Optical Navigation Window Using Per-Slice Illumination Thresholds
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Solution Overview
Problem
Optical navigation systems face navigation errors due to uneven illumination, which can cause tracking errors and degrade image feature contrast, especially when the illumination source is misaligned or intensity drops off suddenly.
Innovation Solution
The technique involves establishing a navigation window by summing image data on a per-slice basis, comparing these sums to a pre-established intensity threshold, and defining boundaries at points where the sums equal the threshold, thereby excluding poorly illuminated areas from the correlation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire image data is used in the correlation process, then the tracking process is simple and fast, but navigation errors occur due to poorly illuminated areas with insufficient contrast
Solution Approach 1:
The patent divides the image data into multiple slices (rows or columns) and evaluates illumination quality for each slice independently. By segmenting the image into manageable units, the system can identify and exclude only the poorly illuminated portions while retaining properly illuminated areas for correlation processing, thus maintaining tracking accuracy without requiring complex global illumination correction
Solution Approach 2:
The patent extracts and removes poorly illuminated slices from the image data before performing correlation processing. By identifying slices that fail to meet illumination thresholds and excluding them from the correlation calculation, the system eliminates the source of navigation errors while keeping the processing pipeline relatively simple and fast
2Measurement precision
If poorly illuminated areas are excluded from correlation processing, then navigation accuracy improves, but the processing time and computational complexity increase
Solution Approach 1:
The patent performs illumination evaluation and identifies poor-quality slices before the correlation processing begins. By pre-processing the image data to mark or exclude problematic areas in advance, the system avoids wasting computational resources during correlation on data that would not contribute to accurate measurement, thus reducing overall processing time
Solution Approach 2:
The patent applies different quality standards to different regions of the image data by evaluating illumination characteristics locally for each slice. Instead of requiring uniform high quality across the entire image, the system accepts locally varying quality and selectively uses only those regions that meet the illumination threshold, improving measurement precision without uniformly increasing processing complexity
Data Source
AI summary
A technique for reducing navigation errors that are caused by uneven illumination involves using only the portion of the image data that is properly illuminated in the correlation process. The portion of the image data that is used for optical navigation is established by summing the image data on a per-slice basis, comparing the per-slice sums to a pre-established intensity threshold, and defining boundaries of the navigation window in response to the comparison. Boundaries are set at the points where the per-slice sums equal the pre-established intensity threshold.