Filter
Top Products
System Administrator’s Guide
Document K14392V1 Rev A 77
07/07
Security and Presence
Before critical events occur, it is worthwhile to compare video recorded at Continuous values with
video recorded using Event values. You can establish if the resolution is high enough for your
organization’s security needs. Consult your security personnel to find out whether you need to:
• Establish the presence of known individuals. Lower resolutions are usually adequate and take
less storage. Some samples of low-resolution and high-resolution video images are shown in
Comparing the Resolutions of Recorded Video, p. 76.
Video images are bitmaps. When a camera window is dragged to a larger size, the pixels of the
video feed are also enlarged. The image’s sharpness is not preserved; more stretching can
degrade the subject of an image beyond recognition. Compare figures 5–11 and 5–12. A high
resolution of 704 × 480 (NTSC) shows recognizable facial characteristics and very few artifacts—
such as “pixelation”, color variance and so on. If storage time is an issue, recordings at a more
modest resolution of 320 × 240 shows almost as much detail. Applications to establish presence
or absence of personnel can use even lower resolutions. At 160 x 120 (NTSC) many facial
characteristics of a known person are still recognizable even when the imaged is stretched, as in
fig.
5–12.
Fig. 5–12. Using Low Resolution, 160 x 120 (NTSC) to Show Presence.