Vivotek IP Surveillance, Обзор

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Chap.2 Lens and Image Sensor Technology
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With the refresh rate of a LCD monitors and a LCD TV enhancing to the same level of human eyes, there is no
need to use interlaced scan to reduce screen flickers. Progressive scan is thus replacing interlaced scan and will
become the mainstream scan technology.
2.2.4 Wide Dynamic Range
When shooting in high contrast, backlight, glare and light reflection environments such as the entrance, ATM or the
window side, the object will appear dark and unrecognizable. WDR (Wide Dynamic Range) technology can ensure
an identifiable image of all objects under such conditions by appropriately exposing the entire scene, both the
darkest and brightest parts. VIVOTEK’s award-winning IP7142 and FD7141 support WDR, enabling the camera to
cope with challenging light conditions.
Figure 2.13 Image quality (a) without WDR and (b) with WDR
(a) (b)
2.3 Lens and Image Sensor Considerations
2.3.1 Lens Form Factors for Image Sensor
Sensor sizes are specified by the diagonal and mainly include 1/4", 1/3”, and 1/2". A lens can fit in with a smaller
sensor. When using with a larger-sized sensor, for example, a 1/4” lens with a 1/3” sensor, the situation of dark
corners in the image will be caused.
6.4 mm
4.8 mm
1/2”
1/3”
4.8 mm
3.6 mm
1/4”
3.6 mm
2.7 mm
1/3” lens
1/3”
1/3” Sensor
1/3”
1/4” lens
1/3”
1/2” lens
1/3”
Figure 2.14 Sensor size and comparative lens size