Comparison Dahua P5AE-PV vs Xiaomi Outdoor Camera CW400

— LAN. The LAN (Ethernet) interface was originally designed to build wired computer networks. Cameras with such a connector, as a rule, also work as network devices. The advantage of this option over the Wi-Fi described below is a higher actual throughput, over BNC — the ability to connect without additional equipment, directly to a standard network router used for a regular computer network. Of the disadvantages, one can note only the need to pull a wire, but this point is common to all wired connection options. In terms of other features, LAN is the most convenient, due to which it has become widespread in modern surveillance cameras.

— Wi-Fi. 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 absence of wires, but with an abundance of other wireless devices connected to the router, the channel throughput and image quality can significantly deteriorate. Note that recently it has also been possible to use this connection in Direct mode - for direct connection of the camera to 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, usually used to transmit an analog video signal. Refers to professional video interfaces; special equipment is required to work with such a camera. However, cameras with this type of connector are usually in the lower price range. This is due to the limited connectivity options via BNC — it can only transmit a video signal, which limits the functionality of such cameras compared to models that work via LAN or Wi-Fi (see above).

— Aviation port. It is a round multi-pin connector designed for reliable connection of cameras. Such ports provide a stable connection even in conditions of vibration and high humidity, due to which it is used in car video surveillance systems. Power, video signal and control (for example, for PTZ cameras) can be transmitted through one aviation port, which simplifies installation and reduces the number of required cables.

— 3G / 4G. Connecting to the Internet via 3G / 4G mobile networks; as a rule, this requires installing a SIM card from a mobile operator in the camera. The speed of such networks allows, among other things, to broadcast video in fairly high resolution. So such a connection (of course, if there is coverage) is well suited not only as a backup option in case of Internet outages, but also as the main communication channel if there is no fixed Internet connection at all. A typical example of the second situation is monitoring a country house located “far from civilization”, but in an area with reliable mobile phone reception. In both cases, you can contact the camera via the Internet from anywhere on the planet.

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.

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.

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.

— 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.

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.