OPTOELECTRONIC HARDWARE-SOFTWARE MONOMODULAR SENSOR OF METEOROLOGICAL RANGE OF VISIBILITY AND ATMOSPHERE TRANSPARENCY WITH AUTOMATIC CORRECTION OF EXTERNAL POLLUTION EFFECT OF OPTICAL SYSTEMS

2021 ◽  
Vol 56 ◽  
pp. 50-60
Author(s):  
V.S. Kretulis ◽  
Keyword(s):  
Meteorological Parameters ◽  
Optical Systems ◽  
Time Interval ◽  
Automatic Correction ◽  
Pollution Effect ◽  
Operational Characteristics ◽  
Self Testing ◽  
Model Sample ◽  
K Factor ◽  
Optoelectronic Sensor

A model sample of a monomodular hardware-software optoelectronic sensor of k-factor, meteorological range of visibility and atmosphere transparency with high technical and operational characteristics of small -sized execution is developed and created. The combination in the algorithm of functioning of the developed hardware-software methods of sensor creation provided increase of accuracy and invariance of results of measurement concerning external background illumination and self-testing with automatic correction of pollution effect of optical windows of the sensor. Continuous monitoring of the degree of contamination of optical windows provides an opportunity in case of detection of exceeding the permissible level of pollution to provide the operator with information about the need for preventive work. The proposed method of automatic correction of contamination of optical windows either completely eliminates or significantly increases the time interval of their mechanical cleaning operations, which reduces labour costs for maintenance of the sensor. The analysis of technical capabilities of the nodes of the model sample of the sensor allowed to estimate its basic meteorological parameters: the k-factor – (0.17÷1.11∙10-4) m-1, the meteorological visibility – (18÷27∙103 ) m and the atmosphere transparency per 1 km of the layer – (0÷0.895). The developed meteorological sensor can be used as a basic remote-controlled instrument for measuring meteorological parameters of the state of the atmosphere at the hydrometeorological stations of the country, mobile meteorological stations, stationary meteorological stations of road and air services to ensure guaranteed safety of workers.

Automatic correction of aberrations in astro-optical systems

1978 ◽  
Vol 2 (2) ◽  
pp. 171-182 ◽  
Author(s):  
Su Ding-qiang ◽  
Wang Ya-nan
Keyword(s):  
Optical Systems ◽  
Automatic Correction

Automatic Correction of the Aberrations of Complex Optical Systems

1969 ◽  
Vol 8 (2) ◽  
pp. 289 ◽  
Author(s):  
D. S. Volosov ◽  
N. V. Zeno
Keyword(s):  
Optical Systems ◽  
Automatic Correction

Finite amplitude waves in bounded media: nonlinear free vibrations of an elastic panel

1970 ◽  
Vol 318 (1533) ◽  
pp. 169-196 ◽  
Keyword(s):  
Small Amplitude ◽  
Mathematical Problem ◽  
Free Vibrations ◽  
Finite Amplitude ◽  
Optical Systems ◽  
Time Interval ◽  
Nonlinear Phenomena ◽  
Gas Flows ◽  
Strain Rates ◽  
Nonlinear Elastic

The equations governing the stretching of a nonlinear elastic panel of finite length are integrated in the limit when the strains are small but the strain rates are comparable with the natural frequency of the panel. Such a theory is needed to describe many small amplitude but nonlinear phenomena, such as near-resonant oscillations. It is shown that such a theory must be used when investigating the distortion and decay of free vibrations. These are discussed in detail. A brief discussion of the effect of friction on such vibrations is also given. The mathematical problem reduces to solving nonlinear difference equations and involves functions whose values repeat at a sequence of times which are separated by a time interval which depends on the value repeated. Although the problem is stated in the language of elasticity theory the results are directly applicable to nonlinear optical systems and gas flows in Kundt tubes.

Study of methods for measuring distances in scanning range

2020 ◽  
pp. 21-37
Author(s):  
Aleksander Ulyashin ◽  
◽  
Aleksander Velichko ◽  
Keyword(s):  
Three Dimensional ◽  
Accurate Method ◽  
Unmanned Vehicles ◽  
Optical Systems ◽  
Time Interval ◽  
Unique Approach ◽  
Pros And Cons ◽  
Scanning Range ◽  
To Receive ◽  
Laser Emitter

Recently, the market for scanning rangefinders, in other words, LIDARS, has begun to develop rapidly due to the new course for unmanned vehicles and the need for high-precision positioning of objects in construction, geodesy, military Affairs, navigation, etc. The leading manufacturers of such scanning devices are currently Velodyne, Ouster and Luminar. Each company has its own unique approach to creating LIDAR, which has both pros and cons. LIDAR itself is a scanning device designed to receive and process information about remote objects using active optical systems that use the phenomena of light absorption and scattering in optically transparent media. In other words, a LIDAR is a device that uses a laser emitter to detect an object, after which the beam from the object is reflected and hits the photodetector, which, in turn, generates a signal and transmits it to the time interval meter. The output is a two-or three-dimensional image of the scanned object in the form of dots, depending on the type of LIDAR. The more of them, the clearer the picture we have, their number directly depends on the number of lasers and the processing speed of the system. This work is devoted to a comparative analysis of methods for constructing LIDAR systems. The analysis is carried out in order to identify the most accurate method of measuring the distance to an object under various conditions, and a new self-oscillating principle of distance measurement is proposed, which allows you to bring the measurement accuracy to a new level.

Comment on “Persistence and Recurrence Probabilities of Cloud-Free and Cloudy Lines of Sight through the Atmosphere”

1991 ◽  
Vol 30 (7) ◽  
pp. 1034-1036 ◽  
Author(s):  
Charles L. Medler ◽  
Kenneth B. MacNichol
Keyword(s):  
Matrix Model ◽  
A Priori ◽  
Optical Systems ◽  
Line Of Sight ◽  
Time Interval ◽  
Persistence Probability ◽  
Elapsed Time ◽  
The Subject

Abstract Although published some time ago, the subject paper represents a well-known resource for modeling and assessing cloud impacts on land-based and air-based electro-optical systems. The Lund dataset, derived from whole-sky photographs taken during the summer months at Columbia, Missouri, remains unique and valuable and has been used in assembling critical cloud-free line-of-sight models. In Lund's paper, cloud-free and cloudy persistence and recurrence probabilities, plotted versus elapsed time interval for each of 11 categories of fractional sky cover, are provided. The purpose of this comment is to provide an expression that properly combines these probabilities to produce persistence and recurrence probabilities irrespective of sky cover category (i.e., probabilities that are valid when the sky cover is not known a priori). Lund presented a “matrix model” for representing these probabilities. Lund's matrix model does not represent the average recurrence or persistence probability over all sky cover conditions, as is shown in the Appendix.

Atomic Resolution in Crystal Aperture Stem

1990 ◽  
Vol 48 (1) ◽  
pp. 236-237
Author(s):  
J T Fourie
Keyword(s):  
Optical System ◽  
Spherical Aberration ◽  
Three Dimensional ◽  
Transmission Function ◽  
Optical Systems ◽  
Bragg Angle ◽  
Electron Optical System ◽  
Intimate Contact ◽  
Diffraction Effects ◽  
Design Aspect

The attempts at improvement of electron optical systems to date, have largely been directed towards the design aspect of magnetic lenses and towards the establishment of ideal lens combinations. In the present work the emphasis has been placed on the utilization of a unique three-dimensional crystal objective aperture within a standard electron optical system with the aim to reduce the spherical aberration without introducing diffraction effects. A brief summary of this work together with a description of results obtained recently, will be given.The concept of utilizing a crystal as aperture in an electron optical system was introduced by Fourie who employed a {111} crystal foil as a collector aperture, by mounting the sample directly on top of the foil and in intimate contact with the foil. In the present work the sample was mounted on the bottom of the foil so that the crystal would function as an objective or probe forming aperture. The transmission function of such a crystal aperture depends on the thickness, t, and the orientation of the foil. The expression for calculating the transmission function was derived by Hashimoto, Howie and Whelan on the basis of the electron equivalent of the Borrmann anomalous absorption effect in crystals. In Fig. 1 the functions for a g220 diffraction vector and t = 0.53 and 1.0 μm are shown. Here n= Θ‒ΘB, where Θ is the angle between the incident ray and the (hkl) planes, and ΘB is the Bragg angle.

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