For a single high-definition network camera, the main sync adjustment the following three types: internal synchronization, the use of hd ip camera inside the crystal oscillation circuit generates a sync signal to the
completion of the operation; external synchronization using an external
sync signal generator synchronization signal to the outside of the
high-definition network camera synchronization input to achieve
synchronization; linear locking or row locking AC power to complete the
vertical promote the use of hd ip camera synchronization, HD ip cameras
and the power zero line synchronization.
System managers hope the video input signal is a vertical synchronization of multiple high-definition network camera surveillance system, which transform the output of hd ip camera screen
without causing image distortion, but due to the monitoring system
consists of more than one monitoring HD ip cameras, camera composition,
power may be provided by the different phases of the three-phase power,
or even the entire monitoring system and AC power are not synchronized,
the measures to be taken at this time: by an external sync signal
generator external synchronization input of the synchronization signal
is fed into the high-definition network camera to adjust the
synchronization. HD ip camera phase adjustment potentiometer, due to the
high-definition network camera at the factory, the vertical sync on the
rising edge of the in-phase AC power is zero crossing, each hd ip
camera has a different phase shift through the use of phase delay
circuit to obtain the appropriate vertical sync phase adjustment range
from 0 to 360 degrees.
All hd ip camera has a video amplifier from the CCD signal amplification can use the
standards, the gain is equivalent to a higher sensitivity, can guarantee
its sensitivity in low-light environments, however, the amplifier will
overload so that the video signal will distortion highlight illumination
environment, and to this end, we need to take advantage of
high-definition network camera automatic gain control (AGC) circuit to
detect the level of the video signal to switch the AGC timely, so that
the hd ip camera can be larger illumination within the scope of the
work, this is the dynamic range of the illumination automatically
increases the sensitivity of the hd ip camera, thereby increasing the
intensity of the image signal to obtain a clear image. HD ip camera
usually the AGC working point is determined by the average of the
contents of the entire field of view, but if a bright background area
exists in the same field of view and a very dark foreground object, then
the determined AGC point there may be inappropriate for foreground
objects backlight compensation is likely to improve the prospects of the
target display condition. When the backlight compensation is turned on,
the high-definition network camera only for the entire field of view of a sub-regional average to
determine its AGC operating point, if the foreground object is located
within the sub-region, the foreground object visibility is expected to
improve .
The charge accumulation time of the imaging surface of
the optical electric control to manipulate the shutter, the electronic
shutter controls the CCD accumulation time in the CCD within the definition network camera is, when the electronic shutter is closed, for NTSC hd ip camera, the CCD accumulation time is 1 / 60 seconds; PAL HD
ip camera compared to 1/50 of a second. When the the HD camera
electronic shutter open, the the NTSC HD network camera electronic
shutter covering the range from 1/60 sec to 1/10000 sec 261 Step by step
311; the PAL type definition network camera electronic shutter cover
from 1/50 seconds to the range of 1/10000 sec. When the electronic
shutter speed increases, the time allowed in each video field, focusing
light on the CCD to reduce the sensitivity of high-definition network
camera, the result will be reduced, however, a higher shutter speed for
the observation of the moving image will produce a "pause action
"effect, which will greatly increase the dynamic resolution of hd ip
camera.