Quantitative photoplethysmography: Lambert-Beer law or inverse function incorporating light scatter

Cejnar, M.; Köbler, H.; Hunyor, Stephen N.

doi:10.1016/0141-5425(93)90047-3

Cited by 21 publications

(16 citation statements)

References 10 publications

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“…The temperature reaches so high that it leads the material to melting or vaporization state. The light absorption phenomenon is classically presented by BeerLambert Law [19]. It states that when a light of certain wavelength is transmitted through the material, its absorption depends on the material path length and is totally independent of the incident intensity.…”

Section: Laser Ablation Mechanismmentioning

confidence: 99%

Laser Ablation and Laser-Hybrid Ablation Processes: A Review

Ahmed¹,

Darwish²,

Alahmari³

2015

Materials and Manufacturing Processes

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Laser beam machining (LBM) has proven its applications and advantages over almost all the range of engineering materials. It offers its competences from macro machining to micro and nano-machining of simple-to-complex shapes. The hybrid approaches in laser ablation have demonstrated much improved results in terms of material removal rate, surface integrity, geometrical tolerances, thermal damage, metallurgical alterations and many more. The flipside of LBM is the existence of universal problems associated with its thermal ablation mechanism. In order to alleviate or reduce the inherent problems of LBM, a massive research has been done during the past decade in order to build a relatively new route of laser-hybrid processes. This paper reviews the research work carried out so far in the area of LBM and its hybrid processes for different materials and shapes. The article also highlights the research gaps and future research directions in the context of laser and laser-hybrid ablation.

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Section: Laser Ablation Mechanismmentioning

confidence: 99%

Laser Ablation and Laser-Hybrid Ablation Processes: A Review

Ahmed¹,

Darwish²,

Alahmari³

2015

Materials and Manufacturing Processes

View full text Add to dashboard Cite

show abstract

“…The temperature reaches so high that it leads the material to melting or vaporization state. The light absorption phenomenon is classically presented by the Beer-Lambert Law [25]. It states that when a light of certain wavelength is transmitted through the material, its absorption depends on the material path length and is totally independent of the incident intensity.…”

Section: Laser Ablation Mechanismmentioning

confidence: 99%

Laser Beam Machining, Laser Beam Hybrid Machining, and Micro-channels Applications and Fabrication Techniques

Darwish

Ahmed

Al‐Ahmari

2016

Machining, Joining and Modifications of Advanced Materials

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Laser beam machining (LBM) has proven its applications and advantages over almost all the range of engineering materials. It offers its competences from macro machining to micro and nano-machining of simple-to-complex shapes. The flipside of LBM is the existence of universal problems associated with its thermal ablation mechanism. In order to alleviate or reduce the inherent problems of LBM, a massive research has been done during the past decade and in turn build a relatively new route of laser-hybrid processes. The hybrid approaches in laser ablation have demonstrated much improved results in terms of material removal rate, surface integrity, geometrical tolerances, thermal damage, metallurgical alterations and many more. This chapter reviews the research work carried out so far in the area of LBM and its hybrid processes for different materials and shapes.

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“…The first approach is based on the Beer-Lambert law [11]. The law states that there is a logarithmic dependence between the transmission of light through a substance and the product of the absorption coefficient of the substance and the distance the light travels through the material.…”

Section: Fractional Oxygen Saturationmentioning

confidence: 99%

“…From their amplitude ratio and corresponding DC amplitude of the PPG waveform the corresponding SpO 2 value can then be computed. This computation usually involves an empirically-derived calibration factor [6,11]. Thus, there is an assumption that the AC component of the PPG signal results solely from the arterial blood volume changes with each heartbeat.…”

Section: Limitationsmentioning

confidence: 99%

Clinical applications and issues of oxygen saturation level measurements obtained from peripheral sites

Foo

Chua

Tan

2013

Journal of Medical Engineering & Technology

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Studies have suggested that the saturated oxygen level within one's arterial blood can provide crucial information about the status of one's cardiopulmonary system. Currently, a popular and convenient approach is to obtain this vital physiological sign through non-invasive measurement on suitable peripheral sites such as a finger, toe or ear lobe. This measurement is known as the SpO2 parameter. It has been increasingly adopted in not only clinical settings but also remote monitoring purposes. In order to measure this optical based parameter, light sources of both the red and infrared wavelengths are required. The most recognized waveform feature is the peripheral pulse or its AC component which is synchronized to each heartbeat. The AC component is superimposed on a constant DC baseline attributed to breathing efforts, sympathetic nervous system activities and thermoregulation. The popularity of the SpO2 parameter may be due to its viable cost, simplicity to build and portability. Moreover, the basic building blocks of a SpO2 based measurement consists of control, filtering and amplification functions that can easily be incorporated with an embedded system. In this review, a brief description of the SpO2 measurement, its normative values and technical issues in its application as a clinical monitor are discussed.

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Quantitative photoplethysmography: Lambert-Beer law or inverse function incorporating light scatter

Cited by 21 publications

References 10 publications

Laser Ablation and Laser-Hybrid Ablation Processes: A Review

Laser Ablation and Laser-Hybrid Ablation Processes: A Review

Laser Beam Machining, Laser Beam Hybrid Machining, and Micro-channels Applications and Fabrication Techniques

Clinical applications and issues of oxygen saturation level measurements obtained from peripheral sites

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