INVESTIGATION OF THE POSSIBILITIES OF USING TELEVISION METHODS IN SYSTEMS

FOR THE PROCESSING OF SPECTROANALYTICAL INFORMATION

I. D. Bulaevskii, V. A. Gubanov, and L. K. Lapotnikova

UDC 621.385.832.5

The development of analytical investigations is inseparably associated with automation and the application of computer technology. The use of computers makes it possible to sig- nificantly shorten the treatment time and increase the efficiency of analytical work. In the overall set of analytical methods emission spectral analysis is one of the most large-scale forms of investigation of the properties of a substance. This has stimulated the develop- ment of work in the field of automating the treatment of the results of analyses. The auto- mation of the treatment of spectrograms involves the creation of specialized devices for feeding the spectroanalytical information into a computer. This may be visualized as two major trends:

-- the development of devices for feeding spectroanalytical information into a computer based on opticomechanieal measuring systems (mierophotometers and densitomers) [1-5];

-- the use of electrooptic converters, which permit the siitless recording of a section of a spectrum with programmed reading of the measurement data over the entire section re- corded.

The television methods [6, 7], which are widely used in the analysis of photographic images of information processing systems, have been the most extensively developed methods based on electrooptic converters [8-10].

Various television camera tubes with an internal photoelectric effect (vidicons and silicon beam tubes) and mesh targets and dissector tubes with slit apertures have been used as spectrum detectors [6, ii, 12]. The effectiveness of the use of TV camera tubes in data- processing systems depends on the optimal nature of the combinations of the characteristics of the TV camera tubes with the parameters of the image. In fact, a spectrogram may be treated as a test object with groups (series) of lines with a variable distance and a distri- bution of the illumination perpendicular to the line. Such an hypothesis is in good agree- ment with the T-shaped distribution of the light transmission in ordinary objects with a regular structure used in television [12]. The investigation of the optical and geometric characteristics of spectrograms has shown that the light range is 0.2-2.5 D, that the max- imum half-width of analytical lines is ~ 120 ~, that the minimum half-width is ~i0 ~, and that the minimum distance between lines is ~25 ~. The present work was devoted to the investigation of the possibility of using a TV camera tube as a multichannel device for feeding spectroanalytieal information recorded on a photocarrier into a computer and to the selection of the technical solutions which provide for the recording of the data in the re- quired range. The photometering results obtained on the television analyzer are transferred to the computer, where their further treatment and the calculation of the concentrations are carried out. The structure and organization of the regulatory and processing programs are to be presented in subsequent publications. Figure i presents a functional diagram of a television analyzer (which was developed by Nikolaev and Landau). The image of the spectro- gram (3), which is placed in a special casette and fastened to a moving carriage (4) passes through an Orion-18r reproduction objective (6) with a resolution of 100-i20 lines/mm and twofold magnification to reach the photocathode of the television camera tube~ i.e,, an LI-4i8-9 vidicon. The image of the section of the spectrogram selected by the operator is transferred to the plane of the photocathode of the TV camera tube. A focusing deflection system, a preamplifier, and a panel of controls for adjusting the conditions of the tube are

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 30, No. 6, pp. 1075-1079, June, 1979. Original article submitted November 23, 1977; revision submitted January 24, 1979.

0021-9037/79/3006-0775507.50 �9 1979 Plenum Publishing Corporation 775

- I

I

I

I

I

I , II I I i

L 17 I

Fig. i. Functional diagram of a television analyzer: i) illuminator; 2) neutral light filters; 3) spectrogram; 4) table carriage; 5) interchangeable diaphragm; 6) Orion-18r objective; 7) television camera; 8) thermoelectric battery; 9) vidicon; i0) power supply of illuminator; ii) video signal processing unit; 12) gating unit; 13) amplitude- measuring unit; 14) video monitor; 15) digital voltmeter; 16) power supplies for television channel; 17) channel unit.

Fig. 2. Structural scheme of the information-- measurement system: i) television analyzer; 2) SHCH 1312 digital voltmeter; 3) linking unit; 4) Saratov minicomputer.

structurally joined to the television camera. The television signal produced under progres- sive conditions with the decomposition of the image into 312 lines at 50 frames per second is supplied to the terminal of the camera channel, where it is shaped, and supplied to a video monitor through an amplifier. The camera channel is also composed of units which guarantee the necessary parameters of the decomposition of the image on the target of the TV camera tube, a generator of synchronizing pulses, a line-and-frame sweep generator, and a panel for controlling the conditions of the tube. The circuits of these units have the traditional character in contrast to the units intended for the amplification, gating, and recording of the signal of the spectral line under analysis, which consist of a gate-forming unit and a storage amplifer. The gate former produces a gating pulse for each of the 312 lines in the raster in order to single out the signal of the reference level (gate I), and in the 16 lines in the center of the raster it forms gate 2 for singling out the signal of the spectral line under analysis. Both gates are admitted to the control circuit by switches in the storage amplifier. The video signal from the preamplifier is supplied to a storage device, where the suppression of the low-frequency background and the gating of the neces- sary portions of the image of the spectrogram take place. Measuring gate 2 is admitted to the circuit for the measruement of the amplitude and the video monitor (the size of the mea- suring gate can be regulated with respect to its width). By moving the carriage with the spectrogram, the operator scans the portion of the spectrum with the analytical line with the aid of the measuring gate. A signal proportional to the blackening density is supplied to the input of the computer. Digital voltmeter 2 serves as an analog--digital converter (Fig. 2). The measurement channel of the television analyzer was investigated with spectro- grams obtained on an STE-I spectrograph (the reciprocal linear dispersion was 0.47 nm/mm). Figure 3 presents the light-signal characteristics of the measurement channel. The mean- square error of the measurements over the entire range of Unorm values recorded lies within • the resolving power of the system in the plane of the plate is i00 ~m, and the con-

776

U norm 1,0

0,5'

i L:

Fig. 3. Light-signal characteristic of the measuring channel. Here T is the trans- mission coefficient the sections of the spectrogram tested; Unorm is the normalized value of the voltage corresponding to the radiant flux passing through the sections of the spectrogram tested, i.e., Unorm = (U -- Uo)/AU, where U is the voltage detected by the voltmeter, Uo is the value of the voltage corresponding to the most illuminated sec- tion of the spectrogram, and AU is the range of voltages corresponding to the range of transmission values from the most illum- inated to the most unilluminated portions of the spectrogram.

TABLE i. Comparison of Results of the Determination of Lead and Nickel in Granitoid Rocks Obtained with the aid of an MF-2 Microphotometer and the Television Analyzer

Pb (. | 0 - | ) , %

MF-2

9 12 11 17 13 15 2O 17 19 13 9

24 22 83 27 83 19 14 6

52 84 23 21 33

TV

lO 11 11,5 I5 20* 12 25 30* 19 13 13 22 22 76 34 125" 11,5 13 15" 35 100 14 16 21

Ni (.I 0-~), %

lVIF-~

15,5 13,5

18 17 21

3,3 29 24 11 14 20 13 14 26 12 25 2,5

9 2O

4,3 7,5 5,1 4,8 12

J , i

TV

15 15 17 15 17

2,6 17" 19

9,7 11 17 12 11

18" 14

18" 1,4 11 15

4,0 8,5 4,3 5,2 9,7

Note. The disparity between the results is attributed to the influence of nearby darkened sections and spec- tral lines with high intensities (emulsion impurities) on the amplitude of the recorded signal of the tele- vision analyzer.

trast sensitivity is 0.04-0.9. In order to eliminate the influence of the nonuniformity of the vidicon noise, the photometering is carried out in the central region of the photo- cathode. The selected portion of the target provides for the simultaneous recording of seven analytical lines with adjustment of the measuring gates to the right and the left, making it possible to take into account the noise directly during the treatment of the re- sults.

The characteristics of the measuring channel presented in the foregoing made it poss- ible to carry out quantitative determinations of the concentrations of ii chemical elements, near whose analytical lines there is practically no interference, in samples of rocks. The lines used were Mn 293.31, Ni 305.08, Ti 331.80, Mo 317.04, Zr 327.30, Cu 327.40, Pb 283.31, Y 332.79, Yb 328.94, V 295.21, Ag 338.29 nm.

777

A comparison of the results of the photometering of the same spectrogram with the spec- tra of granitoid rocks on an MF-2 microphotometer and the te!evision analyzer was made. A calibration curve for the calculation of the concentration was constructed with the aid of standard specimens of rock compositions with conversion to intensity. Table i presents the results of the comparison for lead and nickel. The comparison of the results demonstrated the possibilityof using a TV camera tube (a vidicon) as a multichannel device for feeding spectrographic information into a computer. The further improvement of the system will make it possible to increase the number of elements which can be analyzed and increase the re- solving power and contrast coefficient by decreasing the duration of the gate pulse. We thank V. P. Orlovskii for advice on the use of TV camera tubes in data-processing systems.

LITERATURE CITED

i. V. N. Nikitin, E. B. Chamlik, V. A. Zubkovskii, and Yu. P. Ivanov, Zh. Prikl. Spektrosk., 12, No. 6, 1143 (1976).

2. O. D. Gorokhov and V. N. Nikitin, Zh. Prikl. Spektrosk., 20, No. i, 22 (1974). 3. J. A. Detrio and V. L. Donlan, Appl. Opt., 13, No. i0, 2235 (1974). 4. B. L. Taylor and F. T. Birks, Analyst, 97, 115, 681 (1972). 5. G. Riesel, Einsatz der EDVbei. Z. Angew. Geol., iO, 513 (1975). 6. A. Danielsson, P.-Lindblom, and E. S~derman, Chem. Scripta, 6, 5 (1974). 7. S. L. Gorelik and B. M. Kats, Electron-Ray Tubes in Information-Processing Systems

[in Russian], i Energiya, Moscow (1977). V. B. Nikonov (editor), Television Astronomy [in Russian], Nauka, Moscow (1974). A. V. Petrakov, Vopr. Radioelektron., Set. IX, No. 4 (1966). A. I. Petrenko, Automated Input of Graphs into Computers [in Russian], Energiya, Moscow (1968). V. M. Tarasov, Tekh. Kino Telev., No. 3, 15 (1972). V. G. Avakumov and A. A. Petrenko, Vidicon Device for Feeding Graphs into Computers [in Russian], ~nergiya, Moscow (1967).

,

9. i0.

Ii. 12.

CHANGES IN OPTICAL PROPERTIES IN GRADIENT COMPOSITION GLASSES

V. Ya. Livshits and G. O. Karapetyan UDC 539.213

A glass with a regular change in chemical composition has a gradient in physicochemical properties. This composition gradient is formed as a result of the chemical and thermo- dynamic interaction of the original homogeneous glass with its surroundings, lon exchange methods of obtaining gradient glasses are widespread. The influence of ion exchange in the glass--salt melt system on the electrode properties, mechanical strength, and optical and spectral properties of glasses is well known. The production of optical focussing elements, or lenses ("self'fok,""optelfok," etc.) with dimensions of the gradient region to tenths of millimeters raises the question of the properties of the gradient glassy materials. Where earlier (glass electrodes and reinforcements), only the properties of the surface layer of a homogeneous glass were modified, in lenses the chemical properties and all physicochem- ical characteristics of the glass change continuously from the surface to the axis of the cylinder [i].

An estimate of the change of each property of the gradient glass is necessary. Here it is obvious that the properties of gradient glasses are significantly determined by the properties of the components of the glass.

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 30, No. 6, June, 1979. Original article submitted May ii, 1978.

778 0021-9037/79/3006-0778507.50 �9 1979 Plenum Publishing Corporation