Time-of-Flight Camera Frequency Mode Sharing
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Solution Overview
Problem
Current Time-of-Flight (ToF) cameras face challenges in scaling performance across a wide range of operating conditions, including varying distances and object reflectivities, leading to issues with depth measurement precision and power consumption, as well as difficulties in handling both close and far objects effectively without losing accuracy or expending unnecessary power.
Innovation Solution
The approach involves configuring ToF cameras with multiple frequency modes that share modulation frequencies and integration times, allowing for dynamic trading of range, exposure time, and power consumption without additional calibration, and using phase unwrapping techniques in the complex domain to resolve depth ambiguities and improve robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple frequency modes are used to handle different operating conditions, then depth measurement precision and adaptability are improved, but device complexity and calibration requirements increase
Solution Approach 1:
The patent implements multiple frequency modes within a single ToF camera system, where each frequency mode is optimized for different operating conditions (close-range vs. far-range imaging). The system can dynamically switch between frequency modes based on scene requirements, making the device adaptable to various distances and reflectivity conditions without requiring multiple separate cameras or complex external calibration equipment.
Solution Approach 2:
The patent changes the modulation frequency parameter to adapt to different operating conditions. By switching between different frequency modes (e.g., higher frequencies for close-range, lower frequencies for far-range), the system optimizes depth measurement precision for each scenario. This parameter-based adaptation allows the single device to handle diverse conditions effectively.
2Measurement precision
If multiple frequency modes with different frequencies are used, then measurement precision across different distances is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic frequency mode selection based on the imaging conditions. The system can switch between frequency modes adaptively - using higher frequencies when close-range precision is needed and lower frequencies when imaging distant objects. This dynamic adjustment optimizes the balance between measurement precision and power consumption, avoiding unnecessary energy expenditure on high-frequency modes when not required.
Solution Approach 2:
The system changes the modulation frequency parameter dynamically based on operating conditions. By selecting appropriate frequency modes for different distance ranges and reflectivity conditions, the patent achieves high measurement precision only when necessary, thereby reducing overall power consumption compared to continuously operating at maximum frequency.
3Reliability
If multiple frequency modes are implemented, then robustness across varying conditions is improved, but calibration time and costs increase
Solution Approach 1:
The patent designs frequency modes that can be universally applied across different operating conditions without requiring separate calibration procedures for each mode. The system uses a unified calibration approach that works across multiple frequency modes, significantly reducing calibration time and costs compared to traditional methods that would require independent calibration for each frequency or camera setup.
Solution Approach 2:
The patent performs preliminary calibration that establishes a foundation for multiple frequency modes to operate from. By setting up the calibration framework in advance that supports multiple frequencies, the system avoids repeated calibration procedures when switching between modes, thereby reducing overall calibration time and computational overhead.
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 method enables efficient and flexible handling of different operating conditions, reducing calibration time and costs, while maintaining high accuracy in depth measurements across a wide range of distances and reflectivities, and optimizing power usage.
Implementation Method 1
light emitted by the camera travels out to that point and then returns back to a sensor array
Implementation Method 2
control the sensor array to receive the periodic modulated light reflected from objects within the scene
Implementation Method 3
each frequency mode including two or more different frequencies, and at least two different frequency modes of the plurality of frequency modes having a common frequency shared between the at least two frequency modes
Implementation Method 4
The distance to a point on an imaged surface in the environment is determined based on the length of the time interval in which light emitted by the camera travels out to that point and then returns back to a sensor array
Data Source
AI summary
Examples are disclosed herein that relate to a time-of-flight camera that performs phase unwrapping in an efficient manner. In one example, a time-of-flight camera includes a light emitter, a sensor array, and a controller. The controller is configured to select a frequency mode from a plurality of frequency modes, each frequency mode including two or more different frequencies, and at least two different frequency modes of the plurality of frequency modes having a common frequency shared between the at least two frequency modes, control the light emitter to illuminate a scene with modulated light of the two or more different frequencies of the frequency mode selected, control the sensor array to receive the modulated light reflected from objects within the scene, and process the modulated light received to determine unwrapped phases for the frequency mode selected based on the two or more different frequencies of the frequency mode selected.