Passive Vision HAGL Measurement via Optical Flow Depth Mapping
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Solution Overview
Problem
Current systems for obtaining height above ground level (HAGL) measurements and terrain data for aircraft are costly and suffer from interference issues, with limited effectiveness beyond a few hundred meters altitude.
Innovation Solution
A system comprising an image capturing device, a navigation system, and processors that estimate optical flow and determine rigid flow per depth bin to generate a dense depth map, providing HAGL measurements and terrain data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active sensors (RADAR, LIDAR) are used for HAGL measurement, then measurement range is improved, but cost increases significantly
Solution Approach 1:
The patent replaces active sensing systems (RADAR, LIDAR) with a passive vision-based system using standard cameras and computational algorithms. The optical flow estimation and rigid flow determination methods enable depth and HAGL measurement without emitting signals, substituting expensive active sensors with affordable passive imaging devices while maintaining measurement capability
Solution Approach 2:
The patent creates a virtual depth map from 2D image sequences through computational processing of optical flow and pose data. Instead of directly measuring depth with expensive hardware, the system generates a computational copy of the 3D scene from multiple 2D views, enabling accurate HAGL estimation using inexpensive camera hardware
2Measurement precision
If active sensors emit signals for HAGL measurement, then measurement capability is improved, but interference with other systems occurs
Solution Approach 1:
The patent substitutes active signal-emitting sensors with passive optical imaging systems. By using standard cameras to capture image sequences and computing depth through optical flow and geometric relationships, the system eliminates radio frequency emissions that interfere with telecommunications and other electronic systems while maintaining HAGL measurement accuracy
3Measurement precision
If active sensors are used for HAGL measurement, then measurement range is extended, but detectability by other systems increases
Solution Approach 1:
The patent replaces active sensing systems that emit detectable signals with passive vision-based systems. The use of standard cameras and computational optical flow methods enables the system to operate without emitting electromagnetic radiation, making it undetectable by signal-detection systems while achieving extended measurement range through algorithmic processing
Data Source
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AI summary
Systems and methods for low-cost HAGL measurement and terrain database updates are provided. In one example, a system includes an image capturing device configured to capture first and second images and a navigation system configured to generate pose data. The system further includes processor(s) communicatively coupled to the image capturing device and the navigation system and a non-transitory, computer-readable medium communicatively coupled to the processor(s) that stores instruction(s) which, when executed by the processor(s), cause the processor(s) to: estimate optical flow between the first and second images; determine rigid flow per image for each depth bin of a group of depth bins based on the pose data, wherein each depth bin corresponds to a particular depth range; and generate a dense depth map by determining a depth bin, for each pixel, that minimizes a difference between the estimated optical flow and the determined rigid flow for the respective pixel.