Photon Timing Sketching for Low-Data ToF Imaging
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Solution Overview
Problem
Existing time of flight (ToF) imaging systems face challenges with high data volumes and computational burdens due to large numbers of photons per pixel, fine time resolution, and high spatial resolution, leading to data processing bottlenecks and compromised accuracy or resolution.
Innovation Solution
A sensor device that generates a compressed representation, or 'sketch', of photon detection events using feature functions to preserve signal information while suppressing background noise, allowing for efficient storage and transmission of reduced data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lens is used for focusing light in a sensor device, then imaging quality is improved, but the device size increases and back focus length is extended
Solution Approach 1:
The patent removes the lens component from the sensor device, extracting the focusing function to a separate external device. This eliminates the need for internal lens structures, thereby reducing device size and back focus length while maintaining imaging quality through the external focusing device.
Solution Approach 2:
The sensor device is designed to work with various types of imaging plates (film, digital sensors, etc.) without requiring an integrated lens. The universal design allows the same sensor structure to be used across different applications by simply changing the imaging plate or external focusing device, reducing the need for lens-specific adaptations.
2Measurement precision
If a lens is integrated into the sensor device, then light focusing capability is improved, but the distance between the light-receiving element and the focal point (back focus) increases
Solution Approach 1:
The focusing function is extracted from the sensor device and performed by an external device. This allows the light-receiving element to be positioned very close to the imaging plate (short back focus) while still achieving proper light focusing through the external device, thereby decoupling the focusing capability from the back focus length.
3Reliability
If protective measures are added to prevent bacterial growth and fogging in the lens, then reliability is improved, but device complexity increases
Solution Approach 1:
By removing the lens from the sensor device, the patent eliminates the enclosed space between the lens and imaging plate that would otherwise require protective measures. The external focusing device performs the focusing function without creating a sealed environment within the sensor device, thereby preventing bacterial growth and fogging issues while reducing structural complexity.
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 compressed representation reduces storage and communication requirements by up to 30 times while maintaining high accuracy and precision in depth estimation, enabling fast 3D imaging with low power consumption.
Implementation Method 1
an infrared cut filter that transmits only a specific wavelength range of light
Implementation Method 2
a low-pass filter that transmits only a specific wavelength range of light
Implementation Method 3
a photoelectric converter that converts an optical signal into an electrical signal
Data Source
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AI summary
A sensor device (10) for photon-based imaging comprising one or more photon detectors configured to produce a plurality of photon detection signals in response to a plurality of photon detection events, wherein each photon detection event has a corresponding detection time and wherein the detection times of the plurality of photon detection events are distributed in accordance with a distribution over time; and processing circuitry configured to perform a sketching process using timing information of the plurality of photon detection events to obtain a compressed representation of the distribution over time, wherein the sketching process comprises: generating a plurality of feature values based on the timing information of the plurality of photon detection events using one or more feature functions; combining the generated plurality of feature values to obtain the compressed representation of the distribution over time, wherein the feature functions have one or more properties such that combining the plurality of feature values generated using the one or more feature functions preserves signal information and/or supresses background information and/or distinguishes signal information from background information in the compressed representation, wherein the compressed representation is such that at least one or more desired parameters of the distribution over time can be estimated by performing a parameter estimation process using the compressed representation, wherein the parameter estimation process is based on a model of the distribution over time.