A Comparison of 2-D Molecular Tagging Velocimetry (MTV) and Micro Particle Image Velocimetry (µPIV) for Microscale Flows

2010 ◽  
Author(s):  
Farhan Ahmad ◽  
Mona Abdolrazaghi ◽  
David S. Nobes
Keyword(s):  
Laser Beam ◽  
Flow Velocity ◽  
Laser Scanning ◽  
Imaging System ◽  
Single Point ◽  
Field Of View ◽  
Scanning System ◽  
Molecular Tagging Velocimetry ◽  
Molecular Tagging ◽  
Micro Particle Image Velocimetry

A 2-D scanning molecular tagging velocimetry technique is presented. The described MTV technique utilizes a scanning laser system enabling two-dimensional flow velocity measurements. The laser scanning system allows the tagging of molecules seeded in the flow of any desired pattern. This array of small dot markers in the region of interest is visualized using an epi-fluorescent optical imaging system. The scanning system facilitates the convenient maneuvering of the laser beam allowing the tagging of either a single point or a pattern. The laser beam is focused onto a single point leading to a more efficient tagging process. A standard particle tracking velocimetry (PTV) approach is used to resolve the two components of the flow velocity. Results obtained show the capability of the designed system to tag a region in the centre of the field of view. The tagging laser will be moved to any desired location within the field of view to tag the desired region.

scholarly journals POSSIBILITIES OF THE APPLICATION OF THREE-DIMENSIONAL TECHNOLOGIES AND MODERN TECHNOLOGICAL MEANS IN THE CRIME INVESTIGATION ACTIVITY

2018 ◽  
Vol 18 ◽  
pp. 98-105
Author(s):  
N. V. Pavliuk
Keyword(s):  
Digital Media ◽  
Technology Use ◽  
Laser Scanning ◽  
3D Model ◽  
Imaging System ◽  
3D Visualization ◽  
Three Dimensional ◽  
Scanning System ◽  
Crime Reconstruction ◽  
Technological Means

The issues related to the introduction of innovative methods, technologies and technological means in the investigation of crimes are considered. It is noted that one of the main directions of the development of Criminalistics is the assimilation of the virtual reality associated with computerization of spheres of life, implementation of modern technologies and their use in law enforcement. Technology use of laser scanning of terrain and objects resulting in 3D model is produced allows several times to increase informative value of data collected at the incident scene, provides a visual and convenient visualization in three-dimensional form. As against photo and video images, 3D model has a stereoscopic image and the ability to freely change the angle while viewing. Besides to scanning results can be stored on any digital media without the possibility of changes or adjustments. Attention is focused on the technological capabilities of 3D-visualization systems on examples of their use in foreign countries as technological means of capturing the situation of the scene and the subsequent of a crime reconstruction. Thus, using a portable three-dimensional imaging system for working with volumetric traces at a crime scene, it is possible to obtain accurate three-dimensional images of traces of protectors or footprints (shoes) on soil and snow. This system is an alternative to traditional methods of fixing evidence: photofixing and making plaster casts. Unlike other systems, new approach does not require the use of lasers. The expediency of expanding the range of 3D laser scanning system use in modern investigative and judicial practice of our state with the aim of increasing the level of provision of pre-trial investigation authorities with technological means and bringing it closer to European standards is argued.

scholarly journals DESIGN AND IMPLEMENT OF A CONICAL AIRBORNE LIDAR SCANNING SYSTEM

2020 ◽  
Vol XLII-3/W10 ◽  
pp. 1247-1252
Author(s):  
H. C. Hu ◽  
G. Q. Zhou ◽  
X. Zhou ◽  
Y. Z. Tan ◽  
J. D. Wei
Keyword(s):  
Single Point ◽  
Airborne Lidar ◽  
Field Of View ◽  
Scanning System ◽  
Dual Frequency ◽  
Scanning Device ◽  
Scanning Area ◽  
Laser Frequencies ◽  
Low Dispersion ◽  
Scanning Density

Abstract. At present, the main LiDAR is single-point lidar. APD arrays and laser arrays are restricted to exit, so the number of area array LiDAR is scarce. Single-point lidar can't form a scanning pattern with only one laser point on the ground after launching laser, so it must have a set of scanning device for single-point lidar. The scanning device designed in this paper forms a circular scanning area on the ground by rotating the refraction prism, and at the same time forms a conical field of view. At present, marine LiDAR uses this kind of scanner more frequently. The advantages of this scanner are: simple mechanical structure and smooth operation. Overlapping elliptical scanning trajectories can be obtained during flight, which increases scanning density. Ultra-low dispersion glass is used as refractive prism in this paper. In a certain range of laser frequencies, the refractive prism has almost the same effect on laser refraction at different frequencies. The simulation results show that the scanner can be used as a common LiDAR scanner or a dual-frequency LiDAR scanner.

Investigation of Textile Materials for Laser Light Beam Scanning

2011 ◽  
Vol 222 ◽  
pp. 40-43 ◽  
Author(s):  
Inga Dabolina ◽  
Ausma Vilumsone ◽  
Juris Blums
Keyword(s):  
Laser Beam ◽  
Light Beam ◽  
Human Body ◽  
Laser Scanning ◽  
Material Selection ◽  
Scanning System ◽  
Angle Of Incidence ◽  
Beam Scanning ◽  
Textile Materials ◽  
Beam Reflection

The scanning of human body as a method for gaining human measurements has several preferences. The gathering of data is possible in a very short time. In comparison to manual measuring methods, scanning acquires a larger amount of measurements. There are several modes of gaining human body measurements using the scanning system: laser scanning, light beam scanning, etc. A research on the laser beam reflection capabilities on different textile materials has been performed. The description of laser reflections has been compared to the Lambert’s law’s characteristics. The matrix of material selection is made in the process of planning the experiment and all possible materials are presented in this matrix. Eight textile materials are chosen for the experimental work: six lingerie and two additional materials. A laser beam with an angle of incidence of 0º and 45º is used to make the experiment. The dependence of the results on the wavelength of laser beams has also been compared.

Fast Dispersive Laser Scanner by Using Digital Micro Mirror Arrays

2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Salih K. Kalyoncu ◽  
Rasul Torun ◽  
Yuewang Huang ◽  
Qiancheng Zhao ◽  
Ozdal Boyraz
Keyword(s):  
Laser Scanning ◽  
Imaging System ◽  
Laser Scanner ◽  
Scanning System ◽  
Current State ◽  
Scan Rate ◽  
Mapping Technology ◽  
Mems Technology ◽  
Laser Scanning System ◽  
State Of Art

We demonstrate a fast dispersive laser scanning system by using MEMS digital micro-mirror arrays technology. The proposed technique utilizes real-time dispersive imaging system, which captures spectrally encoded images with a single photodetector at pulse repetition rate via space-to-time mapping technology. Wide area scanning capability is introduced by using individually addressable micro-mirror arrays as a beam deflector. Experimentally, we scanned ∼20 mm2 at scan rate of 5 kHz with ∼150 μm lateral and ∼160 μm vertical resolution that can be controlled by using 1024 × 768 mirror arrays. With the current state of art MEMS technology, fast scanning with <30 μs and resolution down to single mirror pitch size of 10.8 μm is also achievable.

scholarly journals Designing and Testing a Closed-loop Magnetically Actuated Laser Scanning System for Tissue Ablation

2021 ◽  
Author(s):  
Hamed Mohammadbagherpoor ◽  
Alperen Acemoglu ◽  
Leonardo S. Mattos ◽  
Darwin Caldwell ◽  
James J. Johnson ◽  
...  
Keyword(s):  
Laser Beam ◽  
Laser Scanning ◽  
Fiber Optic ◽  
Laser Scanner ◽  
Heat Diffusion ◽  
Tissue Ablation ◽  
Scanning System ◽  
Test Bed ◽  
Physical Test ◽  
New Device

Abstract Biomedical robotic systems continue to hold unlimited potential for surgical procedures. Robotized laser endoscopic tools provide surgeons with increased accuracy in the laser ablation of tissue and tumors. The research here catalogs the design and implementation of a new laser endoscopic tool for tissue ablation. A novel feature of this new device is the inclusion of a feedback loop that measures the position of the laser beam via a photo-detector sensor. The scale of this new device was governed by the dimensions of the photo-detector sensor. The tip of the laser's fiber optic cable is controlled by the torque interaction between permanent magnet rings surrounding the fiber optic and the custom designed solenoid coils. Prior to building the physical test-bed the system was modeled and simulated using COMSOL software. In pre-clinical trials, the physical experimental results showed that the designed prototype laser scanner system accurately track different ablation patterns and gives a consistent output position for the laser beam however, the heat diffusion into the tissue around the desired line of the geometric shape would give wider ablation margins than was desirable.

Characterization of the Hydrodynamically Developing Flow in a Microtube Using Molecular Tagging Velocimetry

2003 ◽  
Author(s):  
B. R. Thompson ◽  
D. Maynes ◽  
B. W. Webb
Keyword(s):  
Laser Beam ◽  
Ultra Violet ◽  
Ccd Camera ◽  
Velocity Profiles ◽  
Molecular Tagging Velocimetry ◽  
Vena Contracta ◽  
Entry Length ◽  
Molecular Tagging ◽  
Developing Flow ◽  
Tracer Molecules

There is a need for increased understanding of the momentum transport phenomena in micro-fluidic geometries to aid in the design and optimization of such devices. Micro-molecular tagging velocimetry (μMTV) has been used to characterize the hydrodynamic developing flow in a microtube with an inner diameter of 180 μm. μMTV is a non-intrusive laser-based technique for obtaining detailed measurements of velocity profiles in flows dominated by a single velocity component. μMTV measurements are made by directing an ultra-violet laser beam into a flow containing phosphorescent tracer molecules. The laser beam excites a line of phosphorescence in the flow. Subsequently, two digital images, separated by a short time delay, of the line are captured by a CCD camera. The displacement of the tracer molecules between the images can be determined from the two images and the velocity of the flow is thus calculated. Velocity profile data at ten axial locations within the hydrodynamic developing region of a 180 μm diameter tube were acquired using the μMTV approach. The uncertainty for these measurements ranged from 1.5% to 5.5% of the center line velocity. Data were taken at Reynolds numbers, Re, of 60, 140, 290, and 340. It was observed that a vena-contracta existed in the first few tube diameters for all Re. The velocity profiles obtained very close to the tube entrance exhibited a uniform velocity core flow surrounded by regions of relatively stagnant fluid in the near wall regions. The profiles evolved in the downstream direction until the classical parabolic distribution was observed. The total hydrodynamic entry length agrees well with values published in the literature for macroscale flows, obtained from numerical simulation.

Dual-beam diode laser scanning system with a spot control method for ultrahigh-speed laser beam printers

1986 ◽  
Author(s):  
Akira Arimoto ◽  
Susumu Saito ◽  
Takeshi Mochizuki ◽  
Minoru Seino ◽  
Yasuo Kikuchi ◽  
...  
Keyword(s):  
Laser Beam ◽  
Diode Laser ◽  
Laser Scanning ◽  
Control Method ◽  
Scanning System ◽  
Dual Beam ◽  
Laser Scanning System

scholarly journals The Visual Measurement of Velocity Profile Distribution in Silt Carrying Flow by Using Ultrasound PIV and Iterative Multi-Grid Deformation Technique

2021 ◽  
Vol 11 (15) ◽  
pp. 6952
Author(s):  
Xianjian Zou ◽  
Wenbin Hu ◽  
Huan Song ◽  
Bingrui Chen
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Measurement Technique ◽  
Imaging System ◽  
Single Point ◽  
Interrogation Window ◽  
Measured Velocity ◽  
Visual Measurement ◽  
Grid Deformation ◽  
Profile Distribution

Flow velocity in silt carrying flow is one key parameter to many river engineering problems. A visual measurement technique of velocity profile distribution in silt carrying flow is provided using a portable ultrasound imaging system and an improved iterative multi-grid deformation algorithm. A convex array probe in the system is used to obtain a series of ultrasonic images at different times. Window offset and an iterative computing scheme for reducing interrogation window size in the algorithm improve the accuracy and efficiency of flow velocity measurement in regions with velocity gradients. Results show that the measured profile velocities can be more acceptable after being compared with time-averaged stream-wise velocities of profiles at ten positions in the same silt carrying flow and subsequently verified by comparing the point-by-point standard value. The measured velocity is more in agreement with the theoretical value, with the minimum root mean square error in the ultrasound beam sweep effect calculated by using optimal interrogation size parameters. The system is a feasible alternative to the single-point measurement technique in silt carrying flow. The iterative multi-grid deformation algorithm can analyze velocity profile distribution with gradients simultaneously, which can help the real-time measurement of multiple spatial velocity distribution and turbulence.

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