High-resolution measurement of birefringent fine structure in living cells using a new polarized light microscope

1995 ◽  
Vol 53 ◽  
pp. 54-55
Author(s):  
Rudolf Oldenbourg
Keyword(s):  
Light Microscope ◽  
Fluorescent Dyes ◽  
Polarized Light ◽  
Processing System ◽  
Video Camera ◽  
Molecular Organization ◽  
Computer Assisted ◽  
Image Recording ◽  
Birefringent Crystal ◽  
Technological Advances

The recent renaissance of the light microsope is fueled in part by technological advances in components on the periphery of the microscope, such as the laser as illumination source, electronic image recording (video), computer assisted image analysis and the biochemistry of fluorescent dyes for labeling specimens. After great progress in these peripheral parts, it seems timely to examine the optics itself and ask how progress in the periphery facilitates the use of new optical components and of new optical designs inside the microscope. Some results of this fruitful reflection are presented in this symposium.We have considered the polarized light microscope, and developed a design that replaces the traditional compensator, typically a birefringent crystal plate, with a precision universal compensator made of two liquid crystal variable retarders. A video camera and digital image processing system provide fast measurements of specimen anisotropy (retardance magnitude and azimuth) at ALL POINTS of the image forming the field of view. The images document fine structural and molecular organization within a thin optical section of the specimen.

New polarized-light microscope for fast and orientation independent measurement of birefringent fine structure

1993 ◽  
Vol 51 ◽  
pp. 82-83
Author(s):  
Rudolf Oldenbourg
Keyword(s):  
Light Microscope ◽  
Polarized Light ◽  
Video Camera ◽  
Limited Range ◽  
Image Point ◽  
Computer Assisted ◽  
Optical Modulators ◽  
Anisotropic Structures ◽  
Long Time ◽  
Computer Assisted Image

The polarized light microscope has the unique potential to measure submicroscopic molecular arrangements dynamically and non-destructively in living cells and other specimens. With the traditional pol-scope, however, single images display only those anisotropic structures that have a limited range of orientations with respect to the polarization axes of the microscope. Furthermore, rapid measurements are restricted to a single image point or single area that exhibits uniform birefringence or other form of optical anisotropy, while measurements comparing several image points take an inordinately long time.We are developing a new kind of polarized light microscope which combines speed and high resolution in its measurement of the specimen anisotropy, irrespective of its orientation. The design of the new pol-scope is based on the traditional polarized light microscope with two essential modifications: circular polarizers replace linear polarizers and two electro-optical modulators replace the traditional compensator. A video camera and computer assisted image analysis provide measurements of specimen anisotropy in rapid succession for all points of the image comprising the field of view.

Light microscopy of ceramics

1993 ◽  
Vol 51 ◽  
pp. 908-909
Author(s):  
Walter C. McCrone
Keyword(s):  
Refractive Index ◽  
Light Microscopy ◽  
Light Microscope ◽  
Polarized Light ◽  
Refractive Indices ◽  
Complete Coverage ◽  
The Subject ◽  
Lower Refractive Index

An excellent chapter on this subject by V.D. Fréchette appeared in a book edited by L.L. Hench and R.W. Gould in 1971 (1). That chapter with the references cited there provides a very complete coverage of the subject. I will add a more complete coverage of an important polarized light microscope (PLM) technique developed more recently (2). Dispersion staining is based on refractive index and its variation with wavelength (dispersion of index). A particle of, say almandite, a garnet, has refractive indices of nF = 1.789 nm, nD = 1.780 nm and nC = 1.775 nm. A Cargille refractive index liquid having nD = 1.780 nm will have nF = 1.810 and nC = 1.768 nm. Almandite grains will disappear in that liquid when observed with a beam of 589 nm light (D-line), but it will have a lower refractive index than that liquid with 486 nm light (F-line), and a higher index than that liquid with 656 nm light (C-line).

Computer-Assisted High-Re Solution TEM

1990 ◽  
Vol 48 (1) ◽  
pp. 162-163
Author(s):  
F.A. Ponce ◽  
H. Hikashi
Keyword(s):  
Signal To Noise Ratio ◽  
Accurate Determination ◽  
Computer Software ◽  
Video Camera ◽  
Image Contrast ◽  
Objective Lens ◽  
Computer Assisted ◽  
Optical Parameters ◽  
Astigmatism Correction

The determination of the atomic positions from HRTEM micrographs is only possible if the optical parameters are known to a certain accuracy, and reliable through-focus series are available to match the experimental images with calculated images of possible atomic models. The main limitation in interpreting images at the atomic level is the knowledge of the optical parameters such as beam alignment, astigmatism correction and defocus value. Under ordinary conditions, the uncertainty in these values is sufficiently large to prevent the accurate determination of the atomic positions. Therefore, in order to achieve the resolution power of the microscope (under 0.2nm) it is necessary to take extraordinary measures. The use of on line computers has been proposed [e.g.: 2-5] and used with certain amount of success.We have built a system that can perform operations in the range of one frame stored and analyzed per second. A schematic diagram of the system is shown in figure 1. A JEOL 4000EX microscope equipped with an external computer interface is directly linked to a SUN-3 computer. All electrical parameters in the microscope can be changed via this interface by the use of a set of commands. The image is received from a video camera. A commercial image processor improves the signal-to-noise ratio by recursively averaging with a time constant, usually set at 0.25 sec. The computer software is based on a multi-window system and is entirely mouse-driven. All operations can be performed by clicking the mouse on the appropiate windows and buttons. This capability leads to extreme friendliness, ease of operation, and high operator speeds. Image analysis can be done in various ways. Here, we have measured the image contrast and used it to optimize certain parameters. The system is designed to have instant access to: (a) x- and y- alignment coils, (b) x- and y- astigmatism correction coils, and (c) objective lens current. The algorithm is shown in figure 2. Figure 3 shows an example taken from a thin CdTe crystal. The image contrast is displayed for changing objective lens current (defocus value). The display is calibrated in angstroms. Images are stored on the disk and are accessible by clicking the data points in the graph. Some of the frame-store images are displayed in Fig. 4.

Study on the Crystalline Morphology of HDPE/E-TMB Blends

2012 ◽  
Vol 200 ◽  
pp. 406-410
Author(s):  
Wei Hua Fan ◽  
Ren Jie Wang ◽  
Yu Kun Liu ◽  
Kai Guo ◽  
Jin Zhou Chen ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Light Microscope ◽  
Polarized Light ◽  
Crystalline Morphology ◽  
Master Batch

HE1/E-TMB and HE2/E-TMB blends are prepared by thermal mechanical blending of toughening master batch (E-TMB) with 2200JHDPE (HE1) and 5000SHDPE (HE2), respectively. The crystalline morphology of HE1/E-TMB and HE2/E-TMB blends were studied with polarized light microscope (PLM), and compared with those of HE1/E-SMB and HE2/E-SMB blends. The results showed that the crystallite size of HDPE/E-TMB and HE/E-SMB blends was remarkably smaller than that of the pure HDPE, while the number of the crystals increased. At the same elastomer content, the refined extend of the crystallite of HE2/E-TMB blends obviously increased than that of the HE1/E-TMB blends. The number of the crystal gradually increased and the crystallite size substantially reduced with the elastomers ratio (M/N) increasing. The refined extend of the crystallite of HDPE/E-TMB blends gradually enhanced and the number of the crystal substantially increased as the elastomer content gradually growing.

scholarly journals Strobing the moving objects marks in the image processing system with stationary video camera

ScienceRise ◽  
2017 ◽  
Vol 3 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Oleksii Bieliaiev ◽  
Volodymyr Kartashov ◽  
Francy Loutouangou
Keyword(s):  
Image Processing ◽  
Moving Objects ◽  
Processing System ◽  
Video Camera ◽  
Image Processing System

scholarly journals Depolarization of elliptically polarized light in birefringent crystal

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
Andrzej Witold DomaĹ„ski ◽  
Łukasz Michalik ◽  
Marcin Redek ◽  
Piotr Leszek Makowski
Keyword(s):  
Polarized Light ◽  
Birefringent Crystal ◽  
Elliptically Polarized Light ◽  
Elliptically Polarized

A remote center of motion robotic arm for computer assisted surgery

Robotica ◽  
1996 ◽  
Vol 14 (1) ◽  
pp. 103-109 ◽  
Author(s):  
B. Eldridge ◽  
K. Gruben ◽  
D. LaRose ◽  
J. Funda ◽  
S. Gomory ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Computer Assisted Surgery ◽  
Video Camera ◽  
Robotic Arm ◽  
Computer Assisted ◽  
Robot Arm ◽  
Minimally Invasive Surgical ◽  
Tissue Manipulation ◽  
Servo Controller ◽  
Rotation Stage

SummaryWe have designed a robotic arm based on a double parallel four bar linkage to act as an assistant in minimally invasive surgical procedures. The remote center of motion (RCM) geometry of the robot arm kinematically constraints the robot motion such that minimal translation of an instrument held by the robot takes place at the entry portal into the patientApos;s body. In addition to the two rotational degrees of freedom comprising the RCM arm, distal translation and rotation are provided to manoeuver the instrument within the patient's body about an axis coincident with the RCM. An XYZ translation stage located proximal to the RCM arm provides positioning capability to establish the RCM location relative to the patients anatomy. An electronics set capable of controlling the system, as well as performing a series of safety checks to verify correct system operation, has also been designed and constructed. The robot is capable of precise positional motion. Repeatability in the ±10 micron range is demonstrated. The complete robotic system consists of the robot hardware and an IBM PC-AT based servo controller connected via a custom shared memory link to a host IBM PS/2. For laparoscopic applications, the PS/2 includes an image capture board to capture and process video camera images. A camera rotation stage has also been designed for this application. We have successfully demonstrated this system as an assistant in a laparoscopic cholecystectomy. Further applications for this system involving active tissue manipulation are under development.

Visualization of Flow-Field between the Flapper and Nozzle in a Hydraulic Servo-Valve

2011 ◽  
Vol 402 ◽  
pp. 407-411 ◽  
Author(s):  
Jacob M. Mchenya ◽  
Sheng Zhuo Zhang ◽  
Song Jing Li
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Video Camera ◽  
Computer Assisted ◽  
Servo Valve ◽  
High Speed Video ◽  
High Speed Video Camera ◽  
Hydraulic Servo ◽  
Working Principle ◽  
Computer Assisted Image

In order to understand the mechanism and get rid of the high-frequency self-excited noise in a hydraulic servo-valve, in this paper, the flow field distribution in the pilot stage of a hydraulic flapper-nozzle servo-valve is investigated. An assembly is prepared representing the construction and working principle of the flow field inside the pilot stage of a hydraulic flapper-nozzle servo-valve. A method of visualization is developed by taking videos for the flow field inside the transparent assembly with a high speed video camera. In this study, at different inlet pressure the high speed video camera was utilized for flow visualization together with computer-assisted image measurement. The shape of the jet flow, the cavitations and vortex flow inside the flow field can be visualized clearly. The proposed method enables to analyze the flow-field in the pilot stage of a hydraulic flapper-nozzle servo-valve by giving useful information for better design.

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