Chapter 5 General Operation Factors 63
takes place. Because this scheme is less time efficient than that used in the overlapped
mode, the frame rate may be lower in non-overlapped operation than it is in overlapped
operation with the some exposure time settings.
Part 4 of Figure 20 illustrates the situation at the end of the readout. Both the imaging and
storage cells are empty. In Free Run operation, the imaging cells will be switched back on
immediately, allowing charge accumulation to begin. In Ext Sync operation with no
PreOpen, they are not switched back on until after the External Sync pulse is detected.
Figure 20. Non-Overlapped Mode Exposure and Readout
A subsection of the CCD can be read out at full resolution, sometimes increasing the
readout rate while retaining the highest resolution in the region of interest (ROI).
Readout Rate for Interline
Below are the equations that determine the rate at which the CCD is read out. Tables of
values for CCDs supported at the time of the printing of this manual also appear below.
Assuming the shutter selection is None, the time needed to take a full frame at full
resolution in non-overlapped timing mode is:
t
R
+ t
exp
(1)
where
t
R
is the CCD readout time,
t
exp
is the exposure time.
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