Variable Focus Lens Code Reader for Extended Range
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Solution Overview
Problem
Conventional image formation systems in code readers have limited reading range, struggling with obtaining sharp images over long distances, sufficient resolution at large distances, and maintaining continuous illumination, especially in handheld devices with space and power constraints.
Innovation Solution
An image-based code reader with a variable optical power lens and an orientation sensor, allowing for adjustable focus distance and illumination settings based on the reader's mode and angle, using a processor to control the lens and LED banks for optimal image acquisition within a region of interest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional image formation system is used, then the device structure is simple, but the reading range is limited and resolution deteriorates at large distances
Solution Approach 1:
The patent implements a variable focus lens that can dynamically adjust its focal length to accommodate different reading distances. The lens transitions between a first focus state for close-range reading and a second focus state for long-range reading, enabling the system to maintain sharp focus across a broad reading range from close to far distances without sacrificing resolution at any distance.
Solution Approach 2:
The system changes optical parameters by switching the lens between different focus states. The variable focus lens alters its optical properties based on the reading distance requirements, allowing the same optical system to achieve high resolution at both close and far distances by adjusting the focal length parameter.
2Area of stationary object
If the entire sensor is used for image acquisition, then the field of view is maximized, but power consumption and data processing increase
Solution Approach 1:
The patent extracts and processes only the relevant portion of the captured image by identifying a region of interest (ROI) that contains the code. Instead of processing the entire sensor data, the system isolates and processes only the necessary area, reducing computational load and power consumption while maintaining effective code reading capability.
Solution Approach 2:
The system applies different processing quality levels to different regions of the sensor output. The region containing the code receives full processing attention, while other areas are either discarded or processed with minimal effort. This local quality approach optimizes the balance between field of view utilization and processing resource consumption.
3Measurement precision
If illumination is increased to prevent blur at long distances, then image quality improves, but power consumption increases
Solution Approach 1:
The patent adjusts illumination parameters dynamically based on reading distance. The system uses different illumination intensities and patterns for close-range and long-range reading scenarios. By changing the illumination parameters to match the specific reading conditions, the system achieves sufficient image sharpness without unnecessarily consuming power in all reading scenarios.
4Measurement precision
If a variable focus lens is added to extend reading range, then reading range and resolution improve, but device complexity increases
Solution Approach 1:
The patent implements a variable focus lens that can dynamically adjust its focal length to accommodate different reading distances. The lens transitions between a first focus state for close-range reading and a second focus state for long-range reading, enabling the system to maintain sharp focus across a broad reading range from close to far distances without sacrificing resolution at any distance.
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
Enables improved reading and decoding of codes over a broader range (0.3 meters to 15 meters) with enhanced resolution and continuous illumination, reducing power consumption and data processing by focusing only on necessary image areas.
Implementation Method 1
a lens configured to project an image scene including the code onto the image sensor, the lens comprising a variable optical power that controls a focus distance
Implementation Method 2
an image sensor configured to acquire an image of a code
Data Source
AI summary
An image based code reader comprises an image sensor. The image sensor is configured to acquire an image of a code. Additionally, the image based code reader includes a lens configured to project an image scene including the code onto the image sensor, the lens comprising a variable optical power that controls a focus distance of the image based code reader. The image based code reader further includes a processor operatively coupled to the image sensor and the lens. The processor is configured to acquire the image of the code using only pixels located within a region of interest of the sensor, and a size of the region of interest is selected based on the focus distance of the reader.