Shared-Mirror Hyper Camera for Oblique Imaging and Vignetting Control
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Solution Overview
Problem
Existing aerial camera systems face inefficiencies in capturing oblique images due to difficulties in fitting long focal length lenses and matched aperture mirrors, yaw correction gimbal space inefficiencies, and low image quality issues like blurriness and vignetting.
Innovation Solution
An imaging system with a camera and scanning mirror structure featuring a first mirror portion and a second portion of low reflective material, configured to reflect and block light at specific angles, allowing for efficient capture of oblique images along a scan path, and a drive mechanism to rotate the mirror structure based on scan angles, ensuring optimal image capture and minimizing vignetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a scanning camera system uses long focal length lenses and matched aperture mirrors to capture oblique imagery, then image quality and coverage are improved, but device complexity and space requirements increase
Solution Approach 1:
The scanning mirror is divided into multiple independent segments (first mirror portion, second mirror portion, third mirror portion), each controlling a specific scan angle range. This segmentation allows the system to achieve complex oblique imaging coverage without requiring a single large, complex mirror or multiple complete lens-mirror assemblies, thereby reducing overall device complexity while maintaining image quality.
Solution Approach 2:
The scanning camera system uses a single camera platform that captures images across multiple scan angles (vertical, forward-oblique, and side-oblique) by rotating the segmented scanning mirror. This multi-functional approach allows one camera system to perform what would traditionally require multiple specialized cameras, reducing device complexity while maintaining comprehensive image quality.
2Area of stationary object
If the scanning mirror structure is enlarged to capture wider scan angles, then coverage area increases, but space efficiency in the aerial vehicle decreases
Solution Approach 1:
The scanning mirror is divided into multiple independent segments (first mirror portion, second mirror portion, third mirror portion), each controlling a specific scan angle range. This segmentation allows the system to achieve complex oblique imaging coverage without requiring a single large, complex mirror or multiple complete lens-mirror assemblies, thereby reducing overall device complexity while maintaining image quality.
Solution Approach 2:
The patent utilizes angular dimensionality by rotating the segmented scanning mirror through multiple axes to achieve wide coverage. Instead of expanding the physical size of the mirror in linear dimensions, the system achieves broader coverage by exploiting the angular space available in the aerial vehicle, thereby maintaining space efficiency while increasing effective coverage area.
3Area of stationary object
If light is allowed to pass around the mirror portion at extreme scan angles, then complete scene coverage is achieved, but image quality deteriorates due to vignetting
Solution Approach 1:
The patent extracts and removes the harmful peripheral light rays that would cause vignetting at extreme scan angles. By using the third mirror portion to redirect the imaging beam and the aperture stop to block peripheral rays, the system eliminates the source of vignetting while preserving the necessary scene coverage, thereby maintaining image quality without sacrificing coverage area.
Solution Approach 2:
The patent converts the potential harm of peripheral light rays (which cause vignetting) into a benefit by using the aperture stop to selectively block these rays. The aperture stop, positioned strategically in the optical path, transforms what would be a quality-degrading factor into a quality-enhancing feature by ensuring uniform illumination across the image sensor even at extreme scan angles, while the segmented mirror system maintains comprehensive scene coverage.
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
The solution enhances image quality and efficiency by allowing for precise control of light reflection and blocking, reducing blurriness and vignetting, and optimizing the use of space within aerial vehicles, resulting in improved orthomosaics and textured 3D models from aerial photos.
Implementation Method 1
a scanning mirror structure including at least one surface for receiving light from the object area, the at least one surface having at least one first mirror portion configured to reflect light from the object area over a set of scan angles
Implementation Method 2
the camera includes a lens to focus an imaging beam reflected from the at least one surface of the scanning mirror structure to an image sensor of the camera
Implementation Method 3
at least one second portion comprised of low reflective material arranged around a periphery of the first mirror portion, the low reflective material being less reflective than the first mirror portion, and the at least one second portion is configured to block light
Data Source
AI summary
The present disclosure is directed to a camera configured to capture a set of oblique images along a scan path on an object area; a scanning mirror structure including at least one surface for receiving light from the object area, the at least one surface having at least one first mirror portion at least one second portion comprised of low reflective material arranged around a periphery of the first mirror portion, the low reflective material being less reflective than the first mirror portion; and a drive coupled to the scanning mirror structure and configured to rotate the scanning mirror structure about a rotation axis based on a scan angle. The at least one second portion can be configured to block light that would pass around the first mirror portion and be received by the camera at scan angles beyond the set of scan angles.