SVS-Vistek ECO Series, Руководство пользователя

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SVS-VISTEK
Feature description 23
6.1.5 Exposure
See various exposure and timing modes in chapter: Basic capture modes .
Combine various exposure timings with PWM LED illumination, refer to
sequencer .
Setting Exposure time
Exposure time can be set by width of the external or internal triggers or
programmed by a given value.
6.1.6 Auto exposure
Auto Luminance or auto exposure automatically calculates and adjusts
exposure time and gain, frame-by-frame.
The auto exposure or automatic luminance control of the camera signal is
a combination of an automatic adjustment of the camera exposure time
(electronic shutter) and the gain.
The first priority is to adjust the exposure time and if the exposure time
range is not sufficient, gain adjustment is applied. It is possibility to pre-
define the range (min. / max. -values) of exposure time and of gain.
The condition to use this function is to set a targeted averaged brightness
of the camera image. The algorithm computes a gain and exposure for
each image to reach this target brightness in the next image (control
loop). Enabling this functionality uses always both – gain and exposure
time.
Limitation
As this feature is based on a control loop, the result is only useful in an
averaged, continuous stream of images. Strong variations in brightness
from one image to next image will result in a swing of the control loop.
Therefore it is not recommended to use the auto-luminance function in
such cases.
6.1.7 Bit-Depth
Values of brightness are internally represented by numbers. The number
of bits for brightness representation is limiting the number of colour values
that can be represented. Bit depth defines how many unique colors or
grey levels are available in an image after digitization. The number of bits
used to quantify limits the number of levels to be used.