Axis Communications 2100 Picture frequency for Networking Applications, Image Compression Ratios

AXIS 2100 User’s Guide Choosing Your Application 27

Picture frequency for Networking Applications

When used in a TCP/IP networking environment, the AXIS 2100 delivers up to 10 images/second; where the actual image frequency is typically limited by:

•your browser/computer

•the image size

•the lighting conditions at the point of installation.

•the available network bandwidth

•complexity of detail and color variation within the image

Image Compression Ratios

The file size of a JPEG-compressed image depends upon the actual content of the image. Images containing a lot of detail will generate larger files. Image quality is controlled by the level of compression; high compression yields small files, while low compression maintains higher image quality at the expense of larger files. The table below contains average file sizes in kilobytes, derived from real-life tests:

	Typical File Sizes (kbytes)
	At lowest	At low	At medium	At high
Resolution	compression	compression	compression	compression
640 x 480	250 kb	20 kb	13 kb	8 kb
320 x 240	70 kb	8 kb	5 kb	3 kb

Note: Using a modern computer will avoid introducing any unnecessary bottleneck when viewing the images.

Lighting Conditions

Just like any camera, the shutter time of the AXIS 2100 increases in low light conditions to guarantee optimal image quality.

The actual frame rate for your images is affected by the prevailing light conditions in your application environment. Although the AXIS 2100 will produce good quality images right down to 3 Lux, local lighting should ideally be stable at 40 Lux or more to achieve optimal image frequency. Consequently, you can expect a reduced frame rate under low light conditions in your application environment, as shown in the diagram (right).

Images / sec.
10				e
				ramerat
			better	f
		=
	light
More
2				40	Lux
3