Specifications
53
6.3 Megapixel resolutions
A network camera that oers megapixel resolution uses a megapixel sensor to deliver an image
that contains one million or more pixels. The more pixels a sensor has, the greater the potential
it has for capturing ner details and for producing a higher quality image. Megapixel network
cameras can be used to allow users to see more details (ideal for identication of people and
objects) or to view a larger area of a scene. This benet is an important consideration in video
surveillance applications.
Table 6.3 Above are some megapixel formats.
Megapixel resolution is one area in which network cameras excel over analog cameras. The
maximum resolution a conventional analog camera can provide after the video signal has been
digitized in a digital video recorder or a video encoder is D1, which is 720x480 pixels (NTSC) or
720x576 pixels (PAL). The D1 resolution corresponds to a maximum of 414,720 pixels or 0.4
megapixel. By comparison, a common megapixel format of 1280x1024 pixels gives a 1.3-mega-
pixel resolution. This is more than 3 times the resolution that can be provided by analog CCTV
cameras. Network cameras with 2-megapixel and 3-megapixel resolutions are also available,
and even higher resolutions are expected in the future.
Megapixel resolution also provides a greater degree of exibility in terms of being able to pro-
vide images with dierent aspect ratios. (Aspect ratio is the ratio of the width of an image to its
height.) A conventional TV monitor displays an image with an aspect ratio of 4:3. Axis mega-
pixel network cameras can oer the same ratio, in addition to others, such as 16:9. The advan-
tage of a 16:9 aspect ratio is that unimportant details, usually located in the upper and lower
part of a conventional-sized image, are not present and therefore, bandwidth and storage
requirements can be reduced.
Display format No. of megapixels Pixels
SXGA 1.3 megapixels 1280x1024
SXGA+ (EXGA) 1.4 megapixels 1400x1050
UXGA 1.9 megapixels 1600x1200
WUXGA 2.3 megapixels 1920x1200
QXGA 3.1 megapixels 2048x1536
WQXGA 4.1 megapixels 2560x1600
QSXGA 5.2 megapixels 2560x2048
RESOLUTIONS - CHAPTER 6