Time of Flight Imaging Calibration Circuitry for Depth Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing 3D imaging systems face challenges in creating high-resolution 3D images in real time due to the complexity and high cost of laser trigger systems, as well as the need for significant computer processing power, especially in small devices.
Innovation Solution
The implementation of a calibration architecture with on-chip programmable delay lines in time of flight imaging systems, using LEDs as optical trigger sources, to synchronize light source and image sensor signals, achieving sub-nanosecond accuracy with minimal hardware cost and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser trigger systems are used to achieve high depth resolution, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces expensive laser trigger systems with inexpensive LED light sources that have sufficient lifespan for the application. The LED-based optical trigger sources provide the necessary temporal precision for depth measurement without requiring complex laser systems, thereby reducing device complexity and cost while maintaining measurement precision.
Solution Approach 2:
The patent substitutes complex electronic laser trigger systems with a simpler optical-based LED triggering mechanism. This substitution uses optical signals instead of complex electronic timing circuits, reducing system complexity while achieving the required temporal precision for time-of-flight depth measurement.
2Measurement precision
If laser trigger systems with sharp rise/fall edges are used, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The patent employs energy-efficient LED light sources that consume significantly less power compared to laser systems. These LEDs provide sufficient temporal precision for depth measurement while operating at lower power levels, making them suitable for portable and battery-powered 3D imaging devices.
3Measurement precision
If extensive post-signal processing is performed to compensate for electronic delays, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent implements delay compensation in advance during system initialization or calibration phases, rather than performing extensive post-signal processing for each depth measurement. By pre-characterizing and compensating for electronic delays in the signal path, the system achieves high depth resolution without requiring computationally intensive real-time processing, thereby maintaining high productivity and real-time imaging capability.
4Measurement precision
If multiple cameras are used for stereo imaging, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple camera functions into a single time-of-flight imaging sensor that performs active depth imaging. Instead of using separate cameras for stereo imaging, the system integrates optical trigger sources, photodetector arrays, and time-correlated single-photon counting electronics into a unified sensor module, reducing device complexity while maintaining 3D imaging capability.
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 low-cost, efficient, and accurate 3D imaging with reduced processing requirements, allowing for real-time high-resolution depth measurements.
Implementation Method 1
a time of flight pixel cell array coupled to sense the reflected light pulses in response to respective pulses of a pixel modulation signal
Implementation Method 2
a processing unit that calculates the distance to the object based on the round trip time that it takes for light to travel to and from an object
Data Source
AI summary
A time of flight imaging system includes a light source coupled to emit light pulses to an object in response a light source modulation signal generated in response to a reference modulation signal. Each pixel cell of a time of flight pixel cell array is coupled to sense light pulses reflected from the object in response a pixel modulation signal. A programmable pixel delay line circuit is coupled to generate the pixel modulation signal with a variable pixel delay programmed in response to a pixel programming signal. A control circuit is coupled to receive pixel information from the time of flight pixel array representative of the sensed reflected light pulses. The control circuit is coupled to vary the pixel programming signal during a calibration mode to synchronize the light pulses emitted from the light source with the pulses of the pixel modulation signal.