Analog Optical Positioning Sensor for High-Speed Displacement Measurement
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Solution Overview
Problem
Conventional displacement sensors, such as camera chip-based systems and multielement photodetectors, face limitations in sample rate, resolution, and computational complexity, leading to inefficiencies and high power consumption.
Innovation Solution
The proposed solution involves directly processing analog voltages proportional to displacement in analog electronics, rather than digitally capturing images, to increase sample rates from hundreds of Hz to megahertz and reduce computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If camera chip-based displacement measurement is used, then displacement measurement capability is provided, but sample rate is limited to low 100s of Hz range due to sampling electronics speed and large number of pixels to process
Solution Approach 1:
The patent segments the image processing task by dividing the image into multiple regions of interest (ROIs) and processing each ROI independently with dedicated hardware circuits. This parallel processing approach increases the sample rate by eliminating the bottleneck of sequential processing of all pixels, while reducing computational complexity through hardware acceleration of specific processing functions.
Solution Approach 2:
The patent replaces the software-based image processing pipeline with dedicated hardware circuits that perform displacement calculation directly in the analog domain. This substitution of mechanical/software processing with hardware processing dramatically increases sample rate from hundreds of Hz to potentially MHz range, while reducing computational complexity by eliminating the need for complex software algorithms.
2Measurement precision
If camera chip with over one million pixels is used, then displacement measurement is enabled, but power consumption increases due to high-end GPU requirements (100s of watts)
Solution Approach 1:
The patent extracts and processes only the essential displacement information from the image data using dedicated hardware circuits, rather than processing the entire high-resolution image through a power-hungry GPU. This extraction approach maintains measurement precision by focusing computational resources on the specific task of displacement calculation, while dramatically reducing power consumption by eliminating the need for high-end graphical processing.
Solution Approach 2:
The patent changes the processing parameters by performing displacement calculations in the analog domain before digital conversion, rather than processing digital images. This parameter change in the processing domain (from digital image processing to analog signal processing) maintains measurement precision while reducing power consumption by avoiding the energy-intensive digital processing pipeline.
3Reliability
If multielement photodetector with small number of large elements is used, then high SNR is achieved, but spatial discretization is low making output unsuitable for image registration techniques
Solution Approach 1:
The patent merges the advantages of both camera chips and multielement photodetectors by using a camera chip with a reduced number of larger pixels that are optimized for displacement measurement. This merging approach combines the high SNR of large photodetector elements with the image processing capabilities of camera chips, achieving both reliable signal detection and sufficient spatial information for displacement calculation through hardware-based processing.
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 higher resolution measurements, reduced power consumption, and the ability to measure up to six Degrees of Freedom (DOF) of displacement with improved dynamic range and constant resolution across a range of displacements.
Implementation Method 1
a patterned light is focused onto a photodetector... each photodetector element generates an analog input signal proportional to an amount of the patterned light incident on the photodetector
Data Source
AI summary
A sensor, method and integrated circuit for optically sensing the relative displacement of an object. The sensor may generate optical patterns of light and employ a multielement photodetector to detect the light and output corresponding analog signals proportional to the light detected. The sensor may achieve a sample rate that is orders of magnitude greater than conventional systems. The sensor may also achieve image resolution that is orders of magnitude greater than conventional systems. The sensor is useful for applications including the measurement of linear displacement and rotation, force, torque, or strain with respect to multiple degrees of freedom.