Photon Focus MV1-D1024E User Manual page 28

4 Functionality
Sequential readout mode For the calculation of the frame rate only a single formula applies:
frame rate equals approximately the inverse of the sum of exposure time and readout
time.
Simultaneous readout mode (exposure time < readout time) The frame rate is given by the
readout time. frame rate equals approximately the inverse of the readout time.
Simultaneous readout mode (exposure time > readout time) The frame rate is given by the
exposure time. frame rate equals approximately the inverse of the exposure time.
The simultaneous readout mode allows higher frame rate. However, If the exposure time
strongly exceeds the readout time, then the effect on the frame rate is neglectable.
In simultaneous readout mode image output faces minor limitations. The overall
linear sensor reponse is partially restricted in the lower gray scale region.
A new calibration of the image correction is required when changing the read-
out mode from sequential to simultaneous readout mode or vice versa.
Sequential readout
By default the camera continuously delivers images as fast as possible ("Free-running mode")
in the sequential readout mode. Exposure time of the next image can only start if the readout
time of the current image is finished.
A x p o s u r e
Figure 4.2: Timing in free-running sequential readout mode
When the acquisition of an image needs to be synchronised to an external event, an external
trigger can be used (refer to Section 4.4). In this mode, the camera is idle until it gets a signal
to capture an image.
A x p o s u r e
Figure 4.3: Timing in triggered sequential readout mode
Simultaneous readout (interleave exposure)
To achieve highest possible frame rates, the camera must be set to "Free-running mode" with
simultaneous readout. The camera continuously delivers images as fast as possible. Exposure
time of the next image can start during the readout time of the current image.
When the acquisition of an image needs to be synchronised to an external event, an external
trigger can be used (refer to Section 4.4). In this mode, the camera is idle until it gets a signal
to capture an image.
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