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| ......CCTV Camera features learning |
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What is 3D DNR?
Noise reduction ( DNR) is a function that reduces the image noise in order to improve the image quality of the
camera. In particular, it reduces the noise which is generated under low-brightness shooting conditions and
other high-gain states.
3D refers to three dimensions and the Built-in 3D DNR is a circuit of digital noise reduction, able to reduce
image noise, and improve the failure of mixture of colors and contract of colors.
The difference in the methodology of the noise reduction in DNR is totally different from the one that is used in
the 3D DNR, where 3D DNR compares one frame to the next one and then removing the non similar tiny points
which does not exist in the original frame. Obviously, 3D DNR is higher technically than its preceded built- in
feature, the DNR, where the 3D DNR can deal not only with temporal reduction, but also with spatial noise
reduction where it detects the unwanted noise in the same frame and get rid of it. They can also remove the
noise from the video frame |
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What is WDR?
The Wide Dynamic Range (WDR) is a function that it can acquire natural images with fewer blown out highlights
and blocked up shadows by combining a multiple number of images, shot at different exposure times, using
digital signal processing |
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What is Pulse-width modulation (PWM)?
Amodulation technique that uses a digital circuit to create a variable analog signal. PWM is a simple concept:
open and close a switch at uniform, repeatable intervals. Analog circuits that vary the voltage tend to drift, and
it costs more to produce ones that do not than it does to make digital PWM circuits. In addition, control of almost
everything today is already in the digital realm. For example, PWM is widely used to control the speed of a DC
motor and the brightness of a bulb, in which case the PWM circuit is used to open/close a power line. If the line
were opened for 1ms and closed for 1ms, and this were continuously repeated, the target would receive an
average of 50% of the voltage and run at half speed or half brightness. If the line were opened for 1ms and
closed for 3ms, the target would receive an average of 25%. Today, PWM technique has been used in wide
applications, such voltage control, current control, motor control, power control, UPS, inverter. |
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