7.7 Sub-array / Region of Interest (ROI )
In many applications, users wish to designate a particular Region of Interest (ROI) within the entire
image.
The ROI feature of the DVC-1412 allows the definition of a band of pixel-rows that are selected
for readout. The CCD is then fast-scanned through the un-selected areas, allowing for a faster
overall frame rate of only the selected area. Since the faster frame rate is created by the selection of
fewer pixel-rows, only the vertical “Y” parameter needs to be set within the camera.
The application software may also allow the designation of unwanted columns (for example, by
allowing the user to draw a ROI box around the selected region. In that case, the application may
“blank” the unwanted columns for a convenient presentation to the user. However, the de-selection
of columns from readout has no effect on the frame rate.
7.7.1 Functional Description
Under normal conditions, every pixel of the CCD array is read out to crack an image frame for
display. The camera images, transfers, and read-outs. With the 1412, there is a 1/10 second
exposure, occurring concurrently with 1/10 second read-out. Thus, while readout N-1 takes place,
exposure N is also happens.
100 mSec (10 f/s)
Normal Exposure
EXP
N
EXP
N+1
EXP
N+L
Readout
RDT
N-1
RDT
N
RDT
N+1
10 ms
100 f/s
Exposure EXP
N
EXP
N+1
EXP
N+L
Sub-
array /
ROI
(16XN)
Readout
F
A
S
T
RDT
N-1
NORMAL
F
A
S
T
RDT
N
RDT
N+1
ROI 512 X N 256 X N 64 X N 16 X N
Table
Frames/sec 19 32 70 100
27
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