Laser Interferometric Vehicle Motion Detection

The patent replaces the mechanical/optical imaging system with a laser-based interferometric system. Instead of using cameras and lighting devices to capture images of the vehicle underside, the invention uses laser beams that interact with the road surface and vehicle components to directly measure speed through interference patterns. This substitution eliminates the need for complex lighting systems while providing more reliable measurements independent of soiling issues.

The patent introduces laser light as an intermediary between the vehicle motion and the measurement system. The laser beams serve as a mediator that interacts with the road surface and vehicle components, creating interference patterns that encode speed information. This intermediary approach allows direct measurement without requiring optical imaging systems or additional lighting, thereby reducing device complexity while maintaining measurement precision.

The patent replaces the camera-based optical imaging system with a laser interferometric measurement system. The laser-based system does not require optical paths that are vulnerable to soiling in the same way cameras do. By using laser beams that create interference patterns through interaction with the road surface and vehicle components, the system achieves reliable motion detection without the susceptibility to soiling that plagues camera-based underbody installations.

The patent extracts the measurement function from the vulnerable camera system and implements it through a separate laser interferometric system. By separating the measurement mechanism from the optical imaging components that are prone to soiling, the invention achieves reliable motion detection. The laser system measures speed through interference patterns without requiring the same optical clarity and cleanliness as camera-based systems.

The patent extends the measurement capability from two-dimensional plane detection to three-dimensional speed component detection. By using laser beams directed at different angles relative to the road surface and analyzing the interference patterns produced, the system can determine speed components in multiple dimensions including those perpendicular to the roadway plane. This dimensional extension allows comprehensive motion analysis while maintaining relatively simple sensor configuration.

The patent uses multiple laser units arranged to emit beams in different directions, effectively segmenting the measurement task across multiple independent laser channels. Each laser unit measures specific speed components based on its orientation, and the combined data from multiple segmented measurements provides complete three-dimensional motion information. This segmentation approach enables versatile speed component detection without requiring a single complex sensor system.