Principles and Practice of On-Line Data Acquisition For Transmission Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 528-529
Author(s):  
R. Tietz
Keyword(s):  
Image Processing ◽  
Image Analysis ◽  
Data Acquisition ◽  
Photographic Plate ◽  
Video Tape ◽  
Dynamic Events ◽  
Camera Systems ◽  
Transmission Electron ◽  
On Line ◽  
Beam Currents

For about 15 years now TV-camera based image acquisition systems have been used in many laboratories. These TV-systems facilitate focusing and stigmating of the instrument at low beam currents and the recording of dynamic events in the microscope with a video-tape recorder. Recently, digital image processing systems have become available which make image accumulation or averaging possible, or which can correct for uneven illumination conditions. This simple image processing is the basis for further image analysis (Automatic control of TEM parameters or real analysis of the specimen).The bottle neck in on-line data acquisition for a TEM is the image pick-up system. Compared to a photographic plate, which has about 10.000 by 10.000 resolved pixels, the resolution of commercial, TV-based camera systems is very poor, in the best case about 500 by 500 pixels. The poor resolution of TV-systems restricts the use of image analysis to objects which do not need large image fields.Fig. 1 illustrates the principles of TV-based image pick-up systems.

Recent developments in automated Transmission Electron MI

1989 ◽  
Vol 47 ◽  
pp. 46-47
Author(s):  
W.J. de Ruijter ◽  
P. Rez ◽  
David J. Smith
Keyword(s):  
Image Analysis ◽  
Computer Image ◽  
Lens Design ◽  
Computer Image Analysis ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Recent Developments ◽  
On Line ◽  
Routine Procedures ◽  
Near Future

There is growing interest in the on-line use of computers in high-resolution electron n which should reduce the demands on highly skilled operators and thereby extend the r of the technique. An on-line computer could obviously perform routine procedures hand, or else facilitate automation of various restoration, reconstruction and enhan These techniques are slow and cumbersome at present because of the need for cai micrographs and off-line processing. In low resolution microscopy (most biologic; primary incentive for automation and computer image analysis is to create a instrument, with standard programmed procedures. In HREM (materials researc computer image analysis should lead to better utilization of the microscope. Instru (improved lens design and higher accelerating voltages) have improved the interpretab the level of atomic dimensions (approximately 1.6 Å) and instrumental resolutior should become feasible in the near future.

Computer Image Analysis of the Ocular Fundus

1982 ◽  
Vol 21 (01) ◽  
pp. 23-25 ◽  
Author(s):  
J. Pe’er ◽  
G. Zajicek
Keyword(s):  
Image Processing ◽  
Image Analysis ◽  
Computer Image ◽  
Computer Control ◽  
Gray Level ◽  
Original Image ◽  
First Line ◽  
Computer Image Analysis ◽  
Ocular Fundus ◽  
On Line

Photographic transparencies of the ocular fundus were scanned with an image dissector under computer control. The image is digitized into 400 X 400 points each exhibiting 256 gray level values. During analysis, the computer stores in its buffer only five consecutive lines upon which image processing is performed; only then is the first line projected on the scope and the following line (the sixth in the original image) introduced into the buffer. In this setup, digitization may be manipulated on-line in real time.

In Situ Annealing Observations of Silicon Cross-Sectional TEM Specimens

1988 ◽  
Vol 46 ◽  
pp. 904-905
Author(s):  
E.M. Fiore ◽  
R.A. Herring
Keyword(s):  
Real Time ◽  
Network Formation ◽  
High Energy ◽  
Video Tape ◽  
Cross Sectional ◽  
Dynamic Events ◽  
Transmission Electron ◽  
Minute Period ◽  
Different Temperatures ◽  
A New Technique

With conventional transmission electron microscopy (TEM), dynamic events are pieced together with micrographs from a multitude of specimens annealed at different temperatures over the range of interest. Real-time imaging of dynamic events in the microscope provides the ability to view the entire anneal temperature span with one specimen. As reported by Parker, cross-sectional TEM can be used to observe real-time kinetic phenomena in silicon. Fiore and Herring later reported a new technique for preparing cross-sectional specimens that are annealable to temperatures as high as 1300°C. Both of these recently developed techniques have been used to observe the amorphous-to-crystalline phase transformation and defect network formation in high-energy ion implanted silicon.Cross-sectional specimens were annealed in a Philips CM 12 transmission electron microscope equipped with a heating holder. The specimens were prepared from [111 ]-oriented silicon wafers implanted with 5.5 Mev Ga ions at a dose of lO15 cm-2. Using a ramp-up temperature from ∽30°C to 1000°C over a 5-minute period, the dynamic events were recorded on 3/4-inch video tape from a TEM TV system.

In situ TEM studies of deformation and fracture

1989 ◽  
Vol 47 ◽  
pp. 622-623
Author(s):  
I.M. Robertson ◽  
T.C. Lee ◽  
D.K. Dewald ◽  
H.K. Birnbaum
Keyword(s):  
Grain Boundary ◽  
Video Camera ◽  
In Situ Tem ◽  
Video Tape ◽  
Slip Systems ◽  
Camera System ◽  
Dynamic Events ◽  
Transmission Electron ◽  
Deformation And Fracture

The in-situ TEM straining technique has been used to investigate the micromechanisms of deformation and fracture in several ductile and semi-brittle systems. Attention has been focussed on the dislocation structures ahead of advancing cracks and on the interaction between lattice dislocations and grain boundaries.The deformation experiments were performed in-situ in a transmission electron microscope equipped with a video camera system. The dynamic events were recorded on video tape with a time resolution of l/30th of a second. Static interactions were recorded using the regular microscope plate system. The straining stage deforms the samples in Mode I and can operate at a displacement rate of 4 in sec-1.An example of one of the possible interactions between lattice dislocations and a ∑- 3 ([ll)/60°) grain boundary in 310 stainless steel is shown in the micrograph in Figure 1. The dislocations on slip systems A (a/2[110)1 (ll) 1 ) and B (a/2[101] (11) 1 ) impinge on the grain boundary, generating slip systems C (a/2[l0) 2/(111) 2) and D (a/2[l0) 2/(111) 2). To understand this effect three conditions were considered:

Current and future directions of on-line Transmission Electron Microscope image processing and analysis

1989 ◽  
Vol 47 ◽  
pp. 48-49
Author(s):  
Michael A. O’Keefe ◽  
Roar Kilaas
Keyword(s):  
Image Processing ◽  
Internal Controls ◽  
Transmission Electron Microscope Image ◽  
Future Directions ◽  
Image Processing And Analysis ◽  
Line Image ◽  
Memory Card ◽  
Transmission Electron ◽  
On Line ◽  
Electron Microscope Image

Image processing and analysis are increasingly employed in order to extract the maximum amount of useful information from transmission electron micrographs. Whereas most processing is carried out a posteriori, i.e. from images that have been recorded on film then digitized for computer processing, it is obviously useful to be able to improve the on-line image in near-real time for the benefit of the microscope operator. In addition, interfacing an external computer to the internal controls of modern TEMs allows on-line image analysis to provide the first step in algorithms designed to assist the operator in adjustment of microscope parameters such as alignment, astigmatism and defocus.The hardware required for on-line image processing can be as simple as a detector coupled to a TV camera, the signal from which is digitized, stored and averaged by a set of cards controlled by a host computer, with a monitor displaying the image stored in the memory card.

Determining chromatin structure by computer-aided image analysis

1993 ◽  
Vol 51 ◽  
pp. 222-223
Author(s):  
James B. Olesen ◽  
Carol A. Heckman
Keyword(s):  
Image Processing ◽  
Image Analysis ◽  
Polytene Chromosomes ◽  
Razor Blade ◽  
Preliminary Step ◽  
Pattern Recognition Methods ◽  
Transmission Electron ◽  
Computer Aided ◽  
Microscope Slides ◽  
Glass Microscope

In the present research, we address the problem of how chromatin fibers are ordered in band and interband regions along the length of a Drosophila polytene chromosome. Our approach employs image processing as a preliminary step to amplify the image contrast. Then, computerized pattern recognition methods are used to study how the chromatin is arranged.Polytene chromosomes were isolated from salivary glands and squashed on glass microscope slides. The slides were immersed in liquid nitrogen and the coverslips were removed with a razor blade. Small droplets of a polymer developed in our laboratory called HACH (a mixture of 2- hydroxyhexanedial, carbohydrazide and hydrazine) were then placed over individual chromosome spreads and the slides were left at 26°C overnight to allow for HACH polymerization. HACHembedded samples were removed from the slides, mounted on resin blocks, trimmed and thinsectioned at a thickness of approximately 100 nm. Sections were floated onto formvar-coated gold grids and viewed with a Zeiss 10C transmission electron microscope operated at 80kV.

Mickey, A Computer Helping Hand for the Everyday use of the T.E.M.

1990 ◽  
Vol 48 (1) ◽  
pp. 602-603
Author(s):  
Chemelle Pierre ◽  
Muller Bernard ◽  
Crouillère Michel
Keyword(s):  
Photographic Plate ◽  
X Ray ◽  
Performance Improvements ◽  
Transmission Electron ◽  
The Everyday ◽  
On Line ◽  
Ethernet Network ◽  
Time Required ◽  
Line Analysis ◽  
Serial Line

The efficiency of transmission electron microscopy investigations is drastically impaired by the time required for photographic plate development, measurements and interpretation. Very often, the operator has to go back to the microscope to complete his analysis. The evolution of the TEM, through the automation of an increasing number of operating parameters and the increasing use of small computers has led to a variety of performance improvements.The outline of the microscope facility that we developed is shown in Figure 1. The TEM/STEM EM400T PHILIPS microscope is linked simultaneously to the EDAX PDP devoted to X-ray microanalysis and to a DEC μPDP for diffraction analysis. This second computer, operating in a multitask RSX environment can be used for on-line and off-line analysis of patterns, microanalysis data and crystallographic calculations. The μPDP is coupled to the microscope via ADC/DAC converters and the Hybrid Diffraction STEM apparatus. The two computers are connected through a serial line for data transmission (i.e. spectra and chemical analysis). As a whole, this facility is integrated in a DEC ETHERNET network connected to a mainframe VAX computer. Several image workstations, are among the other nodes of the network.

The direct determination of magnetic domain wall profiles using a split detector STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 466-467
Author(s):  
J.N. Chapman ◽  
P.E. Batson ◽  
E.M. Waddell ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Domain Wall ◽  
Transmission Electron Microscope ◽  
Domain Walls ◽  
Photographic Plate ◽  
Magnetic Domain ◽  
Direct Determination ◽  
Quantitative Information ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.

Image registration with a computer driven S.T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 98-99
Author(s):  
A.M.H. Schepman ◽  
J.A.P. van der Voort ◽  
J.E. Mellema
Keyword(s):  
Spot Size ◽  
Scanning Transmission Electron Microscope ◽  
Small Computer ◽  
Structural Studies ◽  
Area Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Specimen Area ◽  
On Line ◽  
Minimum Distances

A Scanning Transmission Electron Microscope (STEM) was coupled to a small computer. The system (see Fig. 1) has been built using a Philips EM400, equipped with a scanning attachment and a DEC PDP11/34 computer with 34K memory. The gun (Fig. 2) consists of a continuously renewed tip of radius 0.2 to 0.4 μm of a tungsten wire heated just below its melting point by a focussed laser beam (1). On-line operation procedures were developped aiming at the reduction of the amount of radiation of the specimen area of interest, while selecting the various imaging parameters and upon registration of the information content. Whereas the theoretical limiting spot size is 0.75 nm (2), routine resolution checks showed minimum distances in the order 1.2 to 1.5 nm between corresponding intensity maxima in successive scans. This value is sufficient for structural studies of regular biological material to test the performance of STEM over high resolution CTEM.

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