AHD video surveillance - is there any point in switching to AHD-H?

In the field of video surveillance, rapid changes are occurring. The old analog video formats D1 and 960N disappear forever in the past, as obsolete - in the modern world very few people use the technology of "yesterday", especially when it comes to security. In place of the old analog technology came AHD, HDCVI and HDTVI. Their huge plus was that they are able to work without problems with the already existing infrastructure of video surveillance systems based on coaxial cable. Among these technologies, AHD, HDCVI, and slightly less HDTVI (as a result of problems with proper support for the hybrid mode, when analog and IP cameras work with the DVR at the same time) earned the most popularity. AHD and HDCVI, thanks to obvious advantages - versatility (AHD is also an open format, accessible to everyone), affordability, developed support for hybrid modes and a clear superiority in operational and technical terms have become the most common.





Naturally, the leading technology of analog HD video surveillance does not stand still and continue to develop intensively. For example, AHD technology is now experiencing another round of technical evolution, when the more common AHD-M recording standard (720p) is replaced by the more progressive AHD-H standard (1080p), which introduces a Full HD quality image to analog video surveillance. AHD-H cameras make it possible to see controlled territory with detail and clarity unattainable on AHD-equipment! The AHD-H format surpasses in resolution the traditional frame format of analog D1 cameras (720x576) by 5 times, and the recently considered 960H format (960x576) is 3.75 times. And even the seemingly good standard AHD-M is 2.25 times lower than AHD-H by resolution. It is obvious that with other things being equal, on a frame with twice to five times higher resolution you can see a lot more fine details and subtle nuances than on a smaller image. This is a very convincing “theoretical” argument in favor of the transition to AHD-H technology. But what is the advantage in practice, is it really noticeable? Let's try to check!

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Alignment on AHD-H



While the new AHD-H equipment is not too common on the market. If we talk about Ukraine, at the time of writing the article AHD-H, video equipment was available only to one company (by the way, this is the company that in its time delivered the first honest AHD (AHD-M) equipment to the Ukrainian market, while many did not disdain to haggle over Chinese registrars and cameras of the so-called AHD-L standard, which in essence was the renamed standard for the conjuncture of the standard 960H - that was it). But the saturation of the market is a matter of time, but what is more important to us is another thing, namely, that this company, if desired, gives a “hot” novelty to our partners and regular customers. As a regular customer of this company, we could not miss the opportunity and took on a test 2MP AHD camera Tecsar AHDW-2M-20F ( http://secur.ua/videonablyudenie/analoghd/ahdcams/AHDW-2M-20F.html ) paired with the recorder Tecsar B84-2FHD2P-H ( http://secur.ua/videonablyudenie/analoghd/ahdvideoregi/TecsarB84-2FHD2P-H.html ) to personally evaluate the relevance of the transition to AHD-H.

Our team, responsible for security photography of various outdoor activities "in nature" (and the areas there are usually considerable and high detail is more important than when shooting in a small room), armed with a new AHD-H technique, went to test it. Actually, that's what came out of it. In the course of testing, the guys settled on a bridge over the busy Moskovsky Prospect and filmed this video. Here all the charms of work in real conditions are just perfect shaking from the transport passing over the bridge.







On the video with the naked eye it is perfectly noticeable that the D1 cameras do not withstand any criticism, they are trivially unable to produce such a high-quality image so that you can see important details on the frames - the car’s brand (not to mention the number), small elements of the environment, movement of people in the distance and etc. AHD-M video surveillance, due to its significantly higher resolution, improves the situation, but some small details in the image are still not clearly visible. And only AHD-H drastically changes the image for the better!















Look at the clarity of the display of the number of a passing car on the snapshots of each video clip - no camera except AHD-H made it possible to see the number so clearly as to recognize all the numbers and letters without a doubt. This is the most visual demonstration of the real benefits of AHD-H. (For perfectionists who are already starting to bluff like “all this is nonsense, ordinary autonumbers won’t be seen on machines even once” I’ll say that the issue of detailed examination of license plates on a passing vehicle is just a matter of changing the lens of the camera. In this case, all The cameras were tested with a standard complete lens with a focal length of 3.6 mm / F2.0. In addition, the distance to the car is quite large here - a high bridge, plus the installation angle for cameras here is generally not the one that is chosen if necessary but consider car number).



Obviously, AHD-H class equipment does indeed demonstrate a significantly clearer picture with good detail visibility. Plus AHD-H frame has the same Full HD resolution as the screens of many modern monitors and TVs. This allows you to see a perfectly coordinated image size without geometric distortion and interpolation, which has a very positive effect on the usability of the video surveillance system.



By the way, if the readership has a desire to see the source videos from which this video was mounted, I can post it separately, although there will be absolutely no additional benefit from them.



AHD cameras vs. IP



It is not surprising that in the world of the universal dominance of “digital” technologies, many, without hesitation, prefer digital IP cameras. Of course, nobody argues about the big prospects of IP cameras. But still, these cameras have a couple of “sins”, which make them far from the best choice for security surveillance systems ...



For example, analog cameras of the new generation, including AHD-H ( http://secur.ua/videonablyudenie/analoghd/ahdcams/ ), are capable of transmitting video signal over coaxial cable up to 300 m long without significant distortion (even officially). more (for the AHD-M cameras, the 800 m version was tested and was fully functional) without the use of intermediate signal amplifiers. And what about the "advanced" digital IP cameras? They are limited to an Ethernet cable length of 100 meters. Well, the maximum that can be pulled out without critical interference is 120 meters. It is obvious that such a significant limitation on cable length does not allow installing digital cameras in the right places on a large object without additional tweaks and extra expenses. After all, the cable leading to the camera is usually forced to follow the bends of the walls inside the room, as a result of which it is significantly “extended”. And 100 meters may not be enough. Also, when it comes to outdoor video surveillance (for example, monitoring a private area with a large area), the use of intermediate signal amplifiers is often impossible at all. And in this case, the option of IP cameras simply disappears. Standalone digital Wi-Fi cameras are also not an option here - such a solution is not a priori suitable for any serious security system. And even if you can use various intermediate amplifiers indoors (such as self-powered hubs or even PoE technology support), you need to understand that any additional electronic components greatly reduce the reliability of the video surveillance system. However, a short distance - this is not the most significant "sin" of IP cameras.



The biggest problem with IP video surveillance is the transmission of images with a time delay. In order to digitize an image, break it into packets and transfer it over the network, the camera objectively takes a certain amount of time. While analog cameras, including AHD, do not digitize video and always broadcast the image in real time without noticeable delays. For example, even in a small local network that uses only 1 switch, video from an IP camera may be "delayed" by 2-4 seconds relative to the AHD camera. It would seem, well, what is a couple of seconds? This is quite a bit! But let's use the objective language of numbers - let's try to calculate how far an attacker will have time to overcome in this seemingly short time.



Slow pitch 0.5 m / s: a distance of 1 - 3 m (for 2 and 4 seconds, respectively);

Rapid pitch 1.2 m / s: distance 2.4 - 4.8 m;

Running 4 m / s: distance 8 - 16 m;

Quick run 7 m / s: 14 - 28 m.



As a simple mathematical calculation shows, the IP camera “deigns” to transmit video during the time it takes, even moving just by a quick step, an attacker can go a considerable distance of about 5 m, leaving not only the camera’s field of view, but also the entire territory of a small store. And if the offender starts to run, then by the time the security guards only notice an alarming event on the IP surveillance system screen, the thief may well leave the limits of a large building and get lost somewhere on the street. And we did not even take into account that in large or loaded networks, as well as increasing the video resolution, the delay in the image from IP cameras grows significantly. Let's say even more - if a person flashes in front of the lens quickly, the IP camera may not capture this event in the video sequence at all! This is the infamous "drop out of frames" from IP cameras, because of which the guard will not see the alarming event on the video monitor at all. All of the above questions the use of IP cameras in security systems, where the speed of response to an event is one of the most important criteria. After all, okay, petty thief, but imagine that armed robbers or terrorists burst into the room. An unhappy guard may feel the trunk at the back of his head before he sees the picture from the IP camera, indicating that an alarming event has occurred. As proof of the foregoing, we present a video where a 2MP IP camera (image below) and a 2MP AHD-H camera (image above) are filming the same scene. Events are filmed in real time while displaying the image on the TV so that no one reproaches us in the attempt of editing.







If this video made you think, then we assure you that the transition from “brooding” IP to fast AHD cameras is much easier than many people think. At the same time, there is no need to replace the cable infrastructure: AHD-H cameras work fine using the same Ethernet cable as the IP cameras. And even the power for the AHD cameras can be arranged over the same wire (since only one pair of 2 wires are used to transmit the video signal, another pair can be used for power supply). Moreover, one 8-core Ethernet cable can be used to tie several AHD cameras at once (up to 2 with power transfer and up to 4 without power transfer), if required. The only thing - AHD cameras need a compatible DVR ( http://secur.ua/videonablyudenie/analoghd/ahdvideoregi/ ). While IP cameras can do without it, recording directly to a computer, cloud service or mobile device. AHD cameras can also write to a computer, cloud service or mobile device - but only through a DVR.



findings



To summarize So, does it make sense to switch to AHD-H? Definitely there, if the surveillance system still uses old analog cameras of the D1 or 960H standards. In this case, you will get a much higher image quality, without the need to change the already used cable infrastructure. If “slow” IP cameras are used in security surveillance, the benefit of using AHD-H will also be: thanks to the image broadcast in real time, the guard will be able to respond quickly to incidents, which will reduce losses from theft, vandalism and other offenses.



Actually, the use of AHD-H equipment is more than relevant at any objects: from small private shops to huge warehouses, from a private residence of a country house to the vast territory of a large industrial enterprise. Moreover, the AHD-H technology makes it possible to get a video image not only quickly, but also with excellent quality, which is quite comparable with the picture quality of more expensive IP cameras.



Plus, on the basis of AHD-H video recorders, it is easy to build hybrid video-monitoring complexes, in which cameras of various generations, standards and resolutions can be used. So, sections that are not too critical in importance can be monitored with the help of old analog cameras - they will not have to be written off. But in important areas or in areas of increased risk, high-resolution AHD-H cameras and IP cameras can be used simultaneously.



The equally reliable operation of AHD-H cameras over coaxial or Ethernet cable allows these cameras to be used in any existing video surveillance system without costly changing the cable infrastructure. And since the deployment and management of AHD video surveillance systems is much simpler than IP-based solutions, plus AHD cameras are also significantly cheaper than digital ones - AHD-H technology turns out to be a good option in the current difficult economic situation, when the private sector and companies have to save on expenses, including security.



PS As an additional introductory material, here is a link to the video recorded by Tecsar AHDW-2M-20F AHD-H video camera.