Megapixel Technology for Security Cameras
Megapixel technology is effectively the same type of technology in digital cameras and modern video and television resolution. A megapixel is one million pixels. Security cameras are rated in megapixels, resolution or TVL (TV Lines).
Resolution is the pixel measurement in width multiplied by height. 720p and 1080p are short-hand for 1280×720 and 1920×1080 respectively. If you multiply the numbers 1280 by 720 the result is 921,600 just a few pixels short of one million or 1 megapixel. 720p is the referenced equivalent to 1 megapixel. 1080p is the referenced equivalent to 2 megapixels.
Resolution of CCTV security cameras is measured primarily in TVL (TV Lines). TVL is the number of horizontal lines. The higher the number of TV lines a camera can produce, the better the quality of image the camera can potentially produce. TVL is an analog CCTV specification and cannot be directly translated to pixel resolution like IP cameras. Ten years ago the standard was 400TVL – today the standard is between 700TVL and 1000TVL for CCTV installations.
CCTV Digital Recording Resolutions
Digital video recorders capture the CCTV image and digitizes it for live display and recoding. Its capture and recording capabilities are measured in CIF (Common Intermediate Format). CIF was part of the H.261 standard format used to standardize the horizontal and vertical resolutions in pixels of YCbCr sequences in video signals. The most commonly used CIF resolutions are:
- QCIF – 176 x 144 (0.02 Megapixel)
- CIF – 352 x 240 (0.1 Megapixel)
- 2CIF – 704 x 240 (0.17 Megapixel)
- 4CIF – 704 x 480 (0.3 Megapixel)
- D1 – 702 x 480 (0.3 Megapixel)