You've probably seen advertisements for POE switches and POE-compatible IP cameras. Here's what this all means, at least as far as IP cameras and other devices that are installed over an Ethernet network.
POE is an established technology that provides low-voltage direct current (DC) power delivery to network devices over the same wires that currently carry data. This means you can now run only one cable and still be able to both power the device and transfer data. The specifications come from the IEEE standard 802.af. This allows the powering device to use a voltage from 36-57 VCD. The most common voltage found is 48 volts.
Here are the different classes of POE devices.
Class Usage Maximum Power Levels at Input of Powered Device [Watt]
0 Default 0.44 - 12.94
1 Optional 0.44 - 3.84
2 Optional 3.84 - 6.49
3 Optional 6.49 - 12.95
4 Reserved (PSEs classify as Class 0)
One of the problems with CCTV IP cameras is that sometimes a heater, blower and a PTZ device are needed in some applications. The current standard only provides a maximum of 15.4 watts. Most PTZ devices and heaters and blower exceed this maximum.
There is good news on the horizon. A future standard, commonly referred to as POE+, is being developed by the IEEE 802.3at task force. There is still debate on the maximum wattage, but it is typically between 24 and 30 watts. This will allow many manufacturers to design their PTZ cameras with heaters and blowers around this new standard and still only run one cable to the camera location from the network switch.
Monday, July 27, 2009
Friday, July 10, 2009
Understanding IP Megapixel Resolution
Many end users will specify a mega pixel resolution camera but not consider what they will actually see with the cameras themselves. Many manufacturers have their own numbers for the ability to identify people and license plates. This number is called the pixel density (how many pixels are available in a given space) and is stated as pixels per foot. We will use one manufacturer’s number of 45 pixels per foot to be able to read a license plate.
Let’s say we have a three megapixel camera and we want to know if we will be able to have license plate recognition (LPR). The formula for determining this is as follows:
Pixel Density (PD) = Pixels (camera resolution)/ Field of View.
For our example, our field of view is 30 feet.
The horizontal pixel count for a 3 mega pixel camera is 2048 pixels.
PD = 2048 / 30
PD = 68.2 pixels per foot
The answer is yes, we will be able to read the license plate with a field of view of 30 feet, using a 3 megapixel camera.
We can look at this from another perspective. What would my field of view be if I have a 5 megapixel camera and I still want to have the ability to view license plates?
The horizontal pixel count for a 5 mega pixel camera is 2592 pixels.
Field of View (FOV) = Pixels / Pixel Density
FOV = 2592 / 45
FOV = 57.6 feet
Before the camera system is installed, examine what exactly you want to view and don't just blindly install cameras in all locations.
Let’s say we have a three megapixel camera and we want to know if we will be able to have license plate recognition (LPR). The formula for determining this is as follows:
Pixel Density (PD) = Pixels (camera resolution)/ Field of View.
For our example, our field of view is 30 feet.
The horizontal pixel count for a 3 mega pixel camera is 2048 pixels.
PD = 2048 / 30
PD = 68.2 pixels per foot
The answer is yes, we will be able to read the license plate with a field of view of 30 feet, using a 3 megapixel camera.
We can look at this from another perspective. What would my field of view be if I have a 5 megapixel camera and I still want to have the ability to view license plates?
The horizontal pixel count for a 5 mega pixel camera is 2592 pixels.
Field of View (FOV) = Pixels / Pixel Density
FOV = 2592 / 45
FOV = 57.6 feet
Before the camera system is installed, examine what exactly you want to view and don't just blindly install cameras in all locations.
Monday, July 6, 2009
Success in Flushing Community School District
Between top education priorities and the Fourth of July weekend, we didn't have time to put together a new tip for you. Fortunately, our friends at Exacq have a success story to share.
The Flushing Community School District covers 65 square miles, with a population of approximately 25,000. K-12 enrollment is approximately 4,277 students, with 8 school buildings serving the educational needs of the students.
exacqVision video management software (VMS) was installed to help Flushing administration "monitor student behavior after the fact." exacqVision is installed on two industry standard servers with video recording to a 30TB iSCSI disk array. ExacqVision manages 149 IP cameras and encoders located throughout 8 school buildings to provide a safe and orderly environment in which all student have an opportunity to realize their potential.
Each school has the exacqVision client software installed on the principals' and secretaries' PCs, giving them access to only those cameras located in their buildings. When an incident is reported, staff will search digital video recorded on the servers to investigate and support their findings. Video can be easily exported to a DVD or USB flash drive and may be shown to students, parents or police as per board policy. Video evidence helps Flushing reduce repeat offenses.
The complete success story can be found at http://www.exacq.com/downloads/exacqvision-education-fcs.pdf.
The Flushing Community School District covers 65 square miles, with a population of approximately 25,000. K-12 enrollment is approximately 4,277 students, with 8 school buildings serving the educational needs of the students.
exacqVision video management software (VMS) was installed to help Flushing administration "monitor student behavior after the fact." exacqVision is installed on two industry standard servers with video recording to a 30TB iSCSI disk array. ExacqVision manages 149 IP cameras and encoders located throughout 8 school buildings to provide a safe and orderly environment in which all student have an opportunity to realize their potential.
Each school has the exacqVision client software installed on the principals' and secretaries' PCs, giving them access to only those cameras located in their buildings. When an incident is reported, staff will search digital video recorded on the servers to investigate and support their findings. Video can be easily exported to a DVD or USB flash drive and may be shown to students, parents or police as per board policy. Video evidence helps Flushing reduce repeat offenses.
The complete success story can be found at http://www.exacq.com/downloads/exacqvision-education-fcs.pdf.
Friday, June 26, 2009
Designing your networks for IP video
So you've made the decision to go with an IP Video Management system. How do you design your network to handle all of the video from the IP cameras? Here's what to think about:
A. Bandwidth available: If you're installing the new camera system on an existing network (not recommended), how much overhead do you have to devote to the new system?
Some common guidelines include:
1. A maximum of 5 Mbps on each network port
2. Not more than 100 Mbps per uplink
3. Not more than 500 Mbps per NVR server port
Remember that to transmit IP video images that are measured in bytes per second across networks that are measured in bits per second, you have to multiply by 8.
B. Power and signal feeds: CAT 5e and CAT6 cabling, already installed in the building, has distinct advantages. Connecting a Power over Ethernet (POE) switch port to an IP camera allows both the signal and the power to be transmitted across the cable. This can result in saving thousands of installation dollars since the additional power cable does not have to be run. Next, determine what the powered device will require from the switch. This is referred to as a POE class, and there are four classes, zero through three, each requiring a different amount of power draw in watts. The design engineer can also figure in uninterrupted power supplies (UPS) back in the data room. When the power is lost, the camera is still recording and video is still available from PCs with UPS backup. It is now easy to figure the power budget by using the following formula:
Number of cameras x power class (in watts) = power budget
C. Traffic Segmentation: There are two different ways to divide or segment traffic on an Ethernet network. One is to physically separate the IP camera network from the company’s production network by running separate network cables and installing new switches. This is by far the most expensive way to segment traffic. The other way is to program Virtual Local Area Networks (VLANs). This method utilizes the existing switch and separates specific ports into their own smaller networks.
A. Bandwidth available: If you're installing the new camera system on an existing network (not recommended), how much overhead do you have to devote to the new system?
Some common guidelines include:
1. A maximum of 5 Mbps on each network port
2. Not more than 100 Mbps per uplink
3. Not more than 500 Mbps per NVR server port
Remember that to transmit IP video images that are measured in bytes per second across networks that are measured in bits per second, you have to multiply by 8.
B. Power and signal feeds: CAT 5e and CAT6 cabling, already installed in the building, has distinct advantages. Connecting a Power over Ethernet (POE) switch port to an IP camera allows both the signal and the power to be transmitted across the cable. This can result in saving thousands of installation dollars since the additional power cable does not have to be run. Next, determine what the powered device will require from the switch. This is referred to as a POE class, and there are four classes, zero through three, each requiring a different amount of power draw in watts. The design engineer can also figure in uninterrupted power supplies (UPS) back in the data room. When the power is lost, the camera is still recording and video is still available from PCs with UPS backup. It is now easy to figure the power budget by using the following formula:
Number of cameras x power class (in watts) = power budget
C. Traffic Segmentation: There are two different ways to divide or segment traffic on an Ethernet network. One is to physically separate the IP camera network from the company’s production network by running separate network cables and installing new switches. This is by far the most expensive way to segment traffic. The other way is to program Virtual Local Area Networks (VLANs). This method utilizes the existing switch and separates specific ports into their own smaller networks.
Thursday, June 18, 2009
CCD vs CMOS
The image sensor is the camera component which captures light and begins the process of turning it into a digital image. There are two types of security camera sensors: CCD (charge coupled device) and CMOS (complementary metal oxide semiconductor). Which of the two you choose depends on your application.
With a CCD sensor, every individual pixel's charge is transferred through an output node, which is converted into an electrical signal. The signal is then buffered and sent as an analog signal. Because the pixels are devoted to light capture, the image quality is usually pretty high.
With a CMOS sensor, every individual pixel performs its own charge-to-voltage conversion, and the sensor performs amplification and noise-correction. The sensor also includes digitization circuits, which allow the component to output information in a digital format. Because of the complexity of this design, the area devoted to light capture is reduced. And because each pixel must perform its own conversion, uniformity (image quality) is lower.
Both technologies have their place in the marketplace. If your goal is to have good low-light-level surveillance, then a CCD camera is the best. If there is little to no light, CCD sensors used with IR illuminators produce an excellent picture. If indoor lighting is adequate, and megapixel quality is your goal, then CMOS technology may be your best bet.
Make sure you test your camera with the lighting that will actually be present in the field of view. Do not rely on manufacturer’s data sheets for the minimum useable picture. This figure is often subjective, and your customer may not find the results acceptable. CMOS cameras are more prevalent in the IP network world. These cameras are typically equipped with built-in Web Servers, which enable remote viewing of video from other locations, by using IP network protocol.
In conclusion, CCD sensors are the best for outdoor applications, low light scenarios or when a higher quality image is required. CMOS sensor cameras should mostly be considered for indoor applications, though with adequate lighting conditions, they may also work well outdoors.
With a CCD sensor, every individual pixel's charge is transferred through an output node, which is converted into an electrical signal. The signal is then buffered and sent as an analog signal. Because the pixels are devoted to light capture, the image quality is usually pretty high.
With a CMOS sensor, every individual pixel performs its own charge-to-voltage conversion, and the sensor performs amplification and noise-correction. The sensor also includes digitization circuits, which allow the component to output information in a digital format. Because of the complexity of this design, the area devoted to light capture is reduced. And because each pixel must perform its own conversion, uniformity (image quality) is lower.
Both technologies have their place in the marketplace. If your goal is to have good low-light-level surveillance, then a CCD camera is the best. If there is little to no light, CCD sensors used with IR illuminators produce an excellent picture. If indoor lighting is adequate, and megapixel quality is your goal, then CMOS technology may be your best bet.
Make sure you test your camera with the lighting that will actually be present in the field of view. Do not rely on manufacturer’s data sheets for the minimum useable picture. This figure is often subjective, and your customer may not find the results acceptable. CMOS cameras are more prevalent in the IP network world. These cameras are typically equipped with built-in Web Servers, which enable remote viewing of video from other locations, by using IP network protocol.
In conclusion, CCD sensors are the best for outdoor applications, low light scenarios or when a higher quality image is required. CMOS sensor cameras should mostly be considered for indoor applications, though with adequate lighting conditions, they may also work well outdoors.
Monday, June 15, 2009
School Visitor Management Software
Your secretaries might be getting tired of issuing paper badges to visitors and signing them in with pen-and-paper logs. Do they want an easier way to track who is inside the school and make sure everyone is evacuated during an emergency? Are you sure you aren't giving access to suspect individuals?
There's a system to address this. It's called Secure Visitor Management Software (SVMS). SAGE isn't an approved vendor, but the technology is definitely interesting enough to highlight here.
It's very simple to operate. A visitor comes into the lobby and has his or her driver’s license scanned. The SVMS converts the information on the driver’s license to a defined format and prints out a temporary badge allowing access to certain areas of the building, using your existing access control software. The software can even check a national database to ensure visitors aren't on a convicted offender list. (If they are, it sends an email and alerts administrators that he or she is attempting to gain access to the school.) It can even track ongoing custody battles between parents.
Read more about SVMS
There's a system to address this. It's called Secure Visitor Management Software (SVMS). SAGE isn't an approved vendor, but the technology is definitely interesting enough to highlight here.
It's very simple to operate. A visitor comes into the lobby and has his or her driver’s license scanned. The SVMS converts the information on the driver’s license to a defined format and prints out a temporary badge allowing access to certain areas of the building, using your existing access control software. The software can even check a national database to ensure visitors aren't on a convicted offender list. (If they are, it sends an email and alerts administrators that he or she is attempting to gain access to the school.) It can even track ongoing custody battles between parents.
Read more about SVMS
Thursday, June 4, 2009
Designing Access Control
In a traditional wired access control deployment, a door controller is connected back to either a (non-IP) network controller or a building controller. The door controller typically handles two card readers, so it can regulate one or two doors, depending on whether one door is using a card reader for both entrance and exit. It would typically control three devices: a door contact (which tells the system if the door is opened or closed), the door lock and a card reader. Above the door frame would be a powered junction box, which powers each of the devices.
Security systems are now being designed across networks, and are using TCP/IP protocol to communicate to remote devices. Access control is no exception.
In IP-based systems, there is a direct network connection to either the door controller or the card reader, with the network connection providing low-voltage power, typically called Power Over Ethernet (POE). POE powers the door contact, the lock, the card reader and the request to exit (REX) device.
One of the most critical issues in designing access control or any network infrastructure is ensuring the right power source equipment is selected for the job. Many POE network switches do not have full POE capability to every port. When specifying a certain POE switch, make sure it provides the maximum POE wattage of out every port. The current standard is 15.4 watts; however, a new standard of POE plus is being developed, which will provide a maximum wattage of 30 watts.
One excellent example of an IP-based access control system is MAXxess’ netEDGE door controller. The NetEDGE is a high-performance, single-door controller that features a Linux operating system. The Linux OS is embedded in the netEDGE and greatly enhances the reliability and capability of the security management system. In addition, it provides several features to improve performance in any size application.
Because the netEDGE utilizes POE, separate power supplies and multi-door controllers are no longer needed. When utilizing POE for the controllers, readers, lock and REX power, a reduction in installation costs of at least 25% can be realized.
For more information on MAXxess’ netEDGE products, go to http://www.maxxess-systems.com/ or email me at ddamron@sagetechs.com.
Security systems are now being designed across networks, and are using TCP/IP protocol to communicate to remote devices. Access control is no exception.
In IP-based systems, there is a direct network connection to either the door controller or the card reader, with the network connection providing low-voltage power, typically called Power Over Ethernet (POE). POE powers the door contact, the lock, the card reader and the request to exit (REX) device.
One of the most critical issues in designing access control or any network infrastructure is ensuring the right power source equipment is selected for the job. Many POE network switches do not have full POE capability to every port. When specifying a certain POE switch, make sure it provides the maximum POE wattage of out every port. The current standard is 15.4 watts; however, a new standard of POE plus is being developed, which will provide a maximum wattage of 30 watts.
One excellent example of an IP-based access control system is MAXxess’ netEDGE door controller. The NetEDGE is a high-performance, single-door controller that features a Linux operating system. The Linux OS is embedded in the netEDGE and greatly enhances the reliability and capability of the security management system. In addition, it provides several features to improve performance in any size application.
Because the netEDGE utilizes POE, separate power supplies and multi-door controllers are no longer needed. When utilizing POE for the controllers, readers, lock and REX power, a reduction in installation costs of at least 25% can be realized.
For more information on MAXxess’ netEDGE products, go to http://www.maxxess-systems.com/ or email me at ddamron@sagetechs.com.
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