scholarly journals A Study of Noise Characteristics on Images in Computer Microscopy Systems

2020 ◽  
Vol 26 (4) ◽  
pp. 598-603
Author(s):  
E. V. Polyakov ◽  
Keyword(s):  
Automated Analysis ◽  
Low Contrast ◽  
Noise Characteristics ◽  
Computer Microscopy

The characteristics of noise on images in computer microscopy systems are investigated, which is important when solving problems of automated analysis of low-contrast objects. The parameters of noise in a computer microscopy system were determined using a Watec 231 camera and an Olympus CX31 motorized microscope. Recommendations for suppressing the detected noise are given.

Spherical aberration and the information content of optical images

1957 ◽  
Vol 239 (1219) ◽  
pp. 522-540 ◽  
Keyword(s):  
Information Content ◽  
Spherical Aberration ◽  
Signal To Noise Ratio ◽  
Fourth Power ◽  
Low Contrast ◽  
Information Density ◽  
Noise Characteristics ◽  
Special Cases ◽  
Basic Ideas ◽  
Airy Disk

The main purpose of the paper is to investigate the effect of spherical aberration on the information content of low-contrast photographic images with specified spread and noise characteristics. In § 1 an outline is given of the basic ideas and the relevant formalism. In § 2 the response functions of monochromats with spherical aberration and defocusing are considered, and their computed values in selected special cases are displayed in figures 3 to 5. A digression is made in § 3 in order to discuss, with the help of these values, a point of topical interest, namely, the variation of best focus with the line frequency of a sinusoidal test object. In § 4 the notion of the equivalent receiving surface of a low-contrast photographic process is introduced and two equivalent receiving surfaces are defined, with the help of some experimental results of Higgins & Jones (1952), which correspond to model photographic processes used with low-contrast objects. In § 5 the mean information density in the images of an aberration-free monochromat is calculated for two model emulsions, at selected noise levels, over a range of focal settings. In both models, the correctly focused images of a random object set are found to contain about one bit per Airy disk when the signal-to-noise ratio is 100 and the effect of defocusing are similar in the two cases. The effect of spherical aberration on information density at different focal settings is then examined in the second model. It appears that, for amounts of fourth-power aberration up to two fringes, the informationally best focus is approximately midway between paraxial and marginal foci, and that the acceptance of a 20% drop in information content corresponds to a focal tolerance of approximately ± ½ fringe.

scholarly journals Influence of Sinogram Affirmed Iterative Reconstruction of CT Data on Image Noise Characteristics and Low-Contrast Detectability: An Objective Approach

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e56875 ◽  
Author(s):  
Christian von Falck ◽  
Vesela Bratanova ◽  
Thomas Rodt ◽  
Bernhard Meyer ◽  
Stephan Waldeck ◽  
...  
Keyword(s):  
Iterative Reconstruction ◽  
Image Noise ◽  
Low Contrast ◽  
Noise Characteristics ◽  
Ct Data

DETECTION OF BLOOD VESSELS FROM RETINAL IMAGES USING WATERSHED TRANSFORMATION

2009 ◽  
Vol 09 (04) ◽  
pp. 633-642 ◽  
Author(s):  
A. BESSAID ◽  
A. FEROUI ◽  
M. MESSADI
Keyword(s):  
Blood Vessels ◽  
Automated Analysis ◽  
Retinal Images ◽  
Fundus Images ◽  
Vascular Tree ◽  
Important Indicator ◽  
Watershed Transformation ◽  
Low Contrast ◽  
Retinal Blood Vessels ◽  
Diagnostic Step

Automated analysis and interpretation of retinal images has become an incontournable diagnostic step in ophthalmology. Retinal blood vessels morphology can be an important indicator for diseases such as diabetic retinopathy; and their detection also serves for image registration. This paper presents a method based on mathematical morphology for extraction of vascular tree in color retinal image with low contrast. It consists in contrast enhancement and application of watershed transformation in order to segment blood vessels in digital fundus images.

Exploring Coronal Structures with SOHO

2000 ◽  
Vol 179 ◽  
pp. 403-406
Author(s):  
M. Karovska ◽  
B. Wood ◽  
J. Chen ◽  
J. Cook ◽  
R. Howard
Keyword(s):  
Solar Corona ◽  
Image Enhancement ◽  
Coronal Mass Ejections ◽  
Dynamical Evolution ◽  
Small Scale ◽  
Low Contrast ◽  
Contrast Structures ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Coronal Structures

AbstractWe applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.

One Million Direct Magnification Microscopy

1971 ◽  
Vol 29 ◽  
pp. 166-167
Author(s):  
J. A. Hugo ◽  
V. A. Phillips
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Illumination Level ◽  
Level Of Detail ◽  
Photographic Emulsion ◽  
Low Contrast ◽  
Fluorescent Screen ◽  
Resolution Electron ◽  
Lattice Images ◽  
Electron Microscopes

A continuing problem in high resolution electron microscopy is that the level of detail visible to the microscopist while he is taking a picture is inferior to that obtainable by the microscope, readily readable on a photographic emulsion and visible in an enlargement made from the plate. Line resolutions, of 2Å or better are now achievable with top of the line 100kv microscopes. Taking the resolution of the human eye as 0.2mm, this indicates a need for a direct viewing magnification of at least one million. However, 0.2mm refers to optimum viewing conditions in daylight or the equivalent, and certainly does not apply to a (colored) image of low contrast and illumination level viewed on a fluorescent screen through a glass window by the dark-adapted eye. Experience indicates that an additional factor of 5 to 10 magnification is needed in order to view lattice images with line spacings of 2 to 4Å. Fortunately this is provided by the normal viewing telescope supplied with most electron microscopes.

Field Emission SEM Equipped With Noise Compensator

1973 ◽  
Vol 31 ◽  
pp. 302-303
Author(s):  
S. Saito ◽  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Contrast ◽  
Probe Current ◽  
High Resolution Images ◽  
Scanning Electron

Field emission scanning electron microscope (FESEM) features extremely high resolution images, and offers many valuable information. But, for a specimen which gives low contrast images, lateral stripes appear in images. These stripes are resulted from signal fluctuations caused by probe current noises. In order to obtain good images without stripes, the fluctuations should be less than 1%, especially for low contrast images. For this purpose, the authors realized a noise compensator, and applied this to the FESEM.Fig. 1 shows an outline of FESEM equipped with a noise compensator. Two apertures are provided gust under the field emission gun.

Analysis of 3-d molecular distribution with the digital imaging microscope

1988 ◽  
Vol 46 ◽  
pp. 40-41
Author(s):  
W.A. Carrington ◽  
F.S. Fay ◽  
K.E. Fogarty ◽  
L. Lifshitz
Keyword(s):  
Image Restoration ◽  
Digital Imaging ◽  
Fluorescent Dyes ◽  
Optical Axis ◽  
Computer Hardware ◽  
Computer Algorithms ◽  
Low Contrast ◽  
Specific Proteins ◽  
Effective Use ◽  
Single Living Cells

Advances in digital imaging microscopy and in the synthesis of fluorescent dyes allow the determination of 3D distribution of specific proteins, ions, GNA or DNA in single living cells. Effective use of this technology requires a combination of optical and computer hardware and software for image restoration, feature extraction and computer graphics.The digital imaging microscope consists of a conventional epifluorescence microscope with computer controlled focus, excitation and emission wavelength and duration of excitation. Images are recorded with a cooled (-80°C) CCD. 3D images are obtained as a series of optical sections at .25 - .5 μm intervals.A conventional microscope has substantial blurring along its optical axis. Out of focus contributions to a single optical section cause low contrast and flare; details are poorly resolved along the optical axis. We have developed new computer algorithms for reversing these distortions. These image restoration techniques and scanning confocal microscopes yield significantly better images; the results from the two are comparable.

Resistance Monitor and Control for Vacuum Evaporation of Metals and Carbon

1976 ◽  
Vol 34 ◽  
pp. 572-573
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe ◽  
J. Michael Moseley
Keyword(s):  
Electronic Device ◽  
Point Sources ◽  
High Contrast ◽  
Variable Resistor ◽  
Quality Of Results ◽  
Low Contrast ◽  
Evaporation Source ◽  
And Control ◽  
At Will

We have designed and built an electronic device which compares the resistance of a defined area of vacuum evaporated material with a variable resistor. When the two resistances are matched, the device automatically disconnects the primary side of the substrate transformer and stops further evaporation.This approach to controlled evaporation in conjunction with the modified guns and evaporation source permits reliably reproducible multiple Pt shadow films from a single Pt wrapped carbon point source. The reproducibility from consecutive C point sources is also reliable. Furthermore, the device we have developed permits us to select a predetermined resistance so that low contrast high-resolution shadows, heavy high contrast shadows, or any grade in between can be selected at will. The reproducibility and quality of results are demonstrated in Figures 1-4 which represent evaporations at various settings of the variable resistor.

“High Resolution High Voltage Electron Microscopy”

1968 ◽  
Vol 26 ◽  
pp. 326-327
Author(s):  
Benjamin M. Siegel
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Voltage ◽  
Full Potential ◽  
Contrast Imaging ◽  
High Voltage Electron Microscopy ◽  
Low Contrast ◽  
Voltage Electron ◽  
Critical Areas ◽  
High Voltage Electron

The potential advantages of high voltage electron microscopy for extending the limits of resolution and contrast in imaging low contrast objects, such as biomolecular specimens, is very great. The results of computations will be presented showing that at accelerating voltages of 500-1000 kV it should be possible to achieve spacial resolutions of 1 to 1.5 Å and using phase contrast imaging achieve adequate image contrast to observe single atoms of low atomic number.The practical problems associated with the design and utilization of the high voltage instrument are, optimistically, within the range of competence of the state of the art. However, there are some extremely important and critical areas to be systematically investigated before we have achieved this competence. The basic electron optics of the column required is well understood, but before the full potential of an instrument capable of resolutions of better than 1.5 Å are realized some very careful development work will be required. Of great importance for the actual achievement of high resolution with a high voltage electron microscope is the fundamental limitation set by the characteristics of the high voltage electron beam that can be obtained from the accelerator column.

Sign in / Sign up

Export Citation Format

Share Document