Why is surveillance spelled this way?

Because it is a site word and does not follow the rules.
Main Entry: sur-vei-lance
Pronunciation: \ser-'va-len(t)s
Function: noun
Etymology: French, from surveiller to watch over, from sur- + veiller to watch, from Old French veillier, from Latin vigilare, from vigil watchful
Date 1802: close watch kept over someone or something (as by a detective);

Camera Information:

CMOS and CCD:  Digital Cameras have become extremely common as the prices have come down. One of the drivers behind the falling prices has been the introduction of CMOS image sensors. CMOS sensors are much less expensive to manufacture than CCD sensors.

Both CCD (charge-coupled device) and CMOS (complimentary metal-oxide semiconductor) image sensors start at the same point -- they have to convert light into electrons.  One simplified way to think about the sensor used in a digital camera is to think of it as having a 2-D array of thousands or millions of tiny solar cells, each of which transforms the light from one small portion of the image into electrons. Both CCD and CMOS devices perform this task using a variety of technologies.

CCD is the new standard with sizes ranging 1/4" 1/3" or 1/2" in size

PTZ: a camera that will point, tilt and zoom.  Some can be adjusted remotely from the DVR, others are manually adjusted

Lens Iris options:
The Manual Iris lens is the simplest type of iris control lens with manual adjustment to set the iris opening in a fixed position. These are generally used for fixed lighting applications or where the camera to be used is readily accessible. The lens is outfitted with a ring on the body that can be turned to alter the aperture directly. There are two types of Manual iris lenses, fixed manual iris lens and vari focal iris lens.  The Manual Iris lens is convenient to use where it is not necessary to adjust the lens continuously for correct picture brightness. These types of lens are used with constant light. It is applicable in shopping centers, schools, libraries, and offices. The lens can be turned to alter the aperture directly with the help of a ring which is present on the body.  Manual Iris lens would be used in rooms where the lighting is constant.

The Auto Iris Lens is a type of lens that can be electronically controlled. This type of lens allows maintaining the lighting level. It is applicable where the light condition varies continuously. Auto iris lens allows the camera to adjust to get the best picture in the given lighting conditions. There are two types of Auto iris lenses, Fixed Auto Iris lenses and Vari focal Auto Iris lens. Auto iris lenses are best lens to use in any application as they are flexible and can adjust to changing light levels. Auto iris lenses are used to produce consistent video signals from cameras that view scenes in any varying light levels. Auto iris lenses combines an electronically controlled iris, which allows the lens to maintain one light level making them ideal for outdoor use or any other applications.  Auto Iris lens would be used in parking lots, Front doors and rooms with large windows.

Lux: The minimum amount of light, stated in lux, necessary to record a clear picture. Lux (1/10 of a foot candle) is a standardized method by which to measure a security camera's sensitivity to light. The lower the number, the less light it will take to reproduce a clear image. For example: A security camera that sees down to 1 LUX, means it generally has the ability to see an image during early evening hours or just before dusk. A security camera that's down to .1 has the ability to see an image in let's say, a well lit parking lot. A rating of .05, the ability to clearly view an image in a dimly lit area at night. A .05 image can usually enable a security camera to actually see better than the human eye at night!

Dome: Bubble style of camera

Bullet: Longer tube shape camera

Hidden: Camera that is not easily seen.

Motion Tracking: Camera that will track a moving object.

LED: light-emitting diode.  IR Leds are used in cameras to see in the dark.

mm lens:  Standard sizes range from 3mm for close indoor use to 12mm for back yard use.  The higher the mm, the further away an object can be clearly seen however the width of vision becomes narrower.

TVL:  TV lines.  Range from 320 - 750.  The higher the lines a camera will produce, the better the video. If you have a DVR that records high res but a camera that only produces low res, you will see only low res.  To view high resolution, both the camera and the DVR must be high res.

Mega Pixil:  New very high resolution cameras.

DVR Information:

CCTV:  Most common CCTV used a tape to store video data

PC Based:  Computer system with video capture card installed. Operating system is usually Linux or Windows.

Hardware Based:  Looks like a DVD player.  Operating system is hard coded into the DVR main board on a chip and is usually Linux based.

What is the difference between H.264 and MPEG4 video compression?

MPEG4: was introduced in 1998 as the next generation of file compression for delivering audio & video over a wide range of bandwidths.  It achieves this by compressing data to form small bits that can be transmitted and than decompressed for viewing.  It stores and transmits only the changes from one frame to the next, instead of each frame however the amount of data that is removed is not noticed by the human eye

H.264: is now the newest generation of audio & video compression format which allows transmission of higher quality video at a lower bit rate using the same bandwidth.  It provides the latest in advanced video encoding and decoding technologies delivering smaller file sizes, higher performance, solid reliability and longer recording times over previous standards. H.264 file compression reduces the file size and therefore requires less space on a hard drive or server than MPEG4.  Higher image quality than MPEG4. H.264 is the most efficient codec available in a Standalone DVR. 30% more storage and higher quality video than MPEG4 format. Enjoy the smooth video quality both locally and remotely through the Internet. Easy to use interface and extreme reliability.

In selecting a DVR, you should make sure it uses H.264 video compression.

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