Effect of anomalous particle light scattering on PIV image quality

1998 ◽  
Author(s):  
J. Kostas ◽  
J. Cater ◽  
J. Soria
Keyword(s):  
Light Scattering ◽  
Image Quality ◽  
Anomalous Particle

scholarly journals Study of air-bubble-induced light scattering effect on image quality in 193-nm immersion lithography

2004 ◽  
Author(s):  
Yongfa Fan ◽  
Neal V. Lafferty ◽  
Anatoly Bourov ◽  
Lena V. Zavyalova ◽  
Bruce W. Smith
Keyword(s):  
Light Scattering ◽  
Image Quality ◽  
Air Bubble ◽  
Immersion Lithography ◽  
Scattering Effect ◽  
193 Nm ◽  
Light Scattering Effect

scholarly journals Corneal light scattering following excimer laser surgery

2008 ◽  
Author(s):  
Dirk De Brouwere
Keyword(s):  
Wound Healing ◽  
Light Scattering ◽  
Theoretical Model ◽  
Image Quality ◽  
Excimer Laser ◽  
Laser Surgery ◽  
Morphological Changes ◽  
Optical Parameters ◽  
Foam Layer ◽  
Healing Response

Introduction Increased corneal scattering is assumed to be a considerable side-effectof refractive surgery due to the postoperative healing response after photoablativesurface treatments. Clinically, corneal scattering is associated with haze development.Corneal haze is subjectively evaluated method based on the observation of the lightbackscattered on the cornea as seen under a slit lamp. However, corneal light scatteringaffects the retinal image quality only by its forward scattering component. The scopeof this thesis is to evaluate the the effect of corneal light scattering on the retinal imagequality, specifically in relation to the morphological changes in the cornea followingexcimer laser surgery.Methods Initially, the optical mechanisms of the image formation on the retina arediscussed. Following, the optical parameters of the corneal morphology are characterizedto form a theoretical model describing the forward light scattering in the cornea.Simulation of this theoretical model is done by a physical model of light scatteringon microspheres. This model is evaluated both by psychophysical and optical measurements.Further, we compared the use of two psychophysical and three opticalmethods to evaluate both the amount of light scattered in the cornea and the angulardistribution of the scattered light.Results Based on histological data of stained corneal samples and in vivo confocalmicroscopy, the morphologic corneal changes addressed to the wound healing responseare induced by the activation of keratocytes, inhibiting a newly formed unorganizedcollagen layer, a scar tissue called the foam layer. The theoretical models developed in this thesis reveal the presence of scattering particles that cause a local distortion of theincoming wavefront. The point spread function of this scattered wavefront is stronglyforward distributed with a full width at the half maximum of approximately 20 minutesof arc. After refractive treatments, the light scattering increases until 1 month aftertreatment, reducing to a long term moderate level of increased light scattering after6 months. Moreover, we derived that where, in a healthy cornea approximately 20percent of the incoming light is scattered, this value increases up to 70 percent forcorneas with marked haze. Furthermore, psychophysical data suggest that the amountof light scattered over angles from 5 to 10 degrees increases in a similar extend asobserved in the ageing eye.Conclusion The wound healing response of the cornea on photorefractive ablationtreatments result in an increase of corneal scattering. The light distribution of thisscattered light is narrowly forward peaked. Correlation of the foam layer with amountof forward light scattering suggests that the increased corneal scattering followingrefractive surgery mainly originates on this foam layer. Therefore, a correct postoperativecare of the cornea following excimer laser surgery is detrimental for an optimalretinal image quality. The effect of light scattering in the eye results on a lowering ofthe contrast sensitivity and an increased disability glare around light sources in nightvision.

scholarly journals The influence of atmospheric light scattering on reflectance measurements during photogrammetric survey flights at low altitudes over forest areas

2018 ◽  
Vol 79 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Anna Mazur ◽  
Mariusz Kacprzak ◽  
Katarzyna Kubiak ◽  
Jan Kotlarz ◽  
Krzysztof Skocki
Keyword(s):  
Image Processing ◽  
Light Scattering ◽  
Image Quality ◽  
Atmospheric Correction ◽  
Aerial Images ◽  
Image Correction ◽  
Affect Image Quality ◽  
Imaging Sensors ◽  
Reflectance Measurements ◽  
Atmospheric Light

Abstract In this article, we describe methods for the correction of multispectral aerial images by accounting for atmospheric interference. We also summarize the first correction results for images acquired at flight altitudes and evaluate the suitability of selected methods for the atmospheric correction of these images. Furthermore, processes and phenomena occurring in the atmosphere that potentially affect image quality and interfere with the electromagnetic radiation registered by the imaging sensors are discussed as well. The purpose of atmospheric correction is to reduce or eliminate atmospheric interference during multispectral image processing. Here we present methodology for image correction based on data gathered at various altitudes during the autumn flights conducted as a part of the HESOFF project.

Air bubble-induced light-scattering effect on image quality in 193 nm immersion lithography

2005 ◽  
Vol 44 (19) ◽  
pp. 3904 ◽  
Author(s):  
Yongfa Fan ◽  
Neal Lafferty ◽  
Anatoly Bourov ◽  
Lena Zavyalova ◽  
Bruce W. Smith
Keyword(s):  
Light Scattering ◽  
Image Quality ◽  
Air Bubble ◽  
Immersion Lithography ◽  
Scattering Effect ◽  
193 Nm ◽  
Light Scattering Effect

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

An Environmental Wet Cell For High Voltage Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 18-19
Author(s):  
N.J. Tighe ◽  
H.M. Flower ◽  
P.R. Swann
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Image Quality ◽  
Inelastic Scattering ◽  
High Voltage ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Environmental Cell ◽  
Water Saturated ◽  
High Temperature Gas

A differentially pumped environmental cell has been developed for use in the AEI EM7 million volt microscope. In the initial version the column of gas traversed by the beam was 5.5mm. This permited inclusion of a tilting hot stage in the cell for investigating high temperature gas-specimen reactions. In order to examine specimens in the wet state it was found that a pressure of approximately 400 torr of water saturated helium was needed around the specimen to prevent dehydration. Inelastic scattering by the water resulted in a sharp loss of image quality. Therefore a modified cell with an ‘airgap’ of only 1.5mm has been constructed. The shorter electron path through the gas permits examination of specimens at the necessary pressure of moist helium; the specimen can still be tilted about the side entry rod axis by ±7°C to obtain stereopairs.

Image quality vs data obtainment in biological electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 42-43
Author(s):  
J. E. Johnson
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Beam ◽  
Image Quality ◽  
High Speed ◽  
Early Period ◽  
Early Years ◽  
Fluorescent Screen ◽  
Embedding Medium

In the early years of biological electron microscopy, scientists had their hands full attempting to describe the cellular microcosm that was suddenly before them on the fluorescent screen. Mitochondria, Golgi, endoplasmic reticulum, and other myriad organelles were being examined, micrographed, and documented in the literature. A major problem of that early period was the development of methods to cut sections thin enough to study under the electron beam. A microtome designed in 1943 moved the specimen toward a rotary “Cyclone” knife revolving at 12,500 RPM, or 1000 times as fast as an ordinary microtome. It was claimed that no embedding medium was necessary or that soft embedding media could be used. Collecting the sections thus cut sounded a little precarious: “The 0.1 micron sections cut with the high speed knife fly out at a tangent and are dispersed in the air. They may be collected... on... screens held near the knife“.

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