Camera Image Correction for Perspective Distortion
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Solution Overview
Problem
Wide angle distortion in photographed images, particularly perspective distortion, remains unaddressed in three-dimensional objects even after two-dimensional distortion correction, leading to enlarged images of individuals at the edge of the frame.
Innovation Solution
A camera with a processing unit that adjusts distortion correction based on the focal length and incident angle of the photographing optical system, incorporating a face detection unit to modify correction amounts, and employing specific correction patterns expressed by conditional equations to minimize wide angle distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a wide angle lens is used to photograph the background as widely as possible, then the photographing angle is increased, but perspective distortion occurs causing individuals at the edge portion to be enlarged horizontally
Solution Approach 1:
The patent applies different correction amounts to different regions of the image based on the incident angle. Specifically, the correction amount is adjusted according to the position in the image (center vs. edge portions) and the detected object type (face vs. non-face). This local differentiation allows the system to correct perspective distortion at edge portions where faces are detected while preserving the wide angle effect in other regions, thereby resolving the contradiction between wide photographing angle and perspective distortion.
Solution Approach 2:
The patent dynamically changes the correction parameter (correction amount) based on the incident angle θ and the detected object characteristics. The correction amount is not fixed but is adjusted according to the position in the image and whether a face is detected at that position. This parameter adaptation allows the system to minimize perspective distortion for faces while maintaining the overall wide angle photographing effect.
2Manufacturing precision
If distortion correction is performed based on focal length and incident angle, then two-dimensional distortion is corrected, but three-dimensional perspective distortion remains
Solution Approach 1:
The patent performs preliminary detection of faces in the image before applying distortion correction. By detecting the presence and position of faces in advance, the system can prepare appropriate correction amounts for different regions. This preliminary action allows the correction process to account for three-dimensional object characteristics (faces) while correcting two-dimensional distortion, thereby resolving the contradiction between correction precision and three-dimensional representation.
Solution Approach 2:
The patent introduces dynamic adjustment of correction amounts based on detected object characteristics. Rather than applying a static correction formula, the system dynamically modifies the correction amount for each region based on whether a face is detected and the incident angle at that position. This dynamic approach allows the system to adapt to three-dimensional object representation needs while maintaining two-dimensional distortion correction.
3Device complexity
If uniform distortion correction is applied across the entire image, then processing is simplified, but faces at edge portions remain distorted
Solution Approach 1:
The patent segments the image into different regions based on face detection results and incident angle zones. The image is divided into regions with faces and regions without faces, and correction amounts are determined separately for each segment. This segmentation allows the system to apply higher precision correction to face regions while using simpler correction for other regions, resolving the contradiction between processing complexity and face image accuracy.
Solution Approach 2:
The patent applies excessive correction (larger correction amounts) only to the extent necessary for face regions at edge portions, rather than uniformly across the entire image. The correction amount is increased locally where faces are detected and the incident angle indicates significant perspective distortion, while other regions receive standard correction. This partial application of excessive action resolves the contradiction by providing high precision where needed without unnecessarily increasing overall complexity.
Data Source
AI summary
A camera 1 for forming an image using an imaging lens 3 comprises a distortion correction unit 44 which, when a distortion of an image is corrected based on a focal length of the imaging lens 3 and an incident angle of rays from an object to the imaging lens 3, changes the amount of the correction according to the incident angle.