (10) having a housing (11) and a window (17). The imaging system (20) includes a dual camera assembly (22) having a first camera assembly (24) and a second camera assembly (26) mounted within the housing (11) to image a target object (14a, 14b). The first camera assembly (24) includes a first field of view (FOV1) and the second camera assembly (26) including a second field of view (FOV2). The imaging system (20) further includes a fold mirror (36, 37) and positioned within the bar code reader housing (11) to intersect and direct the field of view of at least one of the first and second camera assemblies (24, 26) such that the first and second fields of view (FOV1, FOV2) pass through the exit window (17) and are substantially congruent exterior of the housing (11).