Friday, November 20, 2009

Understanding Different Types of CCTV Cameras

Prologue: I find this as the most End-user-friendly Guide to Understanding the Different Types of CCTV Cameras available in the market. I don't own any of the below info. All credits to Aventura.

CCTV Camera Styles:

DOM Camera
Dome cameras typically are the best choice whenever possible
  • When the camera is within someone’s reach domes cannot be easily manipulated or vandalized
  • Domes Installs easy in drop ceilings – usually 2 screws
  • Since a dome has a covered lens the direction the camera is pointing is hidden
  • Domes can accommodate infra-red for Night Vision
NOTE: While dome cameras are the installation choice there are limitations. As the domes themselves are typically small you are limited in the size lens available. If you need to focus on long distances which requires a lens of 50mm focal length or greater it will not fit inside a standard dome camera. Dome cameras can be simple plastic ones or metal vandal-proof for public places.

Box Camera
  • When mounting to a wall or any vertical area
  • When viewing long distances where a long lens is required, which would not fit inside a dome or bullet camera
  • When extreme low light conditions are not a consideration
NOTE: If the box camera is within someone’s reach the camera is usually inserted in a protective enclosure. If the lighting is extremely low box cameras can be inserted inside enclosures that have built-in infra-red illuminators but the camera must be infra-red sensitive. Meaning it is able to utilize the infra-red illuminators from an external source.

Infra-red Camera
  • When there are extreme low light conditions
  • When the camera is not within someone’s reach
NOTE: The distances infra-red cameras can see are based upon its illumination capacity. Infra-red cameras have LED’s, which cast out into the darkness. Realistically, a good rule of thumb (but not an absolute) is figure 1 foot for each LED. Therefore, if a camera has 30 LED’s then it probably can see about 30 feet. There are some newer LED’s called Cat’s Eyes, which have more power, but they are not very common. You would notice a Cat’s Eye by the extra large size of the LED’s. With respect to infrared quality it has more to do with the intensity of the LED's and the distance they cover. One thing to note is that infrared LED's do have a limited life since they are illuminating so they do burn out over time. Just because one camera has more LED's than another does not mean it can cast a longer distance, there are different strengths in the LED's. Unfortunately, again for the consumer it is hard to properly compare.

Bullet Camera
  • When you want the camera to be inconspicuous but not covert
  • When the camera is not within someone’s reach
  • When extreme low light conditions are not a consideration
  • For shorter to middle distances
NOTE: As bullet cameras are small the type of internal boards and lens is limited. Accordingly, the picture quality of the bullet cameras cannot compare with other more traditional cameras, which can have double layer boards and camera function controls.

Covert Camera
  • Just as they say, these are meant not to be seen and come in all shapes and sizes from a wall clock to a sprinkler head or smoke detector

NOTE: It is important to check your local laws with respect to surreptitious recording. In some states certain types of covert cameras are illegal. For example, in New York State you are not allowed to install smoke detector cameras. With respect to recording audio, there are very specific laws, which vary from state to state. Some states require all parties consent to recording, while others only require a single individual.

Wireless Camera
  • When connection to the digital video recorder is not practical
NOTE: Remember though wireless is just for the video signal, you still need a method to power the camera. Wireless cameras can be found in most styles. For the most part wireless cameras require a line-of-sight to function properly. Distances will vary depending upon the strength of the transmitter and receiver, what other devices are in the same spectrum, etc. Realistically, you are looking at distances of 100’ or less on affordable wireless equipment. There are external wireless transmitters and receivers that can attach to any standard camera and make them wireless, but the costs are incredibly prohibitive.

Pan Tilt Zoom (PTZ) Camera
  • When you want live control of the camera and adjusting the manual pan, tilt or zoom on a fixed cameras is not practical
  • When you want to set up a camera to tour the premises
  • When you want to view several angles from a single camera
NOTE: Pan, Tilt, Zoom cameras cost anywhere from 5x – 10x the cost of a fixed camera. The Pan, Tilt, Zoom camera cannot record or see where it is not looking. You cannot pan, tilt or zoom after it has been recorded (this can only be done with a 360 degree camera). Making a PTZ camera wireless adds thousands to the cost. PTZ cameras can though perform various functions not possible with a fixed camera. You can control a PTZ camera and zoom in optically up to 36x and beyond digitally up to 12x giving zoom capabilities in the 100’s. The PTZ’s have intelligence and can be programmed to perform pre-defined tours and upon the event of an alarm the camera can swing to a specified location before continuing its tour. An operator can override and take control of the camera at any time.

CCTV Camera Categories:

Indoor vs Outdoor Cameras

Ostensibly, indoor and outdoor cameras are the same in terms of styles, sizes and shapes. The principle difference is outdoor cameras are at a minimum weather-proof.

While rain is a primary issue other considerations such as moisture, dust, sand, snow, frost and humidity need to be addressed. Accordingly, some cameras are equipped with heaters and blowers to counteract the elements, while others can be housed in outdoor enclosures for the specified purpose.

Outdoor cameras most likely have to address low light conditions for evenings. Accordingly, they either have to have infra-red or some day/night technology, which today are quite affordable.

Night Vision and Day/Night Cameras

For low light situations there are two possible camera technology solutions. If there is total darkness then the only possibility is infra-red or otherwise known as night-vision.

Infrared (IR) Radiation — electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. The name means "below red" (from the Latin infra, "below"), red being the color of visible light of longest wavelength. The infrared portion of the spectrum has a number of technological uses, including target acquisition and tracking by the military; remote temperature sensing; short-ranged wireless communication; weather forecasting and for our purposes night-vision.

Infrared is used in night-vision cameras when there is insufficient visible light to see an object. The camera uses the infrared portion of the electromagnetic spectrum, sometimes referred to as thermal imaging. The radiation is detected and turned into an image, hotter objects showing up in different shades than cooler objects, enabling the camera to see warm targets, such as human beings and automobiles.

Day/Night — a sensitivity enhancement technology which improves light sensitivity of a camera by a factor of 2 for visible light and a factor of 4 for near-infrared wavelengths. It still cannot work in near zero light as will an infrared camera.

While both infrared and day/night technology sound expensive, both have become commercialized and are surprisingly affordable. The difference in camera pricing for one of these cameras versus a traditional camera is nominal.

The rule of thumb we like to use is if you walk the area where you intend for the camera to be and view it at its lowest possible lighting, if you can see with the naked eye, then the day/night camera should be fine. If you cannot see, then an infrared camera would be recommended.

CCTV cameras similar to your movie camera are rated in terms of “lux” for purposes of lighting. In addition to night vision and day/night cameras there are low light cameras, which are standard cameras with a low lux rating (0.1).

Tuesday, November 17, 2009

Video Compression Technology

We're familiar with the more common video compression technologies used for DVR Applications in the market today like MPEG-4 and H.264. We know that H.264 is a higher compression standard over MPEG-4; but do we know why and how is that so? We need not to go deeply into the compression rates comparisons and very technical stuffs. Here's a layman presentation of the Basic Image Compression Standards - what they offer and where they are more commonly used for.

Video Compression Technology

At its most basic level, compression is performed when an input video stream is analyzed and information that is indiscernible to the viewer is discarded. Each event is then assigned a code - commonly occurring events are assigned few bits and rare events will have codes more bits. These steps are commonly called signal analysis, quantization and variable length encoding respectively.

Compression Standards

MPEG stands for the Moving Picture Experts Group. MPEG is an ISO/IEC working group, established in 1988 to develop standards for digital audio and video formats. There are five MPEG standards being used or in development. Each compression standard was designed with a specific application and bit rate in mind, although MPEG compression scales well with increased bit rates. They include:

Designed for up to 1.5 Mbit/s
tandard for the compression of moving pictures and audio. This was based on CD-ROM video applications, and is a popular standard for video on the Internet, transmitted as .mpg files. In addition, level 3 of MPEG-1 is the most popular standard for digital compression of audio--known as MP3. MPEG-1 is the standard of compression for VideoCD, the most popular video distribution format throughout much of Asia.

Designed for between 1.5 and 15 Mbit/sec
tandard on which Digital Television set top boxes and DVD compression is based. It is based on MPEG-1, but designed for the compression and transmission of digital broadcast television. The most significant enhancement from MPEG-1 is its ability to efficiently compress interlaced video. MPEG-2 scales well to HDTV resolution and bit rates, obviating the need for an MPEG-3.

Standard for multimedia and Web compression. MPEG-4 is based on object-based compression, similar in nature to the Virtual Reality Modeling Language. Individual objects within a scene are tracked separately and compressed together to create an MPEG4 file. This results in very efficient compression that is very scalable, from low bit rates to very high. It also allows developers to control objects independently in a scene, and therefore introduce interactivity.

MPEG-7 - this standard, currently under development, is also called the Multimedia Content Description Interface. When released, the group hopes the standard will provide a framework for multimedia content that will include information on content manipulation, filtering and personalization, as well as the integrity and security of the content. Contrary to the previous MPEG standards, which described actual content, MPEG-7 will represent information about the content.

MPEG-21 - work on this standard, also called the Multimedia Framework, has just begun. MPEG-21 will attempt to describe the elements needed to build an infrastructure for the delivery and consumption of multimedia content, and how they will relate to each other.

JPEG stands for Joint Photographic Experts Group. It is also an ISO/IEC working group, but works to build standards for continuous tone image coding. JPEG is a lossy compression technique used for full-color or gray-scale images, by exploiting the fact that the human eye will not notice small color changes.

JPEG 2000 is an initiative that will provide an image coding system using compression techniques based on the use of wavelet technology.

DV (Digital Video) is a high-resolution digital video format used with video cameras and camcorders. The standard uses DCT to compress the pixel data and is a form of lossy compression. The resulting video stream is transferred from the recording device via FireWire (IEEE 1394), a high-speed serial bus capable of transferring data up to 50 MB/sec.

H.261 is an ITU standard designed for two-way communication over ISDN lines (video conferencing) and supports data rates which are multiples of 64Kbit/s. The algorithm is based on DCT and can be implemented in hardware or software and uses intraframe and interframe compression. H.261 supports CIF and QCIF resolutions.

H.263 is based on H.261 with enhancements that improve video quality over modems. It supports CIF, QCIF, SQCIF, 4CIF and 16CIF resolutions.

H.264, also known as MPEG-4 AVC (Advanced Video Coding), is a video compression standard that offers significantly greater compression than its predecessors. The standard offers up to twice the compression of the current MPEG-4 ASP (Advanced Simple Profile), in addition to improvements in perceptual quality. The H.264 standard can provide DVD-quality video at under 1 Mbps, and is optional for full-motion video over wireless, satellite, and ADSL Internet connections.

DivX Compression

DivX is a software application that uses the MPEG-4 standard to compress digital video, so it can be downloaded over a DSL/cable modem connection in a relatively short time with no reduced visual quality. The latest version of the codec, DivX 4.0, is being developed jointly by DivXNetworks and the open source community. DivX works on Windows 98, ME, 2000, CE, Mac and Linux.



International Organization for Standardization - a non-governmental organization that works to promote the development of standardization to facilitate the international exchange of goods and services and spur worldwide intellectual, scientific, technological and economic activity.

International Electrotechnical Commission - international standards and assessment body for the fields of electrotechnology

Codec - A video codec is software that can compress a video source (encoding) as well as play compressed video (decompress).

CIF - Common Intermediate Format - a set of standard video formats used in video conferencing, defined by their resolution. The original CIF is also known as Full CIF (FCIF).

QCIF - Quarter CIF (resolution 176x144)
SQCIF - Sub quarter CIF (resolution 128x96)
4CIF - 4 x CIF (resolution 704x576)
16CIF - 16 x CIF (resolution 1408x1152


Monday, November 16, 2009

CCTV DVR Glossary of Terms

In choosing the CCTV system that is most suitable for a specific application, we will need to consider some important parameters to meet the standards and requirements of the project. We may encounter some terms like fps, resolution and compression which are common terms in the CCTV and Video Surveillance world. We may hear them often but we don't really understand them (esp. the End-users). It would be better to know how relevant they are to the CCTV system's functionality and operation so we can evaluate if a CCTV system falls short of our requirement or is too high-level for our desired application.

Let's try to understand some of these common terms:

Analog Video Signal - Video signal which contains the luminance (brightness) and chrominance (color information) of the image, which may be carried in separate or combined channels. This is the type of camera signal used by older cameras, often called analog cameras or CCTV cameras. These cameras transmit the signal via Co-ax Cables, which are not network-ready.

ASIC - (Application Specific Integrated Circuit) Integrated circuit is customized based on the user’s specific needs. Basically, the circuit has a specific use.

Bandwidth - The channel capacity for information transmission over an internet connection. If the information flow is too much for the bandwidth, the bandwidth is said to “choke.”

CIF - (Common Intermediate Format) Video size format measuring 360 x 240 pixels for NTSC and 360 x 288 pixels for PAL.

Compression - In surveillance, compression refers to the process in which the data used to present an image or a video is reduced.

D1 - A video size format measuring 720 x 480 for NTSC and 720 x 576.

Decode/Decoding - It is the process of transforming information or data from one format into another. In surveillance, it is the process in which the compressed video data is transformed to raw video data.

Digital Video Signal - Digital video signals are digital representations of discrete-time signals. In surveillance, it is the type of camera signal used by newer cameras. These cameras transmit the signal via Cat5 Cables, which are network-ready. Digital Video Signal is also known as IP Signal.

DVR - (Digital Video Recorder) A device that records videos onto a hard disk drive.

DVR Card - Also called DVR capture card. The DVR card, which allows a computer to receive television signals, record video, and/or playback video content is the center or heart of the DVR system.

Embedded DVR - Embedded DVRs are all-in-one, often times plug and play standalone DVRs. A PDA phone is an example of embedded technology. DVRs such as Standalone DVRs or embedded DVRs are manufactured for the sole purpose of being a DVR. These typically contain a single circuit board with DVR software implanted into the chip.

Encode/Encoding - It is the process of transforming information or data from one format into another. In surveillance, it is the process in which the raw video data is transformed to compressed video format.

FPS - (Frames Per Second). A measurement standard for the viewing and recording speeds of videos. Real-time viewing and recording speed is at 30 fps for NTSC and at 25 fps for PAL. When a video plays at these speed rates, it is as good as watching the action face to face, hence the term “real-time”.

Half D1 - A video size format measuring 720 x 240 pixels for NTSC and 720 x 288 for PAL.

Hardware Compression vs. Software Compression - Hardware compression happens on the level of the microchip (or chip). Because the compression is done “physically,” none of the CPU space is eaten up. In software compression, the data is compressed using the memory and the speed of the CPU, as the software resides in the CPU. Since the CPU receives a continuous flow of data to be compressed, there is a possibility for it to be overwhelmed and thus hang. Since hardware compression uses only the microchip and does not involve the CPU, the risk of the computer hanging is totally avoided.

Hardware MPEG4 Compression - A compression capability that combines hardware compression technology and the MPEG-4 compression standard.

Hybrid DVR - A DVR capable of accepting both analog and digital video signals.

Linux - A freely available open-source operating system. As compared to other operating systems sold commercially, Linux is royalty-free, highly customizable and more stable. CentOS is one of the more popular the Linux distributions.

MPEG4 Compression - MPEG 4 is a measurement standard for digital video and digital audio compression. In the DVR market today, MPEG 4 compression is considered to be one of the higher compression rates available. Other compression standards are MPEG 1, MPEG 2, and MJPEG.

Network - A series of computers or mobile devices that are connected to each other with the purpose of communicating and sharing information. A Local Area Network (LAN) is a type of network connection usually found among the computers in an office or an internet café. A Wide Area Network (WAN) on the other hand, is a network connection that spans over a broad geographical area. For data to travel via the network, it must be in digital format.

NTSC - (National Televisions Standards Committee) Standard video signal for the US and the Philippines.

PAL - (Phase Alternating Line) Standard video signal for Europe and some countries in Asia.

PC-Based DVR - A DVR using the hardware format of a regular PC.

QCIF - (Quarter Common Intermediate Format). A video size format measuring 180 x 120 pixels for NTSC and 180 x 144 pixels for PAL.

Resolution - A measurement standard for how clear (level of detail) the video is. The resolution is usually measured by the number of pixels shown on screen. The more pixels shown, the higher the resolution.

SDK - (Software Development Kit or Systems Disk Kit). A start up kit usually offered by DVR manufacturers to users who wish to build their own DVR system.

Video Server - A device that accepts analog signal and converts it to digital signal. This allows the video to be viewed remotely via a network connection.

Tuesday, November 10, 2009

The DVR Software GUI

The DVR Software GUI is one determining factor of the user-friendliness of a specific DVR Application. Less is better when it comes to this element. It's straining in the eyes and kind of confusing to look at a crowded or a not-so-very-well organized user-interface. Would you go for a complicated GUI with lots of buttons filling out the screen or a simplified version offering the same functions. A sound mind will surely go for the simplified version. However, simplifying the GUI is not enough. We need to take into account the organization of the buttons - they should be arranged throughout the screen in the most orderly way as possible.

Here are just some of the better DVR Software GUIs in my opinion.

Hawkeye Software GUI:

AverMedia Software GUI:

NUUO Software GUI:

Geovision Software GUI:

Still, it's all up to you. We all have different tastes and preferences. Choose wisely!

Friday, November 6, 2009

PCI Express (PCIe) DVR Cards

The PCIe bus is becoming the dominant interface on PC Motherboards nowadays. With this current advancement in the technology, the PC-based DVR industry was driven to adjust and adapt to the improving and fast-paced PC world. Thus, the entrance of PCIe DVR Cards into the CCTV scene.

Most of the DVR Cards available in the CCTV market today are still referenced to PCI. But how long will the PCI technology last? How long can we make use of our PCI DVR Cards? New motherboards are introduced in the market almost every month like crazy. Having said that, it won't be a big surprise if the PCI technology gets obsolete before we know it. This is where the industry is headed to and we have to face that fact. The PCI DVR Cards will soon be replaced by PCIe DVR Cards. And it's for the better. c",)

Why we moved to PCI Express?

PCI Express has several advantages, not only to the users but to manufacturers. It can be implemented as a unifying I/O structure for desktops, mobiles, servers and workstations, and it's cheaper than PCI or AGP to implement at the board level. This keeps costs low for the consumer. It is also designed to be compatible with existing Operating Systems and PCI device drivers.

PCI Express is a point-to-point connection, meaning it does not share bandwidth but communicates directly with devices via a switch that directs data flow. It also allows for hot swapping or hot plugging and consumes less power than PCI.

However the most promising feature is that it is scalable meaning greater bandwidth can be achieved through adding "lanes," ostensibly future-proofing into the next decade.

While we've spent plenty of time and energy improving the speed of processors, memory, and other parts of the PC, we've done virtually nothing with the main connection betweern many devices - the PCI. As such we are stuck with a technology in our PCs and Servers that still runs at the speeds and bandwidth we were comfortable with in the 90's. PCI as we know it is holding us back - it is a bottle neck - a limitation to the maximum performance of our systems.

We all want the most from our PC. To get the most out of our PC we must remove all bottlenecks (obstacles to performance). To that end we must turn to the next best alternative: PCI Express.

Increased bandwidth can be equated into increased system performance. We've long known that to get the most out of your processor you need to get as much information into it as possible, as quickly as possible. Chipset designers have consistently addressed this by increasing Front Side Bus speeds. The problem with this is that front side bus speed increases the speed of transfer between the memory and CPU but often you've got data that's coming from other sources that needs to get to the memory or CPU like drives, network traffic, video, etc. PCI Express addresses this problem head on by making it much faster and easier for data to get around the system.