Self-mixing laser speckle velocimeter for blood flow measurement

Özdemir, Şahin Kaya; Takamiya, S.; Ito, Satoshi; Shinohara, S.; Yoshida, H.

doi:10.1109/19.872925

Cited by 57 publications

(27 citation statements)

References 15 publications

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“…The resulting signal is the binary pulse train. The number of pulses during a measuring time is the speckle frequency which is related with the velocity of the moving object [18,19,22]. A pulse train obtained from the speckle signal can be seen in Fig.…”

Section: Counting Methodsmentioning

confidence: 99%

“…To our knowledge, a theoretical analysis of self-mixing signals from living tissues has not been developed yet due to the complicated structure of the self-mixing effect and the living tissues [19]. Despite that, M0 and M1 will be evaluated as M1 was previously evaluated by other authors [25,27].…”

Section: Power Spectrum Methodsmentioning

confidence: 99%

“…Several signal processing methods were proposed in the literature for self-mixing signals processing, namely the counting method (CM), the autocorrelation method (AC) and the power spectrum method (PSM) [19,20]. These methods will be evaluated for both in vitro and in vivo validations.…”

Section: Brain Microcirculation and Motivationmentioning

confidence: 99%

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Self-mixing microprobe for monitoring microvascular perfusion in rat brain

Figueiras

Oliveira

Lourenço

et al. 2012

Med Biol Eng Comput

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Measuring functional activity in brain in connection with neural stimulation faces technological challenges. Our goal is to evaluate, in relative terms, the real-time variations of local cerebral blood flow in rat brain, with a convenient spatial resolution. The use of laser Doppler flowmetry (LDF) probes is a promising approach but commercially available LDF probes are still too large (450 lm) to allow insertion in brain tissue without causing damage in an extension that may negatively impact local measurements. The self-mixing technique coupled to LDF is herein proposed to overcome limitations of the minimal diameter of the probe imposed by non-self-mixing probes (commercial available probes). Our Monte Carlo simulations show that laser photons have a mean penetration depth of 0.15 mm, on the rat brain with the 785 nm laser light microprobe. Moreover, three self-mixing signal processing methods are tested: counting method, autocorrelation method, power spectrum method. The perfusion signal computed shows a good linearity with the scatterers velocity, for the three methods (a determination coefficient close to one is obtained), for the in vitro measurements. Furthermore, we believe that these indicators can be used to monitor local blood flow changes in the rat brain.

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Section: Counting Methodsmentioning

confidence: 99%

Section: Power Spectrum Methodsmentioning

confidence: 99%

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Self-mixing microprobe for monitoring microvascular perfusion in rat brain

Figueiras

Oliveira

Lourenço

et al. 2012

Med Biol Eng Comput

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show abstract

“…Inspired by the success of such measurements on solid objects, the use of Doppler effect in SM-LD schemes has been proposed and applied for blood flow measurement [15], [16]. In the same way, we proposed to use speckle effect in the SM-LDs and shown that it can be used for the velocity measurement of non-cooperative surfaces, and as well as for the profiling of blood flow over the skin [17], [18], [19]. Despite the simplicity of SM-LD systems, careful attention has to be paid to parameters, such as the back-coupled light intensity and the distance from the laser to the external object to avoid chaotic laser dynamics.…”

Section: Introductionmentioning

confidence: 96%

Assessment on Self-mixing Laser Interferometry for Blood flow Measurement over Skin Surface

Ozdemir

Ohno

Shinohara

2006

2006 IEEE Instrumentation and Measurement Technology Conference Proceedings

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We study self-mixing laser diode (SM-LD) as a low-cost and compact optical sensor for non-invasive blood flow measurement and profiling over the skin surface. By making in-vivo and in-vitro measurements, we compare the SM-LD based sensor with the commercially available flowmeters to assess the accuracy and feasibility of SM-LD sensors for such applications. For the SM-LD based sensor, we apply two different signal processing methods (i) counting the intensity fluctuations of the signal from the SM-LD to obtain a frequency value, and (ii) the autocorrelation of the signal. In-vitro measurements show good agreement with the commercially available flowmeters. In-vivo measurements performed on test subjects revealed that autocorrelation technique shows much better results than the counting technique in blood flow profiling and SM-LD based sensor suffers from errors caused by external artifacts during measurements.

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“…The technique is realized with a self-mixing technique [2]- [4] and an explanation of the theory of operation has been reported in [5]. This kind of interferometry, applied to laser diodes (LDs), has been used for different applications, in addition to velocity measurements [6], [7]: from vibrations [8], [9] to distance [10]- [12], flow [13]- [16], and displacement [17], [18] contactless measurements. The self-mixing effect is induced by the back-reflection or back-scattering of a small part of emitted light into the laser cavity.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Self-Mixing Interferometer for Long Distances

Magnani

Pesatori

Norgia

2014

IEEE Trans. Instrum. Meas.

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This work describes a novel instrument based on a self-mixing optical interferometer, able to reconstruct the target speed and direction, without heterodyne detection. The real-time elaboration employs the signal non-linearity in order to recover the speed sign in the frequency domain. The target speed is measured by the signal frequency, while the speed sign is evaluated by the phase of the harmonics in the frequency domain. The high-sensitivity of the elaboration allows the measurement over diffusive target with distances up to 10 m. The measurements results have been successfully compared with a very-high resolution a commercial calibrated instrument

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Self-mixing laser speckle velocimeter for blood flow measurement

Cited by 57 publications

References 15 publications

Self-mixing microprobe for monitoring microvascular perfusion in rat brain

Self-mixing microprobe for monitoring microvascular perfusion in rat brain

Assessment on Self-mixing Laser Interferometry for Blood flow Measurement over Skin Surface

Real-Time Self-Mixing Interferometer for Long Distances

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