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4 Functionality
4.3 Reduction of Image Size
With Photonfocus cameras there are several possibilities to focus on the interesting parts of an
image, thus reducing the data rate and increasing the frame rate. The most commonly used
feature is Region of Interest (ROI).
4.3.1 Region of Interest (ROI)
Some applications do not need full image resolution (e.g. 1312 x 1082 pixels). By reducing the
image size to a certain region of interest (ROI), the frame rate can be increased. A region of
interest can be almost any rectangular window and is specified by its position within the full
frame and its width (W) and height (H). Fig. 4.18, Fig. 4.19 and Fig. 4.20 show possible
configurations for the region of interest, and Table 4.3 presents numerical examples of how
the frame rate can be increased by reducing the ROI.
Both reductions in x- and y-direction result in a higher frame rate.
The minimum width of the region of interest depends on the camera model. For
more details please consult Table 4.5 and Table 4.7.
The minimum width must be positioned symmetrically towards the vertical cen-
ter line of the sensor as shown in Fig. 4.18, Fig. 4.19 and Fig. 4.20). A list of
possible settings of the ROI for each camera model is given in Table 4.7.
Colour models only: the vertical start position and height of every ROI should be
an even number number to have the correct Bayer pattern in the output image
(see also Section 3.4).
It is recommended to re-adjust the settings of the shading correction each time
a new region of interest is selected.
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