Vehicle Photometric Stereo Navigation in Low-Light Scenes
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Solution Overview
Problem
Existing vehicle navigation systems struggle to effectively navigate in low-light environments and at low speeds, where traditional sensors may provide inadequate information about the scene.
Innovation Solution
The system uses a computer to sequentially activate multiple lamps on a vehicle, capture image data with a camera, and apply a photometric stereo algorithm to generate a map of surface normals, allowing the vehicle to navigate based on this enhanced scene information when the speed is below a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensors are used for vehicle navigation, then the system is simple and easy to operate, but the navigation accuracy deteriorates in low-light environments and at low speeds
Solution Approach 1:
The patent combines multiple lamps and a camera into an integrated photometric stereo system mounted on the vehicle. This merging of components creates a unified navigation system that captures images from multiple lighting angles simultaneously, enabling accurate 3D surface reconstruction even in low-light conditions where traditional single-sensor systems fail.
Solution Approach 2:
The system employs periodic activation of multiple lamps at different angles to illuminate the scene. By sequentially activating lamps while capturing images at each illumination angle, the system periodically samples the scene from different lighting perspectives, enabling robust surface normal estimation that works independently of ambient light conditions.
2Loss of information
If multiple lamps are sequentially activated to capture image data, then enhanced scene information is obtained, but the time required for data capture increases
Solution Approach 1:
The system pre-positions multiple lamps at specific angles around the vehicle before capturing images. This preliminary arrangement of lighting components allows the system to quickly switch between illumination angles without mechanical adjustment, reducing the time penalty associated with capturing multiple views while ensuring optimal lighting geometry is already in place for immediate data acquisition.
Solution Approach 2:
The patent implements rapid sequential activation of lamps with brief exposure times for each angle. By skipping prolonged illumination at each angle and using quick flash-based lighting, the system rushes through the data capture process, minimizing total capture time while still gathering sufficient photometric information from multiple angles to reconstruct accurate surface normals.
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 provides enhanced scene information, particularly in low-light environments, enabling more accurate navigation at low speeds by identifying objects and determining distances with greater precision.
Implementation Method 1
receive image data of the scene generated while sequentially activating the lamps
Data Source
AI summary
A computer includes a processor and a memory, and the memory stores instructions executable by the processor to sequentially activate a plurality of lamps aimed at a scene, the lamps mounted to a vehicle; receive image data of the scene generated while sequentially activating the lamps; generate a map of surface normals of the scene by executing a photometric stereo algorithm on the image data; and in response to a speed of the vehicle being below a speed threshold, navigate the vehicle based on the map of the surface normals.