RU2626244C1 - Method and system of positioning group of submarine objects in limited water volume - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: optical beacons are installed on each of the objects, the number of which and their locations on the underwater object are chosen from the condition of ensuring continuous monitoring of, at least, two video cameras. The radiation of optical beacons of the objects are fixed by using four video cameras located at the ends of mutually perpendicular axial lines of the horizontal section of the controlled volume. Initiation of optical beacon radiation is carried out by means of a signal radiated by four initiator-initiators in the optical wave band, the duration of which is equal to the duration of the video frame Δt, the repetition period of which is T=Δt*(N+1), where N - the number of objects in the group, and the beginning of the radiation is synchronized with the camera synchronization pulses. As an identifying feature of the object, a preset video frame number is used, in which the optical beacon of this object emits a signal. Video sequences are allocated in the video frames corresponding to each identified object, by which the coordinates and parameters of the movement of each object are calculated. The processing of video information from video cameras is performed on a computer complex located at the control point for the actions of underwater objects outside the controlled water volume.

EFFECT: identification and continuous determination of coordinates and parameters of the motion group of underwater objects, including partial overlapping of objects.

14 cl, 5 dwg

Description

The group of inventions relates to the field of underwater navigation and can be used to determine the coordinates of a group of underwater objects, mainly submariners and underwater swimmers when practicing joint actions in a pool or diving tower.

There are various methods for determining the coordinates of underwater objects. In the patent US 7512036 B2, IPC G01S 3/80, publ. 03/31/2009 swimmer's coordinates are determined using the well-known acoustic navigation system with a long base, based on the use of three buoys equipped with receivers of the global positioning system (GPS). The location of the buoys limits the area of underwater operations.

A known system for determining the coordinates of underwater objects according to the patent RU 2437114 C1, IPC G01S 3/80, publ. 12/20/2011, which can be used in determining the geographical coordinates of a group of underwater objects, such as underwater swimmers, managed and uncontrolled underwater devices, marine animals.

The system contains buoys in the amount of no less than sin, located on the sea surface with a distance of 1-3 kilometers between them, which receive signals from hydroacoustic emitters (hydrophones) of underwater objects.

Coordinates are calculated based on the calculation of distances determined by the hydroacoustic method with measurement of the delay time of the hydroacoustic signal by the correlation receiver-demodulator of buoys relative to the synchro-sending of a given type emitted by the hydrophone. At the same time, underwater objects are equipped with highly stable watches, previously synchronized by the GPS clock. The hydrophone is emitted at a predetermined point in time, synchronous with the clock and different for each underwater object. The signal from a specific object is received by the correlation receiver-demodulator of the buoys, where the delay time to each buoy is calculated using the controller-meter of time intervals. Next, each buoy, using a radio modem, transmits these times over the air to a monitoring station, where the computer, using a known algorithm, calculates the coordinates of a specific object and displays them on the display.

The disadvantage of the system according to patent RU 2437114 C1 is the need to have a highly stable watch on each underwater object, pre-synchronized by the GPS clock.

In addition, due to the specific geometry of the diving tower, which is a cylinder of small length and diameter with smooth hard walls, the use of hydroacoustic systems for determining the coordinates of underwater objects is complicated by the presence of numerous powerful spurious reflections.

The prior art methods for determining the three-dimensional coordinates of objects from video sequences from two surveillance cameras, while the optical axis of the cameras can be parallel or arbitrarily oriented. Known methods for estimating the three-dimensional coordinates of a point include: determining the internal parameters of the cameras (calibration task), determining the parameters of the relative positions of the cameras (mutual orientation), determining the coordinates of the corresponding conjugate points on the images (the task of searching for conjugate points) (see, for example, Digital image processing in information systems: Textbook / I. S. Gruzman, BC Kirichuk et al. - Novosibirsk: NSTU Publishing House, 2002. Chapter 6. Photogrammetry and stereo vision. P. 168-185).

As a prototype for the method and device, the robot control system according to the patent RU 139478 U1, IPC B25J 19/00, published on 04/20/2014, which implements a method for determining the three-dimensional coordinates of objects from video sequences from two surveillance cameras and includes two synchronously working digital cameras, is adopted A computer with software installed on it. Video cameras are stationary at a distance from each other and their optical axes are mutually oriented in the direction of the space surrounding the robotic object. Computer software provides the ability to obtain a three-dimensional image of the space surrounding the object and control the current position of the robotic object. The robotic object is marked with control elements, providing the ability to uniquely determine the coordinates of its current position relative to the underlying surface by stereogrammetric methods using video cameras and computer software. The control elements are made in the form of at least two LEDs located on each controlled element. Identification of the position of the object by easily detectable control LEDs can significantly simplify and increase the accuracy of positioning and relieve the computing system. However, the system according to patent RU 139478 U1 does not provide identification and positioning of a group of moving objects in an aquatic environment.

The basis of this group of inventions is the task of creating a method for positioning a group of objects in a limited water volume and a system for its implementation, which would allow for the identification and continuous determination of coordinates and motion parameters of a group of underwater objects, including partial overlap of objects.

In relation to the method, the problem is solved by the fact that in the method of positioning a group of underwater objects in a limited water volume, including installing optical beacons on each of the objects, emitting signals from the optical beacons of the objects, receiving signals at separated points of reception, which are used to identify and calculate coordinates and parameters the movement of objects, according to the invention, record the radiation of optical beacons of objects using four cameras located at the ends of mutually perpendicular axial horizontal section of the controlled volume, the emission of optical beacons is carried out using a signal emitted by at least one emitter-initiator in the optical wavelength range, the duration of which is equal to the duration of the video frame Δt, the repetition period of which is T = Δt * (N + 1), where N - the number of objects in the group, and the beginning of the radiation is synchronized with the pulses of the frame synchronization of the cameras, as an identifying feature of the object using a predefined number of the video frame, in which optical the cue beacon of this object emits a signal, video sequences are allocated in the video frames corresponding to each identified object, which are used to calculate the coordinates and motion parameters of each object, while the number of optical beacons and their location on the underwater object is selected from the condition of providing continuous monitoring by at least two video cameras .

The technical result in the method is also achieved by the fact that:

the number of emitters-initiators is chosen equal to four and set them at the locations of the cameras;

an optical beacon emits signals in the near ultraviolet and / or near infrared wavelength range;

the emitter-initiator emits signals in the near infrared wavelength range;

as the signal of the emitter-initiator use an encoded signal with amplitude modulation by a sequence of pulses;

the duration of the signal of the emitter-initiator corresponds to the duration of the video frame;

processing of video information from video cameras is carried out at a computer complex located in the control point for the actions of underwater objects outside the controlled water volume.

In relation to the system, the problem is solved by the fact that the positioning system of a group of underwater objects in a limited water volume, containing in the control point a computer system with a program for identifying objects, calculating and displaying coordinates and motion parameters of objects on the display device, installed in remote points of the video camera for receiving signals optical beacons, which are equipped with objects of the group, according to the invention, contains a synchronizer, four cameras that operate in at least one initiator emitter, which is configured to emit in the optical wavelength range of the signal, the duration of which is equal to the duration of the video frame Δt, the repetition period is equal to T = Δt * (Hadron synchronization and placed at the ends of mutually perpendicular horizontal lines of the controlled water volume N + 1), where N is the number of objects in the group, and the beginning of the radiation is synchronized with the frame synchronization pulses of the cameras, the optical beacons are configured to receive the emitter signal -initiator and signal emission in the optical wavelength range in a predefined video frame number for each object, while the separate outputs of the synchronizer are connected to the synchronization inputs of the cameras and the emitter-initiator, the signal outputs of the cameras are connected to the separate inputs of the computing complex, the separate outputs of which are connected to the input of the display device and the input of the synchronizer, and the number of optical beacons and their location on the underwater object is selected from the condition of ensuring continuous surveillance by at least two cameras.

The technical result in the system is also achieved by the fact that:

the number of emitters-initiators is chosen equal to four and set them at the locations of the cameras;

an optical beacon emits signals in the near ultraviolet and / or near infrared wavelength range;

the emitter-initiator emits signals in the near infrared wavelength range;

as the signal of the emitter-initiator use an encoded signal with amplitude modulation by a sequence of pulses;

the duration of the signal of the emitter-initiator corresponds to the duration of the video frame;

a computer complex, a synchronizer and a display device are located in the control point for the action of underwater objects outside the controlled water volume.

The invention is illustrated by drawings, on which:

in FIG. 1 is a structural electrical diagram of the inventive positioning system;

in FIG. 2 - timing diagrams explaining the principle of operation of the proposed method and system;

in FIG. 3 - local coordinate system of the controlled water volume;

in FIG. 4 - horizontal section of a controlled water volume;

in FIG. 5 is a vertical section of a controlled water volume.

In FIG. 1-5 introduced the notation:

1 - underwater objects;

11, 12, ..., 1N - numbers of underwater objects;

111, 121; ..., 1NM - numbers of optical beacons located at underwater objects;

2 - video cameras;

21, 22, 23, 24 - camera numbers;

3 - initiator emitters;

31, 32, 33, 34 - numbers of emitters-initiators;

4 - control point;

5 - computer complex;

6 - display device;

7 - synchronizer;

8 - controlled water volume;

9 - body of the diving tower.

The description of the method for positioning a group of underwater objects in a limited water volume is compatible with the description of the system for its implementation.

Underwater objects 1 are located in a limited water volume, while the water volume can be structurally limited, for example, by the body of the diving tower, the walls of the pool or determined only by the location of the cameras. Outside the controlled water volume, a control point 4 is located, containing a computer complex 5, the separate outputs of which are connected to the input of the display device bis by the input of the synchronizer 7. The signal outputs of the video cameras 21-24 are connected to the separate inputs of the computer complex 5, and the separate outputs of the synchronizer 7 are connected to the synchronization inputs video cameras 21-24 and with synchronization inputs of emitter-initiators 31-34.

Drawings illustrating the inventive method and device shown in FIG. 3 of FIG. 5 are given as an example for a controlled water volume 8 limited by the hull 9 of a cylindrical diving tower with a diameter D. The drawings show one object 11 with coordinates X11, Y11 and Z11.

Each of the N objects of the group from 11 to 1N is equipped with optical beacons 111, 121; ..., 1NM, respectively, the number of which and their location on the underwater object is selected from the condition of providing continuous monitoring by at least two video cameras. For example, to control an underwater swimmer, it is preferable to use four optical beacons located on the back, chest and shoulders.

At the ends of the mutually perpendicular axial lines X and Y of the horizontal section of the controlled water volume (see Fig. 4), four video cameras 21-24 are placed with which objects are monitored, and four initiating emitters 31-34. At angles A of the field of view of the cameras 2 in the horizontal and vertical planes of at least 90 °, such an arrangement of the cameras ensures that each of the objects is monitored by at least two cameras with mutually perpendicular axes, which is sufficient to determine the coordinates of the object.

When the radiation pattern B of the initiator emitters 3 in the horizontal and vertical plane is not less than 90 °, this arrangement of the initiator emitters ensures the presence of the emitted signal in the entire controlled water volume.

With easily accessible angles of field of view of the cameras A = 140 °, the height H of the controlled water volume at D = 5 m is 13.7 m.

The operation of the method and positioning system of a group of objects in a limited water volume is illustrated by time charts, which are shown in FIG. 2, where are indicated:

IKS - impulses of frame synchronization;

SI - signal of the emitter-initiator;

OM11, ..., OM1N - signals of optical beacons of objects;

WIS - synchronization pulses of cameras.

Video cameras 3 operate in a single-frame mode, which is set by the synchronization pulses of the cameras (WIS) from the synchronizer 7 to the synchronization inputs of the cameras 2.

Initiating emitters 3 emit SI signals in the optical wavelength range, the duration of which is equal to the duration of the video frame Δt, and the repetition period is T = Δt * (N + 1), where N is the maximum number of objects in the group. The beginning of the radiation of the initiator emitters 3 is synchronized with the IRS of the cameras 2 and is set by pulses from the synchronizer 7 to the synchronization inputs of the initiator emitters 3.

As the signal of the emitter-initiator, preferably a coded signal is used, for example, a signal with amplitude modulation by a pulse train.

The positioning system of a group of underwater objects of limited water volume works as follows.

Underwater objects 1, equipped with one or more optical beacons, are in a controlled volume. At the same time, they fall into the field of view of cameras 2. All optical beacons are turned off, cameras do not record marks from them. Further, all four initiator emitters 3 send a coded optical signal corresponding to the optical beacon enable command.

Photodetectors of optical beacons of all objects receive and analyze the SI signal. The optical beacons 111 ... 11M of the first object 11 emit OM signals 11 in the first video frame, then the OM12 signal emits the OM12 signal in the second video frame, the optical beacons 121 ... 12M of the second object 12 and so on to the N-th object, then the cycle repeats. Thus, a preset video frame number is used as an identifying feature of the object, in which, after receiving the signal of the emitter-initiator, the optical beacons of this object emit an OM signal.

Due to the fact that all elements of the system, including optical beacons, video cameras, and initiating emitters, are powered by SI signals, the operation of the system is synchronized and does not require a high-precision clock. Optical beacons of the corresponding group generate an optical pulse when an external optical SI signal is incident on their photodetector devices. It is sufficient that the duration of the optical pulse OM generated by the beacon does not exceed the duration of the video frame of the recording camera.

In case of failure of any optical beacon to receive an external optical SI signal, for example, due to the shadowing of its photodetector with partial mutual overlapping of objects, this beacon does not generate an OM response signal. Then the coordinates of the object are determined by other beacons fixed on this object. Moreover, due to the fact that the coordinate information is updated with a frequency of F / N, where F is the frequency of video recording, and low speeds of swimmers in the aquatic environment, the omission of any reference practically does not affect the operation of the system.

To exclude the effect of optical radiation on the eyes of underwater swimmers, the radiation of signals from both initiator emitters and optical beacons is selected at frequencies outside the visible wavelength range, while optical beacons, depending on the optical properties of water, emit signals in preset modes: near ultraviolet ( wavelengths of 360-380 nm) and / or in the near infrared wavelength range (wavelengths of 780-820 nm), and the emitter-initiator emits signals in the near infrared wavelength range.

Due to the fact that the maximum spectral transmission of water falls on the near ultraviolet region of the spectrum, it is preferable to use sources with wavelengths of 360-380 nm in the optical path of the system to minimize the radiation power of optical beacons.

In sequential video frames of video cameras 2, marks from optical beacons of objects 1 with sequential numbers appear, which allows for separate processing of video sequences for each object. Processing of video information from video cameras 2 is performed on a computer complex 5 in a local coordinate system associated with video cameras, with subsequent conversion to a global system in the construction axes of the diving tower.

If there are several optical beacons on the object, marks from one or more optical beacons with different brightness may appear on the image. For processing, select the mark from the optical beacon of the object with the highest brightness. Then, for each object, images from four cameras are compared in pairs and, for further determination of the coordinates of the object, pairs of cameras are selected with minimal errors, whose viewing angles are close to 90 °. If there are several such pairs of cameras, then the object coordinates obtained from several pairs of cameras are averaged. The calculated coordinates and motion parameters of each group object are displayed on the display device 6.

When using a video camera with a video recording speed of F = 60 Hz and a refresh rate of information about the coordinates of objects equal to 5 Hz, which is sufficient to calculate the parameters of the movement of objects, up to 11 objects can be located in a controlled water volume by which identification and continuous determination of coordinates and parameters is provided their movements.

Claims (14)

1. A method of positioning a group of underwater objects in a limited water volume, including installing optical beacons on each of the objects, emitting signals from the optical beacons of the objects, receiving signals at separated points of reception, which are used to identify and calculate the coordinates and motion parameters of the objects, characterized in that they record the radiation of optical beacons of objects using four cameras located at the ends of mutually perpendicular axial lines of the horizontal section of the controlled object a, radiation of optical beacons is initiated using a signal emitted by at least one emitter-initiator in the optical wavelength range, the duration of which is equal to the duration of the video frame Δt, the repetition period of which is T = Δt * (N + 1), where N is the number of objects in group, and the beginning of the radiation is synchronized with the pulses of the frame synchronization of the cameras, as an identifying feature of the object, a predefined video frame number is used, in which the optical beacon of this object emits a signal, I highlight video frames in the video sequence corresponding to each identified object, which is calculated by the position and movement parameters of each object, the number of optical beacons and their location on the underwater object is selected from the condition of providing continuous monitoring of at least two cameras. 2. The method according to p. 1, characterized in that the number of emitters-initiators is chosen equal to four and set them in the locations of the cameras. 3. The method according to p. 1, characterized in that the optical beacon emits signals in the near ultraviolet and / or in the near infrared wavelength range. 4. The method according to p. 1, characterized in that the emitter-initiator emits signals in the near infrared wavelength range. 5. The method according to p. 1, characterized in that as the signal of the emitter-initiator use an encoded signal with amplitude modulation by a sequence of pulses. 6. The method according to p. 1, characterized in that the signal duration of the emitter-initiator corresponds to the duration of the video frame. 7. The method according to p. 1, characterized in that the processing of video information from the cameras is carried out on a computer complex located in the control point for the actions of underwater objects outside the controlled water volume. 8. A positioning system for a group of underwater objects in a limited water volume, containing in the control point a computer complex with a program for identifying objects, calculating and displaying coordinates and motion parameters of objects on a display device, installed at remote points of a video camera for receiving signals from optical beacons that are equipped with objects groups, characterized in that it contains a synchronizer, four cameras that operate in single-frame synchronization mode and are located at the ends of the of perpendicular axial lines of the horizontal section of the controlled water volume, at least one initiator emitter, which is configured to emit in the optical wavelength range of the signal, the duration of which is equal to the duration of the video frame Δt, the repetition period is T = Δt * (N + 1), where N is the number of objects in the group, and the beginning of the radiation is synchronized with the pulses of the frame synchronization of the cameras, the optical beacons are configured to receive the signal from the initiator emitter and the signal from the optical the wavelength range in the preset video frame number for each object, while the separate outputs of the synchronizer are connected to the synchronization inputs of the cameras and the emitter-initiator, the signal outputs of the cameras are connected to the separate inputs of the computing complex, the separate outputs of which are connected to the input of the display device and the input of the synchronizer, and the number optical beacons and their location on the underwater object are selected from the condition of providing continuous monitoring of at least two cameras . 9. The system according to p. 8, characterized in that the number of emitters-initiators is chosen equal to four and install them in the locations of the cameras. 10. The system according to p. 8, characterized in that the optical beacon emits signals in the near ultraviolet and / or in the near infrared wavelength range. 11. The system according to p. 8, characterized in that the emitter-initiator emits signals in the near infrared wavelength range. 12. The system according to p. 8, characterized in that as the signal of the emitter-initiator use an encoded signal with amplitude modulation by a sequence of pulses. 13. The system according to p. 8, characterized in that the signal duration of the emitter-initiator corresponds to the duration of the video frame. 14. The system according to p. 8, characterized in that the computing system, synchronizer and display device are located in the control point for the action of underwater objects outside the controlled water volume.

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