Cheetah KAC Camera User Manual | Camera Link (CLF) Interface
October 1, 2019
Page
89
of
135
Rev 7.2
Figure 49: Horizontal and vertical window positioning.
Color version
users – when AOI is enabled, for proper color reconstruction and WB ‘Offset
X’ and ‘Offset Y’ must be an even number.
5.5.3 Factors Impacting AOI Frame Rate
The camera frame rate depends upon a number of variables including the, integration
time, number of rows in the AOI, the amount of decimation within the image, the A/D
converter bit depth, the bandwidth of the output interface and whether triggered dual
video mode is enabled.
AOI Size:
The camera must readout an entire image sensor row even if the AOI function specifies a
lower horizontal (fewer columns) resolution. The camera need not readout all rows, so
improvements in frame rate are possible as the number of rows in the AOI decreases.
Exposure Time:
The camera overlaps the exposure time and image readout. If it is desired to increase the
exposure time to a value exceeding the minimum readout time, the frame rate must be
reduced accordingly.
Decimation:
The camera supports both sub-sampling and pixel averaging to reduce the output
resolution. Use of the pixel averaging feature does not increase the image sensor frame
rate, because all the pixels must be readout and averaged together. However, sub-
sampling decimation can offer a frame rate improvement by reducing the number of rows
readout from the image sensor.
A/D Bit Depth:
The image sensor has an A/D converter on each column of the image sensor and reads
out two rows (one line) simultaneously. There is a finite time required to reach
