Depth Image Pixel Determination Using Multi-Frequency Complex Signal Comparison
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Solution Overview
Problem
Existing depth sensing systems, such as time-of-flight imaging systems, face challenges in accurately determining depth images due to the need for specialized computational resources and the use of transcendental functions, which can lead to uncertainty and reduced accuracy.
Innovation Solution
The method involves illuminating a scene with amplitude-modulated light of multiple frequencies, detecting the reflected light, and using a comparison function to compare complex signals from the sensor output to modeled signals, allowing for rapid and accurate depth determination without requiring specialized hardware like a system on a chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional time-of-flight depth sensing methods are used, then depth images can be produced, but specialized computational resources and transcendental functions are required, leading to increased device complexity and reduced measurement precision
Solution Approach 1:
The patent creates a comparison function that generates modeled signals representing expected sensor outputs at various depths. Instead of using complex transcendental functions to calculate depth from phase measurements, the system creates lookup tables of modeled signals that can be directly compared to actual sensor signals, replacing complex computation with simpler signal matching operations.
Solution Approach 2:
The patent replaces the traditional mathematical computation system (using transcendental functions and phase calculations) with a signal comparison system. The comparison function evaluates how well modeled signals match actual sensor signals across different depth hypotheses, substituting complex mathematical operations with simpler comparison operations that require fewer specialized computational resources.
2Measurement precision
If multiple frequencies are used for depth determination, then measurement precision improves, but computational demands and processing time increase
Solution Approach 1:
The patent pre-calculates and stores modeled signals for multiple frequencies and depth values in lookup tables before actual depth measurement is needed. This preliminary action allows the system to quickly compare pre-computed modeled signals with actual sensor signals during operation, avoiding the need to perform complex multi-frequency calculations in real-time while maintaining high measurement precision.
Solution Approach 2:
The patent processes each frequency separately by creating independent comparison functions for each frequency's modeled signals. This segmentation allows the system to handle multiple frequencies through sequential or parallel comparison operations rather than requiring simultaneous complex multi-frequency computation, improving processing efficiency while maintaining accuracy.
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 enables more precise and efficient depth calculation across multiple frequencies, reducing computational demands and improving accuracy compared to traditional methods.
Implementation Method 1
A sensor detects the amplitude-modulated light as reflected from the scene
Implementation Method 2
A distance to a point on an imaged surface in the environment is determined based on a time interval for light emitted by the imaging system to travel to that point and return to a sensor of the imaging system
Data Source
AI summary
Examples are disclosed that relate to methods and systems for determining a depth of a pixel of a depth image. In one example, a method comprises illuminating a scene with amplitude-modulated light of a plurality K of different frequencies. A sensor detects the amplitude-modulated light as reflected from the scene. A plurality K of complex signals k is formed by determining, for each frequency k of the plurality of different frequencies K, a complex signal k comprising a real portion k and an imaginary portion k. A comparison function is used to compare the plurality K of complex signals to a corresponding plurality K of modeled signals, each modeled signal k comprising a modeled real portion k and a modeled imaginary portion k. The method further comprises determining the depth of the pixel based at least on the comparison function and outputting the depth of the pixel.