Tissue Spectrophotometry for Motion-Artifact-Resistant Muscle Sensing
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Solution Overview
Problem
Current noninvasive neuromuscular interface systems, such as surface electromyography (sEMG), suffer from motion artifacts, electrical signal degradation, and skin-electrode sensitivity, making them less than satisfactory for robust and inexpensive neuromuscular signal detection.
Innovation Solution
Utilizing spectrophotometric methods and apparatuses, including wearable spectrophotometric sensor sets with arrays of sensors, to detect changes in tissue optical properties for accurate, real-time detection of voluntary and involuntary muscle movements, which are then processed to determine position, movement, and force applied by body parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface electromyography (sEMG) is used to detect neuromuscular signals, then the system can noninvasively read muscle activity, but the system suffers from motion artifacts, electrical signal degradation over time, and skin-electrode sensitivity issues
Solution Approach 1:
The patent replaces electrical sensing mechanisms (EMG sensors that contact the skin) with optical sensing mechanisms (spectrophotometric sensors that use light). This substitution eliminates the harmful factors affecting electrical signals (motion artifacts, skin-electrode sensitivity, signal degradation) by using a completely different physical principle to detect muscle activity through optical property changes in tissue.
Solution Approach 2:
The patent introduces light as an intermediary medium to detect muscle activity. Instead of directly sensing electrical signals from muscles (which causes the harmful effects), the system uses light to indirectly detect muscle activity by measuring changes in optical properties (absorption, reflection, scattering) of tissue that occur during muscle contraction and movement.
2Measurement precision
If traditional electromyographic sensors are used, then neuromuscular signals can be detected, but the sensors require direct skin contact which causes sensitivity issues and degradation over time
Solution Approach 1:
The patent replaces contact-based electrical sensing with non-contact optical sensing. The spectrophotometric sensors detect muscle activity through optical property changes in tissue without requiring direct skin contact, thereby maintaining measurement precision while eliminating the operational complexity and sensitivity issues associated with skin-electrode contact.
Solution Approach 2:
The patent extracts the detection function from the skin contact interface. By using optical sensors that measure tissue optical properties, the system separates the sensing function from the skin contact requirement, allowing accurate neuromuscular signal detection without the need for direct electrode-skin contact and its associated problems.
3Reliability
If spectrophotometric methods are used to detect tissue optical properties, then motion artifacts and skin contact sensitivity are eliminated, but the system must process complex optical signals to isolate muscle activity from other signals
Solution Approach 1:
The patent segments the optical signal into distinct components corresponding to different physiological sources (heartbeat, respiration, muscle activity). By analyzing the spectral characteristics and temporal patterns of the optical signal, the system separates and isolates the muscle activity component from other signals, thereby achieving reliable detection while managing processing complexity through systematic signal decomposition.
Solution Approach 2:
The patent applies local quality analysis by examining spatial and spectral variations in the optical signal. Different tissue regions and wavelength bands provide different information about muscle activity versus other physiological signals. By focusing on local spectral features and spatial patterns, the system can selectively enhance muscle activity detection while filtering out other signals.
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 described methods and apparatuses provide a fast, accurate, and non-invasive means to decode muscle activity for intuitive human-computer and human-machine interaction, leveraging tissue heterogeneity and dynamic changes for precise muscle state inference.
Implementation Method 1
detect changes in an optical property signal from a tissue, such as one or more of light absorption, light reflection, optical density, etc.
Implementation Method 2
detect changes in an optical property signal from a tissue, such as one or more of light absorption, light reflection, optical density, etc.
Data Source
AI summary
Described herein are spectrophotometric methods and apparatuses for determining the position and/or movement of a body part, such as the fingers, hand, wrist, arm, etc. The apparatuses and methods described herein use optical properties, such as one or more of absorption, transmission and reflection, to accurately and quickly determine position and/or movement, which may be used to control one or more devices and/or as an input to a computer or software.