3D Imaging Pixel Circuit for Single-Pulse Time-of-Flight and Flux Sensing
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Solution Overview
Problem
Current 3D active imaging systems face limitations in resolution and power consumption, particularly in real-time applications and stealthy systems, due to the need for multiple pulses and high power usage in time-of-flight measurement techniques, which also compromise on flux measurement and multimode detection capabilities.
Innovation Solution
A device comprising a photosensitive element, a charge integrator, and a comparator that allows simultaneous measurement of reflected flux and time of flight without high power consumption, using a capacitor-based integrator for current-to-voltage conversion and eliminating the need for operational amplifiers, enabling accurate time-of-flight detection and efficient flux measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple laser pulses are used to achieve high resolution in 3D active imaging, then measurement precision is improved, but productivity deteriorates due to longer image reconstruction time
Solution Approach 1:
The patent applies preliminary action by performing time-of-flight measurement and flux measurement simultaneously for each pixel during a single laser pulse exposure. The imaging device captures both the intensity information and distance information in one shot, eliminating the need for multiple pulses and sequential processing. This preliminary capture of all necessary data in a single operation directly resolves the contradiction between resolution and reconstruction time.
2Measurement precision
If multiple laser pulses are used to achieve high resolution, then measurement precision is improved, but loss of time increases due to extended observation period
Solution Approach 1:
The device performs preliminary measurement of both flux and time-of-flight simultaneously during a single pulse exposure. By capturing all necessary data in one observation window rather than requiring multiple sequential pulses, the system eliminates excessive observation time while maintaining high resolution through the dual measurement capability.
3Ease of operation
If conventional flux measurement by current integration is used, then ease of operation is maintained, but measurement precision deteriorates for time-of-flight detection
Solution Approach 1:
The patent segments the measurement function into two independent parallel paths: one for flux measurement using current integration and another for time-of-flight measurement using threshold detection. This segmentation allows each measurement type to use its own optimized method without interfering with the other, maintaining ease of operation for flux measurement while achieving high precision for time-of-flight detection.
Solution Approach 2:
The imaging device achieves multi-functionality by simultaneously performing both flux measurement and time-of-flight measurement using the same pixel array and single laser pulse. The dual measurement capability allows the system to operate in multiple modes (2D imaging, 3D imaging, passive imaging) without requiring separate hardware systems, thereby maintaining operational simplicity while enhancing measurement precision.
4Manufacturing precision
If operational amplifiers are used in the integrator circuit, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the operational amplifier from the integrator circuit, replacing it with a simpler capacitor-based integration mechanism. This extraction eliminates the need for complex operational amplifier circuits while maintaining the integration function through direct charge accumulation on the capacitor, thereby reducing device complexity without significantly compromising manufacturing precision.
Solution Approach 2:
The patent employs a simple capacitor-based integrator that uses basic passive components instead of expensive operational amplifiers. This approach uses simpler, more readily available components that reduce overall device complexity and cost, while the integration function is achieved through the fundamental capacitor charging process rather than requiring complex active circuitry.
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 solution enables accurate and efficient simultaneous measurement of reflected flux and time of flight, reducing power consumption and allowing for multimode imaging without disturbing flux measurement, thus improving resolution and compatibility with real-time and portable imaging systems.
Implementation Method 1
a photosensitive element (42) capable of receiving incident radiation (44) and producing, as a function of the latter, an electric charge
Data Source
AI summary
The invention relates to a device comprising a photosensitive element producing an electric charge as a function of the radiation incident thereon and a charge integrator connected to the photosensitive element and converting the charge to a voltage. According to the invention, the device comprises a comparator capable of comparing the voltage delivered by the integrator with a threshold voltage, and a memory unit for storing the instant when the voltage delivered by the integrator exceeds the threshold voltage.