SU614338A1 - Scanning polarimeter - Google Patents

Description

one

The invention relates to devices for nonnpHMeipH research of extended space objects.

Devices for polarimetric studies are known that make it possible to obtain an integral characteristic of an object. However, in many cases, such a characteristic is insufficient to describe the object. These devices comprise a modulator, an analyzer, a radiation receiver, an information processing unit, and a recording unit.

The closest in technical essence to the proposed is a device for polarimetric study of celestial bodies observed through a telescope. containing a scanning device, an information processing unit and a registration unit. This device allows you to visually observe changes in polarization characteristics on the surface of an object.

The drawbacks of the known device are that they have low speed and do not allow to automate the processing of information.

The purpose of the invention is to increase speed and ensure automatic processing of information.

This goal is achieved by the fact that in a scanning polarimeter containing a scanning device, an information processing unit and a recording unit, the information processing unit is designed as a two-channel selector, logarithmic amplifiers, delay lines, adder, amplitude analyzer and photometric device, and a two-channel selector is connected to an adder through a logarithmic amplifier in one channel and a logarithmic amplifier and a delay line in the other, and the amplitude analyzer and phase meter devices connected to the output of the adder.

The drawing shows a functional diagram of a polarimeter.

The field meter includes a field scanning device 1, an information processing unit and an information recording unit 111. -.

Scanning device j consists of diaphragm 1, Farade phase shifter

2, Wollaston prism 3, a generator of 4 speed current pulses, a television transmitting tube 5 and a photometer of system 6.

 information processing consists of a two-channel selector of 7 video pulses, an ultrasonic delay line 8, logarithmic amplifiers 9 and 10, an adder 11, an amplitude analyzer 12, a phase-measuring device 13, and a selector 14 of clock pulses.

Information recording block III co- keeps two video monitoring devices 15 and 16 and Polarization 17 and Angle 18 digital indicators combined with them, respectively.

The polarimetric scanning device 1 serves to form polarimetric signals, which determine the polarization index and phase angle at each point of the object under study. The optical part of the polarimetric device, consisting of the Farad 2 phase shifter and the Wollaston 3 prism, provides two polarimetric images of the object on the photocathode of the television transmitting tube 5. It is set at the focus of the telescope with which it is observed. The optical portion is aligned so that the prism and scanning directions of the prism are parallel.

The light intensities, depending on the polarization index, phase angle and position angle of the phase shifter, are equal to:

, (F, -807

a2 0,5a 1Usb2 ((.

Index i determines the number of elements in the decomposition of the image on the photocathode of the tube {i 1, 2,3, ...);

Oj - light intensity of the first

images; P - light intensity of the second

images;

OQ is the intensity of the falling. ta;

Polarization index; the position angle of the phase rotation by Farade; S is the phase angle.

During the formation of one line at the output of the television photometric system 6, two video pulses are obtained, the modulation depth of which corresponds to the distribution of the light intensities within identical phaseometric sections of two polarimetric images of the object on the photocathode of the tube,

The scanning polarimeter used the magneto-optical effect of rotation of the polarization plane using a Farad phase shifter 2, performed on a transparent ferromagnet excited by a step-shaped current of the generator 4, synchronized with the frame rate of the television photometric system. Due to the fa / zo-rotator, the position angle during the reverse stroke of the vertical sweep is incremented, changing according to the law of change of the step current:

It m, -.

fm-iT

where gI is the number of the position angle (m 0,1,2, ..., K); maximum number of position angle;

max is the maximum current value in the coil of the phase shifter, corresponding to the position angle A3; the current increment in the coil of the phase shifter during the reverse stroke of the vertical sweep.

A television photometric system 6 generates a complete television signal and provides transmission of polarimetric information. Via a communication channel to the input of the information processing unit 11. Video pulses containing polarimetric information are fed to the input of the video pulse selector 7, which is controlled by the horizontal sync pulses. After selection to individual channels, the first video pulse is delayed by an ultrasonic delay line for a time equal to half the horizontal scanning period, and then fed to the input of a logarithmic amplifier 9. The second video pulse is fed to the input of a logarithmic amplifier 10, where it is amplified and inverted. Thus, the inputs of the adder 11 from the first and second channels are simultaneously received, the video pulses of opposite polarity, and at its output a polarimetric impulse that does not contain a high-frequency image signal.

The distribution of polarization indices over the surface of the object under study is measured by an amplitude analyzer 12c. a variable discrimination threshold, in which for a full cycle of operation of a phase shifter, polarimetric pulses of equal amplitude are selected, corresponding to the polarization index.

.

„- .. g-j-7 (3)

min

k - number of the threshold of discrimination

where ("0,1,2, ..., N;

., ma ks

-1g

7 quantized quantized by sampling the polarization reference values; the coefficient 2.5 corresponds to the values of the polarization indices in stellar magnitudes.

The operation of the generator of blanking pulses (not shown) is synchronized by frame sync pulses allocated by the selector of 14 sync pulses.

Registration of polarimetric information is carried out in block 111 of registration of information using two video monitoring devices and digital indicators combined with them.

The first video monitor device 15 is connected to the output of the amplitude analyzer 12 together with the digital indicator Polarization 17. It serves to sequentially measure the distribution of various polarization indicators over the surface of the object under study. The values of the polarization indices P,, respectively, in each case the distribution of the points of light on the screen of the video monitor / are displayed on the digital indicator Polarization.

The distribution of light points on the screen of the second video monitor device 16 corresponds to the distribution of various polarization indicators with the same phase angles, the values of which are successively displayed on the Angle 18 digital indicator.

In order to automatically identify the distributions of light points with the object under study, video image signals are supplied to the inputs of video monitoring devices. The video signal generation and timing diagram for video monitoring devices with a television photometric system is not shown.

The scanning polarimeter provides for the possibility of visual observation of the distribution of various polarization indicators on the screen of the video monitor device 15. In this case, the polarimetric pulses are taken directly from the output of the adder 11. At the same time, the image elements of the object with greater brightness correspond to the values of large polarization indices.

Claims (2)

1. USSR author's certificate No. 146070, q.Q 01 Ы 2140, 14.03.61. 2. USSR author's certificate No. 165914, class, C (01 N 21/40, 10.26.64. jL L. I IJ