Wide-Angle Camera Cropping With Lookup-Table Distortion Correction
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Solution Overview
Problem
Existing methods for correcting perspective distortion in wide-angle camera images, such as those used in videoconferencing, are either costly due to multiple camera setups or computationally intensive, making them impractical for real-time video streams.
Innovation Solution
A system and method that utilize a lookup table to apply scale factors based on angular position to correct perspective distortion in wide-angle camera images, specifically for individuals outside a central viewing range, using a low-complexity algorithm with minimal processing and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple cameras with narrow fields of view are used to reduce perspective distortion, then image quality improves, but hardware cost and device complexity increase
Solution Approach 1:
The image processing is segmented into different angular zones (central field of view vs. outer field of view). Correction is selectively applied only to individuals in the outer angular range where perspective distortion is significant, while individuals in the central range are processed without correction. This selective segmentation reduces overall processing complexity while maintaining image quality where it matters most.
Solution Approach 2:
Different processing approaches are applied to different regions of the image based on angular position. The lookup table provides locally optimized scale factors for each angular position, allowing precise correction tailored to the specific geometric distortion at each location in the wide-angle field of view.
2Measurement precision
If computationally intensive algorithms are used to correct perspective distortion, then image quality improves, but processing time increases
Solution Approach 1:
The lookup table is pre-computed and stored, containing all necessary scale factors for correcting perspective distortion at different angular positions. During real-time video processing, the system simply performs a table lookup based on the individual's angular position and applies the pre-determined scale factor, avoiding the need for computationally intensive real-time calculations while maintaining correction accuracy.
Solution Approach 2:
Instead of performing complex real-time calculations, the system uses a pre-generated lookup table that copies the results of intensive computations into a readily accessible format. The table stores the relationship between angular position and required scale factors, allowing rapid retrieval and application during video streaming without repeating the intensive computational work.
3Area of stationary object
If a wide field of view camera is used to capture all conference participants, then coverage area improves, but perspective distortion increases
Solution Approach 1:
The correction approach dynamically adapts to the angular position of each individual in the wide-angle field of view. By calculating and applying position-dependent scale factors from the lookup table, the system maintains accurate facial feature representation across the entire wide field of view, with correction intensity varying dynamically based on how far from the central axis each participant is positioned.
Data Source
AI summary
An information handling system supports video conferences with a wide field of view camera that generates a gallery of plural individual participants captured in the wide field of view and cropped to have a gallery window for each individual. Individuals captured in a central region of the field of view are cropped without correction of perspective distortion while individuals captured at the edge of the field of view have their cropped images corrected for perspective distortion by reference to a table with stored correction scales based upon the angles of a trapezoidal bounding box drawn around the individuals to support rapid and real time corrections.