CC BY
20
Radjabov Telma, Professor, Doctor of Physics and Mathematics Tashkent University of information technologies, Faculty of Telecommunications technology, Rakhimov Bakhtiyorjon, Doctor of Technical Sciences, Tashkent University of information technologies, Faculty of Telecommunications technology Fayzullayev Narzulla, Student, Tashkent University of information technologies, Faculty of Telecommunications technology, E-mail: b.rahimov@tuit.uz, brah2008@rambler.ru)
OPTOELECTRONIC SENSOR SOLID SURFACE COLOR ANALYZER
Abstract: A surface color analyzer consisting of a sensor and an electronic unit is described. An embodiment of the sensor in the form of a hemisphere is presented, in which three pairs ofY-shaped supply and outgoing optical fibers are installed.
Keywords: analyzer, color, colors, LED, light-emitting diode, optical fibers, RGB-system.
1. Introduction of the surface of solid materials, for example, metals, At present, optoelectronic methods of control plastic, glass, paper, etc., in those areas of the indusare successfully used for quantitative and qualita- try where color is one of the main indicators of qual-tive analysis of various substances, for example, for ity of production is described.
determining the parameters of liquid semitrans- Filter colorimeters containing light sources, parent media (oil products, vegetable oil, glycerin, correcting light filters (X), (Y), (Z) and a photojuices, drinks, urine, blood, etc.). Compared to oth- cell are known.
er physicochemical methods of analysis, they have However, this device controls on the principle significant advantages such as high accuracy, sensi- of passage, analyzes the colors of only translucent tivity and economy. The essence of optoelectronic fluids, and also has a complex design. monitoring is that any substance reflects, absorbs, The surface color analyzer of solid materials conor emits light. Depending on the chemical composi- sists of an electronic unit containing a master oscillation of the substance and the quantitative ratio of its tor and a trigger switch, a sensor containing three pairs constituent elements, the intensity of light, the ab- of measuring LEDs and three pairs of compensating sorption coefficient, the reflection angle, and other light emitting diodes, three measuring instruments, characteristics of the interaction of light radiation and a measuring system. According to the invention, and matter change [1]. three triggers connected to the trigger switch are con-
2. Analyzer of solid materials nected to it, three identical optical radiation receiv-Further in this chapter the optoelectronic auto- ers are located behind the sensor in the signal path,
matic analyzer for measurement of color parameters three comparison units that receive signals from the
respective optical radiation receivers, a photoelectric signal processing unit that is connected to the three comparison units and a memory associated with the processing unit, in addition, the sensor is in the form of a hemisphere, with an attached annular casing of soft rubber to which is attached Three pairs of optical fibers disposed at an angle, for example 45°, relative to each other and symmetrically with respect to the normal to the test surface at the reflection point.
In (Fig. 1) is a block diagram of the device for analyzing the color of the surface of solid materials, and in (Fig. 2) - one of the embodiments of the sensor. The color analyzer consists of a sensor and an electronic unit. The sensor is made in the form of a hemisphere 1, in which are installed three pairs of Y-shaped supply 2-4 and withdrawing 5-7 optical fibers.
Figure 1. Structural schematic of color analyzer of the solid surface
Narrow beam radiation, which allows control of parameters is beeped and received due to the flow of the light through the leading 2-4 and offtake 5-7 fiber optic.
The device of the analyzer of the surface color of solid materials in fig. 15, and in (fig. 1) - one of options of sensor performance. The analyzer of color consists of the sensor and the electronic block. The sensor is executed in the form of a hemisphere, 1 in which three couples of Y figu-
Figure 2. One embodiment of the sensor
rative bringing 2-4 and taking away 5-7 optical fibers are established.
Physical meaning consists of the following: color parameters are detected as an objective features of the subject developing in spectral composition outcoming from them (transmitted and attracted) radiation and perceived as visual sensation. 3. The device works as follows The master oscillator 9 generates pulses that are supplied to the input of the switch 10. The sepa-
rating pulses are fed to the input of three identical flip-flops 11-13, three outputs of which are connected to three measuring LEDs 14, 16, 18, the second three outputs are equipped with compensation LEDs 15, 17, 19 pulses from the triggers are fed to the corresponding LEDs. Each optocoupler is responsible for monitoring a particular parameter.
The monitored surface 8, which is enclosed in the hemisphere 1, is irradiated by two optical fluxes (measuring and compensating) through the supply optical fibers 2-4.
Optoelectronic pairs are enclosed in a soft rubber casing for the necessary orientation of the sensor and optical isolation of the optical channel and are located at an angle of, for example, 45°, relative to each other and symmetrically with respect to the normal to the monitored surface at the reflection point.
The optical radiation is reflected from the monitored surface and the outgoing optical fibers 5-7 are fed to optical radiation receivers 20-22 operating at wavelengths \ = 680nm, = 560nm , X3 = 450nm and converting the optical signals into electrical ones. Due to the passage of light through the supply and discharge optical fiber, a narrow beam of radiation is fed and received, which makes it possible to control the parameters.
Further, the signal falls on its comparison unit 23, 24, 25, the ratio of the two signals (measuring and compensating) is taken and further the measuring system 26, 27, 28 determines shades of three colors. The measurement process at this stage can be completed. Or, three signals can be fed to the photoelectric signal processing unit 29, where they are matched to any of a series of exemplary stored in the memory 30. Then both signals or their ratio are applied to the measurement system or to the computer 31.
The physical meaning is as follows: color parameters are defined as an objective property of objects, which is manifested in the spectral composition of the radiation emitted from them (transmitted, reflected) and perceived as a conscious visual sensation. In this definition, two aspects are given- physi-
cal and psycho-physiological, inextricably linked to each other.
The modern theory of color recognition is based on the uniquely established fact of human eye trichromatic, i.e. the visual apparatus contains three types of receptors, each of which predominantly reacts to red, green or blue.
4. Characterization
According to this, the color parameter is mathematically expressed by a vector in three-dimensional color space, and the beginning of this vector coincides with the beginning of the color coordinate system (CCS). If we use the unit vectors of three colors of red rn, green gn and blue bn as the primary colors, then any color can be expressed as:
Y = Rrn + Ggn +Bbn where R, G, B are the qualities of the corresponding colors.
In (Fig. 3) the curves for the addition of colors of the systems RGB (a) and XYZ (b) are shown. RGB-system is empirical, which is used as the primary colors of pure spectral radiation of red ( A = 700 nm ), green ( X = 546.1 nm ) and blue ( X = 435.8 nm ) colors. And XYZ is a phenomenological system. The meaning of these systems is that the spectrally pure color with X = 600 nm nm is perceived by the eye as consisting of a red and green component in a 14: 3 ratio, radiation with k = 450 nm is perceived as a ratio of 7.5: 1: 35 red, green and blue colors respectively.
In the RGB system, the curves of red rn, green gn and blue bn are constructed so that for each of the three primary colors only the ordinate of one curve differs from zero. The main disadvantage of these addition curves is the presence of a negative section near the curve. When measuring color coordinates, color subtraction cannot be realized, therefore, in colorimetric this system is not applied.
Thus, the task of controlling color parameters based on the XYZ system is carried out in three ways. The first is a visual comparison of the measured color with the reference one. The standard is chosen from a pre-compiled color atlas or by
computer programming of each of the colors. The second is the spectrophotometry of the observed radiation and the calculation of the X, Y, Z coordinates. The third is the direct measurement of the X, Y, Z coordinates using three reference optical radia-
tion receivers, the spectral functions whose sensitivities exactly correspond to the Yx, Yy, Yz curves. This method is undoubtedly the most promising, since it meets the requirements of the technological process.
Figure 3. Characteristics of sensors a color
To develop this method, the device must perform the following operations:
- the isolation of the analyzing radiation at three wavelengths (red, green and blue);
- receiving the radiation fluxes reflected from the monitored object and converting them into a photoelectric signal;
- processing and comparison of the photoelectric signal.
The purpose of each of the three optocouplers is explained as follows: the monitored surface is irradiated with two light streams with wavelengths ^ and A2, one of which is measurement radiation, and the other is compensatory radiation.
Let the light flux f0 fall on the monitored surface. The illuminated layer will divide the light flux incident onto it into three parts:
1) f - reflected from the surface and incident on the receiver of optical radiation, from which came the falling stream;
2) f^ - reflected from the surface and not incident on the receiver of optical radiation;
3) f^ - absorbed stream, which in the substance of the layer will turn into heat or another form of energy.
analyzer of the surface of solid materials
In accordance with the law of conservation of energy, the sum of the light fluxes is equal to the incident flux:
or
foi = fA1 + "fA2 +
f!1 + f _ ¿2 f + zAl.
foi f l0A f
f,
For colored substances, these coefficients depend on the spectral composition of the incident radiation. For monochromatic radiation with a certain wavelength (as the emission spectrum of a light-emitting diode), we denote p (A), t (A), and a (A).
X + — 8X 2
The spectral dependence of these coefficients is conveniently depicted graphically[2].
The conclusion
The proposed device has improved color recognition accuracy due to three opt couplers that control three color parameters corresponding to the parameters X, Y, Z.
The device has increased accuracy of control due to three-dimensional measurement with wave-
lengths A.J = 680 nm, \2 = 560nm, \3 = 450 nm, when If necessary, the signal from the output of the multi-color photo resistors are used as standard op- photoelectric signal processing unit can be fed tical radiation receivers. into the automatic control system.
References:
1. Rakhimov B.N., Ushakov O.K., Larina T.V., Kutenkova E.Yu. The analyzer of color of a surface of firm materials//the Scientific and technical magazine "Devices and the technician of experiment". - Moscow, - 2012. - No. 3. - P. 131-132.
2. Pat. № 2429456 of the Russian Federation. Analyzer of the color of the surface of solid materials / Rakhimov B.N., Kutenkova E.Yu., Larina T.V., Ushakov O.K. // 20.09.2011. Bul. No. 26.
