RU2674411C1 - Method of registration and formation of signals of multi-spectral images - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to the field of multispectral television and concerns a method for recording and generating signals of multi-spectral images. Method includes the registration of the radiant flux in a wide spectral region from λ₁ to λ_n, its splitting into two identical streams and their transmission through two broadband optical filters OF₁ and OF₂, their spectral characteristics cover the spectral region from λ₁ to λ_n and satisfy certain conditions. Radiant fluxes are converted using matrix photodetectors and form two integral signals in the spectral region from λ₁ to λ_n. Based on the received signals, the values of the signals for the registration areas of the radiant flux in the spectral region from λ₁ before λ_n by processing signals based on solving a system of linear equations with two unknowns. Then, the received signals of multi-spectral images are processed and used for visual or automatic analysis of video information.

EFFECT: technical result is to increase the signal-to-noise ratio.

3 cl, 2 dwg, 2 tbl

Description

The present invention relates to the field of spectrozonal television, based on the registration and conversion of radiant (light) flux in several zones of the ultraviolet, visible and infrared regions of the spectrum into signals of different spectral images. The generated signals of different spectral images can be used to solve problems of detection and selection, measurement of parameters or recognition of objects and find applications in systems of visual or automatic analysis of video information.

The spectral selection of objects is based on the possibility of recording the reflected or radiated radiant flux in several spectral zones Δλ _i , which are selected within a wide spectral region from λ ₁ to λ _n . Moreover, depending on the problem being solved, the number of registration zones can be equal to m = 2,3,4, ..., L.

In the most complete form, the choice of working zones for recording radiant flux and general questions of the theory of spectrozonal systems were consecrated in the works: Zubarev Yu.B., Sagdullaev Yu.S. Spectral selection of optical images. Tashkent: Fan, 1987, 108 p. [1], Quiring G.Yu. Applied Television. / M .: MEIS, 1989, 90 p. [2] and others

Questions related to differential methods for detecting radiant flux are reflected in the works of the authors: Tarasov VV, Yakushenkov Yu.G. Dual and multi-band optoelectronic systems with matrix radiation detectors. - M .: University book; Logos, 2007 .-- 192 p. [3], Sagdullaev V.Yu. The choice of radiation registration zones in multi-angle television systems / T-SOMM-Telecommunications and transport. - M., 2012 - No. 9. - S. 120-121 [4], Sagdullaev T.Yu., Sagdullaev Yu.S. On the choice of registration zones in spectrozonal television. Questions of radio electronics, ser. Television Engineering, 2011, no. 2, S. 3-25 [5] and others.

In fact, the aforementioned works on the whole touch upon the issues of spectral selection of objects using the differential method of detecting radiation, that is, in the relatively “narrow” spectral zones of the ultraviolet (UV), visible (VI) and near infrared (IR) regions of the spectrum, which requires high sensitivity of television ( TV) sensors (matrix photodetectors) with low reflectivity of objects.

In addition to the foregoing, it should be noted that when using the differential method of registering a radiant (light) flux, a low contrast of the formed spectrozonal images is possible. It by its nature can be due to various reasons:

- poor reflectivity of the object and background;

- close spectral characteristics of the object and background;

- selection of non-optimal spectral sections (zones) of registration of the radiant flux for a given combination of the class of target ground objects and background;

- poor illumination of the object and background;

- poor transparency of the remote environment;

- unfavorable conditions for observing objects, etc.

Thus, in such cases, the use of several "narrow" zones of registration of radiant (light) flux within a wide spectral region with wavelengths from λ ₁ to λ _n , including the UV, VI, or IR spectral region, in spectrozonal television systems, based on the differential registration method radiant (light) flux is not effective.

Recently, work has been known related to the possibility of using integrated methods for detecting radiant (light) flux in various spectral regions of the optical spectrum. Among them, for example, Sagdullaev Yu.S., Kovin S.D., Sagdullaev T.Yu., Smirnov A.I. Information-measuring systems of television M .: "Sputnik +", 2013. - 199 p., [6]. According to the patent of the Russian Federation No. 2604898 on “Method for the formation of spectrozonal video signals” / Kovin SD, Sagdullaev Yu.S. - Priority 06/26/2015. Publ. 12/20/2016, Bull. No. 35 [7], a method of forming spectrozonal video signals using a variable width of the registration zone, which uses the integral-differential method of recording the radiant (light) flux, is considered. This method ensures the achievement of a high signal-to-noise ratio by registering the input radiant flux in wide areas of the spectral region with the formation of additional spectrozonal signals in narrow zones of radiant flux recording, by processing (subtracting) the integral signals from each other.

As the closest analogue of the claimed invention, according to the totality of the signs and operations on the signals, a method for generating and displaying spectrozonal television signals according to the RF patent for invention No. 2374783 "A method for generating and displaying spectrozonal television signals" / Vilkova NN, Zubarev Yu.B. , Sagdullaev Yu.S. publ. November 27, 2009 Byul. 33 [8]. This patent describes a method for generating and displaying spectrozonal TV signals, which uses an integrated method for registering a radiant flux. According to this method, the registration of the radiant flux is carried out in a "wide" section of the optical spectrum, compared with the differential registration method, when the registration of the radiant flux is carried out in relatively "narrow" zones of the optical spectrum.

The formation of spectrozonal TV signals occurs according to a two-channel optical scheme, where the registration process of the reflected radiant (light) or emitted stream is carried out within the entire wide spectral region with a wavelength of λ ₁ to λ _n , for which, after splitting the input radiant stream into two identical streams F (λ), it passes through a broadband optical filter (PF) RP ₁ and RP _2, for the first TV encoder having a spectral characteristic F ₁ (λ), and for the second TV transmitter - F ₂ (λ), wherein the spectral characteristics ki of the first and second optical filter covering the entire spectral portion having wavelength of λ ₁ to λ _n and satisfy F ₁ (λ) = 1-P ₂ (λ).

The disadvantage of the considered method is the fact that it is impossible to simultaneously generate the amplitude values of the spectrozonal video signals for wide and narrow zones of registration of the radiant flux in a given spectral region from λ ₁ to λ _n , that is, to combine the advantages of the integral and differential method of recording the radiant flux.

EFFECT: ensuring a high signal-to-noise ratio by registering the input radiant flux in a wide spectral region with the formation of additional spectrozonal signals in narrow zones of registration of the radiant flux to increase the reliability of the selection of control objects.

The technical result is achieved in that, in contrast to the known method for generating and displaying spectrozonal TV signals, including recording the radiant (light) flux F (λ), within a wide spectral range from λ ₁ to λ _n , splitting it into two identical fluxes F (λ ) and their transmission through two broadband optical filters OF ₁ and OF ₂ , the spectral characteristics of which are mutually opposite and satisfy the condition Ф ₁ (λ) = 1-Ф ₂ (λ) in the wavelength range from λ ₁ to λ _n , (light) flux zovaniem matrix of photodetectors and forming two multispectral video signals U ₁ (λ) and U ₂ (λ), receiving the resultant signal U _R (λ) based on performing a division operation multispectral video signals among themselves, which, after splitting the input radiant flux into two identical flow F (λ), it is passed through wideband optical filters OF ₁ and OF _{2 the} spectral characteristic of the first OF τ _τ1 (λ) and the second OF τ _τ2 (λ) covers the spectral region from λ ₁ to λ _n and satisfies the condition

then, radiant (light) fluxes are converted and two integrated signals U _c1 (t) and U _c2 (t) are generated in the spectral region from λ ₁ to λ _n , after which using these signals the signals are found for (λ _i -λ ₁ ) and (λ _n -λ _i ) - zones of registration of the radiant (light) flux in the spectral region from λ ₁ to λ _n by processing signals based on the solution of a system of linear equations with two unknowns

where for the first RP the values of τ _f11 (λ) and τ _f12 (λ) are taken equal to unity, according to (1), and for the second OF, the values of τ _f21 (λ) are 1-ξ ₂ (λ), and the values of τ _f22 ( λ) are taken equal to unity, according to (2), after which the value of the amplitude of the image signal for the first recording zone (λ _i -λ ₁ ) is determined according to the expression

and also determine the amplitude of the image signal for the second recording zone (λ _n -λ _i ) according to the expression

where the determinant of a system of linear equations with two unknowns is calculated according to the expression

then they process the received signals of multispectral images, store them, then feed them to the inputs of a color video monitoring device for visual analysis of information, and also automatically select the set objects based on the distribution of the amplitude values of the signals of multispectral images in the generated areas of registration of the radiant flux.

To achieve this result, we propose a method for recording and generating signals of different spectral images, including the registration of the radiant (light) flux F (λ) in a wide spectral region from λ ₁ to λ _n , its splitting into two identical fluxes F (λ), passing them through two broadband optical filter oF ₁ and RP ₂ spectral characteristic which covers the spectral region from λ ₁ to λ _n, radiant flux transformation using matrix photodetectors to form two integral signal Images U _c1 (t) and U _c2 (t), wherein after splitting the input radiant flux into two identical flow F (λ), it passes through a broadband optical filters PF ₁ and PF ₂ spectral characteristic which for the first RP τ _F1 (λ ) and the second OFF τ _f2 (λ) satisfy the condition

then, radiant (light) fluxes are converted and two integrated image signals U _c1 (t) and U _c2 (t) are generated in the spectral region from λ ₁ to λ _n , after which using these signals the signal values are found for (λ _i - λ ₁ ) and (λ _n −λ _i ) are the registration zones of the radiant flux in the spectral region from λ ₁ to λ _n by processing signals based on the solution of a system of linear equations with two unknowns

where for the first OF, the values of τf ₁₁ (λ) and τ _f12 (λ) are taken equal to unity, according to (1), and for the second OF, the values of τ _f21 (λ) are 1-ξ ₂ (λ), and the values of τ _f22 ( λ) are taken equal to unity, according to (2), after which the value of the amplitude of the image signal for the first recording zone (λ _i -λ ₁ ) is determined according to the expression

and also determine the amplitude of the image signal for the second recording zone (λ _n -λ _i ) according to the expression

where the determinant of a system of linear equations with two unknowns is calculated according to

then they process the received signals of multispectral images, store them, then feed them to the inputs of a color video monitoring device for visual analysis of information, and also automatically select the set objects based on the distribution of the amplitude values of the signals of multispectral images in the generated areas of registration of the radiant flux.

Let a spectral region with a wavelength from λ ₁ to λ _{n be given} . The spectral characteristic (CX) of the matrix photodetector (MFP) is normalized in this region of wavelengths and satisfies the condition

where ξ (λ) is the spectral coefficient taking into account the shape of the spectral characteristic of the MFP. For values of ξ (λ) = 0 in a given spectral region (λ _n −λ ₁ ), expression (7) represents an MFP with a rectangular CX.

Depending on the required number of generated spectrozonal video signals in the spectral region from λ ₁ to λ _n . A TV camera can be built according to a two-channel or multi-channel optical scheme for splitting the input radiant flux into several identical streams.

In the latter case, the spectral section (λ _n -λ ₁ ) is divided into separate registration zones Δλ _i where it is necessary to determine the values of the image signals, for example, in the following form

In the implementation of the integral method of registration of the radiant (light) flux, the key point is the choice of SC OF. In principle, the shape of the CXF can be rectangular, triangular or have any shape. In this case, it is necessary to choose the average values of the coefficients ξ ₂ (λ), ξ ₃ (λ), ..., ξ _m (λ), taking into account the shape of the CXF for the selected detection zones of the radiant (light) flux in the “wide” spectral regions of UV, VI, and IR spectral regions.

Set the requirements for the CX 1,2,3, ..., m-broadband OF in the spectral region (λ _n -λ ₁ )

In contrast to expression (3), to find the signal value in Δλ _i - the registration area of the spectral section with a wavelength from λ ₁ to λ _n, we compose a system of linear equations with two unknowns. In this case, we will take into account the CX of 1,2,3, ..., m-broadband OF in the spectral region (λ _n -λ ₁ ) according to expression (9). CX MFP satisfies expression (7).

Linear equations will have the following form:

The determinant for an i-system of linear equations with two unknowns is found according to the expression

The procedure for calculating the value of the signals in the areas of registration of the radiant (light) flux (8) of the spectral section (λ _n -λ ₁ ) is as follows:

1. Solving the system of linear equations (10), we determine the value of the amplitude of the image signal for the registration area (λ ₂ -λ ₁ )

2. Solving the system of linear equations (11), we determine the value of the amplitude of the image signal for the registration area (λ ₃ -λ ₁ )

3. Solving the system of linear equations (12), we determine the value of the amplitude of the image signal for the registration area (λ ₄ -λ ₁ )

4. Solving each subsequent i-system of linear equations, we determine the value of the amplitude of the image signal for the registration area (λ _i -λ ₁ )

5. Solving the system of linear equations (13), we determine the value of the amplitude of the image signal for the last recording zone (λ _n -λ _n-1 )

We introduce the notation for the i-zones of registration of the radiant (light) flux in the spectral region (λ _n -λ ₁ ) in the form

Then the amplitude values of the signals of different spectral images for the i-zone of registration of the radiant (light) flux Δλ ₁ , Δλ ₂ , ..., Δλ _m can be determined using the operation of subtracting signals

The number of operations required to find the values of signals of different spectral images for the m-zones of registration of the radiant (light) flux with this method is much lower compared to using known unknown calculation methods. Finding signals when solving linear equations with 20 unknowns by Cramer's theorem requires approximately 10 ²¹ multiplications and divisions. When solving a system of linear equations using the exclusion method, the number of operations is also large. To find 20 unknowns, 3270 arithmetic and logical operations are needed.

A spectral TV system that implements the proposed method for recording and generating signals of different spectral images is shown in FIG. one.

Positions:

1 - lens;

2 - a device for splitting a radiant (light) stream into two identical streams;

3 - optical filters (hereinafter referred to as OF);

4 - control unit for optical filters;

5 - converters "radiant (light) stream-signal" (TV sensors);

6 - a sync generator;

7 - amplifiers-shapers;

8 - block generating new signals of different spectral images;

9 - a block of memory and signal processing;

10 - switch and signal inventor;

11 - color video monitoring device;

12 - control unit;

13 - block automatic selection of specified objects.

The sync generator 6 generates the necessary horizontal and frame pulses, which are used to scan (read) the image in the TV sensors 5 ₁ and 5 ₂ , to form the output of the amplifiers - shapers 7 ₁ and 7 ₂ integrated signals U _c1 (t) and U _c2 (t ) The indicated pulses from the sync generator are also sent to the blocks 8, 11. The TV sensors 5 ₁ and 5 ₂ can use any radiant (light) flux-signal converters in the form of known transmitting tubes (such as Vidicon), CCD arrays, CMOS photodetectors or other converters of radiant (light) flux into an electrical image signal.

OF 3 ₁ and 3 ₂ for the first and second channel for generating integrated signals U _c1 (t) and U _c2 (t) have the width of the recording zone and the shape of the spectral characteristics, as shown by way of example in FIG. 2. Since the total number of PFs satisfying this condition may be different, separate groups of PFs are selected. To do this, using the OF 4 control unit, the spectral characteristics of OF 3 ₁ and 3 _{2 are} changed depending on the accepted principle (mechanical — by replacing the OF themselves with other spectral characteristics or electronically). It should be noted that the spectral characteristics of the OB can have a shape other than rectangular.

In the spectrozonal TV system shown in FIG. 1, a two-channel optical circuit is used. Here, the total input radiant flux F (λ) is split into two identical fluxes, each of which passes through its own optical filter having a spectral characteristic to fulfill condition (1).

After passing the first and second OF, the formed radiant fluxes F ₁ (λ) and F ₂ (λ) are projected onto the photosensitive surface of the first and second TV sensors 5 ₁ and 5 ₂ . After the conversion of the radiant fluxes from the output of the TV sensors, each generated integrated image signal is fed to its input of the amplifier - shaper 7 ₁ and 7 ₂ , where the operations of amplification, separate processing of the integrated image signals and their mixing with horizontal and frame pulses take place.

From the output of block 7 ₁ and 7 _{2, the} signals are sent to the block for processing and generating signals of multispectral images 8, from the output of which they are fed to the inputs of the memory and signal processing units 9. Next, the generated signals from the outputs of block 9 through the switch and the inverter of polarity of signals 10 arrive to the RGB inputs of a color video monitoring device (VCU) 11. In addition, the generated signals from the outputs of block 9 are fed to the inputs of block 13 for automatic selection of objects according to the amplitude distribution of signals in the generated zones of the register radios of a radiant stream. From the control unit 12, control signals are received to block 4 for changing the OF, to blocks 9 and 10 for controlling the processing and switching of signals to the inputs of the VKU 11.

In FIG. 2, for example, one of the variants of the SC of broadband _{OFs is} shown, with transparency coefficients τ _φi (λ) in which the values of the coefficients ξ ₂ (λ) = ξ ₃ (λ) = ... = ξ _m (λ), with 0 <ξ _i (λ) <1.

When using a dual-channel optical splitting circuit input radiant flux and integral method of registration radiant flux may be two basic situations (light) (tab. 4) using the PF ₁ and PF _i, which have certain CX.

For example, in one case CX OF first ₁ and second ₂ RP may be constant, in the second case a second SH RP _i may sequentially change (mechanical or electronic means).

Let us take, for example, that the CX of the remote medium, lens, and MFP in a given wavelength range are uniform in the spectral wavelength range from λ ₁ to λ _n and are arbitrarily equal to unity. Then the value of the coefficients τ _f11 , τ _f12 and τ _f21 , τ _f22 will be determined by the course of the spectral characteristics of OF ₁ and OF _i (Table 4, situation 1 and 2).

When using a multi-channel input circuit of a spectrozonal television system, a large number of image signals can be generated. The total number of spectrozonal signals that can be obtained with the integrated radiant (light) registration method is shown in Table. 5. It includes the number of main signals of different spectral images for the registration zones Δλ ₁ = (λ ₂ -λ ₁ ), Δλ ₂ = (λ ₃ -λ ₂ ), Δλ ₄ = (λ ₅ -λ ₄ ), ..., Δλ _m , obtained by solving a system of linear equations with two unknowns and is determined by expressions (15-19) and (21).

In addition, it is possible to obtain additional signals of spectrozonal (multi-spectral) images, for example, by summing the signals of individual recording zones within the spectral region (Δλ _n -λ ₁ ), for example, for recording zones Δλ ₁ + Δλ ₃ , Δλ ₁ + Δλ ₅ , Δλ ₂ + Δλ ₄ , ..., Δλ _m , Δλ ₁ + Δλ ₄ + Δλ _m etc.

The total number of signals of spectrozonal images will be the signals of the individual registration zones Δλ ₁ , Δλ ₂ , Δλ ₃ , ..., Δλ _m and their possible combinations (the number of combinations depends on the number of initial integral signals). The total number will be a value according to the expression

where m is the number of source integral signals.

Consider an example where the number of integrated signals is m = 3. The number of main signals of different spectral images is three and will be Δλ ₁ , Δλ ₂ , Δλ ₃ for registration zones. The number of additional signals of different spectral images is four and will be for the recording zones Δλ ₁ + Δλ ₂ , Δλ ₂ + Δλ ₃ , Δλ ₁ + Δλ ₃ , Δλ ₁ + Δλ ₂ + Δλ ₃ .

Sources

1. Zubarev Yu.B., Sagdullaev Yu.S. Spectral selection of optical images. Tashkent: Fan, 1987, 108 p.

2. Quiring G.Yu. Applied Television. / M .: MEIS, 1989, 90 p.

3. Tarasov VV, Yakushenkov Yu.G. Dual and multi-band optoelectronic systems with matrix radiation detectors. - M .: University book; Logos, 2007 .-- 192 p.

4. Sagdullaev V.Yu. The choice of radiation registration zones in multi-angle television systems / T-SOMM-Telecommunications and transport. - M., 2012-No. 9. - S. 120-121.

5. Sagdullaev T.Yu., Sagdullaev Yu.S. On the choice of registration zones in spectrozonal television. Questions of radio electronics, ser. Television Engineering, 2011, no. 2, S. 3-25.

6. Sagdullaev Yu.S., Kovin S.D., Sagdullaev T.Yu., Smirnov A.I. Information-measuring systems of television M .: "Sputnik +", 2013. - 199 p.

7. RF patent No. 2604898. The method of forming spectrozonal video signals / Kovin S.D., Sagdullaev Yu.S. - Priority 06/26/2015. Publ. December 20, 2016 Bull.№35.

8. RF patent for the invention No. 2374783 "Method for the formation and display of spectrozonal television signals" / Vilkova NN, Zubarev Yu.B., Sagdullaev Yu.S. publ. November 27, 2009 Byul. 33.

Claims (15)

1. A method for recording and generating signals of different spectral images, including registration of the radiant (light) flux F (λ) in a wide spectral region from λ ₁ to λ _n , its splitting into two identical fluxes F (λ), passing them through two broadband optical filters OF ₁ and OF ₂ , the spectral characteristic of which covers the spectral region from λ ₁ to λ _n , the conversion of radiant fluxes using matrix photodetectors with the formation of two integrated image signals U _c1 (t) and U _c2 (t), characterized in that After splitting the input radiant flux into two identical fluxes F (λ), it is passed through the OF ₁ and OF ₂ broadband optical filters, the spectral characteristic of which for the first OF τ _τ1 (λ) and the second OF τ _τ2 (λ) satisfies the condition

then, the radiant (light) fluxes are converted and two integrated image signals U _c1 (t) and U _c2 (t) are generated in the spectral region from λ ₁ to λ _n , after which, using these signals, the signal values are found for (λ _i -λ ₁ ) and (λ _n -λ _i ) are the registration areas of the radiant flux in the spectral region from λ ₁ to λ _n by processing signals based on the solution of a system of linear equations with two unknowns

where for the first RP the values of τ _f11 (λ) and τ _f12 (λ) are taken equal to unity, according to (1), and for the second OF, the values of τ _f21 (λ) are 1-ξ ₂ (λ), and the values of τ _f22 ( λ) are taken equal to unity, according to (2), and then determine the value of the amplitude of the image signal for the first recording zone (λ _i -λ ₁ ) according to the expression

and also determine the amplitude of the image signal for the second recording zone (λ _n -λ _i ) according to the expression

where the determinant of a system of linear equations with two unknowns is calculated according to

then they process the received signals of multispectral images, store them, then feed them to the inputs of a color video monitoring device for visual analysis of information, and also automatically select the set objects based on the distribution of the amplitude values of the signals of multispectral images in the generated areas of registration of the radiant flux. 2. The method according to p. 1, characterized in that during the formation of the second integral signal U _c2 (t), the spectral characteristic of the used optical filters can be changed by changing them mechanically. 3. The method according to PP. 1 and 2, characterized in that when generating integrated signals, the number of which is 3, 4, ..., m, the amplitude values of the signals of different spectral images for the i-zone of registration of the radiant (light) flux Δλ ₁ , Δλ ₂ , ... Δλ _m determine using the operation of subtracting signals according to

Images