Case Study of Emergency Notification System for a University

Introduction
RUniversity is a small private liberal arts university in the Midwest with approximately 2,500 undergraduate students and 500 graduate students. The university has four colleges/schools: the college of arts & sciences, the school of management, the school of graduate and professional studies, and the research college of nursing.

The university upgraded their network over the past three years. They improved the reliability of networks and upgraded their Internet speed. They have also added additional services for redundancy and increased efficiency for all users by replacing old Internet routers and traffic management equipment. This is but a short list of some of the network upgrades that the Computer Services department at R University has been engaged in.

Recently R University approached Kintronics requesting assistance in a new project. The goal of the project was to provide a complete paging system to notify students of emergency situations. A special committee of faculty and staff were tasked with finding a solution that would not only notify students of emergency situations, but also exploit the existing network infrastructure. By using the existing infrastructure they were able to deploy the systems quickly and reduce the labor costs. Since the PA over IP system is treated like any other network with a set of peripheral devices, the in-house IT staff could install and operate the system. This eliminated the need to hire independent installers to install cables and other devices throughout the buildings. Kintronics provided a solution that met their criteria. In what follows is a description of the methodology that we used to develop a system unique to their needs.

Methodology

Clarifying the Objectives:
Our first task was to clarify exactly what the school wanted to accomplish. Did they want the faculty and students to hear the announcement in the halls, in the classrooms, dorm rooms, outdoor areas, etc? This allowed us to determine where the people (the “ears”) would be. They clarified the need for hearing the announcements mostly in the hallways and common areas and in some outdoor areas as well.

The university has approximately 24 buildings situated on approximately 52 acres. Each building varies in size and shape, and total square footage. Given this information we devised a means to determine exactly where the speakers should be placed, so as to ensure that everyone in the target areas would be able to hear the emergency announcements clearly.

Determining where the Speakers would be Located

We started at the location of the “ears”, and determined what the minimum Sound Pressure Level (SPL) was required to be heard over the background noise in each area. Working back from the “ears" we can then determine how far away speakers are from the people based on the sound level output from various types of speakers.

Sound Pressure Level (SPL)
Also, probably more important than either of the aforementioned, is the relationship between the actual Sound Pressure Level and what we perceive as sound. For instance a Sound Pressure Level of 85 decibels would be equivalent to an average amount of traffic on a busy street. Theoretically the sound pressure level associated with a particular sound is based on the geometry of the object producing the sound, and the objects surrounding, or nearby the sound-producing source. As an example consider the objects surrounding the sound-producing source. Let’s say for instance that the point source is a speaker.
Figure 1


Figure 1 depicts a single speaker that radiates sound in all directions. There are no objects in its path to impede the sound from traveling in all directions. The Sound Pressure Level (SPL) is measured with a sound level meter (Figure 2).

Figure 2


In practice a sound level meter is used to determine the precise sound pressure level at a certain distance. To make things easier, all speaker manufacturers provide the SPL at 1 M away from the source, and at 1 Watt power. They sometimes will also provide the sound output at full power input. As an example consider the specifications for the PH10T speaker. It has a SPL of 112 dB at a 1-meter distance, with a full input power rating of 10 WATTS.

We can use a complex formula or use an easier simplified method to determine how much sound is available as we are further away from the speaker. In the article “How Loud is Loud?” an outline of the basic equations for measuring sound pressure levels and determining the relationship between the decrease in sound as a function of distance that the individual is away from the speaker were reviewed. The simplified method says that we lose 6dB of sound each time we double the distance away from the speaker. So at 2 M the sound goes down to 106dB, at 4 M it is at 100 dB, and at 8 M it’s about 94dB. At 10 M we estimate that the sound level is approximately 92 dB. Ten meters is equivalent to approximately 30 feet.

92 dB corresponds to the sound that a diesel truck or motor cycle (loud one) makes. In the results section, we provide a real world example using a set of requirements from a recent client of ours.

Results

The information above can be used to determine approximately where the speakers should be placed for a specific SPL. The objective was to make sure that everyone heard the message. Here’s how we used the information in the previous section to determine near optimal placement of the speakers on one floor of R University’s all-purpose building. Consider Figures 3.

Figure 3

This is the basement floor of the all-purpose building. This floor has an approximate area of 25,000 square feet. Using the floor plan we developed a simple relationship between the drawing measurements and the actual building measurements (i.e. scale). Once the scale was determined, we were able to mark off on the drawing where each speaker should be placed based on the speaker specifications. The details have been omitted for brevity.

Our client determined that each floor should be covered with a SPL of 90-95 dB or greater. For Figure 3 the speakers were placed based on the aforementioned SPL requirement. The speaker that most closely matched our client’s requirements was a PH20T. Each speaker covers an area of approximately 75 feet with an SPL of 90 dB or greater. The orientation of each speaker is largely dependent on the radiation pattern as shown below in Figure 4.

Figure 4

Figure 4, is similar in nature to Figure 1. It demonstrates how far the sound produced by a speaker will reach in all directions. Just like in Figure 1 the speaker is located in the middle of the circle, but it is not shown in this figure, and the dashed line indicates the radiation pattern for the PH20T. It is clear that the radiation pattern resembles a ripple in a pond when a solid object is thrown into the center of it (i.e. omnidirectional). Looking at the radiation patterns we can see that the entire floor is covered with a SPL of at least 90 dB, which coincides with the requirements of our clients. The areas that are not covered have little or no traffic.

We selected the IP7-SS20 amplifier to drive each of the speakers. This amplifier provides an output of up to 20 watts, which is more than enough to achieve the sound level required. Since they connect directly to the network, it was very easy to install. Special software called Talkmaster-EE was installed on two computers (with microphones) that can be used to make announcements. This provided a complete emergency announcement system that used the existing network infrastructure for connecting the amplifiers (with speakers) to the central office. For more details about this system take a look at our article Paging over IP.

Conclusion

R University is one of many clients that we have helped in determining speaker requirements and speaker locations within each building. At Kintronics we use an analytical approach to problem solving. Each solution that we develop for our clients is based on the information that they provide us with. We do not add components superfluously to a client’s system. We pride ourselves on the ability to translate client requirements into system requirements, and make the necessary recommendations. It is our job and responsibility to ensure that the: lives, property, valuables, etc. that our client’s have entrusted us to protect, are safe at all times. We provide the correct solution the first time and provide a very thorough explanation to our clients about the system design.

If you require assistance with translating: ideas or security requirements into system requirements, please contact us at 1-800-431-1658 or 914-944-3425 or use our contact form.

Determining Objectives for IP Cameras

Determine what you want to accomplish
Before purchasing an IP Camera system you should make sure you know what your objectives are. What do you want to accomplish? For example, do you want to catch the criminal, improve productivity, reduce liability, manage a remote office, validate an alarm, or view animals in the wild? Do you want the people to know that you are viewing them or do you want to catch them unawares? Sometimes you may have different objectives for different areas. For example, you may have one objective for cameras viewing the parking lot and other requirements for ones that you place at the doorway. Once you know more about your objectives you can then select the right camera for the job. Here are some guidelines for setting the objectives for your surveillance IP Cameras.
Resolution Required Before we look at applications, let’s first understand how your objectives determine the quality of the video you will need. The surveillance industry defines three different objectives: detection, recognition and identification.
Detection	Recognition	Identification
Detection is just being able to see that a person is there. For example, you are able to differentiate between a person and a horse. This requires the least amount of detail. Axis and other manufacturers have done some evaluation of this and they estimate you need about 5 to 6 pixels/foot to detect a person. Recognition and Identification: It’s easier to identify someone you know, than identifying someone you don’t know from a picture. You can identify a person you know even though you may only see a partial face because you can use many other identifying characteristics such as clothing, body build, etc. If you need to identify an unknown person from a picture you will need more details. It has been estimated by IQinvision and others that you will need about 40 pixels/ft to recognize someone you know, while you will require over 70 - 80 pixels/ft to identify a person you don’t know. All these definitions also assume you are using a camera that provides good performance in many different conditions. Take a look at our previous article for more about the complete specifications of an IP camera. For example, it is very important to consider the type of compression you use. MJPEG provides the best resolution. Other compression schemes such as MPEG4 and H.264 are also good, but can reduce the clarity when things are moving. Whatever you do, don’t use an inexpensive camera if you really want to get the job done. Always remember you get what you pay for. The better IP cameras allow you to identify a person in more situations than a cheap camera. Now let’s look at some objectives. Catch the Criminal So you want to find out who’s stealing the wheelbarrows? In this application you first have to decide if you’re trying to find an employee stealing (someone you know) or trying to catch the crook that breaks into your store. As mentioned above, you will require a different resolution and camera system depending on what you are trying to do. You will need to make sure you have enough pixels/foot to identify the person.
You may want to make the camera visible so that it discourages people from criminal activity, or you may want to catch them unawares. For example the Axis P3344 with a 1280 x 800 resolution is a great vandal resistant dome that can be used to view an area that’s about 32 ft wide. If you need a covert camera, there are a number available, but they are not IP cameras. Instead you will need an analog camera plus a video encoder. Covert cameras are made to look like clocks, sprinklers, desk lamps, smoke detectors and other things. If you want to catch them at night, you may need to add IR illumination. In this case the camera can see what the human eye cannot see. You can select an IP camera such as the Brickcom dome camera which includes a built in IR illuminator. Improve Productivity
Workforce productivity is important to business success. Cameras help to keep people productive and on their best behavior. The cameras can help management monitor and correct work procedures. You probably know the people in the production area and may also know where they should be, so it requires less camera resolution. All you need to see is that a person is at each location, and don’t need to have forensic details. You can use a wide angle lens and view a very large area. In this case you only require about 10 pixels/ft. In this application you can also use a PTZ camera that patrols though many positions. For example the Axis P5534 has high resolution that allows you to view a wide area. You can program it to step through many positions so it can view a very large area.
Reduce Liability Unfortunately there are people who benefit by making false claims against organizations. Cameras can help prevent this type of behavior. Insurance companies are aware of this so they sometimes provide discounts when cameras are installed. It allows them to easily contest erroneous claims. This application requires that you are able to identify the person making the claim. You will also need to decide whether or not you are trying to identify a known or unknown person. The usual assumption is that in the office you will require enough resolution to recognize one of your own people, but require more resolution in the lobby where unknown people are viewed. Since the person could be one of your own employees, and may know where cameras are located, it is a good idea to add some covert cameras. By augmenting the visible cameras with invisible ones, you remove the “off camera” event. The IQ-MX series of cameras provides high resolution so you can view a lobby area and catch everything that’s occurring.
Manage a Remote Office Instead of traveling to your remote sites, you can use IP video cameras to remotely make the visit. In this application you can select IP cameras with two-way audio so you can talk to the people as well as see what’s going on. You probably won’t require very high resolution for this application but you may need to add a microphone and speaker to your remote camera. Note that this is really not the best video conferencing system, since IP systems tend to have delays in transmission. Its primary use is for watching people in remote locations, but using a web browser or NetDVMs software you can have a two-way conversation. Some cameras have a built in microphone and speaker. For example, you can use the Axis M1031-W is a small camera with two-way audio support, built in microphone and speaker to view small conference rooms. If you need to view a larger area, you can use a PTZ type camera with two-way audio like the Axis P5532.
Validate an Alarm
It’s an annoying fact that there are many false alarms from detectors that can be triggered by animals or even the wind blowing a curtain. When you get awakened in the middle of the night it would be great to just go to your computer and look at the store or office to see if anything is going on. Then you can go back to sleep. In this case, you may only need a wide angle view of the area. Of course, if you are also interested in catching the bad person, then you need higher resolution. If you usually have lights on at your facility, you can use a camera such as the IQD40 of if you don’t have lights on at night; you can use a camera with a built-in IR illuminator such as the DDK-1500D.
View Animals in the Wild
We have had a number of requests from people who would like to study or view animals. Sometimes they are in isolated areas and sometimes they are in the local zoo. We still need to ask the question, what do you want to accomplish? If you’re looking at a herd of cows, you need one type of camera, but if you are looking at the small marks on the side of cow, you will need a higher resolution camera system. Things get more complicated when you are out in a remote area. Besides determining the detail required you also need to decide if you want to view animals during the day or at night. You also need to determine how to get power and signal wires to the camera. Since you may need to use solar power system in remote areas, you need a camera that doesn’t use a lot of power. The IQ852 is a good choice since it only requires about 9 Watts of power.
Hope you find all this helpful. If you have a different application and would like some help finding the right IP camera system, just contact us. We can be reached at 1-800-431-1658 (in the USA), or at 914-944-3425 (outside the USA), or just send us a message.

Specifications for IP Cameras

Before purchasing your IP Cameras, it’s best to understand the specifications. IP Cameras have distinct advantages over the older analog cameras, but it’s not always easy to determine the right camera for each viewing situation. For example IP cameras are available with 640 x 480 (VGA) to 2592 X 1944 (5 megapixel) resolution. You certainly don’t need the 5 megapixel camera to view a doorway, so why pay for this extra performance. By reviewing your requirements and camera specifications you can match the camera to each viewing situation. New specifications have been added to the IP Cameras. Specifications to consider include the lens, resolution, light sensitivity, and dynamic range.

THE LENS:
There are a number of different types of lenses. There are fixed focal length, and variable focal length lenses. There are lenses with manual iris and others with auto-irises. Some lenses must be adjusted at the camera, and some new lenses can be adjusted remotely. Here are more details:

Fixed Focal Point Lens: These lenses view a fixed area and you can’t adjust the zoom. They are available with manual and auto iris control. For example the Axis M1101 is a simple indoor camera with a fixed 4.4 mm wide angle lens. It costs under $170

Variable Focal Length Lens: Also called variable lenses, allow you to adjust the field of view by adjusting the focal length setting. These are better lenses since they allow you to make adjustments so that you are viewing exactly what you want. They are available with manual or auto iris.

Iris Control: The iris can be controlled manually or automatically. While it is true that a smaller iris opening often means sharper images, too small an opening may blur an image due to an optical effect called diffraction. This problem can be seen in bright outdoor situations when a camera closes the iris too much and light is diffracted or spread over many pixels. The smaller each pixel is on an image sensor, the more of a problem diffraction becomes because the diffracted light affects more pixels. This can typically happen in cameras that use an automatic DC-iris lens in combination especially with megapixel sensors that have small pixels. (While a megapixel sensor has more pixels than a standard VGA 640x480 image sensor, the size of each pixel on a megapixel sensor is often smaller than the size of each pixel on a VGA image sensor.)

Manual Iris Lens: These lenses are usually used indoors and allow you to adjust the iris opening.

Auto-Iris Lens: The iris of the lens is adjusted by the camera. The iris opening is adjusted automatically when more or less light is required on the sensor of the camera. They are usually required for outdoor cameras. Some IP Cameras like the ones from IQinvision, do not rely on the iris but rather make all the adjustments electronically. The Axis P3343-VE is an example of an outdoor dome camera with an auto-iris lens. This is a very nice camera since the zoom and focus can also be remotely controlled. You can remotely control the view from your computer. It costs less than $1000.

P-iris lenses: P-Iris is a new type of iris control that is both automatic and precise. It works in conjunction with the camera to improve the quality of the video. Unlike a DC-iris lens, the main task of the P-Iris control is not to continuously adjust the flow of light through the lens. The primary objective of P-Iris is to improve image quality by enabling the optimal iris position to be set so that the central and best-performing part of the lens is used most of the time.

The P-Iris works with the electronics of the IP camera. It not only adjusts the iris, it also adjusts the gain (amplification of the signal level) and exposure time. This allows it to manage slight changes in lighting conditions and to further optimize an image. This allows the optimal iris position to be maintained as long as possible. In situations when the preferred iris position and the camera’s electronic processing capabilities cannot adequately correct the exposure, a P-Iris camera will automatically instruct the iris to move to a different position. In dark conditions, for example, the iris will fully open. In bright situations, a camera with P-Iris is programmed to limit the closing of the iris to a position that avoids diffraction or blurring, as explained earlier. Hence, in all lighting conditions, P-Iris can automatically make adjustments to deliver optimal image quality.

Take a look at the two pictures below. You can see the benefits of the p-lens.

Standard auto-iris


P-Iris Lens

At the moment only Axis and CBC have this new functionality. The Axis P1346 and P1347 are examples of cameras with p-iris lenses.

Megapixel Lens: Megapixel cameras require megapixel lenses. These lenses are much clearer than the standard CCTV analog camera lens. They cost more so if you see two megapixel cameras with the same number of pixels but one cost much less, they are probably using a less expensive (not as good) lens. Take a look at our article on how High-Resolution, Megapixel Cameras are not all Alike.

RESOLUTION
The latest IP cameras have the very nice capability of providing much better resolution than the old analog cameras. You can select cameras with 640 x 480 (VGA) lines to 2592 x 1944 pixels (5 megapixels). The resolution of the camera starts with the sensor, but also includes the lens and quality of the processor and compression used in the camera. Take a look at our article High Resolution Cameras are Not all Alike for more about this.

With a higher resolution you can see a wider view. Take a look at the picture below. It gives you some idea of the different views you can see.


To determine what resolution you need, you first consider how wide an area you would like to view and then what detail you need in that field of view. For example, suppose you want to view a doorway and you want to be able to identify a person’s face that comes in the door. In this case you only require a 640 x 480 resolution camera. On the other hand, suppose you want to be able to identify a license plate number in a parking lot that’s 60 ft wide. In this case you need a lot more pixels, and will require a 5 megapixel camera such as the Axis P1347 or IQ755.

COMPRESSION
There are 3 types of compression used by cameras, MJPEG, MPEG4 and H.264. There is some debate about what the best type of compression.

MJPEG requires the most data, provides a complete picture for each frame. Many people say this provides the best resolution.

MPEG4 reduces the amount of data required by only sending the video that change between frames. It improves the compression when there are small parts of the picture that are changing.



H.264 is a version of MPEG4 and provides the best compression. It adds a number of other compression algorithms that dramatically reduce the amount of data transferred. The chart below gives you some idea about the improvement provided by the different compression schemes.



Most new cameras from Axis, IQinvision, Sony and others now provide this compression scheme. This compression uses a lot of computer resources so some high resolution cameras can only handle lower frame rates. As an example, the Axis P1347 provides 5 megapixel resolution and up to 12 fps when using H.264 compression. It sells for under $1499. For more details about the latest compression take a look at our article.

LOW LIGHT AND AMPLIFICATION:
Camera light sensitivity is measured in lux, which is the amount of light reflected from the object being viewed. The lower the lux number the darker the view. For example, 0.27 lux is the amount of light from a full moon on a clear night, while 500 lux is the light in an office.

The low light performance of a camera is determined by:

· The size and sensitivity of the sensor
· The F-Stop and quality of the lens
· The quality of the video amplifier in the camera
· Day/night capability

Sensor: The larger the sensor the more light hits it, so the higher the light sensitivity.

Quality of the Lens (F-Stop): The F-stop and quality of the lens determines how much light gets through the lens. The smaller the F-number the more light gets in.

Amplifier and signal-to-noise: The quality of the amplifier in the camera determines the video performance when there is low light. As the light level goes down, the amplification increases. The signal-to-noise (S/N) of the amplifier becomes important at the lower light levels. When the light level is too low, electrical noise reduces the quality of the video. The better the amplifiers in the camera the less noise will be seen.


The Image on the left has more amplifier noise than the image on the right.

Day/night cameras can operate in greater range of light levels. When it gets dark the camera automatically removes the IR filter allowing more light to hit the sensor. At night the camera also changes to monochrome mode and improves the total light sensitivity of the system.

Cameras from IQinvision and Axis have good low light performance. For example the Axis P3343 and the IQeye IQ752 can operate in light levels as low as 0.05 lux. This means the cameras can see things even our eyes can’t see.

DYNAMIC RANGE
The dynamic range of a camera is a measure of the minimum and maximum light the camera can see in one frame. Wide dynamic range is helpful when you are looking at a person against a very bright background. Sony has introduced cameras with very wide dynamic range that allows you to see the image on the top.

CONCLUSION
As you can see it’s important to consider many of the camera specifications before selecting a camera. This assures you get the right camera at the right price. The type of lens, iris opening, resolution, compression, and dynamic range all need to be considered.

If you need help selecting the camera or lens, please give us a call at 914-944-3425 or send us a message. We are always there to help you get the right IP camera system.

Special IP Cameras for Special Situations

When IP cameras were introduced a few years ago there were very few choices. Today there‘s a wide selection from which to choose. They have really replaced the old analog camera systems. Now there are special IP camera systems that are designed for special situations. There are cameras that see in the dark, others that can see over a mile away, systems that are designed for cities, others that can work no matter where they are, and others that are covert and hidden so no one knows they are being recorded. This article reviews some of these specialized IP camera systems.

The Nite Track IP camera is a special PTZ camera that includes an IR illuminator. This system allows you to see in total darkness over 600 ft from the camera. It is a very effective covert camera system because people can’t see the IR illumination at night. The illuminator can be adjusted to see exactly the area you want to see. Take a look at the web page for more details.

If you need a system that can see over a mile away, there’s the special PTZ IP camera system that uses a focused laser IR illuminator. It’s matched with a high performance 60X optical zoom lens that adjusts from 12.5mm to 750 mm or with doubler adjusts from 25 mm to 1500mm. During the day this amazing camera allows you to recognize things that are 19,685 ft away (6,000 M). At night the special laser illuminator reaches out 4,921 ft (1,500M). There’s more on our web page.

When you need a camera system that can watch almost everywhere at once, take a look at the IPDeputyNVR system. This system mounts on a pole and includes up to two cameras. This rugged outdoor surveillance system includes everything you need to establish a vandal resistant neighborhood surveillance system. The system includes choice of cameras and a built in computer with NVR software that provides up to 1 TB of storage. You can select standard IP cameras, megapixel or PTZ cameras. All this is provided in a complete environmental enclosure with power distributor, surge protection, heater/blower and space for additional components. The system communicates with your network by WiFi wireless, direct Internet connection or even 3G/4G cell communication.

What happens when there’s no Internet connection? Well you can use a complete camera system that includes an NVR system all in a covert box. This box also includes battery backup so that it will operate even if someone cuts the power. The system looks like an electrical box. It has room for a number of different cameras that include the IQ752 camera. With this megapixel camera you get enough resolution to identify a person’s face in an area that’s about 48 ft wide. It can see even when there’s very little light, with sensitivity of less than 0.05 lux. The battery backup allows the system to operate for hours without power. The camera has a CF memory card slot so you can add on board storage that can record many hours of video. This complete solution allows you to place a camera in new locations that were historically not available by IP cameras systems.

There are many more special cameras available and more becoming available every day. Just contact us for the latest and greatest at 1-800-431-1658 or 914-944-3425 or use our contact form.

H.264 Compression

The latest IP cameras are using the new video compression H.264. We have had many questions about this new compression method so here’s an article that provides the information you will need to better understand this new technology.

H.264 is a new version of MPEG4 and it provides about twice as much compression as the older version. Apple has been using this standard for a number of years and it is now available in the latest IP Cameras. A number of manufacturers have begun to introduce this technology. Axis is in the lead at the moment, but other companies such as Sony, IQinvision and others are slowly introducing their new models as well.

This latest video compression standard, H.264 (also known as MPEG-4 Part 10/AVC for Advanced Video Coding), is becoming the video standard of choice.

Compression Concept
The intent of the H.264/AVC project was to create a standard capable of providing good video quality at substantially lower bit rates than previous standards (e.g. half or less the bit rate of MPEG-2, H.263, or MPEG-4 Part 2), without increasing the complexity of design so much that it would be impractical or excessively expensive to implement. An additional goal was to provide enough flexibility to allow the standard to be applied to a wide variety of applications on a wide variety of networks and systems, including low and high bit rates, low and high resolution video, broadcast, DVD storage, RTP/IP packet networks, and ITU-T multimedia telephony systems.

H.264 is an open, licensed standard that supports the most efficient video compression techniques available today. Without compromising image quality, an H.264 encoder can reduce the size of a digital video file by more than 80% compared with the Motion JPEG format and as much as 50% more than with the MPEG-4 Part 2 standard. This means that much less network bandwidth and storage space are required for a video file. Or seen another way, much higher video quality can be achieved for a given bit rate.

Jointly defined by standardization organizations in the telecommunications and IT industries, H.264 is expected to be more widely adopted than previous standards.Video compression is about reducing and removing redundant video data so that a digital video f ile can be effectively sent and stored. The process involves applying an algorithm to the source video to create a compressed file that is ready for transmission or storage. To play the compressed file, an inverse algorithm is applied to produce a video that shows virtually the same content as the original source video. The time it takes to compress, send, decompress and display a file is called latency. The more advanced the compression algorithm, the higher the latency, given the same processing power.

A pair of algorithms that works together is called a video codec (encoder/decoder). Video codecs that implement different standards are normally not compatible with each other; that is, video content that is compressed using one standard cannot be decompressed with a different standard. For instance, an MPEG-4 Part 2 decoder will not work with an H.264 encoder. This is simply because one algorithm cannot correctly decode the output from another algorithm but it is possible to implement many different algorithms in the same software or hardware, which would then enable multiple formats to be compressed. Different video compression standards utilize different methods of reducing data, and hence, results differ in bit rate, quality and latency.

The graph below provides a bit rate comparison, given the same level of image quality, among the following video standards: Motion JPEG, MPEG-4 Part 2 (no motion compensation), MPEG-4 Part 2 (with motion compensation) and H.264 (baseline profile).

Figure 1. An H.264 encoder generated up to 50% fewer bits per second for a sample video sequence than an MPEG-4 encoder with motion compensation. The H.264 encoder was at least three times more efficient than an MPEG-4 encoder with no motion compensation and at least six times more efficient than Motion JPEG.

Frames
Depending on the H.264 profile, different types of frames such as I-frames, P-frames and B-frames, may be used by an encoder.
An I-frame, or intra frame, is a self-contained frame that can be independently decoded without any reference to other images. The first image in a video sequence is always an I-frame. I-frames are needed as starting points for new viewers or resynchronization points if the transmitted bit stream is damaged. I-frames can be used to implement fast-forward, rewind and other random access functions. An encoder will automatically insert I-frames at regular intervals or on demand if new clients are expected to join in viewing a stream. The drawback of I-frames is that they consume much more bits, but on the other hand, they do not generate many artifacts.

A P-frame, which stands for predictive inter frame, makes references to parts of earlier I and/or P frame(s) to code the frame. P-frames usually require fewer bits than I-frames, but a drawback is that they are very sensitive to transmission errors because of the complex dependency on earlier P and I reference frames.

A B-frame, or bi-predictive inter frame, is a frame that makes references to both an earlier reference frame and a future frame.

Figure 2.
When a video decoder restores a video by decoding the bit stream frame by frame, decoding must always start with an I-frame. P-frames and B-frames, if used, must be decoded together with the reference frame(s).In the H.264 baseline profile, only I- and P-frames are used. This profile is ideal for network cameras and video encoders since low latency is achieved because B-frames are not used.

Basic Concepts of Reducing the Data
A variety of methods can be used to reduce video data, both within an image frame and between a series of frames.
Within an image frame, data can be reduced simply by removing unnecessary information, which will have an impact on the image resolution. MJPEG utilizes this algorithm.

In a series of frames, video data can be reduced by such methods as difference coding, which is used by MEPG4 and H.264. In difference coding, a frame is compared with a reference frame (i.e. earlier I- or P-frame) and only pixels that have changed with respect to the reference frame are coded. In this way, the number of pixel values that are coded and sent is reduced.

Figure 3. With Motion JPEG format, the three images in the above sequence are coded and sent as separate unique images (I-frames) with no dependencies on each other.

Figure 4. With difference coding (used in most video compression standards including H.264), only the first image (I-frame) is coded in its entirety. In the two following images (P-frames), references are made to the first picture for the static elements, i.e. the house, and only the moving parts, i.e. the running man, is coded using motion vectors, thus reducing the amount of information that is sent and stored.

The amount of encoding can be further reduced if detection and encoding of differences is based on blocks of pixels (macroblocks) rather than individual pixels; therefore, bigger areas are compared and only blocks that are significantly different are coded. The overhead associated with indicating the location of areas to be changed is also reduced.

Difference coding, however, would not significantly reduce data if there was a lot of motion in a video. Here, techniques such as block-based motion compensation can be used. Block-based motion compensation takes into account that much of what makes up a new frame in a video sequence can be found in an earlier frame, but perhaps in a different location. This technique divides a frame into a series of macroblocks. Block by block, a new frame—for instance, a P-frame—can be composed or ‘predicted’ by looking for a matching block in a reference frame. If a match is found, the encoder simply codes the position where the matching block is to be found in the reference frame. Coding the motion vector, as it is called, takes up fewer bits than if the actual content of a block were to be coded.

Figure 5. Illustration of block-based motion compensation

Improving Compression Even more with H.264
H.264 takes video compression technology to a new level. With H.264, a new and advanced intra prediction scheme is introduced for encoding I-frames. This scheme can greatly reduce the bit size of an I-frame and maintain a high quality by enabling the successive prediction of smaller blocks of pixels within each macroblock in a frame. This is done by trying to find matching pixels among the earlier-encoded pixels that border a new 4x4 pixel block to be intra-coded. By reusing pixel values that have already been encoded, the bit size can be drastically reduced. The new intraprediction is a key part of the H.264 technology that has proven to be very efficient. For comparison, if only I-frames were used in an H.264 stream, it would have a much smaller file size than a Motion JPEG stream, which uses only I-frames.

In this mode, four bottom pixels from the block above are copied vertically into part of an intra-coded macro-block.	In this mode, four right-most pixels from the block to the left are copied horizontally into part of an intra-coded macroblock.	In this mode, eight bottom pixels from the blocks above are copied diagonally into part of an intra-coded macro-block.

Figure 6. Illustrations of some of the modes that intra prediction can take in coding 4x4 pixels within one of the 16 blocks that make up a macroblock. Each of the 16 blocks in a macroblock may be coded using different modes.

Original source image Intra predicted image

Residual image Output image
Figure 7. The above images illustrate the efficiency of H.264’s intra prediction scheme, whereby the intra predicted image is sent for “free”. Only the residual content and the intra prediction modes need to be coded to produce the output image.

Block-based motion compensation—used in encoding P- and B-frames—has also been improved in H.264. An H.264 encoder can choose to search for matching blocks—down to sub-pixel accuracy—in a few or many areas of one or several reference frames. The block size and shape can also be adjusted to improve a match. In areas where no matching blocks can be found in a reference frame, intra-coded macroblocks are used. The high degree of flexibility in H.264’s block-based motion compensation pays off in crowded surveillance scenes where the quality can be maintained for demanding applications. Motion compensation is the most demanding aspect of a video encoder and the different ways and degrees with which it can be implemented by an H.264 encoder can have an impact on how efficiently video is compressed.

With H.264, typical blocky artifacts—seen in highly compressed video using Motion JPEG and MPEG standards other than H.264—can be reduced using an in-loop deblocking filter. This filter smoothes block edges using an adaptive strength to deliver an almost perfect decompressed video.

Figure 8. Blocky artifacts in the highly compressed image at left are reduced when a deblocking filter is applied, as seen in the image at right.

Conclusion
H.264 compression provides a significant improvement in video compression technology. It is supported by many different standards groups making it one of the most accepted standards. Because it provides a dramatic improvement in compression, it reduces the bandwidth and storage required. It provides an 80% improvement over MJPEG compression and about 50% improvement over MPEG4 compression. It is now available in the latest cameras from Axis, and other manufacturers.

Need more information about this compression or the cameras that utilize it, just contact us at 914-944-3425 or by using our contact form.

Access Control Technology Review

Door access control systems have changed over the years. The early units were quite difficult to install. They used simple card readers with all the intelligence located back at the control panel. Over the years more intelligent devices were developed, and now, in the state-of-the-art solutions, most of the intelligence is located at the reader near the door. The latest IP type readers make use of your Ethernet network and are very easy to install. This article reviews the types of systems available and how they can be integrated with IP cameras.

In physical security, the term access control refers to the practice of allowing entrance to a property, a building, or a room only to authorized persons. Physical access control can be achieved by a human (a guard, bouncer, or receptionist), through mechanical means such as locks and keys, or through technological means such as door access control systems that use magnetic locks. In general, in an automated system, access is controlled using a special RFID type proximity card or by keying in an ID number. If the system accepts the person, a relay is activated that unlocks the door.

HISTORICAL REVIEW

Basic non-intelligent Readers: The first automated door access control systems utilized simple non-intelligent reader panels that connected back to a central control panel. All the access requests were forwarded back to the central control panel.

Semi-intelligent Readers: The next generation of readers included some intelligence. These readers included enough intelligence to control the door lock hardware, but did not make any access control decisions. The reader simply passed on the code entered to the main controller and then waited for a response. These readers are usually connected to the main panel via an RS-485 bus.

Intelligent Readers: The first intelligent readers connected back to a centralized control panel via the same RS-485 connection as semi-intelligent readers. They included memory and enough intelligence to make access decisions independently of the control panel. The special control panel provides configuration updates and receives events from the readers and maintains a history of the door access.

Intelligent IP Reader and Controller: This is the latest type of reader (such as the reader from ISONAS). It’s similar to the intelligent reader in that all the decisions are made at the reader, but instead of using a specialized control panel, it uses a standard computer running access control software. It also uses the standard network infrastructure for communication (CAT 5 or 6 cable). Since it totally eliminates any special wiring and specialized control panels, it is the simplest to install and maintain.

IP DOOR ACCESS CONTROL

The latest door control systems use an IP reader and special software that runs in a Windows computer. The IP reader is attached to the Ethernet network. Magnetic locks and strikes secure the doors which are opened by the IP Reader when the right access card (or other RFID device) passes near the IP Reader. Each Reader contains a list of people who are allowed to enter the door. Software running in a Windows computer is used to control the system, add the people who are allowed to enter the door, send the list to the readers and provide reports of who and when people entered.

IP Reader
An IP based system, such as the one from ISONAS, utilizes the latest IP readers. It does not require a centralized control panel. Since this system uses network attached components and standard computer systems it provides a very flexible door control system. The reader is powered over Ethernet (PoE) so you don’t require any additional power wires. The reader includes door sense input connections and provides an output that controls the electric door lock.

These readers are designed for both indoor and outdoor use. The optional keypad can be used for additional personnel verification. There are models that use the HID format RFID proximity devices. The devices are available in many different formats from plastic cards, to keychain fobs.

Magnetic Locks and Strikes
There are a variety of automated door locking systems available. You can select either a magnetic lock or electric strike to secure a door.

Magnetic locks are used in high security areas where you need to monitor the movement of people. Since people are required to use their access cards in both directions, you can track who enters and leaves a secure area.

The locking system uses an electromagnetic and armature plate to secure the door. The electromagnet is attached to the door frame while the armature plate is attached to the door. A current passes through the electromagnetic so that it is magnetically attracted to the armature plate holding the door closed. The magnetic strength can provide over 1500 lbs. of holding force. Locks with higher magnetic force can be used to secure an outer door, while lower force locks can be used to secure inner doors.

The locks require special power supplies that can be integrated into a fire panel. It is important to assure that the locks can be released if an emergency situation occurs.

The electric strike are easy to install and are used to secure outer and inner doors, but do not prevent egress from an area like the magnetic lock. It replaces the fixed strike place in a standard lock. Like a fixed strike, it normally presents a ramped surface to the locking latch allowing the door to close and latch just like a fixed strike would. To exit from a secured area, the door can be opened by using a knob or level.

To simplify installation, it is important to use locks that require less than 500ma of current. This allows the reader to be powered over Ethernet. The electric locks from Rutherford Controls are examples of this type of low power lock.

Electric strikes generally come in two basic configurations:

• Fail-secure. Also called Fail-locked or non-fail safe. In this configuration, applying electrical current to the strike will cause it to open. In this configuration, the strike would remain locked in a power failure, but typically the knob can still be used to open the door from the inside for egress from the secure side. These units can be powered by AC which will cause the unit to "buzz", or DC power which will offer silent operation, except for a "click" while the unit releases.

• Fail-safe. Also called Fail-open. In this configuration, applying electrical current to the strike will cause it to lock. In this configuration, it operates the same as a magnetic lock would. If there is a power failure, the door would open merely by being pushed/pulled open. Fail safe units are always run using DC power.

ADDING THE IP CAMERA

Adding video to a door control system increases the overall security of the system. By viewing and recording the video, you can keep a visual record of all the people entering your facility as well as determining if the access tag matches the person. You can also catch multiple people entering with only one access (tailgating). Adding additional software will even allow you to do this automatically.

IP camera
By adding an IP camera you can view who enters and leaves an area. The video is captured at the computer running the special NVR software. Cameras from Axis, JVC, IQinvison and others can be used to capture the video.

Adding audio: By using an IP camera that supports audio you can even record the audio at the time of entry. There are many cameras that support audio but you must also select cameras that are also supported by the NVR software. Cameras from Axis and Sony are supported by a number of NVRs and are available with 2-way audio support.

Software
It is important to select access control and the video recording software that are compatible. For example, the Isonas Crystal Matrix software and OnSSI’s NetDVMS software work well together.

The IP reader system notifies the Crystal Matrix Software that a person has opened a door. The Crystal Matrix software then notifies the NetDVMS surveillance software that the door has been accessed causing the NVR software to record the video from the specific camera that is watching the door. Since the video is time stamped you can easily match video to the door access software timeline.

Adding additional Intelligence
There is also optional analytic software available (such as AgentVI) that can automatically watch for tailgating and provide alarms if more than one person tries to enter an area.

MANNED ACCESS CONTROL USING JUST AN IP CAMERA AND INTERCOM

As an alternative to an automated system, you can control access by just using an IP camera at each entry door. This works only if you have a centralized security person. Using a camera and intercom, the security person can talk to the person at the door, make a decision based on the picture he sees on his monitor, and then press a lock release button to open the remote door. All communication is done over your Ethernet network so it’s easy to implement.
Here’s what you need to implement the system:

Cameras with Audio
In almost all cases a camera that includes audio, supports MPEG4 compression. This form of compression includes data packets for audio transfer as well as video. For example, the Axis 210A includes two-way audio. It has audio input and audio output so you can attach a microphone and powered speaker. Other cameras with audio include Axis214PTZ and Axis211A.

The intercom and microphone are connected to inputs on the IP camera. All the information from the camera is sent over the standard Ethernet network back to a Windows type PC server.

Doorway Intercoms

To have a two-way conversation with someone at a doorway requires both a microphone and speaker. The microphone and the speaker must be compatible with the input and output requirements of the camera. It’s best to use a directional microphone to minimize any extra noise in the area. Here’s an example of a two way system that is compatible with most cameras.

AOP-SP-WS
Bi-directional Speakerphone. Surface Wall mount speakerphones are designed to interface with various modes of audio/video transmission systems. They provide bi-directional audio with the IP Network cameras that support audio, and video servers with audio support. It contains a built-in electret condenser microphone and a 4" speaker. Also control potentiometers for adjusting the sensitivity of both transmitted and received audio. It can be used outdoors but requires protection from direct exposure to the elements.

NVR IP Software
Special software that runs in your Windows PC computer is used to communicate with the intercom and allows you to view and record the video. For example, NetDVR and NetDVMS from OnSSI provide two-way audio support as well as recording both the video and audio.

These systems are easy to implement but I’m sure you will have questions about all the details. Just contact us at 914-944-3425 or use our contact form to get more information.

What's a Watt

Knowing more about voltage, current and power can help when you are putting together an IP camera system. This is especially true when you are selecting the power supply and running the wire. Computers, light bulbs and cameras have a power rating that is measured in Watts and sometimes in Volt-Amps (VA). Ever wonder what a Watt is, or why we sometimes use watts and other times Volt-Amps? It’s important to know about the power, because if you don’t have enough of it you’re in trouble. This article provides the information you need to stay out of trouble.

Current is the flow of electric charge. The unit of measure for current is the ampere, or abbreviated it’s “amp”. If you stick your finger in an outlet (please don’t do this), it’s the current that knocks you on your rear. The more current you have, the larger the size (or gauge) of the wire you need to carry the flow of the current. If the wire gauge is too small, it resists the flow of the current and it gets hot. (See the description of a resister below.)

Resistance is what generates the heat when voltage and current are applied to an electric circuit. An electric heater is an example of a resister. The more current that follows through a resister the hotter it will get. Resistance is measured in ohms.
Voltage and current are related in electrical equipment by Ohm’s law. Voltage (V) is related to current (I) by the resistance (R) of the electrical circuit. The formula is V=I X R. This means that if you run 2 amps of current through an IP camera that has a resistance of 6 ohms you will get 12 volts (2 X 6 = 12 volts).

Almost everything, including wire, has some resistance. The thicker the wire the less resistance it has to the flow of the current. It’s like having a larger size pipe for water. The thinner the wire gauge the more resistance the wire will have, and the lower the voltage will be at the end of the wire. Also, the longer the length of the wire the more resistance is added. When you have a long run of wire, you should use a larger gauge size wire (thicker) to reduce the resistance.

For those who need more details, here they are, otherwise just go to Voltage description below.
To illustrate the problem of wire resistance, I will use a slightly more complicated drawing. In this example I added the 2 ohm resister to represent the resistance of the wire. Now there is a total of 8 ohms in the circuit (6 + 2 = 8). Since there is now more resistance in the circuit, the amount of current changes and so does the amount of voltage available at the camera. The equation to calculate the current is: I = V/R. So now the current equals 12/8 or 1.5 amps. The camera that was getting 12 Volts before we added the resistance of the wire is now getting only 9 volts (I used the formula V=I X R for this. 1.5 A X 6 R = 9 volts.) This lower voltage could be a problem for the camera. There are some charts on the Internet such as the one at http://www.interfacebus.com/Copper_Wire_AWG_SIze.html. It describes the American Wire Gauge (AWG) for various gauges vs. the resistance of 1000ft of wire.

Voltage is the difference of potential between two points of an electrical circuit. The higher the potential the more volts you have. For example you can generate a lot of voltage by rubbing your feet on a carpet, and make quite a large spark when you touch a metal surface (or someone else).

Another example can be seen at museums that have scientific displays. Sometimes they have displays that show the effect of voltage. They let kids touch the surface of a large metal ball. When they touch it, their hair sticks out in all directions. This is called a Van der Graf generator (but you probably don’t need to know this). It generates a very large voltage on the surface of the metal ball, and the static electricity makes your hair stand on end.

Now for Watts:
Here’s the definition of a watt: the watt (symbol: W) is equal to one joule of energy per second (and about 745 watts equals 1 horsepower). It measures a rate of energy conversion. It was named after our old friend James Watt. Remember his work with the steam engine? If not, you’re not smarter than a fifth grader.

Here are some examples of the Watt. A human climbing a flight of stairs is doing work at a rate of about 200 watts. An automobile engine can produce mechanical energy at a rate of 25,000 watts (which is equal to approximately 33.5 horsepower) while cruising. A household incandescent light bulb uses electrical energy at a rate of 25 to 100 watts, while compact fluorescent lights typically consume 5 to 30 watts. We also have Kilowatts (1,000 watts), Megawatts (1,000,000 watts) and if you have a power station available Gigawatts (too many zeros (9 actually)).

First off, you may know this, but there are two different types of electrical systems. There is Direct Current (DC) systems and Alternating Current (AC) systems. I’m going to start by explaining DC systems which are simpler than AC systems.

The Watt is related to the voltage and current. The formula for calculating the watt is: Watts (W) equal Current (I) X Voltage (V) or W = I x V. For example if I have a camera that requires 12 V DC and it takes 2 amps, it will require a power supply that can provide at least 24 watts. (2 x 12 = 24).

Volt-Amps or Power in an Alternating Current System
Power is fairly simple, when you are using a DC power supply. It gets a little more complicated when you use an AC power supply. In the alternating current world the voltage cycles up and down. This is called a sine wave. The voltage goes positive and then negative and back again. The current goes back and forth as well. These two cycles can be affected by the load, especially when the load includes other components such as a transformer or motor. Pan tilt cameras with motors are an example of a complex load.

When there is a complex load, the sine wave for the voltage can get displaced from the sine wave for the current and this changes the real power we will need. When we compute power in an AC network we use Volt-Amps instead of Watts.
We use the Power Factor to adjust for this variable power load. Now the Volt-amps equal the watts divided by power factor. The power factor is a number between 0 and 1 and its value is determined by the properties of the load. So if you have a system that needs 20 watt but there is a power factor of 0.5, the Volt-Amp required is 20 / 0.5 = 40 watts. Notice that the unit of measure is the same (further confusing things).

If you have a camera or other device that doesn’t have a complex load then the power factor equals “1”. This is true in most fixed IP cameras. In this case, Watts equals Volt-Amps.

In summary, current, resistance and power are important specifications to consider when installing IP cameras or any type of camera system. The gauge (thickness) and length of wire is important because it can affect the voltage. Power is measured in Watts, but it can also be the same as Volt-Amps, it’s just determined by the type of load (or camera) that’s used.

If you would like more information about how voltage, current and power affect your IP camera system, just contact us at 914-944-3425 or use our contact form.