Ray Tracing and Estimation of Image Quality

Author(s):  
Grigoriy I. Greisukh ◽  
Sergei T. Bobrov ◽  
Sergei A. Stepanov
Keyword(s):  
1990 ◽  
Vol 29 (28) ◽  
pp. 4255
Author(s):  
Newton K. Seitzinger ◽  
John C. Martin ◽  
Richard A. Keller

Author(s):  
Grigoriy I. Greisukh ◽  
Sergei T. Bobrov ◽  
Sergei A. Stepanov
Keyword(s):  

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. S251-S259 ◽  
Author(s):  
Claudia Vanelle ◽  
Miriam Spinner ◽  
Thomas Hertweck ◽  
Christoph Jäger ◽  
Dirk Gajewski

True-amplitude Kirchhoff migration (TAKM) is an important tool in seismic-reflection imaging. In addition to a structural image, it leads to reflectivity maps of the subsurface. TAKM is carried out in terms of a weighted diffraction stack where the weight functions are computed with dynamic ray tracing (DRT) in addition to the diffraction traveltimes. DRT, however, is time-consuming and imposes restrictions on the velocity models, which are not always acceptable. An alternative approach to TAKM is proposed in which the weight functions are directly determined from the diffraction traveltimes. Because other methods exist for the generation of traveltimes, this approach is not limited by the requirements for DRT. Applications to a complex synthetic model and real data demonstrate that the image quality and accuracy of the reconstructed amplitudes are equivalent to those obtained from TAKM with DRT-generated weight functions.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0250543
Author(s):  
Seok Ho Song ◽  
In Seok Song ◽  
Se Jin Oh ◽  
Hyeck-Soo Son ◽  
Min Ho Kang

Purpose To evaluate the image quality of intraocular lenses (IOLs) using field-tracing optical simulation and then compare it with the image quality using conventional ray-tracing simulation. Methods We simulated aspheric IOLs with a decenter, tilt, and no misalignment using an aspheric corneal eye model with a positive spherical aberration. The retinal image, Strehl ratio, and modulation transfer function (MTF) were compared between the ray-tracing and field-tracing optical simulation and confirmed by the results reported in an in vitro experiment using the same eye model. Results The retinal image showed interference fringes from target due to diffraction from the object in a field-tracing simulation. When compared with the experimental results, the field tracing represented the experimental results more precisely than ray tracing after passing over 400 μm of the decentration and 4 degrees of the tilt of the IOLs. The MTF values showed similar results for the case of no IOL misalignment in both the field tracing and ray tracing. In the case of the 200-μm decentration or 8-degree tilt of IOL, the field-traced MTF shows lower values than the ray-traced one. Conclusions The field-tracing optical bench simulation is a reliable method to evaluate IOL performance according to the IOL misalignment. It can provide retinal image quality close to real by taking into account the wave nature of light, interference and diffraction to explain to patients having the IOL misalignment.


Photonics ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 71
Author(s):  
Wei-Chia Su ◽  
Shao-Kui Zhou ◽  
Bor-Shyh Lin ◽  
Wen-Kai Lin

Generally, the diffractive waveguide combiner and computer-generated hologram (CGH) technique have the potential to achieve compact head-mounted display (HMD) with a natural 3D display function. However, the diffractive waveguide combiner will degrade the image quality because of aberration. In order to resolve this issue, the complex analysis based on the ray-tracing method is necessary. Since the major aberration of the waveguide combiners is only astigmatism and anamorphic distortion, only these two aberrations were discussed in this paper. Furthermore, two common waveguide structures were discussed here. In total, four formulas were summarized to analyze aberration and anamorphic distortion in these two structures. Finally, the simplified formulas were verified with the commercial ray-tracing software Zemax. The calculated results of the proposed method match the simulation of Zemax software well. Therefore, the aberration of an arbitrary similar diffractive waveguide can be analyzed by the proposed method. This will make the designing process simpler and faster.


2021 ◽  
Author(s):  
Seok Ho Song ◽  
In Seok Song ◽  
Se Jin Oh ◽  
Hyeck-Soo Son ◽  
Min Ho Kang

AbstractPurposeTo evaluate the image quality of intraocular lenses (IOLs) using field-tracing optical simulation and then compare it with the image quality using conventional ray-tracing simulation.MethodsWe simulated aspheric IOLs with a decenter, tilt, and no misalignment using an aspheric corneal eye model with a positive spherical aberration. The retinal image, Strehl ratio, and modulation transfer function (MTF) were compared between the ray-tracing and field-tracing optical simulation and confirmed by the results reported in an in vitro experiment using the same eye model.ResultsThe retinal image showed interference fringes from target due to diffraction from the object in a field-tracing simulation. When compared with the experimental results, the field tracing represented the experimental results more precisely than ray tracing after passing over 400 µm of the decentration and 4 degrees of the tilt of the IOLs. The MTF values showed similar results for the case of no IOL misalignment in both the field tracing and ray tracing. In the case of the 200-µm decentration or 8-degree tilt of IOL, the field-traced MTF shows lower values than the ray-traced one.ConclusionsThe field-tracing optical bench simulation is a reliable method to evaluate IOL performance according to the IOL misalignment. It can provide retinal image quality close to real by taking into account the wave nature of light, interference and diffraction to explain to patients having the IOL misalignment.


2020 ◽  
Vol 1 ◽  
pp. 305-314
Author(s):  
P.-P. Ley ◽  
J. August ◽  
R. Lachmayer

AbstractIn the domain of optical engineering, optomechatronic systems are predominantly developed using conventional ray tracing methods such as sequential and non-sequential ray tracing. However, the increasing complexity of these systems in combination with the demand for high efficiency and high image quality leads to the fact that conventional methods to develop these systems reach their limits. In order to be able to develop highly efficient systems with high image quality, this contribution introduces a hybrid ray tracing method using an advanced optimization function.


Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly

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.


Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike

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.


Author(s):  
N.J. Tighe ◽  
H.M. Flower ◽  
P.R. Swann

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.


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