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Glossary of Terms
Ever wonder what something ment?
Here is a list of terms related to Network Cameras. If there
is a term not located here and you would like it to be added,
please email info@networkcamerareviews.com
with the term.
ActiveX Active X is a set of technologies created by Microsoft that enables website components to interact with one another regardless of the language in which they were created. It is built on the Component Object Model (COM).
CCD - Charge Coupled Device The CCD image sensor offers superior image performance and flexibility at the expense of system size. System Size is greater when compared to CMOS. CCD image sensors feature better light sensitivity when directly compared to CMOS image sensors. As a result, the higher light sensitivity translates into better images in low light conditions. However, bright objects can cause the CCD image sensor to "Bleed" causing vertical stripes on screen. This side effect is referred to as the "Smear" effect. The CCD image sensor remains the more popular of the two technologies because of the higher picture quality level. However, for entry level applications and when cost is a concern, the CMOS image sensor is the preferred choice. CCD image sensors should be used in applications demanding the highest image quality achievable.
CCTV (Closed Circuit Television) CCTV systems usually involve analog cameras that connect to a television system or recorder. The signals are not publicaly distributed but are limited to a small area such as a store, office building, warehouse or school.
CMOS - Complementary Metal Oxide Semiconductor The CMOS image sensor offers integration of added circuitry on a single chip, lower power usage (up to ~1/10 the usage) and a more compact design at the expense of image quality and flexibility. As a result of this, CMOS image sensors are cheaper to manufacture and are usually sold at a lower cost. Also, the smaller system size allows for smaller cameras to be designed. In recent years the gap in image quality between CCD and CMOS image sensors has narrowed greatly. But, when the highest image quality is required, the CCD image sensor is still regarded as the preferred choice. CMOS image sensors are currently limited in low light conditions. With low light conditions the CMOS image sensor can produce either a very dark image or a very noisy image. CMOS image sensors are more susceptible to noise which can create interference or distortion in the image. CMOS image sensors should be used for high-volume, space-constrained applications where obtaining the highest image quality possible is not necessarily vital to the application.
DDNS - Dynamic Domain Naming System Dynamic DNS is a service allowing users to alias their dynamic IP address to a static domain name. Most network cameras have DDNS as a configuration option. Once configured, the camera will update the static domain name with the current IP address of your Internet connection. This allows for easy access to your camera without needing to check your Dynamic IP address. This service is less expensive than having a static IP address and is more flexible.
MJPEG (Motion JPEG) A network camera/video server using MJPEG video compression captures individual images at rates of up to a maximum of 30 individual frames per second. The captured images are presented in succession, thus producing a stream of video. This is referred to as Motion JPEG with each image frame being an entire JPEG compressed image.
The result of compressing all information on each frame is high picture quality but it requires more information to be transmitted and stored. Thus, when compared with MPEG4, bandwidth usage is greatly increased with MJPEG, as is the disk space required for storage.
Motion Detection Network Cameras equipped with motion detection can identify motion or change in the live video. The sensitivity can be set by the user in the configuration settings of the camera. Some network cameras can also email and FTP images or video showing the motion detected.
MPEG4 With MPEG4, only changes to each image on successive frames are actually transmitted, not the complete image. The result of sending only image changes is both reduced bandwidth usage and storage space required, however MPEG4 has a lower image quality when directly compared to MJPEG. IP Network Cameras and Video Servers featuring MPEG4 can capture audio as well as images, with the audio and video being fully synchronized.
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