scholarly journals Method for encryption of cartographic images on the basis of internal reorganization of the digital filter structure

2021 ◽  
pp. 87-98
Author(s):  
Igor L. Zhbanov ◽  
◽  
Vera L. Zhbanova ◽  
Keyword(s):  
Data Transmission ◽  
Internal State ◽  
Spatial Filter ◽  
Spatial Filters ◽  
Transmission Systems ◽  
Filter Methods ◽  
Urgent Task ◽  
Text Information ◽  
Using Data ◽  
Controlled Structure

The paper presents a method for encrypting geo-images based on the reorganization of the internal structure of the filter. Methods for digital image filtering in the MATLAB environment are taken as a basis. The essence of encryption is to control the aliasing of noise and the kernel of smearing. Knowing these values will allow the addressee to recover the transmitted cards with minimal interference, which will be unattainable for the data interceptor. Under conditions of unfavorable factors, conditions sometimes arise that lead to the loss of information content of images and, as a consequence, damage to information. Therefore, the development of methods to minimize their influence is an urgent task of the study. Thus, one of the approaches to the construction of spatial filters with a controlled structure is proposed for the selection of contrasting images in noises of different intensities. The procedure for converting any spatial filter from an initial display to a form that allows you to control its internal state is described. The obtained results of the original and transformed images make it possible to draw conclusions about the possibility of practical application of the proposed invariant spatial filter in the blocks for analyzing the original image. The method can be used to transfer photo, video messages and text information between consumers using data transmission systems for any purpose. Due to the factorial dependence, it is very problematic for information interceptors to find the required resulting position of all image encryption parameters (sizes, type of the distortion function, regularization parameters α and σ) for information interceptors, since the computational costs are not commensurate with the capabilities of modern computers. This can be used to transfer photo, video messages and text information between consumers using data transmission systems for any purpose, especially when transferring cartographic information.

Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

1972 ◽  
Vol 30 ◽  
pp. 596-597
Author(s):  
David A. Ansley
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Spatial Filter ◽  
Operating Conditions ◽  
Objective Lens ◽  
List Type ◽  
Spatial Filters ◽  
Transmission Electron ◽  
Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

Spatial-frequency and orientation tuning in psychophysical end-stopping

1998 ◽  
Vol 15 (4) ◽  
pp. 585-595 ◽  
Author(s):  
CONG YU ◽  
DENNIS M. LEVI
Keyword(s):  
Spatial Frequency ◽  
Frequency Tuning ◽  
Spatial Filter ◽  
Orientation Tuning ◽  
Maximal Strength ◽  
Facilitation Effect ◽  
Spatial Filters ◽  
Spatial Frequency Tuning ◽  
Spatial Frequencies ◽  
Wide Range

A psychophysical analog to cortical receptive-field end-stopping has been demonstrated previously in spatial filters tuned to a wide range of spatial frequencies (Yu & Levi, 1997a). The current study investigated tuning characteristics in psychophysical spatial filter end-stopping. When a D6 (the sixth derivative of a Gaussian) target is masked by a center mask (placed in the putative spatial filter center), two end-zone masks (placed in the filter end-zones) reduce thresholds. This “end-stopping” effect (the reduction of masking induced by end-zone masks) was measured at various spatial frequencies and orientations of end-zone masks. End-stopping reached its maximal strength when the spatial frequency and/or orientation of the end-zone masks matched the spatial frequency and/or orientation of the target and center mask, showing spatial-frequency tuning and orientation tuning. The bandwidths of spatial-frequency and orientation tuning functions decreased with increasing target spatial frequency. At larger orientation differences, however, end-zone masks induced a secondary facilitation effect, which was maximal when the spatial frequency of end-zone masks equated the target spatial frequency. This facilitation effect might be related to certain types of contour and texture perception, such as perceptual pop-out.

DETECTING AND CORRECTING BYTE ERRORS IN DIGITAL DATA TRANSMISSION SYSTEMS

2021 ◽  
Author(s):  
А.А. ПАВЛОВ ◽  
Ю.А. РОМАНЕНКО ◽  
А.Н. ЦАРЬКОВ ◽  
А.Ю. РОМАНЕНКО ◽  
А.А. МИХЕЕВ
Keyword(s):  
Data Transmission ◽  
Digital Data ◽  
Transmission Systems ◽  
Error Vector ◽  
Time Costs ◽  
Additive Error ◽  
Syndrome Decoding ◽  
Hardware Costs

Обоснована необходимость разработки методического аппарата, связанного с построением кода, корректирующего ошибки в заданном числе байтов информации с алгебраическим синдромным декодированием и оценкой аппаратурных и временных затрат, связанных с этой целью. Представлены правила построения корректирующего кода, исправляющего ошибки в заданном числе байтов информации, реализующего линейную процедуру построения корректирующего кода с синдромным декодированием и использованием аддитивного вектора ошибок, что позволило сократить аппаратурные затраты на построение декодирующего устройства (сократить объем памяти для хранения значений векторов ошибок). Получены выражения для оценки аппаратурных затрат на кодирование и декодирование информации при использовании предлагаемого метода коррекции пакетных ошибок. The necessity of developing a methodological apparatus related to the construction of a code that corrects errors in a given number of bytes of information with algebraic syndrome decoding and the estimation of hardware and time costs associated with this purpose is justified. The rules for constructing a correction code that corrects errors in a given number of bytes of information, implementing a linear procedure for constructing a correction code with syndrome decoding and using an additive error vector, are presented. This method made it possible to reduce the hardware costs for constructing a decoding device (reducing the amount of memory for storing the values of error vectors). Expressions are obtained for estimating the hardware costs of encoding and decoding information when using the proposed method of correcting packet errors.

DEVELOPMENT OF AN ALGORITHM FOR FINDING ANOMALIES IN WEATHER REPORTS TO IMPROVE THE QUALITY OF FORECASTS

2021 ◽  
pp. 45-52
Author(s):  
K. G. Yashchenkov ◽  
K. S. Dymko ◽  
N. O. Ukhanov ◽  
A. V. Khnykin
Keyword(s):  
Optimal Method ◽  
Implementation Processes ◽  
Advantages And Disadvantages ◽  
Message Exchange ◽  
Text Information ◽  
Preliminary Preparation ◽  
Using Data ◽  
The Moment

The issues of using data analysis methods to find and correct errors in the reports issued by meteorologists are considered. The features of processing various types of meteorological messages are studied. The advantages and disadvantages of existing methods of classification of text information are considered. The classification methods are compared in order to identify the optimal method that will be used in the developed algorithm for analyzing meteorological messages. The prospects of using each of the methods in the developed algorithm are described. An algorithm for processing the source data is proposed, which consists in using syntactic and logical analysis to preclean the data from various kinds of noise and determine format errors for each type of message. After preliminary preparation the classification method correlates the received set of message characteristics with the previously trained model to determine the error of the current weather report and output the corresponding message to the operator in real time. The software tools used in the algorithm development and implementation processes are described. A complete description of the process of processing a meteorological message is presented from the moment when the message is entered in a text editor until the message is sent to the international weather message exchange service. The developed software is demonstrated, in which the proposed algorithm is implemented, which allows to improve the quality of messages and, as a result, the quality of meteorological forecasts. The results of the implementation of the new algorithm are described by comparing the number of messages containing various types of errors before the implementation of the algorithm and after the implementation.

Analysis of data transmission technique based on pulsed laser

2012 ◽  
Vol 20 (1) ◽  
Author(s):  
T. Drozd ◽  
M. Zygmunt ◽  
P. Knysak ◽  
J. Wojtanowski
Keyword(s):  
Data Transmission ◽  
Continuous Wave ◽  
Pulsed Laser ◽  
Pulsed Lasers ◽  
Transmission Method ◽  
Transmission Systems ◽  
Laser Technology ◽  
Light Pulses ◽  
Transmission Technique ◽  
Transmission Speed

AbstractPulsed lasers are used mainly in lidar systems as sources of short and highly energetic light pulses. In data transmission systems continuous wave lasers are typically applied, however it is also possible to use pulsed lasers in such systems. Such approach seems to be especially reasonable for devices where a pulsed laser is applied anyway and executes another function (rangefinding). The article discusses a data transmission concept based on a pulsed laser technology. Advantages and limits of such a transmission method are described. Influence of individual transmission elements on the effective data transmission speed is analysed.

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