scholarly journals The Use of Supercontinuum Laser Sources in Biomedical Diffuse Optics: Unlocking the Power of Multispectral Imaging

2021 ◽  
Vol 11 (10) ◽  
pp. 4616
Author(s):  
Frédéric Lange ◽  
Luca Giannoni ◽  
Ilias Tachtsidis
Keyword(s):  
Multispectral Imaging ◽  
Spectral Power ◽  
Practical Implementation ◽  
Medical Applications ◽  
Light Sources ◽  
Biomedical Sciences ◽  
Diffuse Optics ◽  
Warm Up ◽  
Supercontinuum Laser ◽  
Technological Limitations

Optical techniques based on diffuse optics have been around for decades now and are making their way into the day-to-day medical applications. Even though the physics foundations of these techniques have been known for many years, practical implementation of these technique were hindered by technological limitations, mainly from the light sources and/or detection electronics. In the past 20 years, the developments of supercontinuum laser (SCL) enabled to unlock some of these limitations, enabling the development of system and methodologies relevant for medical use, notably in terms of spectral monitoring. In this review, we focus on the use of SCL in biomedical diffuse optics, from instrumentation and methods developments to their use for medical applications. A total of 95 publications were identified, from 1993 to 2021. We discuss the advantages of the SCL to cover a large spectral bandwidth with a high spectral power and fast switching against the disadvantages of cost, bulkiness, and long warm up times. Finally, we summarize the utility of using such light sources in the development and application of diffuse optics in biomedical sciences and clinical applications.

scholarly journals Optimising the illumination spectrum for enhancing tissue visualisation

2017 ◽  
Vol 51 (1) ◽  
pp. 99-110 ◽  
Author(s):  
J Shen ◽  
S Chang ◽  
H Wang ◽  
Z Zheng
Keyword(s):  
Biological Tissue ◽  
Power Distribution ◽  
Spectral Reflectance ◽  
Evaluation Method ◽  
Multispectral Imaging ◽  
Spectral Power ◽  
Light Sources ◽  
White Led ◽  
Spectral Power Distribution ◽  
Visual Entropy

In operations, light reflected from biological tissue can be used for disease detection. In this paper, we used a visual entropy evaluation method to design the optimal illuminant to improve colour discriminability of biological tissue. The optimal spectral power distribution of the illuminant was obtained by maximising the visual entropy value of sample tissue based on the human visual system. In the experiment, multispectral imaging was used to measure the spectral reflectance of the tissue and colour clustering was conducted to extract its colour features. To verify the effectiveness of this method, simulated tissue images under illuminations with optimised spectral power distributions were compared with those under other light sources such as the standard illuminant D65 and white LED light sources. Results show that the sample under optimised illumination has a higher visual entropy value with better perceptual visibility.

Supercontinuum laser-based monochromatic radiant source for detector spectral responsivity characterization in the range 0.9–1.6 μm using absolute cryogenic radiometer

2020 ◽  
pp. 28-33
Author(s):  
A. Yu. Dunaev ◽  
A. S. Baturin ◽  
V. N. Krutikov ◽  
S. P. Morozova
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Feedback System ◽  
Operating Mode ◽  
Spectral Responsivity ◽  
Spectral Power Distribution ◽  
Cryogenic Radiometer ◽  
Supercontinuum Laser ◽  
Radiant Power ◽  
Double Monochromator

An improved monochromatic radiant source with spectral bandwidth of 4 nm based on supercontinuum laser and a double monochromator was included in absolute cryogenic radiometer-based facility to improve the accuracy of spectral responsivity measurement in the range 0.9–1.6 μm. The developed feedback system ensures stabilization of monochromatic radiant power with standard deviation up to 0.025 %. Radiant power that proceeds detector under test or absolute cryogenic radiometer varies from 0.1 to 1.5 mW in dependence of wavelength. The spectral power distribution of its monochromatic source for various operating mode is presented.

Evaluation methodology for light sources used to illuminate highly photosensitive artwork

2022 ◽  
pp. 147715352110515
Author(s):  
Z Li ◽  
F Zhang ◽  
X Song ◽  
R Dang
Keyword(s):  
Spectral Power ◽  
Spectral Composition ◽  
Primary Source ◽  
Evaluation Methodology ◽  
Spectral Energy ◽  
Light Sources ◽  
Damage Evaluation ◽  
Colour Difference ◽  
Lighting Intensity ◽  
Reflection Characteristics

Spectral energy radiated by light sources is the primary source of colour damage in highly photosensitive artworks (HPAs). However, spectral power distributions differ for different light sources, and the absorption and reflection characteristics of different materials, when irradiated by each narrow spectral energy band, also differ. This could result in large differences in the degree of radiation damage for materials under the same lighting intensity. In this paper, the suitability of different light sources used to illuminate HPAs was experimentally investigated over a long period of time by irradiating nine types of typical HPA materials with 10 different narrow-band light sources. By analysing the colour difference data of the illuminated material against the amount of exposure, a mathematical model relating the spectral composition and the damage to the colour of HPA materials was obtained. Based on this, a colour damage evaluation equation for light sources used for lighting HPAs was proposed. Finally, the equations were discussed using an example.

AN OVERVIEW OF THE IMPACT OF STRAY LIGHT FROM COMMERCIAL GREENHOUSES

2021 ◽  
Author(s):  
K. Bertin ◽  
G. Zissis ◽  
G. Salas ◽  
P.M. Raynham ◽  
A. Moutsi ◽  
...  
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Stray Light ◽  
Significant Problem ◽  
Light Sources ◽  
Spectral Power Distribution ◽  
Outdoor Work ◽  
Local Residents ◽  
The Impact ◽  
Current Standards

Stray light from commercial greenhouses is becoming a significant problem causing disruption to wildlife activity and annoyance for local residents. To quantify the amount of stray light from a typical large greenhouse the authors have modelled several lighting installations based on a range of generic horticultural light sources. The impact of the stray light is dependent on the spectral power distribution of the sources employed, the intensity and distribution. Current standards for obtrusive light from outdoor work places do not seem to be suitable when applied to greenhouses.

Circadian stimulus – A computation model with photometric and colorimetric quantities

2019 ◽  
Vol 52 (6) ◽  
pp. 751-762
Author(s):  
W Truong ◽  
V Trinh ◽  
TQ Khanh
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
External Validation ◽  
Circadian System ◽  
Model Fit ◽  
Light Sources ◽  
Computation Model ◽  
Internal Validation ◽  
Spectral Power Distribution ◽  
Chromaticity Coordinate

The circadian stimulus is an important, validated and updated metric that describes the invisible influences of light on the human circadian system explicitly and scientifically. However, an absolute spectral power distribution must be supplied for its computation, which is only measurable by an expensive and complicated spectrometer. This paper proposes an alternative circadian stimulus computation model that is identified as the function CS(z, Ev) for white light sources based on the most common and simplest parameters of illuminance Ev in lux and the chromaticity coordinate z. These parameters are well known and widely used in both colour science and lighting technology. In order to prove the accuracy and availability of the model, an internal validation was performed with the adapted method repeating split data to check the goodness of the model fit. The fitted model achieved a maximum residual of 0.058 in the circadian stimulus quantity (R2 = 0.998). An external validation with the maximum residual of 0.030 (R2 = 0.999) provided stronger evidence for the usability of the model in applications.

scholarly journals Simple and effective calculations about spectral power distributions of outdoor light sources for computer vision

2016 ◽  
Vol 24 (7) ◽  
pp. 7266 ◽  
Author(s):  
Jiandong Tian ◽  
Zhigang Duan ◽  
Weihong Ren ◽  
Zhi Han ◽  
Yandong Tang
Keyword(s):  
Computer Vision ◽  
Spectral Power ◽  
Light Sources
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