Tilted Photosensor Imaging System for Keystone Distortion Correction
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Solution Overview
Problem
Digital imaging systems face keystone distortion, resolution non-uniformity, and gradient blur when capturing images of objects with surfaces tilted relative to the camera's optical axis, particularly affecting accuracy in applications with macro lenses and steep angles.
Innovation Solution
The imaging system compensates for these issues by tilting one or more components, such as the photosensor, aperture, and lens elements, to adjust focal lengths and magnification, and using wedge optics to correct keystone distortion and blur, while ensuring modulation transfer function and depth of field requirements are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a camera with a fixed optical axis is used to capture images of tilted objects, then the device complexity is low, but keystone distortion and resolution non-uniformity occur
Solution Approach 1:
The patent applies asymmetry by tilting the photosensor relative to the optical axis of the lens assembly. This asymmetric configuration allows the imaging system to capture tilted objects without keystone distortion, as the photosensor is angled to match the tilt angle of the object plane, thereby achieving uniform image resolution across the entire object surface.
Solution Approach 2:
The patent introduces a angular dimension by tilting the photosensor at a specific angle relative to the optical axis. This dimensional change enables the system to accommodate tilted object planes, transforming a two-dimensional image plane problem into a three-dimensional solution that maintains resolution uniformity across tilted surfaces.
2Manufacturing precision
If the camera optical axis is perpendicular to the object surface, then image resolution is uniform, but the camera cannot capture tilted objects without keystone distortion
Solution Approach 1:
By tilting the photosensor asymmetrically relative to the optical axis, the system gains adaptability to capture tilted objects while maintaining uniform resolution. The photosensor tilt angle corresponds to the object tilt angle, allowing the camera to accommodate various shooting scenarios without losing image quality or introducing distortion.
Solution Approach 2:
The tilted photosensor configuration provides multi-functionality, enabling the same camera system to capture both perpendicular and tilted objects effectively. This universal design allows the imaging system to adapt to different object orientations and shooting angles while maintaining consistent image resolution and avoiding keystone distortion across various scenarios.
3Length of moving object
If macro lens with steep angle is used, then close-up imaging capability is improved, but gradient blur and keystone distortion increase significantly
Solution Approach 1:
The patent applies asymmetry by tilting the photosensor to match the steep angle of the macro lens. This asymmetric configuration compensates for the keystone distortion and gradient blur inherent in macro photography, allowing close-up imaging while maintaining image accuracy and uniform resolution across the entire subject.
Solution Approach 2:
The patent changes the photosensor orientation parameter by tilting it at a specific angle relative to the optical axis. This parameter change optimizes the imaging geometry for macro applications with steep angles, maintaining both close-up capability and image accuracy by aligning the photosensor plane with the tilted object plane.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures that both ends of the object are in focus and maintains high image resolution across the object height, improving the accuracy and quality of captured images by addressing keystone distortion and gradient blur.
Implementation Method 1
two or more refractive lens elements mounted in a lens barrel
Implementation Method 2
a photosensor
Data Source
AI summary
An imaging system including a front aperture, two or more refractive lens elements mounted in a lens barrel, and a photosensor. One or more of the components of the imaging system (e.g., the aperture, lenses, lens groups, and/or photosensor) are tilted with respect to each other and/or with respect to a center (or mechanical) axis of the imaging system to compensate for effects including but not limited to keystone distortion, resolution non-uniformity, and gradient blur that result from tilt of an object in the field of view of the camera with respect to the center axis of the camera.