A Research Grade Computer Controlled Light Source

2018 ◽  
Author(s):  
Kadambari Sharma ◽  
P.P Vaidya ◽  
J.M. Nair
Keyword(s):  
Light Source ◽  
Research Grade ◽  
Computer Controlled

scholarly journals PyPlr: A versatile, integrated system of hardware and software for researching the human pupillary light reflex

2021 ◽  
Author(s):  
Joel T. Martin ◽  
Joana Pinto ◽  
Daniel Bulte ◽  
Manuel Spitschan
Keyword(s):  
Light Source ◽  
Integrated System ◽  
Pupillary Light Reflex ◽  
Integrating Sphere ◽  
Eye Tracker ◽  
Full Field ◽  
Light Reflex ◽  
Pupillary Light ◽  
Wide Range ◽  
Research Grade

AbstractWe introduce PyPlr—a versatile, integrated system of hardware and software to support a broad spectrum of research applications concerning the human pupillary light reflex (PLR). PyPlr is a custom Python library for integrating a research-grade video-based eye-tracker system with a light source and streamlining stimulus design, optimisation and delivery, device synchronisation, and extraction, cleaning, and analysis of pupil data. We additionally describe how full-field, homogenous stimulation of the retina can be realised with a low-cost integrating sphere that serves as an alternative to a more complex Maxwellian view setup. Users can integrate their own light source, but we provide full native software support for a high-end, commercial research-grade 10-primary light engine that offers advanced control over the temporal and spectral properties of light stimuli as well as spectral calibration utilities. Here, we describe the hardware and software in detail and demonstrate its capabilities with two example applications: (1) pupillometer-style measurement and parametrisation of the PLR to flashes of white light, and (2) comparing the post-illumination pupil response (PIPR) to flashes of long and short-wavelength light. The system holds promise for researchers who would favour a flexible approach to studying the PLR and the ability to employ a wide range of temporally and spectrally varying stimuli, including simple narrowband stimuli.

Realization of a Laboratory Tuneable Colour Light Source

2020 ◽  
pp. 90-98
Author(s):  
Nina Carli ◽  
Armin Sperling ◽  
Grega Bizjak
Keyword(s):  
Electric Current ◽  
Light Source ◽  
Closed Loop ◽  
Luminous Flux ◽  
Integrating Sphere ◽  
Practical Implementation ◽  
Light Sources ◽  
Output Spectrum ◽  
Calibration Source ◽  
Computer Controlled

A spectrally tuneable colour light source (TCLS) has been designed and constructed at Physikalisch-Technische Bundesanstalt (PTB), Germany. It consists of an integrating sphere with 24 LEDs which are driven by a computer-controlled power supply. It is intended for producing any visible spectral distribution and to mimic various light sources for use in laboratories as a calibration source. With the help of an integrated spectrometer, a closed loop operation was introduced to improve the performance of the TCLS and to spectrally stabilize its output spectrum. Before practical realization of the TCLS a series of simulations have been made to predict its performance and capability with a number of different target spectrums. During the practical implementation we have encountered difficulties, namely optimization of the output spectrum, dependency of LED spectra on the electric current through the LED and temperature of the LED, non-linearity of LED’s luminous flux with respect to electric current through the LED and some difficulties with small synthesis coefficient values, which were all successfully solved.

scholarly journals PyPlr: A versatile, integrated system of hardware and software for researching the human pupillary light reflex

2021 ◽  
Author(s):  
Joel T Martin ◽  
Joana Pinto ◽  
Daniel P Bulte ◽  
Manuel Spitschan
Keyword(s):  
Light Source ◽  
Integrated System ◽  
Pupillary Light Reflex ◽  
Integrating Sphere ◽  
Eye Tracker ◽  
Full Field ◽  
Light Reflex ◽  
Pupillary Light ◽  
Wide Range ◽  
Research Grade

We introduce PyPlr—a versatile, integrated system of hardware and software to support a broad spectrum of research applications concerning the human pupillary light reflex (PLR). PyPlr is a custom Python library for integrating a research-grade video-based eye-tracker system with a light source and for streamlining stimulus design, optimisation and delivery, device synchronisation, and extraction, cleaning, and analysis of pupil data. We additionally describe how full-field, homogenous stimulation of the retina can be realised with a low-cost integrating sphere that serves as an alternative to a more-complex Maxwellian view setup. Users can integrate their own light source, but we provide full native software support for a high-end, commercial research-grade 10-primary light engine which offers advanced control over the temporal and spectral properties of light stimuli as well as spectral calibration utlities. Here, we describe the hardware and software in detail and demonstrate its capabilities with two example applications: 1) pupillometer-style measurement and parametrisation of the PLR to flash of white light, and 2) comparing the post-illumination pupil response (PIPR) to flashes of long and short-wavelength light. The system holds promise for researchers who would favour a flexible approach to studying the PLR and the ability to employ a wide range of temporally and spectrally varying stimuli, including simple narrowband stimuli.

A Method for Setting the Clearance Angle

1972 ◽  
Vol 30 ◽  
pp. 388-389
Author(s):  
Michael T. Bucek ◽  
Howard J. Arnott
Keyword(s):  
Experimental Evidence ◽  
Light Source ◽  
Black Spot ◽  
Critical Factor ◽  
Clearance Angle ◽  
Crude Approximation ◽  
Ultrathin Sections

It is believed by the authors, with supporting experimental evidence, that as little as 0.5°, or less, knife clearance angle may be a critical factor in obtaining optimum quality ultrathin sections. The degree increments located on the knife holder provides the investigator with only a crude approximation of the angle at which the holder is set. With the increments displayed on the holder one cannot set the clearance angle precisely and reproducibly. The ability to routinely set this angle precisely and without difficulty would obviously be of great assistance to the operator. A device has been contrived to aid the investigator in precisely setting the clearance angle. This device is relatively simple and is easily constructed. It consists of a light source and an optically flat, front surfaced mirror with a minute black spot in the center. The mirror is affixed to the knife by placing it permanently on top of the knife holder.

SPECTRA: A program for processing electron images of crystals

1992 ◽  
Vol 50 (1) ◽  
pp. 132-133
Author(s):  
M.F. Schmid ◽  
R. Dargahi ◽  
M. W. Tam
Keyword(s):  
Lattice Distortion ◽  
Data Transfer ◽  
Reciprocal Lattice ◽  
Data Entry ◽  
Image Data ◽  
Distortion Correction ◽  
Specimen Preparation ◽  
Electron Image ◽  
Computer Controlled ◽  
Program Modules

Electron crystallography is an emerging field for structure determination as evidenced by a number of membrane proteins that have been solved to near-atomic resolution. Advances in specimen preparation and in data acquisition with a 400kV microscope by computer controlled spot scanning mean that our ability to record electron image data will outstrip our capacity to analyze it. The computed fourier transform of these images must be processed in order to provide a direct measurement of amplitudes and phases needed for 3-D reconstruction.In anticipation of this processing bottleneck, we have written a program that incorporates a menu-and mouse-driven procedure for auto-indexing and refining the reciprocal lattice parameters in the computed transform from an image of a crystal. It is linked to subsequent steps of image processing by a system of data bases and spawned child processes; data transfer between different program modules no longer requires manual data entry. The progress of the reciprocal lattice refinement is monitored visually and quantitatively. If desired, the processing is carried through the lattice distortion correction (unbending) steps automatically.

Applications of CCEM to Environmental Health Problems

1985 ◽  
Vol 43 ◽  
pp. 102-103
Author(s):  
R. J. Lee ◽  
J. S. Walker
Keyword(s):  
Electron Microscopy ◽  
Image Analysis ◽  
Environmental Health ◽  
Computer Control ◽  
External Agent ◽  
External Agents ◽  
Computer Controlled ◽  
Primitive State ◽  
Textural Changes ◽  
General Aspects

Electron microscopy (EM), with the advent of computer control and image analysis techniques, is rapidly evolving from an interpretative science into a quantitative technique. Electron microscopy is potentially of value in two general aspects of environmental health: exposure and diagnosis.In diagnosis, electron microscopy is essentially an extension of optical microscopy. The goal is to characterize cellular changes induced by external agents. The external agent could be any foreign material, chemicals, or even stress. The use of electron microscopy as a diagnostic tool is well- developed, but computer-controlled electron microscopy (CCEM) has had only limited impact, mainly because it is fairly new and many institutions lack the resources to acquire the capability. In addition, major contributions to diagnosis will come from CCEM only when image analysis (IA) and processing algorithms are developed which allow the morphological and textural changes recognized by experienced medical practioners to be quantified. The application of IA techniques to compare cellular structure is still in a primitive state.

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

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.

A confocal laser scanning microscope for fluorescence and reflection at video rates

1989 ◽  
Vol 47 ◽  
pp. 134-135
Author(s):  
P.M. Houpt ◽  
A. Draaijer
Keyword(s):  
Light Source ◽  
Laser Scanning ◽  
Focal Point ◽  
Confocal Laser Scanning Microscope ◽  
Confocal Laser ◽  
Point Light Source ◽  
Volume Of Interest ◽  
Ion Laser ◽  
Point Light ◽  
Point Detector

In confocal microscopy, the object is scanned by the coinciding focal points (confocal) of a point light source and a point detector both focused on a certain plane in the object. Only light coming from the focal point is detected and, even more important, out-of-focus light is rejected.This makes it possible to slice up optically the ‘volume of interest’ in the object by moving it axially while scanning the focused point light source (X-Y) laterally. The successive confocal sections can be stored in a computer and used to reconstruct the object in a 3D image display.The instrument described is able to scan the object laterally with an Ar ion laser (488 nm) at video rates. The image of one confocal section of an object can be displayed within 40 milliseconds (1000 х 1000 pixels). The time to record the total information within the ‘volume of interest’ normally depends on the number of slices needed to cover it, but rarely exceeds a few seconds.

The new CM-Series TEMs: integration of a five-axis motorized, fully computer-controlled goniometer

1993 ◽  
Vol 51 ◽  
pp. 258-259
Author(s):  
Marc J.C. de Jong ◽  
P. Emile S.J. Asselbergs ◽  
Max T. Otten
Keyword(s):  
Mechanical Design ◽  
Computer Control ◽  
Objective Lens ◽  
Access Port ◽  
Vibration Stability ◽  
Transmission Electron ◽  
Computer Controlled ◽  
High Degree ◽  
Five Axis ◽  
Five Axes

A new step forward in Transmission Electron Microscopy has been made with the introduction of the CompuStage on the CM-series TEMs: CM120, CM200, CM200 FEG and CM300. This new goniometer has motorization on five axes (X, Y, Z, α, β), all under full computer control by a dedicated microprocessor that is in communication with the main CM processor. Positions on all five axes are read out directly - not via a system counting motor revolutions - thereby providing a high degree of accuracy. The CompuStage enters the octagonal block around the specimen through a single port, allowing the specimen stage to float freely in the vacuum between the objective-lens pole pieces, thereby improving vibration stability and freeing up one access port. Improvements in the mechanical design ensure higher stability with regard to vibration and drift. During stage movement the holder O-ring no longer slides, providing higher drift stability and positioning accuracy as well as better vacuum.

The consolidation of microscopy technology into a university research support facility: Reflections on the 1980's and projections for the 1990's at the university of iowa

1993 ◽  
Vol 51 ◽  
pp. 476-477
Author(s):  
Kenneth C. Moore
Keyword(s):  
Laser Scanning ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Research Support ◽  
University Of Iowa ◽  
Staff Members ◽  
The Past ◽  
Research Grade ◽  
The University ◽  
Support Facility

The University of Iowa Central Electron Microscopy Research Facility(CEMRF) was established in 1981 to support all faculty, staff and students needing this technology. Initially the CEMRF was operated with one TEM, one SEM, three staff members and supported about 30 projects a year. During the past twelve years, the facility has replaced all instrumentation pre-dating 1981, and now includes 2 TEM's, 2 SEM's, 2 EDS systems, cryo-transfer specimen holders for both TEM and SEM, 2 parafin microtomes, 4 ultamicrotomes including cryoultramicrotomy, a Laser Scanning Confocal microscope, a research grade light microscope, an Ion Mill, film and print processing equipment, a rapid cryo-freezer, freeze substitution apparatus, a freeze-fracture/etching system, vacuum evaporators, sputter coaters, a plasma asher, and is currently evaluating scanning probe microscopes for acquisition. The facility presently consists of 10 staff members and supports over 150 projects annually from 44 departments in 5 Colleges and 10 industrial laboratories. One of the unique strengths of the CEMRF is that both Biomedical and Physical scientists use the facility.

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