Remote control of PTZ cameras. PTZ camera control, mobile control PTZ camera control via network

I.V. Oleinik
CEO of DSSL

This review is devoted to ways to control high-speed PTZ integrated cameras SpeedDome.

The consumption of high-speed PTZ cameras has grown dramatically in the market over the past 10 years. Affected by a significant reduction in the price of these devices, as well as their growth technical capabilities: speed, optical magnification, functionality. Now the normal rotation speed during the installation of the "preset" reaches (often exceeds) 400 degrees / s, the optical magnification has long exceeded the 30-fold value, and some cameras even got the opportunity to track objects in their field of view on their own. Modern prices for "domes" range from $ 500 to $ 600 for Chinese brands to several thousand euros for well-known Japanese, American or European brands. Unlike individual rotary mechanisms, where control is carried out by its own pair for each degree of freedom (mainly with an alternating voltage of 24 or 220 V), a telemetry receiver is integrated into the SpeedDome, which allows you to control the camera using just two wires (in the case of RS-485; some models require 4 wires for full duplex control) or over a video cable. And the SpeedDome IP video cameras do not require additional control wires at all, although they usually have the ability to work "the old fashioned way".

Controllers and Keyboards

The simplest and most "ancient" way to control a Speed ​​Dome-camera is using a keyboard, as well as a separate stand-alone device with its own power supply. The lowest cost keyboard will control pan and zoom using buttons and RS-485 protocol only. Buttons are quite enough when you just need to set up cameras and then control, for example, presets. But if the operator needs to constantly control the cameras, the remote control will greatly slow down his work. For such cases, a remote control with a joystick will be much more convenient - it allows you to control the camera in two coordinates at once, focal length lens, as well as the speed of rotation with one movement of the hand. The higher the cost of the keyboard, the more additional features it has (for example, controlling video recorders, displaying signals from video cameras and recorders on the built-in TFT monitor). Working with DVRs is limited only by the fact that they must be produced by the same company as the keyboard; there are no such problems with controlling video cameras - usually remotes support several protocols, which means that you can control cameras from different manufacturers... With the advent of IP video cameras, the question of remote controllers for them arose. Of course, almost all PTZ IP cameras have the ability to control via RS-485, but dragging additional wires when there is already a digital network with high bandwidth is pointless. The only drawback of an Ethernet network based on copper UTP, which is the basis for 99% of IP video systems, compared to an analog one, is the small segment length from the device to the switch (about a hundred meters if you do not use optics).

PTZ camera capabilities

Two things can be said here. First, some camcorders have built-in advanced controls. A properly configured video camera constantly monitors with a maximum viewing angle. When the built-in detector detects movement, the camera zooms in on the area and "guides" the moving object as far as possible. At the moment of such tracking, the camera "does not see" the surrounding environment and cannot switch to another object without returning to its original position with a minimum zoom. Of course, not all cameras even have a built-in motion detector, let alone automatic tracking.

The second concerns only IP video cameras. It has already been said above that the Speed ​​Dome IP camera can be controlled using either a regular remote control or an IP remote control. However, IP PTZ cameras are in some sense self-contained devices and have a Web server on board. Logging in from any computer through a web browser, you can get an image from the camera, configure its parameters and control the rotary mechanism and lens. It offers 2 methods - a simple one that imitates the buttons on the control panel and allows you to simultaneously control two coordinates, and an advanced one that differs for each manufacturer in detail. Here you control rotation and zoom using your computer mouse. By drawing a rectangle in any part of the camera window, you will force it to zoom in on this area, or by moving the cursor to the edge of the image, you will receive an arrow hint; which you can move the camera in the desired direction (at the left edge - to the left, at the right - to the right, and so on).

DVR control non-PC

PTZ camera control has long been an integral basic function of DVRs. Only very cheap and very limited functional DVRs can afford it. Cameras with non-PC DVRs are controlled in 99% of cases using the RS-485 interface. Some newer hybrid DVRs, which can work with both analog and IP cameras, may support control over IP. According to the control method, all DVRs can be divided into 3 types: controllers using the DVR's keyboard (from the front panel), controlling only the mouse (for DVRs where there is no keyboard) and DVRs that support both options. The first option is acceptable only for those who very rarely use manual control of PTZ cameras (cameras are configured to bypass "presets" or "tours" in automatic mode). In most cases, using the front panel of a video recorder to control a PTZ camera is a real torment, since you have to work exclusively with buttons in a limited number: no 3D joysticks. Mouse control can also vary greatly. A simple option is an imitation of the same limited set of buttons from the front panel, it is not much more convenient. Other DVRs can use approximately the same mechanism that is described in the previous section and is presented mainly for IP video cameras. Of course, you will have to configure everything using the same buttons or the on-screen menu, but this is the only option for all recorders. Total: the mouse is good, the keyboard is not very good. The good news is that there are more and more mouse-controlled recorders, but the latter's internal software can vary greatly.

The control methods listed above have one common drawback. Any Speed ​​Dome camera has 2 control speeds. Control speed in manual mode usually does not exceed even half the speed of camera rotation at the time of using the presets. At the same time, it is obvious that the higher the speed of such manual control, the less accuracy, accuracy of positioning the camera on the area or object of interest. It can be noted here that the camera is not used to all 100% of the possibilities it has, and the efficiency of its use could be higher. New computer interfaces and developments are called upon to cope with this task.

Software (PC-based DVR)

DVRs always outperform non-PCs in terms of capabilities. Firstly, new technologies, especially resource-intensive and complex ones, are easier to develop and debug on computers, and secondly, competition with DVRs based on embedded processors forces the same developers to constantly add new functions and capabilities, make their software more flexible and powerful. ... So what new do the developers of programs for video registration and control of PTZ cameras offer us? If we discard the variations associated with the interactivity of controls directly on the image, or the imitation of a 2D joystick, then we can separately distinguish 3 categories of new products (interfaces). The first is to add the ability to automatically control those cameras that do not have it initially, that is, control the camera using a motion detector in the software. Such detectors can be more powerful and advanced than those built into cameras. The second and third are associated with the use of at least one more video camera (overview), the field of view of which fully or partially coincides with the rotary one at the minimum value of the focal length.

Manual control

In this mode, the combination of the overview and PTZ cameras allows the operator to control the PTZ camera with one click of the mouse or, by highlighting a rectangular section of the image with the overview one, to get it optically enlarged using the PTZ camera. At the same time, 2 drawbacks of the interfaces described above disappear at once, control is carried out at a speed1 that is maximum available for a video camera (usually declared as the speed of positioning by presets), and the operator does not lose sight of the protected area - he sees the whole situation as a whole and its details with maximum optical zoom, so it can point the camera from one position to another as quickly as it could not with traditional interfaces.

The fact that the Speed ​​Dome camera does not need to return to the survey position in order to select a new object also plays a role in the control speed, and this, as already noted, is the slowest part of positioning. When the camera is positioned without much zooming (almost without using the zoom), the speed increases significantly.

Automatic control

This refers to the same combination of overview and PTZ cameras. The motion detector analyzes the image from the overview camera and issues commands for the PTZ camera - now the control is fully automatic. Systems of this kind appeared many years ago, however, then they worked according to presets - each square of the overview camera image was assigned its own position, and as we remember, the Speed ​​Dome can have up to 256 presets. However, now developers are using the capabilities of not only modern detectors, but also video cameras. The detectors are smart enough to transmit not just the coordinates of the object, but also the vector of its movement, since while the camera is turning towards the object, it may already be displaced. And cameras have the ability not only to work with presets, but also to execute direct commands for setting along certain coordinates; they are also fast enough. It should only be noted that not all Speed ​​Dome cameras, even from the middle price range, will support these functions. Do not expect that the Chinese noname will be as fast and will have a fully implemented protocol, especially a borrowed one. If several objects appear in the field of view of the overview camera, the PTZ will switch between them, following each one for a set time. Today, some developers supply systems where simultaneous control of several Speed ​​Dome cameras is possible, and almost unlimited combinations of panoramic and PTZ cameras, when you can have a live picture of what is happening in 360 ° around, while providing high resolution and detail of moving objects. It would seem that with an increase in resolution, when there are already digital video cameras with 5, 8 Mpx and more, the need for such a solution is not so high. But the optical zoom is still difficult to replace, and a combination of overview and PTZ cameras using, for example, 35x magnification gives the equivalent of a system resolution of more than 300 Mpx - digital cameras will not be able to achieve the same result soon. Again, the use of megapixel overview and PTZ cameras will always push this barrier forward. Of course, this system also has disadvantages. First, as mentioned, not all PTZ cameras are compatible, and not all of them are fast enough to track objects moving at high angular velocity. Secondly, the system increases in price (however, the cost is worth it - as well as any increase in functionality that increases the safety of the facility or your enterprise). Thirdly, the system requires calibration - setting the correspondence between the coordinates of the overview and PTZ cameras (although there are positive shifts here - for some cameras it is required to set only 9 anchor points, and the rest will be calculated by the system itself).

It can be noted in which direction the development of the technology of manual and automatic control should be expected:

• the transition to megapixel overview and PTZ cameras and the pursuit of more high definition;
• building panoramic images made up of pictures received from a variety of survey cameras, which also contain images of PTZ cameras. Thus, a single interactive scene of an object or its section is created. However, it will be incomplete without the ability to reproduce the archive in the same form (although this can be a serious load on the server);
• improved performance of motion detectors. New technologies for tracing, scene and object recognition, improving the quality of tracing at night.

Of course, you shouldn't rely entirely on the capabilities of the detectors. Don't skimp on video cameras, hoping that the detector will cope with both noise and low-resolution images. The general rule of thumb for any security system is that a system will be as bad as its smallest component. A cheap lens attached to an expensive camera, a cable with a poor quality connector, or any other component can take all your costs away.

Glossary

Speed ​​Dome is a high-speed PTZ dome camera. Fast compared to conventional slewing gears. Dome, since more than 90% of such cameras are designed in the form of a cylinder with a domed optically transparent casing that protects the optics and the mechanism from dust and moisture. Speed ​​Dome cameras are also called integrated cameras, meaning that all the necessary components are assembled in one body: the video camera itself, optics, a two-coordinate mechanism and a telemetry receiver.

Preset - the ability of the Speed ​​Dome to be set to a preprogrammed position at the maximum available speed. Various modifications can memorize from 32 to 256 presets.

Tours - The ability of a PTZ video camera to execute a series of commands, such as a sequence of presets. The extended version assumes that the camera memorizes your actions with subsequent cyclic execution. Protocol is a set of commands for controlling PTZ cameras using a telemetry receiver. Usually large manufacturers use their own protocol, but they also necessarily integrate additional ones such as Pelco, which has become the de facto standard due to the openness of the manufacturer's policy. Small manufacturers use only such open protocols and implement (depending on their laziness or camera capabilities) only a part of the commands. PTZ is an abbreviation for Pan, Tilt and Zoom, respectively, the rotation of the horizontal, vertical and lens control. PTZ-camera - respectively an integrated camera with a rotary mechanism and a zoom-lens.

When organizing surveillance inside a sufficiently large object, monitoring the adjacent territory, there is always the task of tracking penetration or monitoring what is happening over a large area.

The solution may be to install multiple cameras. However, such a step will entail an increase in the cost of the system and the need to monitor and record many video streams. A PTZ camera looks much more attractive for a large area monitoring solution.

How PTZ Cameras Work

PTZ is a technically complex device that implements several mechanics at once, which are necessary for tracking objects over a large area.

A short list of structural components can be described as follows:

1. a recorder consisting of a photosensitive element and a primary signal processing system;
2. an optics system equipped with servo drives for focusing;
3. a rotary unit that rotates the recorder in the horizontal plane;
4. a servo drive that tilts the recorder vertically;
5. secondary signal processing system;
6. a structure that is responsible for the formation of the final video stream, which implements a signal response, which processes control impulses.

Speaking in simple words, PTZ cameras on a control signal can aim at a specified point, focus (including automatic) to form a clear image, at the request of the operator or head unit, zoom (zoom, including digital).

Modern models offer much more. For example, the built-in PTZ control of CCTV cameras can include reacting and fixing the view on a moving object, following the perimeter intruder, determining the range for further adjusting the clarity of the picture.

Design features and technical characteristics of cameras

The choice of the model should be made from the standpoint of the future conditions of its operation. There are several types of cameras on the market today.

Although the main list of structurally significant nodes is the same for them, the devices differ in a number of parameters.

• Robotic cameras. This class of devices is not widespread, since it is considered morally obsolete. This is a kind of hybrid of the average outdoor camera mounted on a positioning system. The devices offer (in most cases) neither automated focusing nor intelligent event-driven control.
• The PTZ camera is designed for indoor use. This segment of models is distinguished by the maximum openness of the design and low protection against moisture and dust. It is recommended to operate such devices at temperatures from 0 to 55 degrees Celsius.
• Dome for indoor installation - such a Ptz camera is notable for its low protection of the structure from moisture and dirt penetration, it can operate at temperatures of 0-55 degrees. It differs from rotary in high aesthetics and slightly reduced need for maintenance.
• dome products with the general name Speed ​​Dome are distinguished by high protection against moisture and dust, and thanks to the installed dome, they are also vandal-proof. Such a camera can operate at temperatures ranging from -50 to 60 degrees Celsius.

The pinnacle of technological excellence is outdoor PTZ dome cameras. They are distinguished by their high-speed drive, powerful, intelligent automated control and response technologies.

In this segment of devices, you can find a model that can solve almost any problem. For example, allowing the connection of external sensors (, water, gas) for event response and focusing on the problem area for monitoring. The outdoor dome camera can operate at temperatures ranging from -40 to 60 degrees, and is protected from water, dust, vandals.

To others design features individual products may include equipment for additional functions.

For example:

1. for recording audio;
2. speaker for two-way dialogue;
3. switchable IR cut filter for a good picture day and night;
4. panoramic view system (drive that continuously rotates the camera 360 degrees);
5. memory card connection port;
6. wireless (or over the networks of mobile providers) communication unit;
7. heating and temperature control system.

Depending on the tasks facing video surveillance, you can opt for a particular model with the required level of reliability, protection and functionality.

Setting up and preparing for work

Setting up a camera is not only setting parameters for working with it in a DVR or other head unit.

A PTZ camera will only show its full potential when:

• the installation site is optimally chosen, without blind spots, with a field of view, implying minimum periods of time for turning the tracking device;
• vibration protection is undertaken, easy access for damage;
• monitored minimum opportunity direct sunlight hitting the observation dome, which can both cause overheating and affect the picture (cause flare).

The software setting of the camera depends on the type of head unit, but in general terms it can be described as follows:

1. channel selection;
2. setting up all broadcast channels (levels of program compensation, brightness-saturation and others);
3. selection of one of the supported control protocols;
4. setting the parameters of the video stream (speed, and hence the degree of loading of the data channel);
5. configuring the stop bit scheme that is used to split the stream;
6. selection of data error correction protocol;
7. filling in the time diagram (intervals of movement, angles of inclination - the formation of a complete map of the territory overview).

The required items for setting up a PTZ camera include setting the IP address for digital devices. Also, it is easy to buy models on the market today that offer support for standard authorization protocols, equipped with their own wireless transmitters.

For such devices, you may need to specify the name of the access point to register with. To carry out the correct setting, it is recommended to follow the manufacturer's instructions.

Advantages and disadvantages

PTZ surveillance cameras should be evaluated comprehensively, in relation to the task for which they can be used.

In some cases, the disadvantages of devices of this class do not play any role, the advantages come to the first position.

Likewise, if you pay attention only to the pros and not fully use the offered possibilities, the minuses can negate the whole usefulness of the PTZ video surveillance system.

Cameras of this class have the following advantages:

• significant viewing angle, up to panoramic and volumetric (360 horizontally and close to 90 vertically);
• scalability, along with optical zoom optics with a servo, most models offer digital zoom;
• the ability to set a schedule, a time chart, which includes both moving the viewpoint and changing the zoom and focus;
• fully robotic control that allows you to set clear goals, the rest (moving, focusing, switching modes) - will be done by smart built-in control of ptz CCTV cameras;
• the ability to implement different schemes of reaction to events.

With the correct design of the surveillance system - PTZ devices are able to show cost savings by replacing several stationary models at once.

However, such technical means have disadvantages:

1. price. The cost of a PTZ camera, equal in terms of its characteristics, is several times higher than that of a similar IP-class device;
2. service. Due to the complexity of the technical implementation, the large number of moving parts, the failure rate and wear of the PTZ system components is quite high. Cameras require periodic service, inspection, preventive maintenance;
3. low rates of standardization. Each PTZ manufacturer offers its own software that is not compatible with competitors' products. Therefore, it is difficult or impossible to build an optimal structure using cameras from different brands.

The disadvantages of robotic cameras are clear and quite expected. Therefore, with the correct design of video surveillance systems and a sober assessment of the possibilities, they do not play an important role.

Conclusion

Robotic PTZ cameras have recently been an expensive luxury.

However, thanks to technological progress, many design solutions have shown a sharp decline in prices and, as a result, smart, automatic devices have become available to the average mass consumer.

With the correct design of a video surveillance system, PTZ cameras are able to realize their full positive potential.

Video: Configuring a PTZ CCTV Camera

An alternative to fixed cameras are pan / tilt / zoom cameras (otherwise known as PTZ cameras), named for their ability to pan left and right, tilt up and down, and zoom in. PTZ cameras accomplish this through a unique combination of pan, tilt, and zoom lens controls. The overall zoom capability of a PTZ camera is the sum of the digital and optical zoom values. Digital zoom uses electronics to zoom in and out, while optical zoom uses lens movement. The total value of the closeness of the video camera can be calculated by multiplying the value of the digital and optical zoom... Camcorders require a keyboard and signal receiver to provide pan, tilt, and zoom capabilities. However, most PTZ dome cameras come with a built-in receiver.

Types of PTZ cameras

PTZ cameras are available for outdoor and indoor use, which adds to their versatility. Outdoor PTZ cameras have a rugged housing that is resistant to harsh weather conditions and are more reliable than indoor cameras. The reason for this is that they have to move a heavy case, sometimes equipped with IR illuminators. PTZ cameras for indoor use are often made with plastic housings and are therefore lighter.

One of the most recent evolutions of PTZ cameras is the popular PTZ dome camera. Dome cameras work in the same way as traditional PTZ cameras, but differ in that the pan / tilt device and control electronics are located inside the dome. The range of domes is extremely varied, from transparent or translucent to opaque, making them suitable even for special applications. PTZ dome cameras have several advantages over traditional PTZ cameras. The dome can move effectively in all directions, including 360 degrees for straight down viewing. Dome cameras have an Auto-Flip feature for viewing directly below it: when, upon reaching the mechanical stop, the camera unit automatically rotates 360 ° and continues in the direction selected by the operator.

PTZ Camera Features

In most PTZ cameras, algorithms can be created to automatically track from a given position along a specific route to continuously survey these areas. The number of preset positions varies depending on the make and model of the camera, but on average from 8 to 32. The ability of a camera to accurately return to a preset position differs depending on the mechanics, electronics and software... In addition to presetting positions, PTZ cameras can be configured so that they only act in case of specific changes in the monitored area, for example, noise, movement. This is possible with the help of motion detectors built into the video camera or integrated with it. Thus, the recording process can be minimized and only for the most important events.

In addition, PTZ IP cameras can provide access to video information and camera control from anywhere in the world thanks to the ability to assign an IP address.

Another feature common to PTZ cameras is the ability to mask. This allows you to mask some areas in the camera's field of view, such as a window or door of one of the houses. The position of the mask can be interconnected with the movement of the camera so that when the camera is tilted or scaled, the mask moves and resizes accordingly. This allows the user to avoid litigation for breach of privacy and invasion of privacy.

Photos before and after masking

Translation by Hi-Tech Security.

The Line video surveillance system controls PTZ cameras using an RS-485 interface converter. IP PTZ cameras are controlled by the system via Ethernet interface. Maybe sharing PTZ and overview cameras, which allows you to automate the transition of a PTZ camera to the zone of detected motion. This function of the program is useful for protected objects with a large territory.
You can restrict access to PTZ control to any user. Just uncheck the box in its settings.

Supports major control protocols (PTZ):

Standard

By launching the widget, you can fine-tune the position of the camera and go to the preset. All possible presets have a preview mode.

Visualization of memorized PTZ camera presets has been implemented, which allows you to see the location of the camera before starting the transition to the selected preset. When saving a preset, the program automatically remembers a snapshot of the camera screen, which allows the user to visually determine the desired transition.

Advanced

When you hover the cursor over the center of the picture, a joystick appears. By holding down the mouse button, you can turn the camera in the direction of the joystick movement. The further the joystick is from the center, the faster the camera turns.

Click on the image to view

Control methods

PTZ cameras can be controlled using a mouse, joystick or USB remote control. There are also keyboard shortcuts.