Cheetah Python Cameras User Manual | CoaXPress (CXP) Interface
August 27, 2019
Page
62
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86
Rev 1.0
Area of Interest
Overview
For some applications, you might not need the entire image, but only a portion of it. To
accommodate this requirement, Cheetah cameras provide one Area of Interest (AOI), also
known as a region of interest. An AOI is a unique field of view created within the camera’s
maximum field of view. This limitation is based on the structure of the camera’s sensor.
When creating an AOI, you will specify its horizontal and vertical dimensions and location
(using horizontal and vertical offsets).
Creating an AOI Window
Set the starting and ending point for each AOI independently in the horizontal direction
(Horizontal Window) and the vertical direction (Vertical Window) by setting the window
(H & V) offset and (H & V) size, as shown in the following figure. The minimum window size
is 320 (H) x 2 (V) pixel/line and the horizontal dimension is limited to multiples of 8 pixels.
In normal operation, the AOI defines the number of columns and rows output. However,
you can apply subsampling and averaging modes to the AOI to reduce the number of rows
and columns output even further. Using the AOI function and subsampling/averaging
modes effectively increases the camera frame rate. The maximum horizontal window size
(H) and the vertical window size (V) are determined by the camera’s image full resolution,
for example, 5120 x 5120 if using the C5180 camera.
Figure 36:
Horizontal and vertical window positioning
For color version use with AOI enabled, use an even number for Offset X and Offset Y to
achieve proper color reconstruction and white balance.
