Signal Processing Apparatus for Lens and Windshield Distortion Correction
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Solution Overview
Problem
Existing technologies require capturing calibration chart images twice, once with and once without a windshield, to correct for both lens and windshield distortions, which increases calibration time and is inefficient.
Innovation Solution
A signal processing apparatus that estimates lens distortion and transmissive body distortion separately using feature points in images captured through a transmissive body, allowing for distortion correction without the need for multiple calibration captures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed by capturing images twice (with and without windshield), then both lens distortion and windshield distortion can be corrected, but calibration time increases and efficiency decreases
Solution Approach 1:
The patent segments the distortion correction process into two independent estimation phases: lens distortion estimation (comparing first image through windshield with second image without windshield) and transmissive body distortion estimation (comparing first image with third image where lens distortion is removed). This segmentation allows each type of distortion to be corrected using appropriate reference images, achieving accurate correction without requiring multiple full calibration cycles.
Solution Approach 2:
The patent performs preliminary lens distortion estimation and removal to generate the third image before estimating transmissive body distortion. By预先 removing lens distortion from the first image to create the third image, the system establishes a clean reference for isolating and correcting only the transmissive body distortion, thereby achieving comprehensive distortion correction in a streamlined single-calibration workflow.
2Measurement precision
If calibration is performed with windshield installed, then windshield distortion can be corrected, but if misalignment occurs between camera body and lens, complete recalibration is required
Solution Approach 1:
The patent separates lens distortion parameters and transmissive body distortion parameters into independent estimation processes. Lens distortion is estimated by comparing the first image (through windshield) with the second image (without windshield), while transmissive body distortion is estimated by comparing the first image with the third image (lens distortion removed). This independence allows selective recalibration of either lens or windshield parameters without requiring complete recalibration, enhancing system adaptability.
Solution Approach 2:
The patent estimates and corrects distortion by adjusting parameters independently: lens distortion parameters are derived from feature point correspondences between images captured with and without the windshield, while transmissive body distortion parameters are derived from comparing images with and without lens distortion. This parameter independence enables flexible recalibration where only the affected parameter set needs to be re-estimated, rather than recalibrating the entire system.
3Loss of information
If multiple images are captured for calibration, then comprehensive distortion data is obtained, but processing complexity and time consumption increase
Solution Approach 1:
The patent segments the distortion correction into two distinct estimation processes using the same set of three images: lens distortion estimation uses the first and second images, while transmissive body distortion estimation uses the first and third images. This segmentation allows comprehensive distortion data to be extracted from a single calibration session without requiring additional images or complex multi-stage processing, thereby reducing overall process complexity while maintaining data completeness.
Data Source
AI summary
Provided is a signal processing apparatus that estimates image distortion in a case where images are captured through a transmissive body allowing light to pass through. The signal processing apparatus includes a lens distortion estimation section that estimates lens distortion based on a location of a feature point in a first image and a second image of an object. The first image is captured by an imaging section through a transmissive body and a lens that allow light to pass through. The second image is free of transmissive body distortion caused by the transmissive body and free of the lens distortion caused by the lens. The apparatus further includes a transmissive body distortion estimation section that estimates the transmissive body distortion based on the location of the feature point in the first image and a third image that is obtained by removing the estimated lens distortion from the first image.