The 2D-S (Stereo) Probe: Design and Preliminary Tests of a New Airborne, High-Speed, High-Resolution Particle Imaging Probe

Abstract The design, laboratory calibrations, and flight tests of a new optical imaging instrument, the two-dimensional stereo (2D-S) probe, are presented. Two orthogonal laser beams cross in the middle of the sample volume. Custom, high-speed, 128-photodiode linear arrays and electronics produce shadowgraph images with true 10-μm pixel resolution at aircraft speeds up to 250 m s−1. An overlap region is defined by the two laser beams, improving the sample volume boundaries and sizing of small (<∼100 μm) particles, compared to conventional optical array probes. The stereo views of particles in the overlap region can also improve determination of three-dimensional properties of some particles. Data collected by three research aircraft are examined and discussed. The 2D-S sees fine details of ice crystals and small water drops coexisting in mixed-phase cloud. Measurements in warm cumuli collected by the NCAR C-130 during the Rain in Cumulus over the Ocean (RICO) project provide a test bed to compare the 2D-S with 2D cloud (2D-C) and 260X probes. The 2D-S sees thousands of cloud drops <∼150 μm when the 2D-C and 260X probes see few or none. The data suggest that particle images and size distributions ranging from 25 to ∼150 μm and collected at airspeeds >100 m s−1 by the 2D-C and 260X probes are probably (erroneously) generated from out-of-focus particles. Development of the 2D-S is in its infancy, and much work needs to be done to quantify its performance and generate software to analyze data.

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Diesel Droplet Diffusion in Isotropic Turbulence With Digital Holographic Cinematography

Volume 2: Fora ◽

10.1115/fedsm2005-77423 ◽

2005 ◽

Author(s):

Balaji Gopalan ◽

Edwin Malkiel ◽

Jian Sheng ◽

Joseph Katz

Keyword(s):

Time Series ◽

High Speed ◽

Isotropic Turbulence ◽

Fluid Motion ◽

Three Dimensional ◽

Time History ◽

Sample Volume ◽

Velocity Autocorrelation Function ◽

Digital Cameras ◽

Velocity Autocorrelation

High-speed in-line digital holographic cinematography was used to investigate the diffusion of droplets in locally isotropic turbulence. Droplets of diesel fuel (0.3–0.9mm diameter, specific gravity of 0.85) were injected into a 37×37×37mm3 sample volume located in the center of a 160-liter tank. The turbulence was generated by 4 spinning grids, located symmetrically in the corners of the tank, and was characterized prior to the experiments. The sample volume was back illuminated with two perpendicular collimated beams of coherent laser light and time series of in-line holograms were recorded with two high-speed digital cameras at 500 frames/sec. Numerical reconstruction generated a time series of high-resolution images of the droplets throughout the sample volume. We developed an algorithm for automatically detecting the droplet trajectories from each view, for matching the two views to obtain the three-dimensional tracks, and for calculating the time history of velocity. We also measured the mean fluid motion using 2-D PIV. The data enabled us to calculate the Lagrangian velocity autocorrelation function.

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Universal Light-Driven Micro/Nanoscale Rotors

10.21203/rs.3.rs-139439/v1 ◽

2021 ◽

Author(s):

Hongru Ding ◽

Pavana Kollipara ◽

Abhay Kotnala ◽

Zhihan Chen ◽

Yuebing Zheng

Keyword(s):

Electrical Coupling ◽

Three Dimensional ◽

Laser Beams ◽

Light Illumination ◽

Momentum Exchange ◽

General Applicability ◽

Direct Light ◽

Universal Approach ◽

Out Of Plane ◽

Particle Imaging

Abstract The capability of rotating micro/nanoscale particles and structures is important for micro/nanorobotics, three-dimensional particle imaging, and lab-on-a-chip systems. Light-driven rotors are especially attractive due to the fuel-free and remote operation. However, relying on a torque that arises from the momentum exchange with photons, current light-driven rotors require laser beams with designed intensity profile and polarization, or rotors with sophisticated shapes or material birefringence These requirements hinder the light-driven rotation of many highly symmetric or isotropic particles, including biological cells, with simple optics. Herein, we report a universal approach to the out-of-plane rotation of various objects, including spherically symmetric and isotropic particles, using single arbitrary low-power laser beams. Moreover, the driving laser beam is positioned away from the rotors to reduce optical damage from the direct light illumination. The working mechanism of the rotors based on opto-thermo-electrical coupling is elucidated by systematic experiments combined with multiscale simulations. With its general applicability and simple optics, our universal light-driven rotation platform will become an essential component in various scientific research and engineering applications.

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High-Speed Time-Resolved Tomographic Particle Shadow Velocimetry Using Smartphones

Applied Sciences ◽

10.3390/app10207094 ◽

2020 ◽

Vol 10 (20) ◽

pp. 7094

Author(s):

Andres A. Aguirre-Pablo ◽

Kenneth R. Langley ◽

Sigurdur T. Thoroddsen

Keyword(s):

High Speed ◽

Low Cost ◽

Proof Of Concept ◽

Video Capture ◽

Pixel Resolution ◽

Time Resolved ◽

Video Cameras ◽

Experimental Systems ◽

Single Frame ◽

Particle Imaging

The video-capabilities of smartphones are rapidly improving both in pixel resolution and frame-rates. Herein we use four smartphones in the “slow-mo” option to perform time-resolved Tomographic Particle Shadow Velocimetry of a vortex ring, using 960 fps. We use background LED-illuminated diffusers, facing each camera, for shadow particle imaging. We discuss in-depth the challenges present in synchronizing the high-speed video capture on the smartphones and steps to overcome these challenges. The resulting 3-D velocity field is compared to an instantaneous, concurrent, high-resolution snapshot with four 4k-video cameras using dual-color to encode two time-steps on a single frame. This proof-of-concept demonstration, supports realistic low-cost alternatives to conventional 3-D experimental systems.

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Improved Enumeration of Weakly Fluorescent CD4+ T-lymphocytes by Confining Cells in a Spinning Sample Cartridge with a Helical Minichannel

Micromachines ◽

10.3390/mi11060618 ◽

2020 ◽

Vol 11 (6) ◽

pp. 618

Author(s):

Subin Kim ◽

Jakir Hossain Imran ◽

Mohiuddin Khan Shourav ◽

Jung Kyung Kim

Keyword(s):

T Lymphocytes ◽

High Speed ◽

Imaging System ◽

Three Dimensional ◽

Focal Depth ◽

Smartphone Application ◽

Sample Volume ◽

Cylindrical Sample ◽

Cd4 Cells ◽

Cd4 Cell Count

The CD4 (cluster of differentiation 4) counting method is used to measure the number of CD4+ T-lymphocytes per microliter of blood and to evaluate the timing of the initiation of antiretroviral therapy as well as the effectiveness of treatment in patients with human immunodeficiency virus. We developed a three-dimensional helical minichannel-based sample cartridge in which a thread-like microgroove formed in the cylindrical surface and configured a particle-positioning and imaging system equipped with a single DC (direct current) motor that can be controlled by a smartphone application. Confinement and enrichment of CD4 cells within a sharp focal depth along the helical minichannel is accomplished by spinning the cylindrical sample cartridge at high speed before acquiring cell images and thus CD4+ cells with weak fluorescence intensity can be detected even in a channel much deeper than existing two-dimensional flat chambers without an autofocusing module. By detecting more cells in a larger sample volume, the accuracy of the CD4 cell count is improved by a factor of 5.8 with a channel of 500 μm depth and the precision is enhanced by a factor of 1.5 with a coefficient of variation of 2.6%.

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Three-Dimensional Laser Machining of Composite Materials

Journal of Engineering Materials and Technology ◽

10.1115/1.2903347 ◽

1990 ◽

Vol 112 (4) ◽

pp. 387-392 ◽

Cited By ~ 41

Author(s):

G. Chryssolouris ◽

P. Sheng ◽

W. C. Choi

Keyword(s):

Composite Materials ◽

High Speed ◽

Three Dimensional ◽

Quality Standards ◽

Groove Depth ◽

Heat Losses ◽

Laser Beams ◽

Laser Machining ◽

Continuous Beam ◽

Model Predictions

This paper presents a concept for performing three-dimensional laser machining on composite materials, using two intersecting laser beams to create grooves on a workpiece. A volume of material is removed when the two grooves converge. An analysis of the grooving process was conducted for carbon/teflon and glass/polyester materials. A model was developed to determine groove depth from process parameters and material properties. Close agreement was found between model predictions and experimental results for groove depths in carbon/teflon. Model predictions consistently overestimated depth values for continuous-beam glass/polyester results, and underestimated depth values for pulsed-beam glass/polyester at low power/high speed. Corrections for heat losses and high-temperature chemical interactions were added to the model to improve agreement with data. Groove width and damage width results were compared with surface quality standards for laser cutting of composites.

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Application of laser scanning for monitoring condition of buildings and structures during reconstruction

Transfer of innovative technologies ◽

10.32347/tit2141.0106 ◽

2021 ◽

pp. 33-36

Author(s):

Irina Rudneva

Keyword(s):

High Speed ◽

Laser Scanning ◽

New Technology ◽

Three Dimensional ◽

Return Time ◽

Measurement Methods ◽

Laser Beams ◽

Operational Control ◽

Labor Costs ◽

Engineering Geodesy

Ground-based laser scanning technology has been increasingly used in the last 15 years to solve problems not only in engineering geodesy, but also in the inspection of buildings and structures, in particular to identify damage and deformation during operation and reconstruction, as well as operational control of construction. and monitoring of their condition during operation, 3D-modeling of complex architectural objects. The growing popularity of laser scanning is due to a number of advantages provided by the new technology in comparison with other measurement methods. Among the advantages are the main ones: increasing the speed of work and reducing labor costs. The emergence of new more productive models of scanners, improving software capabilities allows us to hope for further expansion of the scope of ground-based laser scanning. Three-dimensional laser scanning emits millions of laser beams and, by calculating their return time, can accurately and accurately calculate their three-dimensional locations to make multiple high-speed scans combined into one system. This works by digitally recording the dimensions and spatial communication of objects by reflecting laser radiation.

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Servo Design for a 3-D Laser-Tracking Measurement System

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2801170 ◽

1996 ◽

Vol 118 (3) ◽

pp. 476-481 ◽

Cited By ~ 3

Author(s):

Jia-Yush Yen ◽

Chao-Si Jeng ◽

Kuang-Chau Fan

Keyword(s):

Measurement System ◽

High Speed ◽

Optimization Technique ◽

Three Dimensional ◽

Laser Beams ◽

Measurement Point ◽

Position Measurement ◽

Laser Tracking ◽

Accuracy Measurement ◽

Highly Nonlinear

This paper addresses the servo design for a real-time, laser-tracking, three-dimensional (3-D), position measurement system. The 3-D measurement system uses two sets of tracking mirrors to shine laser beams toward the measurement point. By examining the angles of these mirrors, one can calculate the position of this point. The servo loop in the measurement system corrects the mirror orientations by continuously checking and compensating the offset between the out going laser beam and the beam reflected from a retro-reflector attached to the measurement point. To achieve high speed and high accuracy measurement, the tracking servo system has to compensate for the highly nonlinear nature of the system and maintain the laser beams close to the measurement point. This paper derives the relationship between the tracking angle rotations and the measured beam offsets. By including this relationship in the system model, the linear H∞ optimization technique can be applied for controller synthesis. All the design specifications are then directly implemented.

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High-speed brightfield 3-D imaging and 3-D image analysis of thick and overlapped cell clusters in cytological preparations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168827 ◽

1994 ◽

Vol 52 ◽

pp. 218-219

Author(s):

Robert W. Mackin

Keyword(s):

Image Analysis ◽

High Speed ◽

Three Dimensional ◽

Image Data ◽

Ccd Camera ◽

Objective Lens ◽

Array Processor ◽

Vaginal Smears ◽

Low Contrast ◽

Computer Controlled

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.

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