Aerial Imaging Camera Assembly Using Mirror Folding and Liquid Crystal Shutters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional airborne camera assemblies for aerial photography are expensive, large, and heavy, requiring low-altitude flights to maintain short optical focal lengths, which limits their ability to cover large areas efficiently.
Innovation Solution
The use of small format interline CCDs, mirror-based folding lenses, and light-scattering liquid crystal shutters, combined with gyroscopic sensors and motor encoders for motion compensation, allows for the creation of a lightweight, inexpensive camera assembly that generates wide-angle sweep images and accurate digital terrain models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If large format CCDs with wide-angle lenses are used, then mapping accuracy is improved, but system cost, size, and weight increase significantly
Solution Approach 1:
The patent uses small format CCDs that capture multiple images which are then computationally combined to create a synthetic wide-angle view, copying the function of large format CCDs without the physical bulk and cost
Solution Approach 2:
The patent transitions from a single wide-angle image capture to a multi-image sequence captured at different angles, using computational methods to synthesize the final wide-angle view, thereby achieving wide coverage without large optics
2Measurement precision
If large format CCDs with wide-angle lenses are used, then mapping accuracy is improved, but device size increases
Solution Approach 1:
The patent uses small format CCDs that capture multiple images which are then computationally combined to create a synthetic wide-angle view, copying the function of large format CCDs without the physical bulk and cost
Solution Approach 2:
The patent transitions from a single wide-angle image capture to a multi-image sequence captured at different angles, using computational methods to synthesize the final wide-angle view, thereby achieving wide coverage without large optics
3Area of moving object
If short optical focal lengths are used, then field of view is improved, but flight altitude must be reduced, limiting coverage area
Solution Approach 1:
The patent transitions from a single wide-angle image capture to a multi-image sequence captured at different angles, using computational methods to synthesize the final wide-angle view, thereby achieving wide coverage without large optics
Solution Approach 2:
The patent uses a dynamically sweeping field of view through multiple sequential images captured at varying angles, allowing the system to cover large areas by moving the effective field of view across the terrain rather than relying on a fixed wide-angle lens
4Productivity
If mechanical shutters are used, then image capture is achieved, but reliability decreases and frame rate is reduced
Solution Approach 1:
The patent replaces mechanical shutters with electronic shutter control, eliminating moving parts that fail and enabling higher frame rates through purely electronic timing control of the CCD exposure
5Use of energy by moving object
If polarizer shutters are used, then image capture is achieved, but light energy absorption increases
Solution Approach 1:
The patent replaces polarizer-based optical shutters with electronic shutter control, eliminating the need for light-absorbing polarizing filters and allowing direct electronic timing of CCD exposure without significant light energy loss
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 solution results in a compact, cost-effective system capable of capturing high-resolution images over large areas with minimal size and weight, while maintaining accurate motion compensation and reducing light absorption, thus overcoming the limitations of prior art systems.
Implementation Method 1
the subject invention uses a light-scattering liquid crystal shutter, which absorbs only negligible amounts of light
Implementation Method 2
the subject invention uses a light-scattering liquid crystal shutter
Implementation Method 3
The subject invention uses mirror-based folding lenses to reduce the size of an optical assembly
Implementation Method 4
The subject invention uses gyroscopic sensors, GPS data and motor encoders for calculating motion compensation
Implementation Method 5
Motion compensation is performed by tilting a mirror mounted on the folding optics, using a piezoelectric tilt platform
Data Source
AI summary
Apparatus for capturing images while in motion, including at least one CCD camera housed within an aircraft traveling along a flight path, for capturing aerial images of ground terrain, a motor for rotating an axis on which the at least one CCD camera is mounted, and for generating a sweeping back-and-forth motion for a field of view of the at least one CCD camera, the sweeping motion being transverse to the aircraft flight path, and an optical assembly connected to said at least one CCD camera.