When to use IP cameras or analog cameras?

Sometimes, I allow a discussion stage to be formed to know the opinions of the interested parties; however, I must almost always suspend the activity because tempers rise and even reach vehement extremes. And it is that this technology awakens loves and hatreds that polarize opinion. For many it is the technology of the future and it is absurd to buy something else; for others they are simple toys that have not been finished inventing. While a minority have had bad experiences, in some cases they adore them, for all that it has meant to their work. Finally some do not say anything, simply because they are not clear about the subject and there is only confusion. For them is for whom this article is written.

On this occasion, I wish to raise my opinion on the technology that will surely replace the current one, in a very short time, perhaps faster than many believe, but not immediately.

What you should know about IP cameras

The first thing I must say is that IP cameras are not for everyone, nor are they the best, nor are they the most expensive, nor are they the latest technology. It is clear that many models are no longer toys; they serve only in some cases, when the conditions for their operation are favorable and surely, in a short time, it will be the technology that will replace the current one. So, should I use them? the correct answer is a simple one: it depends... of the application and above all of the communications network on which it will operate.

At present many myths have been created about it that at the moment of truth remain in that, only myths ... see.

An IP camera is nothing more than an image capture unit, which delivers the video signal in digital form, that is, in ones and zeros.

There are two kinds of IP cameras, those created by factories from the world of IT (Information Technology, that is, computers) and those created by factories from the world of traditional electronic security.

IP cameras for monitoring

The former are characterized by being elements that seek to bring video to remote sites under favorable conditions, without a special mission other than to communicate; these were the obvious and natural consequence of the videoconferencing technologies that revolutionized, a few years ago, the way of working in many companies. They are elements whose mission is not necessarily security.

Today they have become widespread and fashionable, thanks to the advance of processing and storage capacity, added to the advance in digital signal processing techniques and of course to the low prices as a result of this. In this group of cameras we have brands to satisfy all tastes, prices, colors and sizes. They are elements, I insist, whose job is to capture a video image, transmit it over a data network, almost always low speed and communicate two points in a video link that was not always designed for security.

The advertising associated with these teams has vices typical of the IT world, where all brands believe they have the best product, at the best price and take advantage of the ignorance of the final consumer.

Sometimes these cameras are sold as enhanced webcams, but with similar quality and performance specifications. At this level of advanced technology, "plug and play" reigns, because end users buy these high-tech "toys" to meet basic communication, control and monitoring needs. Therefore it is logical to think that these cameras are seen in traditional computer equipment, laptops, PDAs or recently in cell phones, more like a snobbery or a High Tech seal.

The most complex and sophisticated thing in these equipment is to connect the RJ45 connector, since lately handling DHCP, it is not even necessary to assign it an IP address and using PoE (Power over Ethernet. 802.11af), not even one should worry about feeding it, because they already come in the network cable. They are oriented to be massified and to be used in all corners of our planet in an unbridled way, to transmit video and monitor some remote or local action.

The IP video craze has taken advantage of the advances in wireless communications (802.11), to finish massifying the concept of video everywhere, because now it is no longer necessary to even lay a cable, because some bring a wireless transmitter and can easily be coupled to a Wi-Fi network under the 802.11a/b/g/n data transmission standard, among others.

These cameras were the first to be known in the market and for a long time, they were the ones used in security applications. However, we must understand that they were not made with our guild in mind. I want to clarify that they are not bad products, it is just that they do not correspond to the characteristics of the products that security professionals are used to having for our work.

IP cameras for security

The second class of IP cameras are a little more recent and were created by factories of the electronic security guild. Here there are well-known brands that know the philosophy of safety, have a mystique of customer service and know that the specifications must be demanding for a mission-critical such as safety.

For us a video camera, is not an accessory more than a PC, it is a vital tool to take care of properties, assets, heritage and human lives, among others; verifying and recording activities that can become high-magnitude claims. Security professionals know perfectly well the importance of a good video system.

This second class of IP cameras is more consistent with the security guild, therefore, the units are not black boxes, like high-tech equipment "señoriteros" that work plug and play and can not be adjusted anything ... such as those manufactured by IT companies. They are professional teams that take into account all the traditional features of high-performance security video.

Here the cameras are units that handle autoiris lenses (DC or video), zoom lenses, have chips (CCD or similar with many improvements, not the -disastrous but economical CMOS types-) of high resolutions and excellent performance at low light. Its digital circuits have DSPs to make color adjustments and give an excellent range of Back Light Compensation. In the same way, the circuits handle low noise levels and support wide ranges of temperature and relative humidity, (that is, they are not designed to be placed only inside computer centers, like many of the economic ones). They have settings (digital with menu on the video or through DIP switch) of all kinds, where you can make manual adjustment of targets (super important in security) and control the speed of the Shutter. Phase adjustments can also be made to synchronize the cameras and mechanical level adjustments to take full advantage of the autoiris lens.
They also allow you to change from monochromatic mode to color and their resolution can be altered according to the lighting level. The newest ones incorporate motion detectors in each camera and allow these adjustments to be made remotely through the same video connection. They are elements that were designed and manufactured to remain on 24 hours, without failures.

In short, as you can see, they are professional type cameras for security, as we see the traditional ones. The only difference is that the NTSC video signal is not delivered to a BNC connector analogously, but delivered digitally to an RJ45 connector.

As we work in security, it is advisable to always use the cameras that are manufactured under a video concept for security.

I also invite the guild to stop using the general manufacturing cameras that our FRIENDS in IT use for other tasks, and that put at risk the credibility and high standards of reliability, which are necessary in the world of professional security.

A lot of people may think right now that I have animosity for the IT world. That is false, I live with several PCs, PDAs and a cell phone less than 3 meters away from 98% of my life; I depend on them, I don't conceive my work and my daily life without YOU. However, the world of electronic security is more demanding and we simply must recognize that high-performance equipment is different from those of home or routine use in the office.

Therefore we will dedicate ourselves to continue knowing the IP cameras of the second group mentioned.

Features for security

As we can understand the security camera, it operates in a traditional way but internally the unit performs some additional processes before delivering the digitized signal.

As a first step, it compresses video information using digital techniques; in this way, it suppresses redundancy, removes irrelevant information, which is not useful to the human (here is the key to good compression), uses advanced algorithms to make the amount of information smaller and smaller without detracting from quality, speed or resolution. The compression algorithm it uses is very efficient and in this one brand differs from another. Although there are some standard compression formats such as MPEG4, Wavelet or H.264, among others; the brand that achieves the most image compression using proprietary algorithms based on other standards will be the most desired.

And why is the information compressed? simply so that the digitized images reach their destination with good resolution and speed, using the minimum amount of existing data network resources. That is, using the lowest possible bandwidth (BW).

Bandwidth

Remember that bandwidth is the maximum simultaneous transmission speed that a communication medium can transmit. It is given numerically in bits per second (bps).

Like the video information in NTSC standard, it is composed of 30 frames per second and each image in good resolution (VGA, D1 or higher), is composed of many pixels organized in rows by columns; then one second of video would occupy (30 FPS x 640 pixels x 480 pixels x 3 bytes of color information x 8 bits per byte = 211 Mbps) approximately, giant speed compared to the speed of data networks available today (less than 100 Mpbs in 85% of cases). A good compression stage, it reduces from 2 to 5 Mbps approximately and this makes it viable to transmit video over current networks. But don't expect the same analog video quality, be aware that you are taking away a lot of information and that is paid with quality.

Inside an IP camera, the digital and compressed signal is delivered through a standard Ethernet type network card, existing in the vast majority of current networks. Finally, the information is ordered following known transmission protocols used in computer networks. Therefore it is desirable that the camera handles multiple protocols, such as HTTP, SMTP, DHCP, FTP, UDP, TCP/IP, HMTL, among others. Market-leading brands use special techniques to decrease their bandwidth according to other parameters that do not sacrifice quality.

Another important point is how the camera handles video streams and how many different users it can serve simultaneously with the same stream or with different streams . This is known as unicast and multicast.

Nowadays many cameras can make their adjustments through the same RJ45 connector using the network as a transmission medium. If not, the cameras bring an additional communications port (RS232, RS485, LAN) through which the parameters are changed.

In the next installment we will analyze more features of IP cameras, the most common mistakes at the time of using them, how the market develops and when they should be used.

*Germán Alexis Cortés H. is an electronic engineer expert in building automation and General Manager of Insetrón Ltda.  He is dedicated to project consulting and specialized training of  a Latin American nature. If you want you can write to the email [email protected]