Single-Image ToF Fourier Embedding for High-Frame-Rate Depth

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing amplitude modulated continuous-wave time-of-flight (AMCW-ToF) cameras require multiple measurements to estimate depth, leading to lower frame rates and motion artifacts due to temporal multiplexing.

Innovation Solution

A system that embeds amplitude and phase as a single time-of-flight hologram in a Fourier transform of a single measured image using continuous-wave amplitude modulated time-of-flight cameras with a defocused cylindrical lens and rolling shutter, allowing simultaneous capture of amplitude and phase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple quadrature measurements are taken to estimate depth, then depth measurement accuracy is improved, but frame rate decreases and motion artifacts increase

Engineering Contradiction:

Improvedepth measurement accuracyVSAvoidframe rate

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent combines multiple quadrature measurements into a single time-of-flight hologram that encodes both amplitude and phase information simultaneously. By merging the four separate measurements into one complex sinusoid representation, the system achieves both high depth measurement accuracy and high frame rates without temporal multiplexing

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from temporal multiplexing to spatial-frequency domain encoding by embedding the time-of-flight hologram in the Fourier transform of a single measured image. This dimensional change allows simultaneous capture of multiple depth measurements in a single frame, eliminating motion artifacts while maintaining measurement precision

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If multiple quadrature measurements are taken to estimate depth, then depth measurement accuracy is improved, but system complexity increases

Engineering Contradiction:

Improvedepth measurement accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple measurement channels into a single complex sinusoid time-of-flight hologram, reducing the number of separate measurement operations from four to one while maintaining depth measurement accuracy through phase encoding

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical/temporal sequence of multiple measurements with a computational approach using Fourier transforms and holographic embedding, simplifying the system architecture by eliminating temporal multiplexing hardware requirements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If temporal multiplexing is used to capture quadrature measurements, then depth measurement is achieved, but bandwidth increases

Engineering Contradiction:

Improvedepth measurementVSAvoidbandwidth

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent combines four separate measurement data streams into a single complex sinusoid hologram, reducing the data bandwidth required for transmission and processing while preserving all depth measurement information in the phase and amplitude components

Inventive Principle:

Principle #5Merging (Combining)

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 increases frame rate by four times, reduces bandwidth, and enhances depth measurement accuracy without additional noise, making it suitable for applications in autonomous navigation, robotics, and augmented reality.

Implementation Method 1

the defocused cylindrical lens may be configured to prefilter images

Methodology Applied

Scientific EffectOptical prefiltering: Filter (optical)

Implementation Method 2

AMCW-ToF cameras operate by projecting a temporally varying (often a sinusoidal) light source, and then correlating it on the sensor side with an appropriate (also often a sinusoid) decoding function. Depth is encoded in the phase of the measurements

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Implementation Method 3

embed the time-of-flight hologram in a Fourier transform of a single measured image

Methodology Applied

Scientific EffectFourier transform:

Data Source

PatentUS20250341620A1Fourier embedding of amplitude and phase for single-image depth reconstruction

Publication Date: 2025.11.06 TRUSTEES OF DARTMOUTH COLLEGE THE

AI summary

A system has at least one continuous-wave amplitude modulated time-of-flight camera and at least one processor in electronic communication with the at least one continuous-wave amplitude modulated time-of-flight camera. The at least one processor may be configured to determine an amplitude and phase together as a single time-of-flight hologram and embed the time-of-flight hologram in a Fourier transform of a single measured image.