Cheetah Python Camera with USB3 Interface
–
User Manual
December 5, 2017
Page
75
of
78
Rev 1.0
5.16.3 Frame Time Monitor
The camera has a built-in frame rate monitor. In any mode of operation (normal, AOI, and
so on) you can query the camera for the current frame time by issuing a command (refer
4.7.4 Acquisition Control). The camera will return the current camera speed in units of
frames per second.
5.16.4 Current image size
The camera image size can change based on a camera feature selected. In any mode of
operation (normal, AOI, and so on) you can query the camera for the current image size
by issuing a command (refer to 4.7.3 Image Format Controls). The camera will return
current camera image size in (pixels x lines).
5.16.5 Auto Gain and Auto Exposure Control (AGC/AEC)
Automatic exposure (and gain) control keep the same image brightness despite changing
light conditions. Both modes
–
automatic exposure and automatic gain
–
can be enabled
simultaneously. In these modes, you set the image brightness (luminance) target level in
counts, and the camera adjusts the exposure and/or gain accordingly. The target
luminance can be the average luminance or peak brightness within the entire image or
within the defined AOI.
If AEC and AGC are both enabled, the camera first adjusts the exposure within the preset
min-max limits you set. If the maximum exposure limit is reached, the camera indicates
the limit has been reached and begins increasing the gain.
The camera displays the current values for AGC/AEC luminance, current exposure, and
current gain.
In some rapidly changing bright light conditions, an image brightness oscillation (image
intensity flipping from bright to dark) could occur. To prevent this situation, increase the
minimum exposure limit, decrease the AEC speed, or use an AOI for the luminance target
to control the intensity variability.
