Doppler Time-Of-Flight Imaging

Simple SummaryContent extracted from patent full text and abstract with AI.

This invention introduces a new imaging technique using Time-of-Flight (ToF) cameras combined with clever coding of illumination and modulation frequencies to directly capture not just depth and color, but also the per-pixel instantaneous velocity (specifically, the radial velocity) of moving objects in a scene. It leverages the Doppler effect: by analyzing the frequency shifts caused by object motion, the system can create detailed velocity maps, enabling 3D velocity field estimation. The approach allows the simultaneous capture of color, depth, and motion information using readily available ToF camera hardware and computational methods.

Use CasesContent extracted from patent full text and abstract with AI.

• Motion tracking for robotics and drones, enabling advanced navigation in dynamic environments.
• Human-computer interaction and gaming, such as gesture recognition or tracking physical game props.
• Medical imaging applications where movement of tissues or fluids needs to be analyzed in real time.
• Industrial automation and machine vision for quality control where both position and velocity of objects are important.
• Surveillance and security for detecting and characterizing moving objects or persons in a monitored area.
• Augmented and virtual reality systems that require accurate sensing of object and user motions for immersive experiences.

BenefitsContent extracted from patent full text and abstract with AI.

• Provides true per-pixel, instantaneous measurement of object velocity (not just depth or position).
• Captures color, depth, and velocity data simultaneously, providing a richer, multi-dimensional understanding of a scene.
• Works robustly even for scenes lacking texture or with high-speed motion, where traditional optical flow methods often fail.
• Enables estimation of the full 3D metric velocity field of a scene when combined with traditional optical flow.
• Can be implemented on existing ToF camera hardware with software modifications, making it accessible and cost-effective.
• Improves motion segmentation, recognition, and tracking capabilities for a wide range of applications impacting automation, safety, and user experience.

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Inventors & Applicants

Patent Abstract

Systems and methods for imaging object velocity are provided. In an embodiment, at least one Time-of-Flight camera is used to capture a signal representative of an object in motion over an exposure time. Illumination and modulation frequency of the captured motion are coded within the exposure time. A change of illumination frequency is mapped to measured pixel intensities of the captured motion within the exposure time, and information about a Doppler shift in the illumination frequency is extracted to obtain a measurement of instantaneous per pixel velocity of the object in motion. The radial velocity information of the object in motion can be simultaneously captured for each pixel captured within the exposure time. In one or more aspects, the illumination frequency can be coded orthogonal to the modulation frequency of the captured motion. The change of illumination frequency can correspond to radial object velocity.