RU2827904C2 - Optical video surveillance system - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to optical video surveillance systems presented in the form of multi-sensor video surveillance devices with the possibility of adjusting the angle of inclination and rotation of each sensor module in the device. Disclosed optical video surveillance system is a support platform with sensor modules, each of which includes a lens and a light-sensitive matrix. Lens with a photosensitive matrix is mounted on a detachable holder which is fixed to the support platform; at that, each holder interacts with at least three micrometric screws, each of which is driven by a micromotor.

EFFECT: creation of a universal flexible video surveillance system providing high-quality panoramic images.

5 cl, 5 dwg

Description

The invention relates to optical video surveillance systems presented in the form of multi-sensor video surveillance devices with the ability to adjust the angle of inclination and rotation of each sensor module in the device.

An optical video surveillance system is a device made in the form of a block with placed sensor modules, each of which includes a lens and a light-sensitive matrix, made with the ability to change their position, and is intended for video surveillance of the controlled territory. All elements are placed on a support platform and represent units connected to each other by assembly operations and are in functional unity.

Based on the provided explanation, it is obvious to a specialist in this field of technology that the claimed optical system consists of structural elements that are assembly units connected to each other by assembly operations (for example, using screws, bolts, pins, soldering, etc.), are made in a single housing and have functional and structural unity.

The expansion of the scope of application of video surveillance systems is due to the need to organize visual control over situations occurring on the territory of transport (bus stations, railway stations, airports, metro, public transport), shopping and entertainment (shopping and entertainment centers), cultural (museums, theaters, exhibitions) and industrial (including specially protected, secret and dangerous industries) facilities in order to identify and promptly prevent offenses, dangerous, abnormal situations, and, as a result, ensure the safety of people (staff, visitors) and property located on the territory of the protected facility.

In connection with this fact, manufacturers of video surveillance systems are faced with the task of developing technical solutions aimed at increasing the viewing angle of video cameras while obtaining high-quality images to enable effective monitoring of large controlled areas.

The following technical solutions are known from this field of technology.

A television camera is known (patent RU 67803), including a holder adjacent to a flange, made in the form of a hollow cup, in the head part of which a rigid stop is made, repeating the shape of the surface of the body of the television camera, made in the form of a ball, fixed in a holder with an outward protrusion, inside which a lens and a CCD matrix are placed, located in the focal plane of the lens, characterized in that a retaining flange is introduced, placed on the holder and an element fixing the position of the body of the television camera, placed between the inner side of the holder and the body of the television camera, wherein the holder, in the head part of which a recess is made, is connected to the flange by means of a retaining flange and clamping screws.

A video camera is known (patent RU 2336656), which contains an image sensor module, a corresponding lens, in particular a wide-angle lens, and a holder. The lens has a thread, by which it is screwed by means of the holder and an elastic intermediate part to the mating thread of the image sensor module in such a way that the threaded connection performs a double function, namely the function of fastening the image sensor module to the holder by means of the lens and the focusing function due to changing the optical distance between the image sensor module and the lens. The lens with its thread can pass through the through holes of the holder and the elastic intermediate part, located between the lens and the holder and made in the form of an elastic ring. Using a rotary element, it is possible to adjust different directions of viewing of the image sensor module.

The presented technical solutions are characterized by the fact that they are not intended for use at facilities where it is necessary to conduct video monitoring of fairly large areas with detailing of individual fragments of the scene due to the limited viewing area provided by video cameras.

A panoramic imaging system is known (US2020195845 (A1)), which includes a central camera, first and second side cameras arranged to obtain an image of a scene in different directions relative to the axis of rotation, wherein the first and second side cameras are arranged on opposite sides of the central camera.

The central camera, the first side camera and the second side camera have a visualization system including a lens and an image sensor; a tilt mechanism allowing the movable panoramic imaging system to tilt around the rotation axis, and an image processing unit including a stitching function configured to stitch images taken by the central camera, the first side camera and the second side camera to form a panoramic image of the scene, wherein the panoramic image has a virtual horizon so that when the movable panoramic imaging system is tilted, the position of the virtual horizon of the panoramic image in the scene is maintained.

In this case, the visualization systems of the first and second side cameras have a larger field of view in the direction perpendicular to the axis of rotation than the visualization system of the central camera.

The disadvantage of this system is that when monitoring a large area, it is not possible to obtain a detailed image of the scene fragment of interest in good quality.

The closest analogue is the product of the German company Dallmeyer, which supplies the world market with the Panomera multifocal matrix video camera under patent DE102011103378 (B3).

This surveillance device includes several cameras, each of which has a plurality of image sensors, which are designed in such a way that they always scan different areas of the surveillance zone with a variable range of the object in the object space and create image data of a sequence of images in a video stream.

In this case, each camera has a control unit, which is designed in such a way that it performs the transmission of image data from image sensors to the network, a control device, which is designed in such a way that it creates a video stream, composed of image data from image sensors, and/or at least a separate area thereof for presentation on a display device or at least in one of its variable-size windows, and an input unit, which is designed in such a way that with its help the area of the observation zone intended for display can be set, as well as, if necessary, the position and size of said at least one window.

Each image sensor is equipped with optics in such a way that at any given time and regardless of the distance of the object, a resolution homogenized across the entire field of view of the image sensors is ensured.

The disadvantage of the Panomera video surveillance device is that the sensor modules are fixed without the ability to change the angle of inclination, which does not allow each sensor module to be directed to a more convenient position, thereby limiting the viewing angle and the capabilities of the video camera in terms of covering the area of interest and obtaining a high-quality image.

The claimed technical solution is a development of the design of an optical video surveillance system according to Russian patent No. 208789, developed by one author.

The task, which the claimed utility model is aimed at solving, is the creation of an optical system that allows for covering a significant area of stage coverage, preventing the occurrence of "dead zones", thereby expanding the viewing angle, while achieving high image quality due to the fact that the sensor modules from the system, including a lens and a light-sensitive matrix, are installed on a holder that allows for adjusting the tilt angle along the vertical and horizontal axes, and containing a movable element designed with the possibility of rotating the sensor module around the horizontal axis.

The technical result is the creation of a universal flexible video surveillance system that provides high-quality panoramic images due to the ability to change the focal length (achieved by rotating the sensor module to determine the position of the rectangular photosensitive matrix, which allows for each module to change the image format from 16:9 to 9:16, or from 4:3 to 3:4), due to the ability to change (expand) the viewing angle of each sensor module, due to the ability to change the lens and photosensitive matrix (achieved by using a removable frame on which the sensor module is installed), due to gluing images from each sensor module into a single panoramic image (due to the ability to change the viewing angle of each sensor module).

The proposed system is a varifocal polyoptic video surveillance system, providing a change in focal length for filming objects, in the case of their location at different distances from the camera.

The technical result is achieved by means of an optical video surveillance system, which is a support platform with sensor modules, each of which includes a lens and a light-sensitive matrix. In this case, the lens with the light-sensitive matrix is installed on a removable frame, which is fixed to the support platform, and each frame interacts with at least three micrometer screws, each of which is driven into rotation by a micromotor.

In a preferred embodiment of the invention, the frame includes an element rotating around a horizontal axis, to which a lens with a light-sensitive matrix is attached.

In another preferred embodiment, the frame is secured to the support platform using tension springs.

In another embodiment of the invention, a groove is added to the frame for fixing the rotating element using set screws with a spring-loaded ball.

In this case, the micromotors are connected via cables to the controller, which provides them with power, feedback and control - sending commands for the number of revolutions and selecting the shaft position.

The placement of each sensor module on a rotating element, which is mounted on a support that can change the angle along the x and y axes using micrometer screws, allows the angle of inclination of each sensor module to be adjusted, thereby changing its direction, ensuring simultaneous coverage of various areas of interest, which leads to an expansion of the area of the controlled zone, and as a result, an expansion of the viewing angle of the video surveillance camera is ensured.

The alternative implementation of the declared optical video surveillance system with the placement of a movable frame rotating around a horizontal axis on a movable support platform for attaching a sensor module allows for the rotation of the light-sensitive matrix depending on the geometry of the zone and the horizon, which also leads to an expansion of the viewing angle of the video surveillance cameras.

In the preferred embodiment of the proposed device, the lens from the sensor module is varifocal. This ensures a change in focal length for shooting objects in the event of their location at different distances from the camera, which makes it possible to obtain both a general panorama and a detailed increase in the desired fragment of the overall picture while achieving high image quality, without reducing detail when scaling.

Thus, the use of a varifocal lens as part of a sensor module also allows for an increase in the viewing angle of a CCTV camera.

The declared optical video surveillance system will be described below using links to drawings:

Fig. 1 - A variant of the proposed optical video surveillance system in the form of an eight-module camera.

Fig. 2 - Rear view of the optical system.

Fig. 3 - View of the sensor module on the frame.

Fig. 4 - Side view of the sensor module.

Fig. 5 - Image of a frame with a rotating element and a locking element in the form of a spring-loaded ball.

Which depict:

1 - Sensor matrix (light-sensitive element)

2 - Base plate

3 - Frame

4 - Micromotor (drive)

5 - Rotating element

6 - Extension spring

7 - Micrometer screw.

The optical video surveillance system, in its preferred embodiment (Fig. 1), contains several sensor modules, each of which includes a lens (1) and a light-sensitive matrix.

The preferred option is a varifocal lens, for example, Theia TL410 R6 from the American company Theia Technologies.

The optical video surveillance system consists of a base plate on which eight frames are installed. Each frame has a rotating element for mounting the sensor module and its rotation.

The frames are connected to the base plate using tension springs.

On the back side of the base plate, three micrometer screws with micromotors are installed on each frame. The micrometer screw with the micromotor provides linear movements of the movable support plate on which the sensor modules are installed, as well as angle adjustment.

The frame has a groove added for fixing the rotating element using two set screws with a spring-loaded ball, which allows not only fixing, but also rotating the element together with the lens. The edges of the base plate can be curved, which allows the outer modules to have a larger angle of deviation.

The optical video surveillance system consists of a base plate (2) on which eight removable frames (3) are installed. Each frame has a rotating element (5) for attaching a sensor matrix (1) and a lens.

The frames (3) are connected to the base plate through a mandrel using 4 tension springs (6).

The frame, rotating element, sensor matrix, lens and light-sensitive element (CMO, CCD sensor matrix) constitute the sensor module.

The number of such modules can vary depending on the width of the observed scene and the choice of the appropriate plate.

The base plate can be either flat or curved. The use of a curved, parabolic shape allows for a single collecting group axis of panoramic image from several optical devices.

The device can use optical devices - lenses with both fixed focal length and varifocal lenses with variable focal length, which can be changed either by manual manipulation or by means of micromotor drives included with the lens used.

The frame is parallel to the base plate in the initial position, and the optical instruments and their optical axis are perpendicular.

Element (5) is a cylinder that rotates inside the frame to determine the position of the rectangular photosensitive matrix, which allows for each module to change the image format from 16:9 to 9:16, or from 4:3 to 3:4.

Rotation can be performed either manually or using an electric motor.

Element (5) has a groove for fixing the frame. The frame is fixed by two mounting screws, at the ends of which a spring-loaded ball is installed. The screw ball enters the groove on element 5, thus fixing the adapter. This method of fastening allows not only to fix the frame, but also to rotate it together with the lens.

The level of screwing in the ball screw determines the speed and force applied to rotate the adapter in the frame.

Frame 3 is made removable for each pair of lenses and sensors individually, which allows to minimize costs and use different lenses with different types of threads, choose different BFL focal lengths, different types of matrices, and provide a flexible and fast approach that does not require changing the entire design of the device.

On the reverse side of the base plate, three micrometer screws (7) with a micromotor are installed on each frame.

A micrometer screw with a micromotor provides linear movements of the movable frame - the support plate on which the modules are installed. The micrometer screw is a hollow cylinder, inside which there is an additional adapter sleeve, which is put on/put on the motor shaft with a chamfer. At the moment of rotation, the screw is telescopically pulled out of the base plate in the direction of the spring-loaded frame and performs its deflection, and the deflection of the optical axis of the lens.

On the base plate for each module there are three threaded holes m6, where three micrometer screws are screwed in, at the end of which there is a hole, balls with a diameter of 4 mm are placed in these holes, on the frame there are 3 corresponding places for balls - a hole, a plane, a groove, which ensures the principle of precise positioning and adjustment of the modules of the polyoptic system. Then these three balls are clamped between the frame and the base plate by springs. With the help of 4 springs, the mutual arrangement of the base plate and the frame, and the balls between them is fixed. In case of rotation of one of the 3 screws, thereby the corresponding side of the frame is moved away and between the planes of the frame and the base plate there is a corresponding spatial angle.

Due to the use of springs that attract the frame to the base plate and a counter-spring screw with a micrometer thread, which, due to the translational movement, counteracts the spring, and thereby ensures changes in the angle (adjustment) of the frame deviation in relation to the base plate, and, consequently, changes the position of the entire module and the axis of the optical system.

The rotation of the screws can be done either manually or with the help of a drive.

The use of three such micrometer screws allows you to set the direction of the axis of the optical system horizontally and vertically, to the required viewing angle of each module - module adjustment.

The device can use various motors. The type of stepper micromotors and the model are not considered in this invention, but are used as a means of converting electrical energy into mechanical energy, allowing for remote (without the presence of a person directly nearby) adjustment of modules, without resorting to the use of a manual key to rotate the screw.

The motors are connected via cables to a controller with a microprogram that provides power to the motors, feedback, and their step control, sending commands for the number of revolutions and selecting the shaft position.

Thus, the controller allows you to control not only the position of the modules, but also the focal length of the module lenses, which allows you to change the viewing angle of both an individual module and the entire group.

The controller provides control of engines in different modes:

• each engine separately by the operator

• a group of engines according to a given algorithm automatically

• set a pre-selected preset for a group of engines (set the appropriate step)

• a group of engines automatically, based on feedback that can be obtained from:

• geomap, by selecting the location of the device on the map and the direction of the lens axis to a given point where the modules need to be directed

• geomaps, by setting the operator's corresponding viewing angle on the map

• geomaps, with the operator setting the required pixel density or the size of the minimum distinguishable detail (for example, 125 pixels per meter or 8 mm per pixel, which ensures recognition of text and numbers at a distance)

• photography or another video camera by searching for identical elements of the observed scene

• the settings set for one of the modules, for example one module provides a viewing angle of 90 degrees, while the other modules evenly fill its view with areas with narrower viewing angles, but with greater detail.

The main task of the device is to obtain a more detailed image or with a greater depth of field, with the same viewing angle, when compared with a video camera with one lens and a sensor matrix.

The use of a remote control controller for each drive eliminates the need to open the housing to re-align the model.

Possibility of automatic angle setting for each module, depending on:

• from the focal length of the lens;

• the required total angle of the entire lens group;

• the required increase in spatial observation (pixel per meter).

The ability to combine (stitch, glue) images into a panorama of different formats, using various algorithms:

• a detailed image is constructed on the basis of software assignment of one pixel of a general image module to a group of pixels of detailed modules;

• search for common pixels between adjacent detailed images;

• image alignment or without alignment, with or without border masking, with or without auto contrast and auto brightness.

Automatic selection of the angle using an interactive geomap, indicating the location of the camera, the distance to the target, the task of detailing and the required viewing width.

The ability to combine (stitch, glue) images into a panorama of different formats, using various algorithms:

• a detailed image is built on the basis of a general one;

• one pixel of the general image corresponds to a group of detail pixels;

• search for common pixels between adjacent detailed images;

• image alignment or without alignment, with or without border masking, with or without auto contrast and auto brightness.

The ability to use different sensors from different manufacturers is possible due to a separate element - a removable support.

The ability to use different lenses with different types of fastenings ensures the flexibility of the system and its adaptability.

In this case, the maximum rotation angle of the movable frame with the lens and light-sensitive matrix placed on it is 92°, which is due to the limitations on the length of the sensor module wire and their distance relative to each other.

The proposed CCTV camera functions as follows.

The CCTV camera unit is installed in the protected area, and the installation is carried out in a selected location depending on the specifics of the object. The initial position of the lens is the position when the longitudinal axis of the lens is perpendicular to the surface of the support platform. The light-sensitive matrix, in the priority version, wide-format, is deployed depending on the geometry of the observed area and the horizon using a movable frame around the horizontal axis, while the maximum rotation angle is 92° due to the restrictions imposed on the length of the sensor module wire and the distance of the modules relative to each other when they are placed on the support platform.

The screws are used to adjust the direction angle of each sensor module along the horizontal and vertical axes.

The mechanism directs each sensor module to its area of responsibility of the scene, which is selected by the operator or can be planned in advance, and is carried out programmatically, providing the required overall viewing angle for the optical system.

It is important to note that the tilt and rotation angle of each sensor module, as well as the focal length of the lens, are calculated based on a given overall viewing angle by means of a controller, which in turn controls the actuators that drive the elements of each sensor module.

Claims (5)

1. An optical video surveillance system, which is a support platform with sensor modules, each of which includes a lens and a light-sensitive matrix, characterized in that the lens with the light-sensitive matrix is mounted on a removable frame, which is suspended from the support platform, while each frame interacts with at least three micrometer screws, each of which is driven into rotation by a micromotor. 2. An optical video surveillance system according to paragraph 1, characterized in that the frame includes an element rotating around a horizontal axis, to which a lens with a light-sensitive matrix is fixed. 3. An optical video surveillance system according to paragraph 1, characterized in that the frame is fixed to the support platform using tension springs. 4. An optical video surveillance system according to paragraph 1, characterized in that a groove is added to the frame for fixing the rotating element using two set screws with a spring-loaded ball. 5. An optical video surveillance system according to paragraph 1, characterized in that the micromotors are connected via cables to a controller that provides them with power, feedback and control - sending commands for the number of revolutions and selection of the shaft position.