Time-of-Flight Camera Multipath Interference Removal
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Solution Overview
Problem
Existing three-dimensional imaging technologies face challenges in accurately identifying objects within three-dimensional spaces due to multipath signal interference and noise, which diminishes the accuracy of distance and object detection.
Innovation Solution
A time-of-flight camera system that projects high-spatial frequency patterns to redistribute spectral energy into higher frequencies and applies high-pass filters to remove multipath signal interference from light data, enabling more accurate distance detection and object identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional time-of-flight camera systems are used for three-dimensional imaging, then object detection can be performed, but multipath signal interference and noise reduce measurement precision
Solution Approach 1:
The patent converts the harmful multipath signal interference into a removable artifact by exploiting its characteristic spectral distribution. Multipath signals, which cause measurement errors, are redistributed to higher frequencies through high-spatial frequency pattern projection, allowing them to be separated and removed from the direct return signals through high-pass filtering, thus transforming the harmful interference into a distinguishable and removable component.
Solution Approach 2:
The patent changes the spectral parameters of the illumination pattern by projecting high-spatial frequency patterns instead of conventional uniform or low-frequency patterns. This parameter change redistributes the spectral energy of the reflected light, causing multipath signals to shift to higher frequencies while direct return signals remain at lower frequencies, enabling frequency-based separation and improved measurement precision.
2Measurement precision
If high-spatial frequency patterns are projected to redistribute spectral energy, then multipath interference can be separated from direct returns, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical optical systems with computational methods. Instead of using complex optical hardware to physically separate multipath signals, the system projects computationally generated high-spatial frequency patterns and uses digital signal processing (high-pass filtering in the spatial domain) to separate and remove multipath interference, substituting mechanical/optical complexity with computational simplicity.
3Measurement precision
If high-pass filters are applied in the spatial domain to remove multipath signals, then distance detection accuracy improves, but processing complexity increases
Solution Approach 1:
The patent replaces complex temporal or frequency-domain signal processing systems with spatial-domain processing. By projecting spatial patterns and applying high-pass filters in the spatial domain, the system achieves multipath removal through simpler computational operations on image data, avoiding the need for complex temporal signal analysis or frequency domain transformations.
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
The system significantly reduces multipath interference and noise, resulting in more accurate distance detection and object identification, enhancing the performance of three-dimensional imaging applications in autonomous vehicles, augmented reality, and virtual reality.
Implementation Method 1
The illumination unit is configured to project a high spatial-frequency pattern onto the target in such a way as to redistribute spectral energy to higher frequencies
Implementation Method 2
A sensor unit acquires reflected light data reflected from the target. The reflected light data comprises an array of spatial domain information received from light reflected by the target
Implementation Method 3
One or more processors process the reflected light data by applying a high-pass filter within the spatial domain to the reflected light data
Data Source
AI summary
A method for facilitating removal of multipath signal interference from light data can comprise illuminating, with an illumination unit, a target with a light source. The illumination unit can be configured to project a high spatial-frequency pattern onto the target in such a way as to redistribute spectral energy to higher frequencies. The method can also comprise acquiring, with a sensor unit, reflected light data reflected from the target. The reflected light data can comprise an array of spatial domain information received from light reflected by the target. Further, the method can comprise processing, with the one or more processors, the reflected light data. The processing applies a high-pass filter within the spatial domain to the reflected light data.