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 more accurate 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 makes the ROI dynamic by linking its position and size to the current aimer position inside the image. Instead of using a fixed ROI, the system continuously updates the ROI based on where the aimer is currently located, ensuring the ROI always encompasses the machine-readable symbol regardless of target distance changes.
Solution Approach 2:
The patent implements feedback by using the aimer position as input to determine the ROI parameters. The system monitors the aimer position in real-time and uses this information to adjust the ROI, creating a closed-loop system that adapts to changing conditions.
2Reliability
If the ROI is adjusted to follow the aimer position, then exposure accuracy improves, but the exposure convergence speed may degrade
Solution Approach 1:
The patent performs preliminary action by calculating and setting the ROI parameters in advance, one frame before the actual exposure is needed. This allows the exposure algorithm to work with pre-determined ROI settings, reducing computational overhead during the critical exposure moment.
Solution Approach 2:
The patent uses partial action by updating the ROI parameters at a lower frequency than the full frame rate. Instead of recalculating ROI every frame, the system updates it at sufficient intervals to maintain accuracy while reducing the overall computational burden.
3Reliability
If the ROI position changes with target distance, then the machine-readable symbol is consistently included, but additional processing is required to determine aimer position
Solution Approach 1:
The patent makes the existing aimer localization functionality serve a dual purpose. The same processing that determines aimer position for display purposes is also used to define the ROI parameters for auto-exposure, eliminating the need for separate ROI calculation logic.
Solution Approach 2:
The patent merges the aimer position detection function with the ROI determination function. By combining these two functions into a single integrated process, the system reduces processing complexity while ensuring the ROI always includes the machine-readable symbol.
Data Source
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.