Photon Focus OEM-D1024E, Руководство пользователя

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4 Functionality
Sequential readout mode For the calculation of the frame rate only a single formula applies:
frames per second equal to the invers 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. Frames per second equal to the invers of the readout time.
Simultaneous readout mode (exposure time > readout time)
The frame rate is given by the
exposure time. Frames per second equal to the invers 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 grey scale region.
When changing readout mode from sequential to simultaneous readout mode
or vice versa, new settings of the BlackLevelOffset and of the image correction
are required.
Sequential readout
By default the camera modules 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.
e x p o s u r e r e a d o u t e x p o s u r e r e a d o u t
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 4.7 and Section 5.4). In this mode, the camera module is
idle until it gets a signal to capture an image.
e x p o s u r e r e a d o u t i d l e e x p o s u r e
e x t e r n a l t r i g g e r
Figure 4.3: Timing in triggered sequential readout mode
Simultaneous readout (interleave exposure)
To achieve highest possible frame rates, the camera module must be set to "Free-running
mode" with simultaneous readout. The camera module 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 4.7 and Section 5.4). In this mode, the camera module is
idle until it gets a signal to capture an image.
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