Vision System Field of View Expander Using Mirrors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vision systems face limitations in expanding their field of view without compromising resolution, particularly in widthwise direction for ID readers, leading to missed IDs outside the field of view when imaging moving lines, and existing solutions like multiple cameras or line-scan systems are costly and complex.
Innovation Solution
A field of view expander (FOVE) system using outer and inner mirrors to direct light from different widthwise portions of a scene onto a camera sensor, ensuring features like IDs are fully imaged across an expanded field without distortion, allowing for conventional sensor use and minimizing heightwise resolution increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single ID reader is used, then the system is simple and cost-effective, but the field of view in the widthwise direction is limited and cannot cover the entire width of the line
Solution Approach 1:
The patent employs multiple cameras positioned at different height levels (vertical dimension) to capture the widthwise scene. By stacking cameras vertically, the system expands the effective field of view in the horizontal direction without increasing device complexity in the horizontal plane. Each camera captures a portion of the widthwise scene, and their combined views provide full coverage.
2Area of stationary object
If multiple ID readers are used to cover the full width, then the field of view is expanded, but the system cost and hardware requirements increase
Solution Approach 1:
The patent makes a single camera perform multiple functions by capturing different portions of the widthwise scene through vertical stacking. Instead of requiring multiple separate ID readers, one camera system with multiple sensors stacked vertically achieves the same functional outcome, reducing hardware requirements and system cost while maintaining full width coverage capability.
3Area of stationary object
If a larger sensor is used to provide desired resolution across the widthwise direction, then the field of view is expanded, but the sensor captures the same ID in multiple frames causing extraneous processing
Solution Approach 1:
The patent divides the widthwise scene into multiple segments, with each vertically stacked camera capturing a specific portion. This segmentation prevents any single camera from capturing the entire width, thereby avoiding duplicate captures of the same ID in multiple frames. Each camera's field of view is optimized to cover a specific horizontal zone, reducing extraneous processing while maintaining full width coverage through coordinated multi-camera operation.
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 FOVE system effectively expands the field of view without losing resolution, ensuring IDs are fully imaged and reducing the risk of double readings by using vertically stacked strips and a moving mirror to capture the full width of the scene in successive frames, thus enhancing the efficiency of ID reading processes.
Implementation Method 1
outer mirrors directed to receive light from different widthwise portions of a scene, which can be a moving line of objects. The outer mirrors thereafter direct the light to associated vertically tilted inner mirrors
Implementation Method 2
a beam splitter that, in turn, direct the light through an aperture in the FOVE substantially in alignment along an optical axis of the camera to avoid distortion of images
Implementation Method 3
The inner mirrors direct the light from each outer mirror into a discrete strip on the sensor, with one strip stacked above the other
Data Source
AI summary
This invention provides a system and method for expanding the field of view of a vision system camera assembly such that the field of view is generally free of loss of normal resolution across the entire expanded field. A field of view expander includes outer mirrors that receive light from different portions of a scene. The outer mirrors direct light to tilted inner mirrors of a beam splitter that directs the light aligned with a camera axis to avoid image distortion. The inner mirrors each direct the light from each outer mirror into a strip on the sensor, and the system searches features. The adjacent fields of view include overlap regions sized and arranged to ensure a centralized feature appears fully in at least one strip. Alternatively, a moving mirror changes position between acquired image frames so that a full width of the scene is imaged in successive frames.