Self-mixing sensor for real-time measurement of harmonic and arbitrary displacements

Zabit, Usman; Bernal, Olivier D.; Bosch, Thierry

doi:10.1109/i2mtc.2012.6229702

Cited by 22 publications

(28 citation statements)

References 9 publications

(17 reference statements)

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“…In this paper, SM signals have been processed in real-time by using the consecutive samples based unwrapping (CSU) method [11] having a measurement precision of λ/8 where λ is the LD wavelength. Note that as mentioned in [13], such precision can only be achieved if:…”

Section: Introductionmentioning

confidence: 98%

Robust Method of Stabilization of Optical Feedback Regime by Using Adaptive Optics for a Self-Mixing Micro-Interferometer Laser Displacement Sensor

Bernal

Zabit

Bosch

2015

IEEE J. Select. Topics Quantum Electron.

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A self-mixing (SM) micro-interferometer laser displacement sensor coupled with an adaptive liquid lens (ALL) system is proposed and implemented. This has been made possible by a new method of real-time estimation of the optical feedback coupling factor C. It is shown that such an estimation of C combined with an appropriate amplification of the SM signal Gain allows the ALL system to seek and maintain the SM signal in the moderate optical feedback regime in spite of variations in the optical feedback. The ALL system thus enables robust real-time displacement sensing in an unmanned autonomous manner. The implemented system has provided measurement precision better than 90 nm for different target surfaces and distances. The paper also investigates the impact of the weighting attributed to C and Gain on the retrieved displacement precision. As this autofocus is presently only performed once during the sensor initialization, so maximum displacement span after achieving optical feedback regime locking has also been investigated and tabulated. This proof of concept, thus paves the way for the deployment of autonomous SM sensors.

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Section: Introductionmentioning

confidence: 98%

Robust Method of Stabilization of Optical Feedback Regime by Using Adaptive Optics for a Self-Mixing Micro-Interferometer Laser Displacement Sensor

Bernal

Zabit

Bosch

2015

IEEE J. Select. Topics Quantum Electron.

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“…When input SM signal convolves with impulse response of MF1 it gives high amplitudes where forward fringes occur in input SM signal on same time axis as shown in Figure 1b, whereas high amplitudes are obtained at the output of MF2 wherever backward fringes occur in input SM signal as shown in Figure 1c. However it is worth-mentioning that the shown output of MF2 is actually inverted as it is a requirement of phase unwrapping methods [4][5][6][7]. A nice performance of DBT method significantly degrades for a low SNR SM signal (presented in Figure 2a).…”

Section: Selection Of Mf Templatesmentioning

confidence: 99%

“…Thus, SM fringe detection becomes a fundamental step which is later built upon by these PUMs. Usually, simple derivative based threshold (DBT) method is sufficient to detect SM fringes [4,5]. However, such a simple approach fails in case of either low signal to noise ratio (SNR).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Detection of Self-Mixing Interferometric Fringes of a Laser Sensor Using Matched Filter

Akmal

Zabit

Bernal

et al. 2017

Proceedings of Eurosensors 2017, Paris, France, 3–6 September 2017

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Self-Mixing (SM) is a promising technique for sensing vibration, distance, velocity etc. To retrieve accurate metric measurements from an acquired SM signal, it is necessary to correctly detect all interferometric fringes. Traditionally, SM fringes are detected by a derivative based threshold (DBT) scheme. However, such a scheme gives correct results only for SM signals with high signalto-noise ratio (SNR) and moderate optical feedback regime. So, in this paper, a better fringe detection method, based on Matched Filter (MF), is proposed which has provided correct SM fringe detection even in case of low SNR and weak optical feedback regime. The proposed approach has resulted in fringe detection accuracy of 100% for a low SNR SM signal belonging to the weak feedback regime.

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“…The basic theory of the self-mixing effect is explained by the presence of two Fabry-Perot cavities whose parameters are sensitive to variations of the external cavity length and frequency shift of the back-scattered light [8][9][10]. The light from the LD is focused on the remote target and undergoes a Doppler frequency shift proportional to the target surface orthogonal velocity.…”

Section: Self-mixingmentioning

confidence: 99%

Submicron Surface Vibration Profiling Using Doppler Self-Mixing Techniques

et al. 2014

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Doppler self-mixing laser probing techniques are often used for vibration measurement with very high accuracy. A novel optoelectronic probe solution is proposed, based on off-the-shelf components, with a direct reflection optical scheme for contactless characterization of the target's movement. This probe was tested with two test bench apparatus that enhance its precision performance, with a linear actuator at low frequency (35 m, 5-60 Hz), and its dynamics, with disc shaped transducers for small amplitude and high frequency (0.6 m, 100-2500 Hz). The results, obtained from well-established signal processing methods for self-mixing Doppler signals, allowed the evaluation of vibration velocity and amplitudes with an average error of less than 10%. The impedance spectrum of piezoelectric (PZ) disc target revealed a maximum of impedance (around 1 kHz) for minimal Doppler shift. A bidimensional scan over the PZ disc surface allowed the categorization of the vibration mode (0, 1) and explained its deflection directions. The feasibility of a laser vibrometer based on self-mixing principles and supported by tailored electronics able to accurately measure submicron displacements was, thus, successfully demonstrated.

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Self-mixing sensor for real-time measurement of harmonic and arbitrary displacements

Cited by 22 publications

References 9 publications

Robust Method of Stabilization of Optical Feedback Regime by Using Adaptive Optics for a Self-Mixing Micro-Interferometer Laser Displacement Sensor

Robust Method of Stabilization of Optical Feedback Regime by Using Adaptive Optics for a Self-Mixing Micro-Interferometer Laser Displacement Sensor

Detection of Self-Mixing Interferometric Fringes of a Laser Sensor Using Matched Filter

Submicron Surface Vibration Profiling Using Doppler Self-Mixing Techniques

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