Researching quality parameters of rainbow holographic image by measuring modulated transfer function

2001 ◽  
Author(s):  
Sergey B. Odinokov ◽  
Evgeny E. Salnikov ◽  
Dmitry S. Lushnikov
Keyword(s):  
Transfer Function ◽  
Quality Parameters ◽  
Holographic Image ◽  
Modulated Transfer Function

Risk assessment for drinking water production: assessing the potential risk due to the presence of Cryptosporidium oocysts in water

2002 ◽  
Vol 2 (3) ◽  
pp. 55-63 ◽  
Author(s):  
J.M. Laîné ◽  
S. Démotier ◽  
K. Odeh ◽  
W. Schön ◽  
P. Charles
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Transfer Function ◽  
Treatment Process ◽  
Produced Water ◽  
Transfer Functions ◽  
Treatment Plant ◽  
Software Tool ◽  
Quality Parameters ◽  
Input Concentration

This paper presents an approach for assessing the risk of producing non-compliant drinking water (i.e. one of the quality parameters exceeds the standards fixed by legislation), taking into account the quality parameters of raw water and the process line of the treatment plant (technology, different failure mode and corresponding failure rate). Firstly, nominal and degraded modes of each step of the treatment line are analysed, in order to obtain transfer functions (which give output concentration of parameters in function of the input concentration) for each step of the treatment and each quality parameter, in nominal and degraded functioning. The transfer function of the whole treatment process can thereby be obtained by combination of transfer function of each step, and failure conditions of the whole treatment process and corresponding degraded global transfer function could be determined. Secondly, an inversion of both global function (nominal and degraded) permits to estimate probability for the resource to exceed thresholds fixed by regulation (in that case, a scenario of non-compliant drinking water exists), and to obtain a compliant water availability. Finally, this paper presents a software tool realised to evaluate the risk of non-compliant produced water, using the described methodology. Finally, an approach of risk assessment for Cryptosporidium is also presented. This method allows to identification and puts priorities for utilities presenting the highest risk.

Radiation Damage of Support Films

1981 ◽  
Vol 39 ◽  
pp. 28-29
Author(s):  
H.A. Cohen ◽  
W. Chiu
Keyword(s):  
Transfer Function ◽  
Low Temperatures ◽  
Carbon Support ◽  
Contrast Transfer Function ◽  
Electron Dose ◽  
Imaging Parameters ◽  
Negative Stain ◽  
Phase Corrections ◽  
Two Parameters ◽  
Medium Dose

The goal of imaging the finest detail possible in biological specimens leads to contradictory requirements for the choice of an electron dose. The dose should be as low as possible to minimize object damage, yet as high as possible to optimize image statistics. For specimens that are protected by low temperatures or for which the low resolution associated with negative stain is acceptable, the first condition may be partially relaxed, allowing the use of (for example) 6 to 10 e/Å2. However, this medium dose is marginal for obtaining the contrast transfer function (CTF) of the microscope, which is necessary to allow phase corrections to the image. We have explored two parameters that affect the CTF under medium dose conditions.Figure 1 displays the CTF for carbon (C, row 1) and triafol plus carbon (T+C, row 2). For any column, the images to which the CTF correspond were from a carbon covered hole (C) and the adjacent triafol plus carbon support film (T+C), both recorded on the same micrograph; therefore the imaging parameters of defocus, illumination angle, and electron statistics were identical.

Possible applications of fraunhofer holography in high resolution electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 222-223 ◽  
Author(s):  
N. Bonnet ◽  
M. Troyon ◽  
P. Gallion
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Transfer Function ◽  
Radiation Damage ◽  
High Resolution Electron Microscopy ◽  
Far Field ◽  
Field Region ◽  
Crystalline Materials ◽  
Resolution Electron ◽  
The Ideal

Two main problems in high resolution electron microscopy are first, the existence of gaps in the transfer function, and then the difficulty to find complex amplitude of the diffracted wawe from registered intensity. The solution of this second problem is in most cases only intended by the realization of several micrographs in different conditions (defocusing distance, illuminating angle, complementary objective apertures…) which can lead to severe problems of contamination or radiation damage for certain specimens.Fraunhofer holography can in principle solve both problems stated above (1,2). The microscope objective is strongly defocused (far-field region) so that the two diffracted beams do not interfere. The ideal transfer function after reconstruction is then unity and the twin image do not overlap on the reconstructed one.We show some applications of the method and results of preliminary tests.Possible application to the study of cavitiesSmall voids (or gas-filled bubbles) created by irradiation in crystalline materials can be observed near the Scherzer focus, but it is then difficult to extract other informations than the approximated size.

Ultimate resolution and information in electron microscopy

1991 ◽  
Vol 49 ◽  
pp. 496-497
Author(s):  
D. Van Dyck
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Transfer Function ◽  
Information Transfer ◽  
Communication Channel ◽  
Structural Information ◽  
Information Rate ◽  
Noise Power ◽  
Signal Power ◽  
Imaging Device

An (electron) microscope can be considered as a communication channel that transfers structural information between an object and an observer. In electron microscopy this information is carried by electrons. According to the theory of Shannon the maximal information rate (or capacity) of a communication channel is given by C = B log2 (1 + S/N) bits/sec., where B is the band width, and S and N the average signal power, respectively noise power at the output. We will now apply to study the information transfer in an electron microscope. For simplicity we will assume the object and the image to be onedimensional (the results can straightforwardly be generalized). An imaging device can be characterized by its transfer function, which describes the magnitude with which a spatial frequency g is transferred through the device, n is the noise. Usually, the resolution of the instrument ᑭ is defined from the cut-off 1/ᑭ beyond which no spadal information is transferred.

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