Modulated Optical Radiation for Diffuse Reflectance Spectroscopy
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Solution Overview
Problem
Current diffuse reflectance spectroscopy (DRS) devices only use non-modulated optical radiation, limiting their ability to accurately measure the attenuation of optical radiation in diffusing and/or absorbent bodies.
Innovation Solution
The process involves using modulated optical radiation in intensity and/or optical frequency to measure the attenuation coefficient of a diffusing and/or absorbing body, by calculating the course length and reflectance of the retraded signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If non-modulated optical radiation is used in diffuse reflectance spectroscopy, then the device complexity is low, but the measurement precision of the attenuation coefficient is insufficient
Solution Approach 1:
The patent applies dynamics by modulating the optical radiation in intensity and/or optical frequency, transforming the static illumination into a dynamic signal that carries additional information about the path length. This modulation allows the system to extract more precise measurement data without proportionally increasing device complexity
Solution Approach 2:
The patent changes the parameters of the optical radiation by introducing intensity modulation and/or optical frequency modulation. These parameter changes enable the system to measure both reflectance and path length information simultaneously, improving the precision of attenuation coefficient measurement
2Measurement precision
If intensity-modulated optical radiation is used in diffuse reflectance spectroscopy, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent uses intensity modulation to create a dynamic optical signal that encodes path length information. By modulating the intensity of the optical radiation, the system can distinguish between photons that have traveled different path lengths through the tissue, thereby improving measurement precision
Solution Approach 2:
The patent employs periodic modulation of the optical radiation intensity at specific frequencies. This periodic action allows the use of lock-in detection and frequency-domain analysis techniques to extract precise measurement information while filtering out noise, improving signal-to-noise ratio and measurement precision
3Measurement precision
If optical frequency modulation is applied, then the path length measurement accuracy improves, but the ease of operation decreases
Solution Approach 1:
The patent applies optical frequency modulation to change the frequency parameter of the optical radiation. This allows the system to measure the phase shift of the modulated signal, which directly relates to the path length traveled by photons through the tissue, thereby improving path length measurement accuracy
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 allows for precise measurement of the attenuation coefficient, achieving performance comparable to or better than existing methods using constant intensity optical radiation, while being simpler to implement.
Implementation Method 1
emission of optical radiation whose intensity and/or optical frequency are modulated
Implementation Method 2
emission of optical radiation whose intensity and/or optical frequency are modulated
Implementation Method 3
reception of a part of the probe signal scattered and reflected by the body
Implementation Method 4
Only a fraction 10−1, 10−2, of the photons is backscattered, that is, it emerges by diffuse reflection from the side of skin tissue 1
Implementation Method 5
The invention employs intensity- and/or frequency-modulated optical radiation for diffuse reflectance spectroscopy in order to accurately measure the path length d of the backscattered signal
Data Source
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AI summary
Method and device for diffuse reflectance spectroscopy comprising intensity and/or optical frequency modulation of optical radiation. The invention relates to a method for measuring, by diffuse reflectance spectroscopy, the attenuation coefficient of a part of a diffusing and/or absorbing body (1), the method comprising the following steps: a) emission of optical radiation whose intensity and/or optical frequency are modulated, at least a part of the optical radiation, called the probe signal, irradiating the body, b) reception of a part of the probe signal scattered and reflected by the body, called the backscattered signal, and measurement of the path length d of the backscattered signal, c) measurement of the reflectance R of the part of the body through which the backscattered signal passes, d) calculation of the attenuation coefficient µ from the measured path length d and reflectance R.