Resolution is the clarity of the Image it holds. For analog systems, this is typically measured in Television Lines (TVL). The higher the resolution, the better the definition and clarity of the picture. The camera “scans” an image in a series of lines running horizontally.Each horizontal line is made up of a number of elements. Once one line is scanned, the second line is scanned, and so on. Resolution is a measure of the quantity of both individual lines and the component elements making up each line. In a CCD camera, resolution has a direct relationship to the number of pixels on the CCD image sensor. Resolution measures the number of horizontal lines a camera uses to produce an image. Horizontal resolution measures the number of elements making up each horizontal line. Vertical and horizontal resolutions typically yield a 3:4 ratio relationship (e.g., 600 vertical lines to 800 elements in each line). CCTV camera resolution is usually in the 380 to 540 TVL range. The higher the camera’s resolution, the more detail visible (because the lines are closer together and there are more elements in each individual line). Lower-resolution cameras produce images with less detail.
The following one explains how the resolution varies for colour and monochrome cameras:
The Image Resolutions for CCTV cameras are as follows:
In terms of Analog the resolution will be described with QCIF, CIF, 2CIF, 4CIF AND D1.The values for the same is mentioned below:
QCIF- 176 X 120
CIF – 352 X 288
2CIF – 704 X 240
4CIF – 704 X 576
D1 – 720 X 576
In IP Camera , resolution is described with VGA, 1.3MP, 3MP, 5MP.
VGA – 640 X 480
1.3MP – 1280 X 1024
3MP – 2048 X 1536
5MP – 2560 X 1920
Recording Resolution of the DVR:
DVRs would record at CIF (352 x 240 pixels), 2 CIF (528x360), and 4CIF (704x480). There are some new DVR that would take high definition, 1920x1080pixels.Comparing to DVR , NVR recording resolution is higher, can be over 2560x1920pixels for 5MP IP cameras @ 15fps.
Camera Resolution:
Camera resolution, usually described in terms of horizontal pixels. Analog cameras usually have 420, 540, 600 pixels/lines of horizontal resolution. Some new Hi-def analog camera with DVI output can handle 1920x1080. IP cameras would cover as much as 2560x1920 pixels.Medium resolution of B/W camera in EIA system is 510 horizontal pixels by 492 vertical pixels and is equivalent to 380 TV lines. High resolution is 768(H) x 492(V) pixels and equivalent to 570 TV lines. Color camera's medium resolution means 330TV lines and high resolution needs more than 460TVlines.
Monitor Resolution:
The monitors in NTSC system have 525 vertical scanning lines regardless of their size. The horizontal 700 TV lines of B/W monitors represents medium level and more than 900 TV lines means high resolution in EIA system. The color monitor's horizontal resolution of 300 TV lines means medium quality and that of more than 450 TV lines means high resolution. To maximize the system's resolution, it is recommended to choose a monitor which has better resolution than that of the camera.
