Ambient Light Cancellation via Signal Correlation
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Solution Overview
Problem
Conventional optical absorption spectroscopy systems face challenges in effectively accounting for ambient light without degrading the signal of interest, particularly in small wearable devices, where mechanical solutions are bulky and electrical solutions can introduce noise or subtract the signal of interest in high ambient conditions.
Innovation Solution
A system that analyzes the correlation between the combined received signal and the ambient light signal to determine the correlation factor, allowing for adaptive cancellation or deactivation of the optical illumination source, thereby reducing noise and preserving signal quality by utilizing the ambient light when highly correlated or maintaining the combined signal when minimally correlated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If mechanical ambient light blocking solutions are used, then ambient light interference is reduced, but the device becomes bulky and unsuitable for small wearable devices
Solution Approach 1:
The patent replaces mechanical ambient light blocking structures with an electrical/digital signal processing approach. The system uses an optical receiver to detect both the interrogation signal and ambient light, then uses a correlation determination circuit to identify the correlation factor between the combined signal and ambient light signal. Based on this correlation factor, the system adaptively cancels or deactivates components to remove ambient light interference without requiring any physical blocking structures, thereby maintaining a compact device form factor suitable for wearable applications.
2Volume of moving object
If electrical ambient cancellation methods are used, then device size is reduced, but noise may be introduced or the signal of interest may be subtracted in high ambient conditions
Solution Approach 1:
The patent implements a dynamic ambient light handling system that adapts its behavior based on real-time correlation analysis. The ambient condition control circuit continuously monitors the correlation factor between the combined optical signal and the ambient light signal, and dynamically adjusts the signal processing approach: when correlation is high, it cancels ambient light; when correlation is low, it preserves the combined signal. This dynamic adaptation prevents noise introduction and signal loss while maintaining compact device size.
Solution Approach 2:
The system employs feedback through the correlation determination circuit that analyzes the relationship between the combined optical signal and ambient light signal. The correlation factor generated by this circuit provides feedback to the ambient condition control circuit, which then adjusts the signal processing strategy accordingly. This feedback mechanism ensures that ambient light cancellation is only applied when appropriate, preventing degradation of signal quality while maintaining the benefits of a compact device design.
3Measurement precision
If ambient light is always canceled, then signal quality is improved, but power consumption increases and the signal of interest may be removed
Solution Approach 1:
The patent implements a dynamic signal processing system that adjusts ambient light cancellation based on real-time correlation analysis. The ambient condition control circuit monitors the correlation factor and dynamically switches between different processing modes: ambient light cancellation when correlation is high, and signal preservation when correlation is low. This dynamic approach improves signal quality only when necessary, avoiding unnecessary power consumption and preventing loss of the signal of interest.
Solution Approach 2:
The system changes the processing parameter (ambient light cancellation) based on the correlation factor threshold. When the correlation factor exceeds a predetermined threshold, the system applies ambient light cancellation; when it remains below the threshold, the system preserves the combined signal. This parameter-based decision-making approach optimizes the balance between signal quality and power consumption by applying cancellation only when the ambient light correlation indicates it is beneficial.
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 reduces power consumption and maintains signal quality by selectively canceling ambient light when necessary, avoiding noise introduction and ensuring accurate signal processing while preserving the signal-to-noise ratio.
Implementation Method 1
light may be transmitted and reflected off of the target object. During this process, some of the light is absorbed by the target object while the remaining light is reflected off of the target object and received by an optical receiver.
Implementation Method 2
Optical absorption spectroscopy is a technique to measure the absorption of light due to the interaction of the light with a target object.
Implementation Method 3
The correlation determination circuit is configured to compare the combined optical signal with an ambient light signal to identify a correlation factor.
Implementation Method 4
based on the correlation factor exceeding the low threshold value and being less than the high correlation threshold value, cancel the ambient light component from the combined optical signal to produce an interrogation signal including the interrogation component.
Data Source
AI summary
An optical system includes an optical illumination source, an optical receiver, a correlation determination circuit, and an ambient condition control circuit. The optical illumination source is configured to emit a light in the direction of a target object. The optical receiver is configured to receive a combined optical signal that includes an ambient light component combined with an interrogation component. The correlation determination circuit is configured to compare the combined optical signal with an ambient light signal to identify a correlation factor. The ambient condition control circuit is configured to compare the correlation factor to a low correlation threshold value and a high correlation threshold value, and, based on the correlation factor exceeding the low threshold value and being less than the high correlation threshold value, cancel the ambient light component from the combined optical signal to produce an interrogation signal including the interrogation component.