Lidar imaging systems are one of the hottest topics in optronics industry. The need to sense surroundings every autonomous vehicle has pushed forward a race dedicated deciding final solution be implemented. However, diversity state-of-the-art approaches brings large uncertainty on decision dominant solution. Furthermore, performance data each approach often arise from different manufacturers and developers, which usually have some interest dispute. Within this paper, we intend overcome...

Optical feedback interferometry (OFI) sensors are experiencing a consistent increase in their applications to biosensing due contactless nature, low cost and compactness, features that fit very well with current biophotonics research market trends. The present paper is review of the work progress at UPC-CD6 LAAS-CNRS related application OFI different aspects biosensing, both vivo ex vivo. This intended variety opportunities potential available field. activities presented divided into two...

With the goal of diagnosing skin cancer in an early and noninvasive way, extended near infrared multispectral imaging system based on InGaAs sensor with sensitivity from 995 nm to 1613 was built evaluate deeper layers thanks higher penetration photons at these wavelengths. The outcomes this device were combined those a previously developed that works visible range (414 nm⁻995 nm). Both provide spectral spatial information lesions. A classification method discriminate between melanomas nevi...

Demagnetization faults have a negative impact on the behavior of permanent-magnet synchronous machines, thus reducing their efficiency, generating torque ripple, mechanical vibrations, and acoustic noise, among others. In this paper, displacement shaft trajectory induced by demagnetization is studied. It proved that such may increase considerably amplitude rotor displacement. The direct measure performed means noncontact self-mixing interferometric sensor. addition, new harmonics in back...

An estimated 60,000 people die annually from skin cancer, predominantly melanoma. The diagnosis of lesions primarily relies on visual inspection, but around half pose diagnostic challenges, often necessitating a biopsy. Non-invasive detection methods like Computer-Aided Diagnosis (CAD) using Deep Learning (DL) are becoming more prominent. This study focuses the use multispectral (MS) imaging to improve lesion classification DL models. We trained two convolutional neural networks (CNNs)—a...

A self-mixing laser diode vibrometer including an adaptive optical element in the form of a liquid lens (LL) has been implemented and its benefits demonstrated. The LL arrangement is able to control feedback level phenomenon, keeping it moderate regime, particularly suitable for displacement measurements. This capability enabled remarkable increase sensor-to-target distance range where measurements are feasible. Target vibration signal reconstructions present maximum error λ/16 as compared...

The viability and performance of using a silicon photomultiplier (SiPM) in atmospheric lidar applications is experimentally compared against the well-established use tubes. By modified setup for simultaneous data acquisition both types sensors, we demonstrate that SiPM can offer appropriate qualities this specific application where detection fast, extremely low light pulses large dynamic range signals are essential capabilities. experimental results show has an behaviour offering suitable...

We propose differential optical feedback interferometry, a technique able to measure nanometer-size amplitude displacements by comparing the power of two lasers subject feedback. In this letter, principles are explained in detail, and its limits explored simulation. Theoretical results presented showing that can nanometer scale with resolution within angstrom scale. An experimental setup for validation has been built, series tests were performed using capacitive sensor as reference. Results...

An analysis of speckle effects and the techniques to overcome them in self-mixing interferometry signals is presented. We characterize effect surface roughness laser spot size on modulation signal, then propose two simple experimental approaches amplitude fading induced by effect. Unlike proposed until now, our first approach uses an adaptive optical element form a voltage-programmable liquid lens, which adaptively changes its focal length modify pattern. Our second combines present...

We demonstrate a novel method that makes an efficient use of laser nonlinear dynamics when subject to optical self-injection for subwavelength displacement sensing purposes. The proposed methodology combines two different phenomena taking place inside the cavity: self-injection, which results in feedback interference, and continuous wave frequency modulation, giving rise wavelength sweeping effect laser's emission. present combination these measure vibration amplitudes below λ/2 with...

We analyze an alternative to classical Zernike fitting based on the cubic B-spline model, and compare strengths weaknesses of each representation over a set different wavefronts that cover wide range shape complexity. The results obtained show low-degree polynomial expansion or with low number breakpoints are best choices for simple wavefronts, whereas approach performs much better when more complex involved. effect noise level in fit quality is also studied.

We present a Shack-Hartmann wavefront sensor (SHWS) based on cylindrical microlens array as device for measuring highly aberrated wavefronts. Instead of the typical spot pattern created by conventional SHWS, two orthogonal line patterns are detected CCD and superimposed. A processing algorithm uses continuity focal to extend dynamic range measurement localizing line, even if it leaves area confined corresponding microcylinder. The from progressive addition lens with an 80λ peak-to-valley...

AbstractA method for general implementation in any software platform of the generalized Coddington equations is presented, developed, and validated within a Matlab environment. The ophthalmic lens design strategy presented thoroughly, basic concepts ray tracing are introduced. methodology shown to include two inter-related processes. Firstly, finite used provide main direction propagation considered at incidence point interest. Afterwards, provides principal curvatures local wavefront that...

In this paper, a self-mixing interferometry sensor has been used as proximity probe to measure possible runout in permanent magnet synchronous motors, for fault diagnosis. A general procedure the measurement of 2-D trajectory motor shaft is described detail, including procedures characterization uncertainty due shape shaft, and management speckle noise. The performance proposed compared that commercial Polytec laser vibrometer, validation purposes. Results show inaccuracies order ±6 μm,...

Peripheral refraction, the refractive error present outside main direction of gaze, has lately attracted interest due to its alleged relationship with progression myopia. The ray tracing procedures involved in calculation need follow an approach different from those used conventional ophthalmic lens design, where errors are compensated only gaze. We a methodology for evaluation peripheral lenses, adapting generalized requirements refraction. nodal point eye and retinal conjugate surface will...

This article proposes a multispectral system that uses the analysis of spatial distribution color and spectral features to improve detection skin cancer lesions, specifically melanomas basal cell carcinomas. The consists digital camera light-emitting diodes eight different wavelengths (414 995 nm). parameters based on lesions such as reflectance color, well others empirically computed using values, were calculated pixel-by-pixel from images obtained. Statistical descriptors for every...

This paper presents a novel calibration method for solid-state LiDAR devices based on geometrical description of their scanning system, which has variable angular resolution. Determining this distortion across the entire Field-of-View system yields accurate and precise measurements enable it to be combined with other sensors. On one hand, model is formulated using well-known Snell's law intrinsic optical assembly whereas hand proposed describes scanned scenario an intuitive camera-like...

This paper focuses on exploring ways to improve the performance of LiDAR imagers through fog. One known weaknesses technology is lack tolerance adverse environmental conditions, such as presence fog, which hampers future development in several markets. Within this paper, a unit designed and constructed be able apply temporal polarimetric discrimination for detecting number signal photons received with detailed control its spatial distribution under co-polarized cross-polarized...

This paper presents the fabrication and characterization of a biaxial MEMS (MicroElectroMechanical System) scanner based on PZT (Lead Zirconate Titanate) which incorporates low-absorption dielectric multilayer coating, i.e., Bragg reflector. These 2 mm square mirrors, developed 8-inch silicon wafers using VLSI (Very Large Scale Integration) technology are intended for long-range (>100 m) LIDAR (LIght Detection And Ranging) applications W (average power) pulsed laser at 1550 nm. For this...

This paper proposes the use of wavelet transform as a technique that is suited for fringe detection and analysis optical feedback interferometry (OFI) signals, thus allowing retrieval extremely small physical motion phenomena. A novel algorithm based on used to process OFI signal simultaneously in time frequency domains, enabling precise fringes and, thus, extraction amplitude features vibrating target with error order 0.1λ. Furthermore, using complex Morlet an analyzing enables us extract...

We present Megacam deep optical images (g and r) of Malin 1 obtained with the 6.5 m Magellan/Clay telescope, detecting structures down to ∼28 B mag arcsec−2. In order enhance galaxy features buried in noise, we use a noise reduction filter based on total generalized variation regularizator. This method allows us detect resolve very faint morphological features, including spiral arms, high visual contrast. For first time, can appreciate an image its morphology full view. The provide...