Surveillance Cameras: specifications, types

This parameter is specified if the device does not belong to traditional optical surveillance cameras.

Recall that optical models operate mainly in the range visible to the human eye. The matrices of such cameras are also sensitive to some part of the infrared radiation — which, in particular, makes it possible to use infrared night illumination and even night mode without illumination in some models; but even in such cases, the main function remains precisely the work in the visible part of the spectrum. Modern optical models have a fairly high resolution, which makes it possible to obtain good detail, and are also often made in colour, but in some situations they turn out to be ineffective. Therefore, on the market you can find more specific equipment — thermal imaging cameras, as well as combined devices that combine optics and a thermal imager. Here are the features of these varieties:

— Thermal imaging. Cameras that work on the principle of thermal imagers and react exclusively to thermal (infrared) radiation from objects: the higher the temperature of an object, the brighter it will glow in the frame. This gives features that are not available with conventional optical cameras. For example, using a thermal imager, you can distinguish between a person or an animal that is invisible to ordinary optics due to a masking background or dense vegetation.... In addition, cameras of this type can work without special illumination even in absolute darkness. On the other hand, such equipment is characterized by high cost and has a number of serious limitations in its application. For example, a thermal imager is not able to clearly distinguish an object if its temperature coincides with the background temperature (as a result, the observation efficiency drops noticeably in hot weather). And the resolution and detail of the picture, usually, even in advanced models is quite low. As a result, few pure thermal imaging cameras are produced — the hybrid models described below are much more common.

— Optics + thermal imager. Cameras that combine classic optics and a thermal imager — in the form of two separate "eyes" located side by side. Usually, they are able to broadcast not only two separate video streams, but also one signal that combines data from both lenses. Cameras of this type combine the advantages of optical and thermal models and mutually compensate for the disadvantages; it is interesting that they are much cheaper than classic thermal imaging devices. This is due to the fact that the thermal imager in this case is not intended to build a full-fledged image, but only as an accessory that supplements the data from classical optics — which means that the “thermal” part of the camera does not need advanced characteristics. So due to the combination of affordability and practicality, such hybrid cameras are quite popular nowadays.

— Indoors. Models designed for indoor installation and designed for relatively favorable conditions, without precipitation, dust, temperature changes and other similar influences. These cameras do not require the enhanced protection required for outdoor installations (see below), making them less expensive. Their main disadvantage is also associated with the lack of the mentioned protection — we are talking about the impossibility of full-fledged use outdoors: outdoor installation, even under a canopy or in another relatively protected place, can eventually lead to premature damage to the camera.

— Street. Cameras designed from the ground up for outdoor use and equipped with the appropriate protections — most notably a rugged housing that provides protection against moisture, pollution, heat/frost, etc. In addition, the design may provide special anti-vandal solutions — for example, automatic notification of an attempt to damage the camera; and in themselves such models are more resistant to vandalism than indoor cameras. Of course, if necessary, an outdoor camera can be installed indoors; however, said protection has a corresponding effect on price, and the real need for such characteristics is only in heavily polluted places such as industrial workshops or closed construction sites.

The case type describes not only its shape, but also some layout features that can affect the functionality of the product.

— Dome. In accordance with the name, on the body of such a camera there is a characteristic transparent dome, inside of which there is a lens — and, usually, controlled by PTZ (see "Camera capabilities"). The dome not only protects the optics from various adverse factors (such as dirt or moisture), but in many models it also hides the position of the lens; for this it is darkened. Thus, the object of observation does not know where the camera is pointed, which is useful in some cases (for example, when observing a suspicious visitor in a supermarket). At the same time, for a number of reasons, this option is poorly suited for advanced optics with large dimensions.

— Directed. Directional cameras are called cameras in which the lens "looks" along the body. This arrangement allows the use of powerful lenses with good aperture and optical zoom (see below), but the cameras are also quite bulky.

— Directional ( without a lens). A variation of the directional cameras described above, which has interchangeable lenses; The lenses themselves are usually not included in the kit, they must be purchased separately. The meaning of such a configuration is that the user can independently choose optics for specific needs. This categor...y includes mostly fairly advanced models.

— Hidden. This category includes cameras of a small size, which allows them to be installed discreetly — for example, in a wall niche. However, even with an external installation (this option, usually, is also allowed), such devices are also very inconspicuous due to the mentioned compactness. By itself, the body shape of hidden cameras is most often close to directional (see above), although there may be different options.

— Desktop. Cameras designed to be mounted on a tabletop or other flat, horizontal surface. For this, an appropriate stand is provided in the design; it can have movable mounts that allow you to tilt the camera and rotate it from side to side. The main advantage of such cameras is the utmost ease of installation; this, in particular, makes them almost perfect for home use.

— Portable with fastening. In fact, it is a kind of desktop cameras (see the relevant paragraph), in which the stand can be used not only for installation on a horizontal surface, but also for wall mounting. From other "wall" varieties — hidden and directional (see relevant paragraphs) — cameras of this type differ in layout: their body is usually flat, rectangular or oval, and the lens is located on the widest edge (similar to how it is done in mobile phones ). The mount is often made movable, to adjust for tilt and/or rotation.

-LAN. The LAN (Ethernet) interface was originally intended for building wired computer networks. Cameras with this connector, usually, also work as network devices. The advantage of this option over the Wi-Fi described below can be called a higher actual bandwidth, over BNC — the ability to connect without additional equipment, directly to a standard network router used for a regular computer network. Of the shortcomings, one can only note the need to pull the wire, but this point is common to all wired connection options. For the rest of the features, LAN is the most convenient, thanks to which it has become widely used in modern security cameras.

— Wi-Fi. The Wi-Fi connection was originally a wireless analogue of the LAN described above and was used to connect to computer networks. When working in such networks, this connection is similar to LAN in the sense that it allows the camera to work through a regular router (of course, supporting Wi-Fi). At the same time, Wi-Fi is more convenient due to the lack of wires, however, with an abundance of other wireless devices connected to the router, the channel bandwidth and image quality can noticeably deteriorate. Note that recently it is also possible to use this connection in the Direct mode — for direct connection of the camera with another device, for example, connecting the camera to a smartphone (see "Design and...capabilities — P2P"). However, this option is less common.

— BNC. Abbreviation for Bayonet Neill Concelman. A bayonet type connector commonly used for analogue video signal transmission. Refers to professional video interfaces, special equipment is required to work with such a camera. However, by themselves cameras with connectors of this type, usually, belong to the lower price range. This is due to limited connectivity via BNC — only a video signal can be transmitted through it, which limits the functionality of such cameras compared to models that work via LAN or Wi-Fi (see above).

— 3G / 4G. Internet connection via 3G / 4G mobile networks; usually, for this you need to install a SIM card from a mobile operator in the camera. The speed of such networks allows, among other things, to broadcast video in a fairly high resolution. So such a connection (of course, with coverage) is well suited not only as a fallback in case of interruptions to the Internet, but also as the main communication channel if there is no fixed Internet connection at all. A typical example of the second situation is the observation of a country house located "far from civilization", but in the zone of reliable mobile communication reception. Moreover, in both cases, you can contact the camera via the Internet from anywhere in the world.

— PTZ (controlled). PTZ is an abbreviation for camera control capabilities - “pan, tilt, zoom”. Accordingly, cameras with this feature are equipped with a movable lens that allows you to aim at the desired object; but the magnification can be either optical (see below) or digital. The advantages of PTZ cameras are obvious: their view is not limited to one position, it can be adjusted at the operator’s request. And some models may provide advanced functions, such as automatic targeting and focusing on movement. On the other hand, similar systems cost accordingly.

- Private mode. A feature that allows you to temporarily pause the camera to protect the privacy of people in its field of view. In private mode, the camera temporarily stops recording video, broadcasting images, and performing other actions related to video surveillance. It is important to note that the implementation of private zones or temporary disabling of recording is available in almost any video surveillance camera. In this case, we are not talking about software capabilities, but about creating conditions in which the camera cannot physically record. So, some models hide the lens inside the body, others turn their “look” away in a predetermined direction (for example, to the corner of a wall). Private mode can be activated forcibly (by pressing a button on the camera body or in a mobile application) or according to a preset schedule.

— PoE power supply. Power technology used in cameras with wired LAN connections. The PoE function allows you to supply power to such a camera through the same cable that is used to transmit the signal - this eliminates the need to run an additional wire to the outlet or use batteries/rechargeable batteries. Of course, to use this technology, the connector of the recorder (or other device) to which the camera is connected must also support it. But it’s worth considering that there are different PoE standards, which primarily differ in power (802.3af power up to 13 W, PoE 802.3at - 25.5 W).

— PoC power supply. An analogue of PoE technology used in traditional cameras: it allows you to supply power through the same cable that is used for the video signal, and thus do without connecting to an outlet and without batteries/batteries. The difference is that PoC operates over a coaxial cable with a BNC connector. Of course, to use this function it must be provided both in the camera itself and in the recorder.

— Panoramic shooting. This feature means that the camera has multiple lenses and covers a horizontal angle of at least 180°, providing a wide field of view when the body is stationary. Such a field of view can be achieved with one fisheye lens (see the corresponding paragraph); however, panoramic shooting has one important advantage: the level of distortion in such video is much lower, even at the edges. On the other hand, the presence of several “eyes” has a corresponding impact on the price and dimensions.

— Setting up a region of interest (ROI). This function allows you to define individual zones in the camera's field of view. Note that the tasks of the selected areas may be different. One option is to configure motion detection zones in the frame, which can reduce the level of false alarms. The second possible implementation is to reduce the quality of less important areas of the image to save storage space. The latter can be especially useful when there is a shortage of data storage capacity, and also if the camera uses communication channels with limited speed or traffic volumes (for example, a 3G/LTE mobile network). Either way, the Region of Interest (ROI) feature reduces camera strain and lets you focus on what's important to you first.

- Light sensor. The presence of a light sensor in the camera design. As a rule, this sensor is used to determine the characteristics of the surrounding environment and automatically adjust to its characteristics - in particular, switching between day and night modes, turning on IR illumination (see below), etc.

— Motion detection. Cameras with this feature are able to detect movement in the field of view. This function is convenient because the vast majority of situations that need to be recorded during video surveillance are associated with movement in the frame. The specific reaction to movement may be different: in some models, recording is turned on, others also send a notification to the recorder or other device, others are able to turn after a moving object, etc. Cameras with this function are especially convenient for monitoring objects where movement is rare - for example, warehouses or underground parking lots at night: for example, turning on motion-based recording only saves storage space and makes it easier to view footage.

— Sound detection. Function for detecting sounds in a protected area. Having “heard” a sufficiently loud sound, a camera with this function can react in one way or another: start recording, sound a warning or alarm, etc. Some models can even play the role of acoustic break sensors, accurately detecting a characteristic impact on the glass and the sound of shrapnel. Support for audio detection automatically means the presence of a microphone (see the corresponding paragraph).

— Microphone. The presence of a microphone in the camera design allows it to record not only the image, but also the sound. This allows you to get a more complete picture of what is happening when recording. In addition, a microphone can be useful if the person in front of the camera wants to communicate something to the operator, and if there is a feedback speaker (see below), even a full dialogue is possible.

— Feedback speaker. The camera has its own built-in speaker. One of the most popular uses of this feature is indicated in the name - it is the operator’s feedback from people near the camera. Thanks to the speaker, you can, for example, voice directly through the camera a hint for a lost visitor, a warning or order for an intruder, etc. In addition, this function can be used for other purposes - in particular, to generate an alarm.

- Mobile app. The ability to work with the camera through an application installed on a gadget such as a smartphone or tablet. As a rule, this control method gives access to both broadcasting/saving video and most settings; but the specifics of the communication between the gadget and the camera may be different. Thus, modern applications often provide for the possibility of remote access via the Internet from anywhere in the world; however, there is another option - a direct communication (usually via Wi-Fi), which only works in the immediate vicinity of the camera. These nuances should be clarified separately. Be that as it may, the mobile application is convenient in that it can be installed on almost any modern smartphone or tablet running Android or iOS, turning the gadget into a portable camera control station.

— Motion alert. A function found in cameras with motion detectors (see above). When motion is detected in the frame, such models are capable of not only taking their own actions (for example, turning on recording), but also sending notifications to the user in one way or another. Specific methods for transmitting alerts may be different - email, SMS, notification on a special web page, etc. But in any case, this function makes it easier to track the observed object and reduces the risk of missing an important event in the frame.

— Alarm input/output. As a rule, cameras with this function are equipped with both inputs and outputs; the number of both may be more than one. These connectors are used to transmit control signals to various components of the security system; they allow you to build a very advanced system and provide additional capabilities for managing its functions. Thus, alarm inputs allow the camera to “react” to commands from other elements - for example, turn on when an electronic lock on the door is triggered. And the outputs, accordingly, are used to transmit commands to external devices - for example, to turn on the spotlight when motion is detected in the frame.

— Audio input/output. The presence of audio input and/or output in the camera design. This feature makes it possible to work with sound, but the features of this work may vary, depending on the specific set of connectors. The audio input itself makes it possible to connect an external microphone, and the audio output allows you to output sound to an external device (for example, a recorder or an amplifier with speakers) via a separate channel. At the same time, these connectors can be used one at a time. For example, a camera with a built-in microphone may only have an audio output, but a model with a LAN or Wi-Fi communication is capable of transmitting an audio signal through the same channel, and for such cameras an audio input is sufficient.

— IR illumination. The presence of an infrared illumination system in the camera design. This illumination is used for operation in night mode: IR illumination is invisible to the naked eye (you can only notice a faint reddish glow of the backlight LEDs, and even then not always), but is well perceived by the matrices of modern surveillance cameras. The ability to do without visible light sources is convenient for a number of reasons: in particular, such work hardly reveals the camera.

— LED backlight. The camera has an LED backlight. Like the infrared illumination described above, this backlight is designed to work in the dark; however, it provides light that is visible to the human eye, allowing the camera to produce a relatively natural-looking color image.

- Card reader. A device for reading removable memory cards, usually standard SD or microSD (specific types of supported cards should be clarified separately). This device performs two main functions. Firstly, it allows you to equip the camera with its own drive - this provides an additional guarantee in case of failures in the external recorder and even allows you to record without any additional equipment at all. Secondly, memory cards allow you to conveniently exchange data with laptops, PCs and other external devices - first of all, transfer footage onto them.

The largest capacity of a memory card with which a video surveillance camera can work correctly.

High-capacity drives require fairly high processing power and may use special technologies that are not supported by all cameras. This is the reason for the limitation on the volume of supported media.

Compatibility of the camera with one or another cloud storage. This paragraph may indicate the very fact of compatibility or specify the specific service (services) for which the device is designed — usually it is Google Drive or Yandex Drive, and often both at once.

Recall that cloud storage is an information storage system located on remote servers. Data is transmitted to such a system via the Internet, and the owner can also access them via the World Wide Web, regardless of their own location. In addition, modern "clouds" allow you to share selected information with other users. The basic functionality of such services and a certain amount of disk space are usually available for free, but for advanced features and increased storage, payment is required (one-time or regular subscription, depending on the specific service).

Specifically, in this case, compatibility with cloud storage means that the camera is able to directly transfer footage and other information to such storage. This provides two important advantages at once. The first has already been mentioned — the ability to work with videos (view, copy, share, etc.) from almost anywhere in the world where there is access to the Internet. The second point is additional reliability and security: even if the surveillance system's own storage device (recorder, local server, etc.) is damaged or destroyed, a copy of the footage will still remain in the "cloud".
<...Br> Note that cloud storage support is also found in registrars with network capabilities. However, the purchase of cameras with such functionality is convenient because such cameras do not need additional equipment to work with the "cloud".

Active protection methods implemented in the camera.

By itself, this function is intended to cause discomfort to the attacker and scare him away, as well as draw attention to the situation. It can be activated both manually and automatically (for example, by a motion sensor or a signal to the alarm input of the camera). There are two main types of active protection:

— Light (strobe). A bright light source that flashes at a rate of several flashes per second. Immediately after turning on, the strobe is capable of disorienting a person for several seconds, and even after that, the flashing light makes it difficult to coordinate and move quickly; all this can give security officers additional time to react to the situation. In addition, flashes are clearly visible not only with a direct look, but also with peripheral vision, and in the form of reflections.

— Sound (siren). A loud beep that is almost guaranteed to attract the attention of people nearby. In some models, the volume of the siren reaches 110 dB — this is comparable to the engine of an old tractor and only slightly below the pain threshold of a person.

Each of these options has its own advantages, and it is not difficult to combine them in one device. Therefore, most modern cameras with active protection use both methods described above at once.

The number of backlight LEDs (see "Design and capabilities") provided in the camera design.

Theoretically, more LEDs provide more power and, accordingly, range (see below) and efficiency of IR illumination or LED illumination. However, in fact, such light sources can vary markedly in performance; in addition, a lot also depends on the features of the camera itself. Therefore, in fact, this indicator is a reference, and when choosing, it makes sense to pay attention to parameters that are closer to practice — in particular, the same backlight range (see below).

Operating range of the backlight (see "Design and capabilities") installed in the surveillance camera. This term usually means the maximum distance from the camera to the observed object, at which it is able to provide a relatively high-quality and legible image in the complete absence of other light sources. Of course, the actual backlight range may differ from the claimed one, and these differences are most often in the direction of increase (for example, due to the presence of the same additional light sources). However, if the possibility of shooting with backlight is important for you, you should focus on the claimed range.

Functions that automate the process of video monitoring, analysis and response to events, which helps to minimize the human factor and increase the efficiency of video surveillance systems.

— Perimeter protection. This option is used when deploying complex video surveillance systems with a recorder and cameras, combining the expanded functionality of intelligent video analytics capabilities for monitoring boundaries. Perimeter protection can cover various functions, for example, tracking the intersection of virtual lines, the appearance or disappearance of objects in the frame, setting up protected zones, if the boundaries of which are violated, an alarm will be activated, and so on. The full list of features should be specified separately. It is important to note that for the listed functions, analysis of objects in the frame can be used - detection of people, classification of vehicles, etc.

— Definition of a person. Cameras with this function can detect the presence of people in the frame by the characteristic outlines of their silhouettes. Once a person's presence is detected, an alarm can be activated, and moving PTZ cameras can follow people in the frame.

— Definition of a car. The ability of a video surveillance camera to automatically recognize and highlight objects in the frame that are vehicles. This can be useful for monitoring t...raffic, controlling parking, or ensuring the safety of roads within a controlled perimeter. A more advanced implementation of this function is license plate recognition (see below).

— Definition of animal. The function of identifying various “living creatures” in the frame: pets, neighbor’s cats and dogs, alien wild animals, etc. Video surveillance systems with this functionality can be used to minimize false alarms, monitor pets to make sure they are safe and in order, and to solve other similar problems.

— License plate recognition. Special tools that provide additional capabilities for reading license plates. The specific capabilities of such tools may be different in different models; they should be clarified separately. So, some cameras only read letters and numbers and transmit the information to the recorder for further processing. Others have built-in databases, so they can compare the read number with the base and provide various actions depending on the result - for example, send a signal to open the barrier if the number is “allowed”. However, in any case, cameras with this feature are well suited for objects where it is necessary to control the movement of cars - for example, parking lots (including closed service ones).

— Facial recognition. Cameras with this function are able to at least recognize the presence of faces in the frame; but the further use of this data and the special functionality of such cameras may be different. Thus, relatively simple models react only to the very fact of detecting a face, but even this provides quite extensive additional capabilities: focusing on a face, tracking a person in the frame (in moving PTZ cameras), etc. And more advanced cameras can recognize characteristic features faces by which a specific person can be identified. This functionality, among other things, allows the surveillance system to compare the faces “seen” by the camera with the stored database and take various actions based on this - for example, allow or deny access, warn about an unwanted visitor or unauthorized use of a key card, etc. P.
Note that face recognition tools can also be found in recorders to which cameras are connected. However, the presence of such functions in the cameras themselves can also be useful - especially if the existing recorder “does not shine with capabilities” in this regard, or the system does not have a recorder at all (for example, it consists of IP cameras connected via a router to a PC).

— People counting. A function that allows the camera to count the number of people in the frame; the received data is stored in its own memory and can be sent to a recorder or other external device. Note that in most models this feature is combined with the face recognition described above, thanks to which the camera is able not only to count all people in a row, but to recognize tech who are in the frame again. However, people counting can be used for both statistical and security purposes. For example, at large facilities such as office and shopping centers, it allows you to determine whether all visitors who entered the premises left it before the end of working hours.

Smart home systems that the camera is compatible with.

The general principle of all such systems is to combine various home electronics and household electrical appliances into a single complex so that all these devices can interact with each other and jointly respond to various events. As for surveillance cameras specifically, their functions in a “smart home” are mainly related to reacting to movement in the frame and broadcasting video. For example, a compatible camera can send a notification to the user’s smartphone when a motion sensor is triggered, or transmit video to a TV integrated into the home network.

Nowadays you can find different smart home platforms, the most popular are Apple HomeKit, Google Home, Amazon Alexa. However, there are other options for branded systems - as a rule, they are sold by manufacturers for their smart home and video surveillance devices. To fully work in a particular system, it is worth using cameras that have expressly stated appropriate compatibility. Also, when purchasing a compatible model, it would not hurt to clarify its specific functionality related to the “smart home”.

Model of the matrix installed in the surveillance camera. Knowing the exact name of the model, you can find detailed information about its operation — from detailed specifications to real user reviews — and assess how this option meets your requirements.

The type of matrix installed in the surveillance camera.

— CMOS. Abbreviation for "complementary metal-oxide-semiconductor" (complementary metal-oxide-semiconductor structure, CMOS). The advantages of CMOS matrices are low cost, low power consumption, as well as high image processing speed and compact dimensions compared to CCDs. The main disadvantage of this technology is the increased image noise, especially at high sensitivity. To eliminate this shortcoming, there are various design tricks, but manufacturers often do not use them for the sake of the low cost of the camera. As a result, CMOS matrices are typical mainly for relatively inexpensive models.

— CCD. Abbreviation for "charge-coupled device" (charge-coupled device, CCD). This type of sensor is more expensive than CMOS and bulkier, but less prone to heat noise and generally more advanced. However CCDs don't handle point light sources very well; however, in this case, manufacturers just quite often use special technologies to neutralize this drawback. Such matrices are typical for advanced surveillance cameras.

— DIS. Abbreviation for "Digital Image System". The key feature of this type of matrices is that they combine both the photosensitive element itself and the image processor in one chip. This reduces the dimensions of cameras with DIS sensors and reduces their cost, while such devices can even surpass similar CCD and CMOS models in image quality. In addition, DIS matrices...are well tolerated by low temperatures (down to -40 °C), which is indispensable for outdoor cameras (see "Use").

The size of the matrix installed in the surveillance camera (diagonally).

In general, larger sensors (with the same resolution and sensor type) are considered more advanced: they get more light, which has a positive effect on image quality (especially in low light). On the other hand, increasing the size affects the cost of the entire device; and in some cases (for example, if the camera is not planned to be used in twilight and darkness), a relatively small sensor may be quite suitable.

As for specific dimensions, the most modest cameras in terms of this indicator have matrices of 1/4 "or less. Models with sensors of 1/3.8" - 1/3" and 1/2.9" - 1/2" are very popular, these values can be called average. And in advanced devices, diagonals and more than 1/2 "(up to 1/1.7") are found.

Camera sensor resolution in megapixels (millions of pixels).

The higher the resolution of the matrix, the higher the video resolution can be (see below), the more detailed the image is capable of providing the camera. At the same time, note that as the number of megapixels increases (without changing the size of the matrix), the size of each individual pixel decreases, which increases the likelihood of noise and deterioration in the overall image quality. Therefore, high resolution in itself is not necessarily a sign of high quality — a lot depends on other things, for example, on the size of the matrix (see above).

As for specific values, in the most modest matrices it does not exceed 1.3 MP, which corresponds to the maximum HD resolution. 2 MP sensors allow for already Full HD resolution (usually 1920x1080 or 1600x1200), 3 MP, 4 MP, 5 MP and 6 MP are capable of better resolution, but still do not reach 4K, which is typical for 8 MP.

The maximum video resolution that the camera can capture.

The higher the resolution of the video, the more details you can see on it, the less details will be blurry. On the other hand, high resolution means large volumes of video materials, which, accordingly, requires capacious media for their storage and fast communication channels for broadcasting video in real time. Yes, and this indicator significantly affects the cost of the camera.

Resolution of the video signal produced by the camera in TV lines (TVL).

A similar resolution designation is used for analogue video; the number of TV lines in this case is the horizontal size of the image. The meaning of such a recording is that in analogue PAL and NTSC formats, which are most often used in video surveillance systems, the vertical size of the video is always the same (625 and 525, respectively), so the frame size in different models of analogue cameras differs only in horizontal. Accordingly, the higher the TVL number, the more detailed the image will be, the more small details will be visible on it. On the other hand, in order to use all the features of a camera with numerous TV lines, a screen corresponding to these features is also required; For more details on compatibility with the screen, see specialized sources.

As for specific numbers, a value of 500 TVL and less is considered very small, 500 – 600 TVL — modest, 600 – 700 TVL — average, 700 – 800 TVL — above average, and in some models this number may exceed 800 TVL.

The maximum frame rate in the video captured by the camera.

The higher the frame rate, the clearer the image, the less noticeable blurring when moving in the frame (especially fast). On the other hand, this indicator affects the amount of information recorded during shooting, as well as the cost of the camera itself. Therefore, it makes sense to specifically look for a video surveillance camera with high-speed shooting(45 fps and higher) only if a clear recording of fast moving objects is important to you.

The highest resolution at which the camera is capable of recording video at a frame rate of at least 25/30 fps. The parameter is specified for models that have high resolution shooting with a low frame rate (for example, 4K at 15 fps). It gives an understanding of the specific resolution at which video recording is supported with a frame rate of 25/30 fps, at which the picture is perceived smoother and details in dynamic scenes are better seen (if there are moving objects in the frame).

The lowest degree of illumination of the scene being shot, in which the camera is able to provide normal visibility. Usually, this item specifies the values for the daytime mode of operation (in the night mode, the minimum illumination in many models may be zero at all, because in such cases the IR illumination is turned on, see "Design and capabilities"). And if the camera is capable of shooting in colour, it usually means the lowest illumination necessary to obtain a colour image.

The lower this indicator, the better the camera works in low light, the brighter and more clearly visible image it is able to provide in such conditions. At the same time, note that in low light, night mode is often preferable, and in the presence of the aforementioned IR illumination, it is more likely to focus on the range of its operation (see above).

There are comparative tables that allow you to evaluate the degree of illumination indicated in the characteristics from a practical point of view: for example, an indicator of 0.2 lux corresponds to clear eyes on a full moon.

Aperture of the lens installed in the camera.

Aperture characterizes the degree of attenuation of the light flux when passing from the front lens of the lens to the matrix. It is denoted as the ratio of the diameter of the active aperture of the lens to the focal length, while the size of the active aperture is designated as f and is taken as a unit — for example, f / 1.4 or f / 2.0. Moreover, the smaller the number in the designation, the higher the aperture (in our example, the second lens will be darker than the first). And for lenses with a variable focal length (see "Focal"), the actual aperture, usually, changes with a change in focal length; for such models, either the range of aperture values, or its maximum value, can be indicated.

By itself, this parameter characterizes, first of all, how light the image taken through the lens turns out, all other things being equal. High values are important, first of all, when shooting in low light conditions: a fast lens allows you to get a fairly high-quality image without increasing the sensitivity of the matrix, which is fraught with noise and “blurring” of the picture. On the other hand, the actual quality of camera operation (including in dark conditions) also depends on many other factors — the type and size of the matrix, signal processing features, etc. Therefore, aperture in most cases is more of a reference than a practically significant parameter.

The signal-to-noise ratio that the surveillance camera corresponds to.

This indicator describes the ratio of the level of the useful signal (the actual image produced by the camera to an external device) to the level of extraneous noise that inevitably arises during the operation of electronic circuits. Such noise appears in the image as characteristic noise (“snow”). The higher the signal-to-noise ratio, the less interference on the screen, the clearer and better the image is, and the smaller the volume of recorded video files. It is believed that visible noise practically disappears at a ratio of at least 45 dB. However, among modern cameras there are also higher rates.

— WDR (Wide Dynamic Range) — extended dynamic range. WDR technology combines several frames with different exposures into one picture, as a result, dark areas are brightened, and overexposures are darkened, and the output is a picture with extremely uniform lighting. The true wide dynamic range technology is called True-WDR and it is implemented in the optical circuit at the hardware level, a special microprocessor is responsible for creating and mixing exposures. A more affordable alternative to wide dynamic range is Digital-WDR technology, which equalizes lighting through software algorithms.

— DWDR (Digital Wide Dynamic Range) — extended dynamic range technology based on software brightening algorithms. DWDR brightens too dark areas of the frame, which can be completely blurred against the background of light areas. Digital brightening allows you to noticeably improve the quality of shooting in contrasting lighting conditions. Digital WDR cameras are noticeably cheaper than true True-WDR optics. Of course, the quality of digital brightening is inferior to True-WDR.

— BLC (Back Light Compensation) — backlight compensation technology. This system is based on the work of digital signal processors DSP. So, the device, relatively speaking, "breaks" the frame into many segments, making its own adjustments to each of them. Backlight compensation brightens dark areas of...the frame well. The main disadvantage of the technology is the increase in the brightness of the already bright areas of the frame, due to which overexposure may appear in the picture.

— WDR+BLC. The camcorder supports several lightening technologies at once, each of which is described in more detail above. Immediately, we note that the combination of WDR + BLC allows you to achieve an extremely clear and clear picture in almost any lighting conditions, from extreme contrast to insufficient and excessively bright.

— DWDR+BLC. The device supports two popular clarification technologies at once, each of which is described in more detail above. The presence of DWDR + BLC technologies allows the camera to effectively brighten the dark areas of the frame. Such video cameras have proven themselves well when working in low light conditions.

The presence of a fisheye lens in the camera. Such a lens provides a very wide field of view — about 180 ° in all directions. Thanks to this, you can, for example, mount the camera on the ceiling and cover the entire room with it. At the same time, such models are much cheaper and more compact than devices with panoramic shooting (see the relevant paragraph), since there is only one lens in the fisheye camera. However fisheye optics give strong distortions at the edges of the image; however, this point is rarely critical in fact, and fisheye cameras are very popular in modern surveillance systems.

Type of camera lens by focal length. Here are the options:

— Permanent. Fixed focal length lenses have a fixed angle of view — in other words, they work at a constant zoom level and are not able to change it (the only option available for such cameras is electronic zoom). The advantages of CCTV cameras with a fixed focal length are simplicity, reliability, almost zero power consumption, small size and low cost. The main disadvantage is the inability to work with optical zoom (see below); and said electronic magnification is less advanced, since when approaching, the clarity of the “picture” decreases.

— Variable (varifocal cameras). Zoom lenses are more complex than "fixed" lenses, are larger, are considered somewhat less reliable, and are noticeably more expensive. However, this type of optics has an important advantage: it is the only one capable of providing optical zoom (see below), which allows you to “zoom in” the image without compromising its quality.

Focal length of the camera lens.

The focal length is such a distance from the lens to the matrix, at which a clear image is obtained on the matrix (when the lens is focused to infinity). The viewing angles of the lens primarily depend on this indicator (see below): the smaller it is, the wider the viewing angles and the smaller the objects in the frame (and vice versa). At the same time, it should be noted that the actual viewing angle is determined not only by the focal length, but also by the size of the matrix (see above). In fact, this means that with different sizes of matrices, lenses with the same focal length will have different working angles. Therefore, only cameras with the same matrix size can be compared with each other according to this indicator. Among CCTV cameras, lenses with a focal length of 2.8 mm, 3.6 mm, 4 mm and 6 mm are considered popular.

In models with a variable focal length (see above), in this case, the range from the minimum to the maximum distance is indicated. Also, using these data, you can derive the optical magnification factor of such a lens: for this, the maximum value must be divided by the maximum (for more details, see below).

Horizontal viewing angle of the surveillance camera. For models with a variable value, the maximum value is indicated, since it is the width of the image that is important, and when zooming in, the zoom factor is more important than the angle. This paragraph also indicates the general angle of view for models with a circular field of view – in particular, cameras with a fisheye lens (see above)

The wider the viewing angle, the more space the camera captures and at the same time, the smaller the images of individual objects in the frame are obtained. Therefore, when choosing by this parameter, it is worth deciding what is more important – the ability to view a large scene or the visibility of small details in a relatively narrow field of view. Also note that with a wide field of view (100° or more), characteristic distortions can be observed at the edges of the frame, and the wider the angle, the more pronounced they are. This phenomenon can be eliminated by panoramic shooting (see "Design and features"), but this feature, in turn, complicates and increases the cost of the camera.

Vertical viewing angle of the surveillance camera. In models with a variable value, the maximum is indicated, and the angle when zooming is not so important.

The wider the viewing angle, the more space the camera captures and at the same time, the smaller the images of individual objects in the frame are obtained. Therefore, when choosing by this parameter, it is worth deciding what is more important – the ability to view a large scene or the visibility of small details in a relatively narrow field of view.

The camera's diagonal field of view is measured from one corner of the image to the opposite, expressed in degrees. For models with variable zoom ratios, the maximum value is indicated, since it is the width of the image that is important, and when zooming in, the zoom ratio is more important, not the angle.

The diagonal viewing angle determines how much of an area of space can be captured by the camera. The wider the viewing angle, the more space the camera captures. But at the same time, the smaller the images of individual objects in the frame are. When choosing according to this parameter, it is worth deciding what is more important - the ability to view a large scene or the visibility of small details in a relatively narrow field of view.

Modern surveillance cameras can provide two types of magnification - optical and electronic. In the first case, the “approximation” of the image is carried out due to the operation of the lens; in the second, a separate area is selected on the matrix and the image from it is “stretched” across the entire frame, creating a magnification effect. Thus, optical zoom is more advanced: it allows you to use the entire sensor area even when zooming in.

Optical zoom is only available if the camera lens has a variable focal length (see “Focal”). And the degree of magnification will correspond to the ratio between the maximum and minimum focal length: for example, for a model with a range of 3 – 15 mm it will be 15/3 = 5x. Thus, we are not talking about how much the camera enlarges the “picture” relative to how it is visible to the naked eye, but about how much larger the image is at the maximum focal length than at the minimum.

The disadvantages of optical zoom systems are directly related to the disadvantages of variable focal length: the lenses are larger, more expensive and less reliable than with electronic ones. In addition, the capabilities of this operating format are limited: too high magnifications would require too bulky and expensive optical systems. Therefore, manufacturers often use a compromise option, supplementing optical magnification with electronic one: the first option is used at low magnifications, the secon...d is turned on when the capabilities of the optics are exhausted.

For a thermal imager on board surveillance cameras, frame resolutions of 320x240 pixels and 640x480 pixels are often used, which is quite enough for the vast majority of tasks. Advanced thermal imaging cameras shoot at 1280 x 1024 pixels for a wider field of view and better target identification.

Interpolation is used during video recording to resize the image's native resolution to a larger size. The technology improves the spatial resolution of thermal images and increases the number of temperature points, allowing you to get a thermogram comparable in quality to that of higher-end detectors.

The focal length value determines the width of the field of view of a thermal imaging camera. Knowing the focal length, you can calculate the range of the video surveillance system and its field of view. So, models with long-focus lenses are intended for obtaining thermal images at a great distance from the camera, with short-focus lenses for close-up observation.

The viewing angle determines how wide the field of view of the thermal imager is and how much of the thermal scene is captured. The dependence here is directly proportional: the larger the viewing angles in the horizontal and vertical planes, the wider the camera “sees”.

The temperature range that the built-in thermal imager unit can “detect”. In many models of video surveillance cameras, it is possible to set the exact temperature, when the threshold is exceeded, an alarm will be issued.

Temperature measurement error by thermal imaging unit. The smaller it is, the more accurately the temperature of objects in the frame is determined. Advanced models of video surveillance cameras with a built-in thermal imager have an error of tenths of degrees, but on average in the ward it is plus or minus a couple of degrees on the measured scale.

The video compression format used by the camera.

Compression is used to reduce the file sizes of captured video; different technologies can be used for this — the so-called codecs, their list is given in this paragraph. From a practical point of view, compatibility with external recording and playback devices primarily depends on the supported codecs. If you plan to use a computer as a recorder / player, you can ignore this list: modern PCs and laptops usually support a very extensive list of formats, and in extreme cases, the missing codecs can be installed separately. But if we are talking about specialized registrars, individual players (like home media centers), etc. — codec compatibility should be clarified further. So, if the advanced modern H.265 standard is very widely supported nowadays, then the more specific H.265+, originally created for surveillance systems, is much less common even in specialized equipment.

The voltage or type of power used by the camera.

It is worth saying that among such equipment it is quite rare to find models originally designed for 230 V - devices with lower supply voltages are much more widespread, in particular, 5 V, 6.5 V, 9 V, 12 V, 14 V and 24 V. To operate such a camera from an outlet, you will need a power supply; it may be included in the delivery package, but this point should be clarified separately. More specific methods of supplying energy are also possible - for example, through a specially organized low-voltage network, or from a car battery (for 12- and 24-volt models). Separately, we note that when operating via POE (see “Design and capabilities”) the supply voltage is standard 48 V, so for models with POE the power supply features are not specified.

A specific category is represented by battery-powered cameras. This power supply ensures autonomy and independence from wires, but the operating time is limited - when the charge is depleted, the camera will have to be connected to an energy source to charge the battery. Therefore, very few battery models are produced - mostly these are compact solutions with a wireless connection, for example, via Wi-Fi...(see above).

Another extraordinary option is cameras powered by a solar panel. Autonomous power supply from solar panels is used in outdoor models of CCTV cameras. During the day, they are supplied with energy from the sun's rays and at the same time accumulate a charge in the battery, which is enough to ensure the operation of the video surveillance system at night. To meet your own needs, solar panels are placed directly on the camera body or somewhere next to it. Cameras powered by solar energy are the best option for installation away from electrical civilization.

The power consumed by CCTV cameras during operation. Knowing the indicator of energy consumption, you can, for example, calculate the battery life of equipment from an uninterruptible power supply or choose a suitable “uninterruptible power supply”. Also, with the support of PoE technology, it is worth considering the power consumption when choosing a PoE switch or PoE adapter.

The ambient temperature range in which the camera can be used normally.

All modern surveillance cameras normally tolerate temperatures typical for houses / apartments, offices and other premises with similar mild conditions. Therefore, it is worth paying attention to this parameter, first of all, if the device is planned to be used outdoors — or in a room where the temperature does not differ much from the street temperature or, for technical reasons, should be low (freezer warehouse, refrigerated car, etc. ). In such cases, the lower temperature threshold is especially important: for example, almost all outdoor cameras have the ability to work in cold temperatures below 0 °, but among indoor models such features are much less common. However, frost-resistant devices(with an allowable temperature of -40 °C and below) can also be found not only among outdoor cameras, but also among “internal” cameras.

As for the upper temperature limit, it is usually not lower than +40 °C, which is quite enough for using the camera in a temperate climate. In some models, this limit reaches +50 °C and even +60 °C, making them suitable even for hot countries. However, note that we are talking exclusively about use in the shade; the possibility of working under direct sunlight should be clarified separately.

The highest relative humidity at which the camera is able to operate normally, without failures and breakdowns, for an unlimited time.

Modern electronics tolerate low humidity well, but high rates affect it negatively — with a long stay in such an atmosphere, moisture can condense on certain parts of the structure and various unpleasant consequences, from corrosion to short circuits and fires. Therefore, you can use the camera effectively and safely only in conditions where the humidity does not exceed the maximum recommended value specified in the specifications. At the same time, we note that many devices are able to endure short-term (up to several hours) exposure to high humidity without consequences.

The degree of protection of the camera against moisture and foreign objects according to the IP standard.

This protection describes how well the camera body protects sensitive internal components from the impacts mentioned. By default, it is denoted by the letters IP followed by two numbers. The first digit means protection against the ingress of solid objects and dust, and the following levels of protection correspond to its individual values:

1 — protection against objects with a diameter of more than 50 mm (large body surfaces)
2 — from objects with a diameter of more than 12.5 mm (fingers, etc.)
3 — from objects larger than 2.5 mm (most instruments)
4 — from objects more than 1 mm (almost all tools, most wires)
5 — dustproof (full protection against contact; dust can penetrate inside, but does not affect the operation of the device)
6 — dust tight (case with full protection against dust and contact).

The second digit characterizes the protection against moisture, here the values \u200b\u200bcan be as follows:

1 — protection against vertically falling drops of water;
2 — from water drops with a deviation of up to 15 ° from the vertical axis of the device;
3 — from water drops with a deviation of up to 60 ° from the vertical axis of the device (the minimum level that allows you to operate the camera in the rain);
4 — from splashes from any direction;
5 — from jets from any...direction;
6 — from sea waves or strong water jets;
7 — the possibility of short-term immersion to a depth of 1 m (without the possibility of continuous operation in immersed mode);
8 — the possibility of long-term immersion to a depth of more than 1 m (with the possibility of continuous operation in immersed mode).

Of course, surveillance cameras are usually not designed for immersion under water — the last two options only characterize a high degree of moisture resistance.

In some models, one of the numbers may be replaced by the letter X — for example, IPX7. This does not mean that there is no protection, but that the corresponding parameter was not certified according to the IP standard. At the same time, the degree of non-certified protection can be quite high — for example, the example above corresponds to the possibility of complete immersion under water, which requires a high degree of closeness (minimum dust resistance level 5). Also note that the complete absence of IP marking also does not mean that the camera is absolutely not protected from negative influences — again, the point is that the case simply did not pass official certification. However, if dust and water protection are critical, you should choose among models with IP certification.

ONVIF in this case is a set of rules (protocols) for the interaction of different components of a video surveillance system. This set was developed by the organization of the same name (Open Network Video Interface Forum) and is widely used in equipment from different manufacturers. In the case of cameras, this means that an ONVIF-compliant camera will be able to work properly with any brand of equipment, as long as it also supports this standard.

The main material used in the construction of the camera body.

— Plastic. Inexpensive and at the same time quite practical material. Plastic is light, quite strong (not as strong as metal, but still quite sufficient for most cases), chemically inert (and therefore not susceptible to corrosion and insensitive to moisture), and also has a relatively low thermal conductivity (which provides additional protection for extreme temperature fluctuations). Due to all this, this material is very popular in indoor chambers (see "Usage"). At the same time, it is somewhat less suitable for outdoor work.

— Metal. The main advantage of metal, in comparison with plastic, in the case of surveillance cameras is high strength and reliability. This allows you to use it even for street models that work in difficult conditions and must have a certain anti-vandal resistance (at least not immediately “give up” when trying to break or break). At the same time, such material is much more expensive, and therefore less common.

Ruggedized housing providing enhanced protection against damage attempts.

The specific degree of strength may vary. For example, many manufacturers use the IK standard for impact resistance. The highest rating in this standard is IK10, providing protection against impact with an energy of up to 20 J, which corresponds to a 5 kg load falling from a height of 40 cm; more detailed information on IK can be found in special sources. At the same time, cameras that do not have IK certification can also be positioned as vandal-resistant.

Note that even the most vandalism-resistant housing does not provide absolute protection against damage. However, this feature, anyway, significantly complicates the attacker's task and may even force him to give up trying to permanently spoil the camera. And the purposeful removal of the camera from the system turns out to be a rather difficult and long matter. And in some models, the increased strength of the case can be combined with other features — for example, a sensor that sends an alarm when attempts are made to damage the camera.