Imperx Cheetah 3G-SDI User Manual page 48

Cheetah Pregius Camera User Manual | 3G-SDI Interface
Exposure Limits:
Speed:
Gain Limits:
Speed:
Iris Limits:
Current:
April 14, 2021
Peak – the firmware calculates the peak luminance value (maximum
•
luminance level) within the image (in output counts) or within the
AOI and compares the value to the target (Limit value) to determine
changes to the exposure/gain settings.
If using AEC, you can specify the range of allowable exposures from
minimum to maximum in microseconds. For example, if anticipating
motion within the scene, you can specify the maximum exposure to be
1 ms to avoid motion blur. Try to set the minimum exposure value as high
as possible to help prevent oscillations in the AEC control loop.
Use the speed drop-down options to set the exposure convergence to 1x
(slow), 2x, 3x, or 4x (fast). Convergence is the speed at which the camera
stabilizes the exposure after lighting conditions change.
Using faster convergence speeds might cause oscillations in
exposure control if the scene changes luminance levels
abruptly, for example, from extremely dark to extremely
bright. In these conditions, use a slower convergence setting
and/or increase the minimum exposure time limit.
If enabled, the automatic gain control process drives gain so the
calculated luminance value from the image is equal to the digital counts
specified in the Luminance Limit field. However, you may want to limit
the amount of gain applied by the AGC. For example, too much gain may
cause the image to be noisy. You can specify the minimum and maximum
gain applied by setting the Gain Limits.
The speed at which the gain converges onto the target luminance level
depends on the Convergence setting. Select one of the following speed of
convergence settings: 1x (slow), 2x, 3x, and 4x (fast).
When enabling the automatic iris control for a P-Iris lens, you can specify
the range of iris positions from minimum to maximum in steps. By
default, the minimum iris limit is 0 which means the iris is Fully Open. The
amount of light reaching the sensor is maximum.
The maximum iris limit is the number of steps needed to set the iris to
the Fully Closed position. The amount of light reaching the sensor is
minimum. The maximum possible iris limit depends on a lens model. By
default, the maximum limit is set to 73. You may need to adjust this limit
if the maximum number of steps of your P-Iris lens differs from 73. Please
refer to the documentation on your lens for this parameter.
Provides live information about the current value of the exposure time,
gain, iris position, and calculated luminance value. Software polling
automatically refreshes the values. Three indicators provide status of the
current exposure, gain, and iris:
Green: the exposure/gain/iris value is within the set limits.
Yellow: the exposure/gain/iris has reached a minimum limit value.
Red: the exposure/gain/iris has reached a maximum limit value.
Page
48 of 99
Rev 1.4