Point Spread Function Estimation Using Display-Based Synthetic Sources
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for estimating the point spread function (PSF) of intrinsic lens blur are either expensive, require sophisticated equipment, or are not applicable to all camera configurations, especially for mobile devices with small sensor areas that generate a lot of noise.
Innovation Solution
A computer-implemented method that displays at least two images with visual features and a test pattern on a display unit, acquires these images using a camera, determines a coordinate transformation to align the camera and display coordinate systems, and corrects the intensity of the acquired images to estimate the PSF, thereby overcoming the limitations of prior methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement methods (laser and precision collimator or pinhole image analysis) are used to measure PSF, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a display unit to generate a synthetic point source image that copies the ideal PSF pattern, eliminating the need for physical laser equipment or pinhole apparatus. The display unit creates a controlled test pattern that can be captured by the camera under test, providing a simplified measurement setup while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces expensive, sophisticated measurement equipment with a inexpensive display unit that can generate the necessary test patterns. The display unit acts as a temporary, disposable test target that can be easily replaced or reconfigured without requiring complex optical benches or precision alignment equipment.
2Ease of operation
If parameterized modeling techniques are used to model PSF, then ease of operation is improved, but measurement precision deteriorates due to applicability limitations
Solution Approach 1:
The patent transforms the PSF measurement problem from requiring complex parameterized modeling to a direct image capture problem. By changing the parameters of the test pattern (using a display unit to generate specific intensity distributions), the method enables direct measurement without needing to adjust modeling parameters for different camera configurations.
3Device complexity
If blind PSF estimation methods are used on mobile devices, then device complexity is reduced, but measurement precision deteriorates due to sensor noise
Solution Approach 1:
The patent applies preliminary intensity correction to the captured test pattern image before PSF estimation. By pre-correcting for vignetting and illumination non-uniformity using a flat-field reference image, the method removes noise sources that would otherwise degrade measurement precision on mobile devices with small sensors.
Data Source
AI summary
A method for determining a point spread function (PSF) of a camera, comprising: displaying on a display at least two images comprising visual features, elements having a different optical intensity, and a test pattern; acquiring the images using the camera; determining a coordinate transformation using the image comprising the visual features and its corresponding acquired image, the coordinate transformation for aligning together a coordinate system of the camera and a coordinate system of the display; aligning the acquired image comprising the elements having a different optical intensity using the determined coordinate system and determining a difference of intensity between the displayed image comprising the elements having a different optical intensity and the corresponding acquired image; aligning the acquired image comprising the test pattern and correcting an intensity of the acquired image comprising the test pattern, thereby obtaining a corrected image; and estimating a PSF using the corrected image.