A Simple Analog Computing On-Line Microdensitometer

1976 ◽  
Vol 30 (4) ◽  
pp. 469-471 ◽  
Author(s):  
L. S. Dale ◽  
R. N. Whittem
Keyword(s):  
Analog Computing ◽  
On Line ◽  
Simple Analog

Linear Wavenumber Plotting of Spectrophotometer Outputs

1969 ◽  
Vol 23 (1) ◽  
pp. 51-54
Author(s):  
Earl W. Baker ◽  
Court L. Wolfe ◽  
Frank W. Noble
Keyword(s):  
Output Voltage ◽  
Absolute Intensity ◽  
Molar Absorptivity ◽  
Slow Step ◽  
Analog Device ◽  
Electrical Circuits ◽  
On Line ◽  
Recording Spectrophotometer ◽  
Simple Analog ◽  
Absorbance Spectra

The quantity of direct interest in the mathematical analysis and correlation of spectra is the integrated absolute intensity, i.e., I = ∫edv, where ∈ is the molar absorptivity at wavenumber #. Its evaluation requires that the spectra be plotted with an abscissa linear in wavenumber (energy) and the ordinate linear in absorptivity or absorbance. Paradoxically, while the convenience of the ratio recording spectrophotometer has long been available with direct plotting of absorbance, spectra linear in wavenumber have generally been obtained by either hand replotting or digitizing and replotting by computer. A simple analog device is described which obviates this slow step and performs an on-line conversion of wavelength to wavenumber according to the equation: 107/m μ = cm−1. The converter, which is mechanically linked to the wavelength scroll of the spectrophotometer, provides an output voltage proportional to the reciprocal of the scroll position. This output is used to position a servo-controlled chart drive (abscissa) on the readout recorder. Electrical circuits and details of construction are given, along with examples of spectra produced.

Simple analog computing conductive calorimeters

1989 ◽  
Vol 32 (5) ◽  
pp. 451-453
Author(s):  
V. M. Gurevich
Keyword(s):  
Analog Computing ◽  
Simple Analog

Value of Rotational Tests in the Diagnosis of Vestibular Disease

1973 ◽  
Vol 82 (4) ◽  
pp. 532-537 ◽  
Author(s):  
Joseph A. McClure ◽  
Paul Lycett ◽  
Walter H. Johnson
Keyword(s):  
Test Procedure ◽  
Slow Phase ◽  
Constant Acceleration ◽  
Standard Size ◽  
Caloric Irrigation ◽  
Canal Irrigation ◽  
Vestibular Adaptation ◽  
On Line ◽  
Comparison Of The Results ◽  
Simple Analog

Caloric irrigation of the external ear canal represents an inadequate vestibular stimulus because the method is not physiologic and the canal irrigation and the heat transfer to the inner ear cannot be well controlled. In rotational testing an accurate acceleration profile can be applied with an appropriate rotating device. A test procedure is presently being used, which consists of constant acceleration at 3°/sec2 for 50 seconds, hold at constant velocity for 240 seconds, followed by a similar deceleration (equivalent to acceleration in the revelse direction) and hold. On-line data reduction of the nystagmus response is accomplished automatically using a simple analog technique. This technique provides a concise presentation (on a standard size sheet of paper) of the total slow phase eye displacement resulting from the primary and secondary responses and enables comparison of the results for both directions of acceleration. Experience with the routine use of rotational testing in a vestibular clinic and the significance of various paterns of response with special emphasis on vestibular adaptation function are discussed.

The on-line use of histogram data for high-speed correction and alignment of electron microscope images

1984 ◽  
Vol 42 ◽  
pp. 556-557
Author(s):  
William Krakow
Keyword(s):  
Power Spectrum ◽  
High Speed ◽  
Direct Memory Access ◽  
Digital Television ◽  
Contrast Transfer Function ◽  
The Past ◽  
High Resolution Tem ◽  
On Line ◽  
Correction Of Astigmatism ◽  
The Fourier Transform

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.

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.

Design and calibration of an IVEM for general 3-dimensional imaging of non-diffracting materials

1992 ◽  
Vol 50 (2) ◽  
pp. 1040-1041
Author(s):  
Neil Rowlands ◽  
Jeff Price ◽  
Michael Kersker ◽  
Seichi Suzuki ◽  
Steve Young ◽  
...  
Keyword(s):  
3D Imaging ◽  
Tomographic Reconstruction ◽  
Three Dimensional ◽  
3 Dimensional ◽  
3D Microstructure ◽  
Image Translation ◽  
Digital Correlation ◽  
On Line ◽  
Mechanical Stage ◽  
Projection Angle

Three-dimensional (3D) microstructure visualization on the electron microscope requires that the sample be tilted to different positions to collect a series of projections. This tilting should be performed rapidly for on-line stereo viewing and precisely for off-line tomographic reconstruction. Usually a projection series is collected using mechanical stage tilt alone. The stereo pairs must be viewed off-line and the 60 to 120 tomographic projections must be aligned with fiduciary markers or digital correlation methods. The delay in viewing stereo pairs and the alignment problems in tomographic reconstruction could be eliminated or improved by tilting the beam if such tilt could be accomplished without image translation.A microscope capable of beam tilt with simultaneous image shift to eliminate tilt-induced translation has been investigated for 3D imaging of thick (1 μm) biologic specimens. By tilting the beam above and through the specimen and bringing it back below the specimen, a brightfield image with a projection angle corresponding to the beam tilt angle can be recorded (Fig. 1a).

Software pattern recognition applied to nanodiffraction patterns from a STEM instrument

1986 ◽  
Vol 44 ◽  
pp. 694-695
Author(s):  
G.Y. Fan ◽  
J.M. Cowley
Keyword(s):  
Image Processing ◽  
Pattern Recognition ◽  
Computer Software ◽  
Processing System ◽  
Light Level ◽  
Host Computer ◽  
Low Light ◽  
Image Processing System ◽  
Recent Developments ◽  
On Line

In recent developments, the ASU HB5 has been modified so that the timing, positioning, and scanning of the finely focused electron probe can be entirely controlled by a host computer. This made the asynchronized handshake possible between the HB5 STEM and the image processing system which consists of host computer (PDP 11/34), DeAnza image processor (IP 5000) which is interfaced with a low-light level TV camera, array processor (AP 400) and various peripheral devices. This greatly facilitates the pattern recognition technique initiated by Monosmith and Cowley. Software called NANHB5 is under development which, instead of employing a set of photo-diodes to detect strong spots on a TV screen, uses various software techniques including on-line fast Fourier transform (FFT) to recognize patterns of greater complexity, taking advantage of the sophistication of our image processing system and the flexibility of computer software.

Thickness Measurement in the AEM by Macintosh-Based Analysis of Two-Beam Convergent Beam Patterns

1990 ◽  
Vol 48 (2) ◽  
pp. 504-505
Author(s):  
John F. Mansfield ◽  
Douglas C. Crawford
Keyword(s):  
Electron Microscope ◽  
Video Camera ◽  
Thickness Measurement ◽  
Specimen Thickness ◽  
Crystalline Materials ◽  
Beam Dynamic ◽  
Line Measurement ◽  
On Line ◽  
Image Position ◽  
Convergent Beam

A method has been developed that allows on-line measurement of the thickness of crystalline materials in the analytical electron microscope. Two-beam convergent beam electron diffraction (CBED) patterns are digitized from a JEOL 2000FX electron microscope into an Apple Macintosh II microcomputer via a Gatan #673 CCD Video Camera and an Imaging Systems Technology Video 1000 frame-capture board. It is necessary to know the lattice parameters of the sample since measurements are made of the spacing of the diffraction discs in order to calibrate the pattern. The sample thickness is calculated from measurements of the spacings of the fringes that are seen in the diffraction discs. This technique was pioneered by Kelly et al, who used the two-beam dynamic theory of MacGillavry relate the deviation parameter (Si) of the ith fringe from the exact Bragg condition to the specimen thickness (t) with the equation:Where ξg, is the extinction distance for that reflection and ni is an integer.

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.

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