Optical Scanner ROI Exposure Control Using Aimer Position
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing auto-exposure algorithms in machine-readable symbol readers often fail to accurately adjust the region of interest (ROI) based on the aimer position, leading to underexposed or overexposed symbols, especially in complex scenes with varying brightness, due to mechanical offsets and changing target distances.
Innovation Solution
Linking the auto-exposure ROI position and size to the current aimer position within the image, using target distance measures from sensors like time-of-flight, to dynamically adjust the ROI for precise exposure settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed ROI is used for auto-exposure, then the exposure algorithm is simple and fast, but the ROI may not include the machine-readable symbol when target distance changes
Solution Approach 1:
The patent implements dynamic ROI adjustment by linking the auto-exposure ROI position and size to the current aimer position inside the image. When target distance changes causing the aimer to move toward the edge, the ROI automatically adjusts to follow the aimer position, ensuring the symbol remains within the exposure calculation area. This resolves the contradiction by making the system adaptive rather than static.
Solution Approach 2:
The system uses feedback from the aimer position detection to continuously adjust the ROI parameters. The auto-exposure algorithm monitors the aimer position and modifies the ROI accordingly, creating a closed-loop control system that maintains exposure accuracy despite changes in target distance or scene conditions.
2Reliability
If the ROI is adjusted to follow the aimer position, then exposure accuracy improves, but exposure convergence speed may degrade
Solution Approach 1:
The system performs preliminary action by pre-calculating and storing the relationship between aimer position and optimal ROI parameters. When the aimer position changes, the system retrieves pre-computed ROI adjustments rather than performing complex real-time calculations, thus maintaining both accuracy and speed.
Solution Approach 2:
The patent changes the parameter representation by using discrete aimer position zones with corresponding pre-determined ROI configurations. Instead of continuous complex calculations, the system transitions between predefined parameter sets based on detected aimer position, balancing accuracy requirements with computational efficiency.
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
Improves system reliability by providing accurate auto-exposure luminance targets for machine-readable symbols, even in complex scenes, without significantly degrading exposure convergence speed.
Implementation Method 1
using target distance measures from sensors like time-of-flight
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
An image-acquisition method includes capturing, with an image sensor that includes a pixel array, a first image-set of a scene illuminated by an aimer-pattern. Each image of the first image-set includes a respective image-region detected by a plurality of pixels of the pixel array that define an aimer-illuminated region of the pixel array that at least in part determines a region-of-interest (ROI) of the pixel array. The method also includes determining an ROI exposure-setting based on ROI pixel-values of the first image-set generated by the ROI of the pixel array. The method also includes capturing a second image-set of the scene while the exposure setting of pixels of the aimer-illuminated region equals the ROI exposure-setting. An optical scanner comprising an image sensor including a pixel array, a light emitter; and circuitry is also disclosed.