scholarly journals АЛГОРИТМЫ ПЕРВИЧНОЙ И ВТОРИЧНОЙ ОБРАБОТКИ СИГНАЛОВ В СИСТЕМАХ АКТИВНОГО АПЕРТУРНОГО СИНТЕЗА

2019 ◽  
pp. 54-67
Author(s):  
Владимир Владимирович Павликов ◽  
Валерий Константинович Волосюк ◽  
Ван Хиу Нгуен ◽  
Алексей Владимирович Одокиенко
Keyword(s):  
Image Quality ◽  
Imaging System ◽  
Block Diagram ◽  
Ambiguity Function ◽  
Physical Sense ◽  
Ideal Image ◽  
Uncertainty Function ◽  
Spatio Temporal ◽  
The Ideal

A method for processing spatio-temporal radio signals, which allows the formation of high spatial resolution images from aerospace carriers, has been synthesized. In this case, a swath is ±15° from the nadir relative to the flight line is considered. Traditionally this swath is not visible from aerospace carriers. A block diagram of an active-passive type radar is proposed. Initially the image obtained at the output of such a radar has a low quality of visual perception. Such image is called primary, since it was obtained at the stage of primary signal processing. The physical sense of such image is investigated. It approximately represents the operation of convolution of the ambiguity function with a spatial function proportional to the ideal image. The physical sense of the ideal image depends on the characteristics of the imaging system. In the problem under consideration, this is the specific radar cross section. In order to improve the quality of the image it is proposed additional processing (filtering). The paper substantiates the method of filtering (secondary processing) of images based on the solution of the inverse integral equation. It is shown that the exact solution to this equation is difficult to obtain because the form of the ambiguity function is not known exactly and can be estimated only approximately and, in addition, not for each ambiguity function it is possible to obtain a non-singular solution of the inversion equation. Therefore, an approximate solution to the problem is given. It solution is sufficient to solve practical problems of improving image quality. Using numerical simulation methods, the influence of the error in determining the shape of the uncertainty function on the task of improving image quality is studied. Examples of primary and secondary images obtained at the output of wideband active aperture synthesis systems with various geometries of spatially distributed antenna systems are given.

scholarly journals Modeling and image quality enhancement for dynamic compressive imaging system

2021 ◽  
Vol 15 ◽  
pp. 174830262110080
Author(s):  
Changjun Zha* ◽  
Qian Zhang* ◽  
Huimin Duan
Keyword(s):  
Image Quality ◽  
Imaging System ◽  
Quality Enhancement ◽  
Target Image ◽  
Compressive Imaging ◽  
Image Quality Enhancement ◽  
System A ◽  
Single Column ◽  
The Impact

Traditional single-pixel imaging systems are aimed mainly at relatively static or slowly changing targets. When there is relative motion between the imaging system and the target, sizable deviations between the measurement values and the real values can occur and result in poor image quality of the reconstructed target. To solve this problem, a novel dynamic compressive imaging system is proposed. In this system, a single-column digital micro-mirror device is used to modulate the target image, and the compressive measurement values are obtained for each column of the image. Based on analysis of the measurement values, a new recovery model of dynamic compressive imaging is given. Differing from traditional reconstruction results, the measurement values of any column of vectors in the target image can be used to reconstruct the vectors of two adjacent columns at the same time. Contingent upon characteristics of the results, a method of image quality enhancement based on an overlapping average algorithm is proposed. Simulation experiments and analysis show that the proposed dynamic compressive imaging can effectively reconstruct the target image; and that when the moving speed of the system changes within a certain range, the system reconstructs a better original image. The system overcomes the impact of dynamically changing speeds, and affords significantly better performance than traditional compressive imaging.

Materials And Image Formation In X-ray Lithography

1993 ◽  
Vol 306 ◽  
Author(s):  
F. Cerrina ◽  
G.M. Wells
Keyword(s):  
Image Quality ◽  
Imaging System ◽  
Spatial Coherence ◽  
Image Formation ◽  
Process Variations ◽  
Grain Structure ◽  
Aerial Image ◽  
Transmitted Beam ◽  
X Ray

AbstractIn proximity X-ray lithography there is no imaging system in the traditional sense of the word. There are no mirrors, lenses or other means of manipulating the radiation to form an image from that of a pattern (mask). Rather, in proximity X-ray lithography, mask and imaging systems are one and the same. The radiation that illuminates the mask carries the pattern information in the region of the wavefronts that have been attenuated. The detector (photoresist) is placed so close to the mask itself that the image is formed in the region where diffraction has not yet been able to deteriorate the pattern itself. The quality of the image formation then is controlled directly by the interaction between the mask and the radiation field. In turn, this means that both the illumination field and the mask are critical. The properties of the materials used in making the mask thus play a central role in determining the quality of the image. For instance, edge roughness and slope can strongly influence the image by providing the equivalent of a blur in the diffraction process. This blur is beneficial in reducing the high frequency components in the aerial image but it needs to be controlled and be repeatable. The plating (or other physical deposition) process may create variation in density (and thickness) in the deposited film, that will show up as linewidth variation in the image because of local changes in the contrast; the same applies to variations in the carrier membrane. In the case of subtractive process, variations in edge profile across the mask must be minimized.The variations in material composition, thickness and density may all affect the finale image quality; in the case of the resist, local variations in acid concentration may have strong effect in linewidth control (this effect is of course common to all lithographies).Another place where materials will affect the final image quality is in the condensing system. Mirrors will exhibit some degree of surface roughness, leading to a scattered radiation away from the central (coherent) beam. For scanning systems, this is not harmful since no power is lost in the scattering process and a blur is actually created that reduces the degree of spatial coherence. Filters may also exhibit the same roughness; typically it will not affect the image formation. The presence of surface (changes of reflectivity) or bulk (impurities) defects may however strongly alter the uniformity of the transmitted beam. This is particularly true of rolled Be filters and windows, which may include contaminants of high-Z materials. Hence, the grain structure of the window plays a very important role in determining image uniformity.Finally, a seemingly minor but important area is that of the gas used in the exposure area, typically helium. The gas fulfills several needs: heat exchange medium, to thermally clamp the mask to the wafer; low-loss X-ray transmission medium; protection from reactive oxygen radicals and ozone formation. Small amounts of impurities (air) may have a very strong effect on the transmission, and non-uniform distributions are particularly deleterious.All these factors need to be controlled so that the final image is within the required tolerances. Unfortunately, some of these are difficult to characterize in the visible (e.g., reflectivity variations) and testing at X-ray wavelengths is necessary. Although these obstacles are by no means unsurmountable, foresight is necessary in order to deliver a functional X-ray lithography process.This work was supported by various agencies, including ARPA/ONR/NRL and the National Science Foundation.

Attachment Styles and the Ideal Image of a Mate

2004 ◽  
Vol 9 (2) ◽  
pp. 87-95 ◽  
Author(s):  
Rami Tolmacz ◽  
Gil Goldzweig ◽  
Ruth Guttman
Keyword(s):  
Romantic Relationships ◽  
Attachment Style ◽  
Attachment Styles ◽  
Insecure Attachment ◽  
Young Males ◽  
Relational Patterns ◽  
Ideal Image ◽  
Personality Patterns ◽  
The Ideal

The study examines, within the framework of attachment theory, relationships of ideal images of young males with respect to their ideal image of a mate. A review of previous studies dealing with partner selection reveals the lack of a theoretical model that combines developmental processes and specific personality patterns with the process of creating an ideal image of the partner. The present study uses Facet Theory and Facet Design to construct a unified conceptual framework for the research in which attachment style and ideal image of the spouse are viewed as two modes of relating to one another. Intercorrelations among replies to the attachment and ideal image questionnaires were subjected to Smallest Space Analysis (SSA). The results indicate a relation between attachment style, the subjects' ideal image of a mate and the ideal images of oneself and one's mother. As predicted, persons with a secure style tended to have high levels of flexibility in their descriptions of the ideal image of the spouse. Males with insecure attachment styles exhibited different relational patterns of ideal image of themselves and their mothers. The SSA results suggest a hierarchic relation between attachment styles and the ideal image of a mate. These findings are consistent with the understanding that attachment styles affect the character and quality of the individual's romantic relationships.

In vitro comparison of subjective image quality of the pana digital intraoral x-ray imaging system and conventional intraoral radiography in caries detection

1998 ◽  
Vol 14 (2) ◽  
pp. 75-83 ◽  
Author(s):  
Yoshiko Ariji ◽  
Jin-ichi Takahashi ◽  
Osamu Matsui ◽  
Tsuneichi Okano ◽  
Munetaka Naitoh ◽  
...  
Keyword(s):  
Image Quality ◽  
Imaging System ◽  
Caries Detection ◽  
Intraoral Radiography ◽  
Subjective Image Quality ◽  
X Ray ◽  
X Ray Imaging ◽  
In Vitro Comparison

Performance Comparison Study of Several Interpolation Methods on Streak Metal Artifacts Reduction of CT Images

2021 ◽  
Vol 30 (06n08) ◽  
Author(s):  
Dianhua Wang ◽  
Yuanjin Li ◽  
Yudong Zhang ◽  
Tao Wang
Keyword(s):  
Ct Images ◽  
Performance Comparison ◽  
Comparison Study ◽  
Metal Artifacts ◽  
Objective Criterion ◽  
Metal Implant ◽  
Ideal Image ◽  
Artifacts Reduction ◽  
The Ideal

In the course of generating the CT images, the streak metal artifacts emerge from the reconstructed images, often degraded the quality of the images and blur the fringe information around the metal implant. Although a number of attempts had been reported, among them, our proposed interpolation-based method is the simplest and most efficient approaches. In this paper, three interpolation approaches are compared with subjective and objective criterion based on both simulation and clinical cases. Our results have shown an improvement from the original images. As for the comparison with NRMSD and MAD. For the execution time, the L-MAR possesses the shortest time with S-MAR time being the slowest among the interpolation-based methods. For NRMSD and MAD, the digits from small to large are P-MAR, S-MAR, L-MAR and original. This shows that among interpolation-based methods the image corrected by P-MAR approach is the closest to the ideal image, followed by S-MAR correction, L-MAR correction, and the gap between the original image and the ideal image is the largest.

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