Ronald 42212TNI, Installation Manual

Page: 7 / 68

7
CAMERA SELECTION
OTDAU software requires one camera, and optionally two, to detect and then track
moving objects. It provides for two types of hardware and software interface to cameras:
•
USB webcams which may be external to your computer or built-in
•
IP cameras by Ethernet connection thru a router or directly to your computer
Two cameras may be used to track and zoom in on an object that may be first detected
in a direction that is much wider than the PTZ camera’s field of view (FOV). Making the
initial detection using a wide-angle fixed camera and handing off continuous tracking to
the PTZ camera can make best use of both their capabilities.
When the general direction of interest is known, then the selection of a single camera
may hinge on its FOV, shown as horizontal angle of view in the table below.
Another aspect of selection is the tradeoff between higher resolution and a PTZ function.
A PTZ camera can continuously track (center) a target while zooming in which
effectively increases the number of active pixels, thus compensating for its lower un-
zoomed resolution. However, a fixed camera will not experience the motion lag of a
PTZ camera and thus does a better job at tracking faster-moving objects.
Note also the difference in light sensitivity between these cameras. In color mode, this
will not be apparent during the day but may result in more granularity of the image in
very dark conditions.
Near-infrared light (700-1000 nm) is beyond what the human eye can see, but most
camera sensors can still detect and use it. When there is plenty of light, a day/night
camera uses an IR-
cut filter to block the IR light so that it doesn’t distort the other colors
in the image. When the camera is in night mode, the IR-cut filter is removed, thus
boosting the camera’s light sensitivity to 0.001 lux or lower.
Each camera may be set to a
“black and white” mode by accessing its Setting menus, in
Camera > Conditions > Day & Night and setting the profile to night. This removes the
IR cut filter and thus enhances the camera’s ability to image near IR wavelengths. If the
camera has an IR illuminator, it should always be disabled by setting its Mode to off in
the Illuminator menu.
Information about the Sony STARVIS sensor used by Dahua cameras may be found at:
https://www.sony-semicon.co.jp/e/products/IS/security/technology.html