RU2657453C1 - Method for forming video signal in a “ring” photodetector for computer system of panoramic television surveillance in conditions of complex illumination and/or complex brightness of objects - Google Patents

Abstract

FIELD: video monitoring.

SUBSTANCE: invention relates to television and computer technology and is oriented to the use in television camera of panoramic observation, which are made on the basis of "ring" television sensors based on the technology of charge-coupled devices (CCD) and are designed to work in conditions where objects of control differ significantly in terms of illumination and / or brightness. Cameras provide simultaneously a surround-view of the situation in an area close to the hemisphere, i.e. in a spatial angle of 360 degrees in azimuth and tens of degrees in the elevation angle, while computer (server) operator evaluates the "sensitivity" of image of received n "rectangular" frames, and according to this evaluation sends a command to the television camera to form a new reference value of control voltage for ARVN and AGC in relation to selected corresponding section of "ring" target with low illumination (brightness), providing increased accumulation time of photodetector and an increased gain constant of video path of television camera for a new "ring" image frame.

EFFECT: increase in sensitivity of these separate "rectangular" frames recorded with low illumination (brightness) of the corresponding fragments of the panoramic image, by increasing the accumulation time of the photodetector and television camera video path gain factor for them.

1 cl, 7 dwg, 1 tbl

Description

The invention relates to a television-computer equipment and is focused on the use of panoramic cameras in television cameras, which are made on the basis of "ring" television sensors using charge-coupled device (CCD) technology and are designed to operate in conditions where the objects of control differ significantly from each other by illumination and / or brightness. These cameras simultaneously perform a circular overview of the situation in the region close to the hemisphere, i.e. in a spatial angle of 360 degrees in azimuth and tens of degrees in elevation.

The closest in technical essence to the claimed invention should be considered a method of generating a video signal in a "ring" photodetector for a computer system for panoramic television surveillance [1], which consists in installing the television camera in a fixed position, capturing an optical image in a television camera with an angular field in the space of objects 360 ° in azimuth, in the "ring" photodetector of a television camera made by the technology of charge-coupled devices (CCD), cat The second one has a crystal in the form of a circular ring and contains within it a “ring” photodetector region (target), a “ring” shift register ending in a charge-voltage conversion unit (BPS), while on the photodetector region of the line of photosensitive elements, alternating with with rulers of light-shielded elements, located along radial directions from the imaginary center of the circular ring to its outer periphery and the “ring” shift register located there, and the number of elements in each “ring” The photodetector region is equal to the number of elements in the “ring” shift register, and the area of photosensitive and shielded elements on the photodetector region is the same in size in each “ring” line and from line to line as it moves to the outer periphery of the photodetector, the charge image of the information frame is accumulated on photosensitive elements of the target in accordance with the control voltage for automatic adjustment of the accumulation time (ARVN) of the photodetector, and the counting value of the control n voltages are performed within the entire target, “ring” sweep of the charge image on the target is carried out, followed by element-wise reading of the charge packets in the “ring” shift register and the formation of the voltage of the analog image signal of the observed space at the output of the SPS, adjust the gain of the video path for the analog video signal in accordance with control voltage of automatic gain control (AGC), using the same reference voltage control value as for ARVN, pre the analog video signal is transformed into a digital video signal, the video signal of the television camera is transmitted via the interface to the operator’s computer, which is the server for the local computer and for the remote computer on the Internet, while the ring television image is converted into a normal image in the operator’s computer, with one current ring "frame is read from the server memory using n" rectangular "frames, the number of which satisfies the ratio:

where γ _g is the horizontal angle of the field of view in degrees observed by the operator of the image.

The disadvantage of the method of generating a video signal in the prototype is the limited sensitivity of individual "rectangular" frames recorded at low light (brightness) of the corresponding fragments of the panoramic image.

The objective of the invention is to increase the sensitivity of these individual "rectangular frames recorded at low light (brightness) of the corresponding fragments of the panoramic image, by increasing for them the accumulation time of the photodetector and the gain of the video path of the television camera.

The problem in the inventive method of generating a video signal in a "ring" photodetector for a computer system for panoramic television surveillance is solved by installing a television camera in a fixed position, capture an optical image in a television camera with an angular field in the space of objects 360 ° in azimuth, in the "ring" "A photodetector of a television camera made by CCD technology, which has a crystal in the form of a circular ring and contains within it a" ring "target, A “circular” shift register ending in an OVL, with the lines of photosensitive elements alternating with the lines of light-shielded elements on the target located along radial directions from the imaginary center of the circular ring to its outer periphery and the “circular” shift register located there, and the number of elements in each “ring” line of the target is equal to the number of elements in the “ring” shift register, and the area of photosensitive and shielded elements on the target is the same in size in each “ ring "line and from line to line as you move to the outer periphery of the photodetector, accumulate the charge image of the information frame on the photosensitive elements of the target in accordance with the control voltage for the ARVN of the photodetector, and the control voltage is counted throughout the target, carry out a" ring "scan charge image on the target, followed by element-wise reading of the charge packets in the "ring" shift register and the formation of the voltage anal of the target image signal of the observed space, the video path gain for the analog video signal is adjusted in accordance with the control voltage of the AGC, using the same control voltage reading as for the ARVN, the analog video signal is converted into a digital video signal, the video signal of the television camera is transmitted via the interface to the operator’s computer, which is the server for the computer of the local user and for the computer of the remote user on the Internet, while in the computer The ora ring television image is converted into a regular image, and one current “ring” frame is read from the server’s memory using n “rectangular” frames, the number of which satisfies relation (1), characterized in that the computer (server) operator evaluates the “sensitivity” parameter "Image obtained n" rectangular "frames, and according to this estimate sends a command to the television camera to form a new reference value of the control voltage of the ARVN and AGC as applied to the selected correspondence the corresponding portion of the “ring” target with reduced illumination (brightness), providing increased accumulation time of the photodetector and increased gain of the video path of the television camera for the new “ring” image frame.

The combination of known and new features for the proposed method is not known from the prior art, therefore, the proposed technical solution meets the criterion of novelty.

According to the claimed method, increasing the sensitivity of individual "rectangular" frames of the video signal is performed in relation to the "ring" photodetector, i.e. it is implemented in a “ring” raster of a television image.

Therefore, this technical solution meets the criterion of the presence of an inventive step.

Therefore, this technical solution meets the criterion of the presence of an inventive step.

In FIG. 1 shows a structural diagram of a computer system for panoramic television surveillance that implements the inventive method of generating a video signal in a "ring" photodetector; in FIG. 2 - circuitry organization of the "ring" photodetector at the CCD; in FIG. 3 - structural of this television camera from the computer system of panoramic television surveillance; in FIG. 4, according to [2], a photograph of an image obtained using a domestic panoramic mirror-lens lens is presented; in FIG. 5 shows the position of the regions of photometry of the charge relief for six formed "rectangular" frames (n = 6) on the target of the "ring" photodetector under conditions of its complex illumination and / or brightness; in FIG. 6b) -6d) with respect to the temporary position of the blanking pulse of the rows shown in FIG. 6a), plots of control signals are given for obtaining the necessary “windows” of photometrics; in FIG. 7 is a functional diagram explaining the organization in a television camera of this photometric process for ARVN.

The device of FIG. 1 contains a television camera 1, an operator’s computer 2 as a server, a router (Russian name of the device is a router) in position 3, a local user computer 4 for working in a local network, a modem 5 for transmitting video signals to the Internet, and a remote user computer 6 for receiving video information from the "cloud" of the Internet.

The television camera 1 (see Fig. 3), as for the prototype [1], consists of sequentially located and optically coupled panoramic lens 1-1 of the solid state photodetector 1-2 and block 1-3 of the “ring” scan of the photodetector and the formation of a digital television signal.

Unit 1-3 of the television camera contains a time controller 1-3-1, a signal processor 1-3-2, a first level converter (PU) 1-3-3, a second PU 1-3-4, as well as an analog-to-digital converter ( ADC) 1-3-5, the output of which is the output of the television camera (the output of the DSP).

At the input of the television camera 1 and in transit to a temporary controller 1-3-1, a control command code from the operator's computer 2 is supplied. This code defines the selected photometric region of the target of the “ring” sensor 1-2 - the “window”, within which the charge relief is estimated using ARVN and AGC as applied to the “rectangular” frames formed in the server 2. Suppose that the number of these "rectangular" frames programmed in server 2 is six, i.e. n = 6. Then the binary code of the control command must have three digits, and the modes determined by it are presented in the table, which are further illustrated in FIG. 5-6.

The organization of the photodetector 1-2 (see Fig. 2) with the target in the form of a circular ring, as in the prototype [1], is implemented using CCD technology.

It contains a photodetector region 1-2-1 on a common crystal, in which lines of photosensitive elements and lines of elements shielded from light (not shown here) are radially located (from the imaginary geometric center of the ring), as well as a “ring” shift register 1 -2-2 and BPZN 1-2-3, and the number of elements in each "ring" line of the photodetector region 1-2-1 is equal to the number of elements in the "ring" shift register 1-2-2.

The panoramic lens 1-1 of the television camera, as in the prototype [1], is intended to form an optical image of a circular view ("ring" image). As a technical solution for a panoramic lens 1-1, a panoramic mirror-lens lens can be proposed, the design of which is patented in Russia by Russian specialists from Moscow State University of Geodesy and Cartography [2].

A photograph of the annular image formed by the panoramic lens is shown in FIG. 6. The angular field in the space of objects for this lens is 360 degrees in azimuth and can reach (75-80) degrees in elevation.

Consider the implementation of the proposed method for generating a video signal in a television camera 1 (see Fig. 1 ... 3).

As in the prototype [1], it is assumed that the television camera 1 is installed in a fixed position, for example using a photographic tripod (here it is not shown).

The optical image of the observed scene is projected from the output of the panoramic lens 1-2 to the target 1-2-1 of the "ring" photodetector.

The photodetector 1-2 of the television camera (see Fig. 2) implements a “ring” scan of the charge image on the photodetector region 1-2-1, followed by element-by-element reading of the charge packets in the “ring” shift register 1-2-2 and the formation of an OTZN output 1-2-3 voltage of the video signal in analog form. At the same time, in the interval of the forward course of the frame, the process of accumulation of charge packets occurs in proportion to the illumination of the panoramic plot, in the photosensitive pixels of the photodetector region 1-2-1. During a short period of the subsequent interval of the reverse rotation of the frame scan, a photo shutter opens, and the charges of all the "ring" lines involved in the accumulation are transferred (in one rotation step) to the screened from light pixels located in the same region 1-2-1. Then the photo shutter closes and, in a new personnel cycle, another charge “picture” is accumulated on the target, and the charge packets accumulated in the previous frame are transferred in radial directions to the periphery of the photodetector crystal, loading the “ring” register 1-2 in the reverse scan interval -2.

The analog video signal of the photodetector at the output of the television camera 1 is converted into a digital television signal (DTS), and then goes to server 2. In server 2, as in the prototype [1], the digital video signal is recorded into RAM on a frame, followed by its reading, and as a result, the conversion of the “ring” frame into ordinary “rectangular” frames with a total number n, as well as the ability to provide video information to users at the “Network” output of server 2.

But back to TV camera 1. Note that by default there is a “000” control command at its input, which means that the photometric area for ARVN and AGC is, as in the prototype [1], the entire sensor target.

This command is supplied to the inputs: “A”, “B” and “C” of the temporary controller 1-3-1, see fig. 7, due to which a pulse signal of a large “window” is formed at its output “D”, see FIG. 6b).

Therefore, the switch is closed for the duration of the large “window”, and at the input “E” of the time controller we obtain a reference of the output voltage level of the amplitude detector of the video signal according to the peak or average value measured over the entire target area, see FIG. 7.

Note that this voltage from the amplitude detector through a similar switch with a "window" is supplied to the input of the signal processor 1-3-2 to control the operation of the AGC.

In conditions of complex illumination and / or complex brightness of objects of a panoramic plot, this photometric algorithm for ARVN and AGC is not optimal. The most favorable for observation is a “rectangular” frame, the potential relief of which is read from the target section of the photodetector with the highest illumination (brightness), and the least favorable “rectangular” frame is read from the site of the target with the lowest illumination (brightness).

Let in our example, where the number n = 6 shown in FIG. 5, under conditions of high illumination of the observed plot, frame 1 turns out to be, frames 2 and 6 under conditions of weakly reduced illumination, frames 3 and 6 under conditions of medium low illumination, and frame 4 under conditions of substantially reduced illumination.

With the input command “000”, the parameters that determine the sensitivity of the image: the accumulation time of the photodetector T _n and the gain of the video path K _y , are fixed when evaluating the charge relief of frame 1 and apply to the entire “ring” target. Moreover, these parameters, which are optimal indicators for frame 1, are not such for frames 2-6, because for them, they are below the optimal indicators.

The computer operator 2 performs an express analysis of television images of “rectangular” frames 2-6 obtained with the input command “000”, and can significantly improve the quality of one of them by choice. To do this, he gives another command to the television camera 1 (see table), which corresponds to his choice of the location of the object of interest and the numbering of the "rectangular" frame.

Then, in the television camera 1, a new photometric “window” will be formed and another readout of the output voltage level of the amplitude detector of the video signal will be made, see FIG. 7. As a result, using ARVN and AGC, new (increased) indicators for the parameters T _n and K _y will be obtained, and, consequently, an increase in the signal-to-noise (ψ) ratio of the video signal and an increase in the image sensitivity of the selected frame will be achieved.

Such an operation can be repeated for any other “rectangular” frame from composition 2-6 when another control command is applied to the input of the television camera 1 in order to obtain another photometric “window”, see FIG. 6c) ... FIG. 6h).

A new high-quality recording of a “rectangular” frame can be submitted to the “Network” output of server 2 and proposed as a replacement for its previous record for computers of local and remote users.

Currently, all the blocks of the functional circuit that implements the proposed method for generating a video signal are mastered or can be mastered by domestic industry.

Therefore, the present invention should be considered as a method for generating a video signal in a “ring” photodetector for a computer system for panoramic television surveillance in conditions of complex illumination and / or complex brightness of objects corresponding to the requirement for industrial applicability.

INFORMATION SOURCES

1. RF patent No. 2545519, IPC H04N 7/00. The device of a computer system for panoramic television surveillance and the organization of a photodetector for its implementation / V.M. Smelkov // B.I. - 2015. - No. 10.

2. RF patent No. 2185645, IPC G02B 13/06, G02B 17/08. Panoramic mirror lens. / A.V. Kurtov, V.A. Solomatin // B.I. - 2002. - No. 20.

Claims (4)

A method of generating a video signal in a "ring" photodetector for a computer system for panoramic television monitoring in conditions of complex illumination and / or complex brightness of objects when high illumination (brightness) in some parts of the field of view is accompanied by low illumination (brightness) in its other parts, which consists in that set the television camera in a fixed position, capture the optical image in a television camera with an angular field in the space of objects 360 ° in azimuth, in the front ”photodetector of a television camera made by the technology of charge-coupled devices (CCD), which has a crystal in the form of a circular ring and contains within it a“ ring ”photodetector region (target), an“ annular ”shift register ending with a charge - conversion unit voltage ”(BPS), while on the photodetector area, the lines of photosensitive elements, alternating with the lines of elements shielded from light, are located along radial directions from the imaginary center of the circular ring to its external periphery and the “annular” shift register located there, and the number of elements in each “annular” line of the photodetector region is equal to the number of elements in the “annular” shift register, and the area of the photosensitive and shielded elements on the photodetector region is the same in size in each “annular” line and from row to row as they move to the outer periphery of the photodetector, the charge image of the information frame is accumulated on the photosensitive elements of the target in accordance with the control voltage for automatic adjustment of the accumulation time (ARVN) of the photodetector, whereby the control voltage is measured across the entire target, a “ring” scan of the charge image on the target is performed, followed by element-by-element reading of the charge packets in the “ring” shift register and the formation of the analog signal voltage at the output images of the observed space, adjust the gain of the video path for the analog video signal in accordance with the control voltage of the machine gain control (AGC), using the same control voltage reading as for the ARVN, convert the analog video signal into a digital video signal, transmit the video signal of the “ring” frame of the television camera via the interface to the operator’s computer, which is the server for the local user’s computer and for a computer of a remote user on the Internet, while in the operator’s computer, the “ring” television image is converted into a regular image, with one current “ring” read frame t from the server memory using n «rectangular" frames, the number of which satisfies the relationship:

where γ _g is the horizontal angle of the field of view in degrees observed by the operator of the image, characterized in that the computer (server) operator evaluates the received n "rectangular" frames according to the "sensitivity" parameter of the image, and according to this estimate sends a command to the television camera to form a new control voltage value for the ARVN and AGC as applied to the selected corresponding "ring" section "Targets with reduced illumination (brightness), providing increased accumulation time of the photodetector and increased gain of the video path of the television camera for the new" ring o "image frame.

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