Area Of Interest (Aoi) - Basler L100k User Manual

3.8 Area of Interest (AOI)

The area of interest feature allows you to specify a portion of the CCD array and during operation,
all pixels are transferred out of the camera but only the pixel information from the specified portion
is signalled as valid to the frame grabber. Pixels outside of the AOI are read out of the sensor, but
transferred to the frame grabber as black pixels and signalled as invalid to the grabber.
The size of the area of interest is defined by declaring a starting pixel and a length in pixels (see
Figure 3-10). For example, if you specify the starting pixel as 10 and the length in pixels as 15, the
camera will output all pixels from the array but only pixels 10 through 24 will be valid.
30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Figure 3-10: Area of Interest
The number of transferred pixels does not decrease when the area of interest feature is used.
The maximum achieveable line rate does not increase when the area of interest feature is used.
Validity of pixels is signalled using the line valid bit.
On the pixel clock cycle where AOI data transmission begins, the line valid bit will become high.
For example, if you specify the starting pixel as 5, the line valid bit will become high on the clock
cycle where pixel 5 is transmitted (see Figure 3-11). After all of the pixels in the AOI have been
transmitted, the line valid bit will become low indicating that valid line data is no longer being
transmitted.
Figure 3-11: Single 10 Bit or Single 8 Bit Output Mode with Edge or Level Controlled Exposure
If you use a frame grabber which does not take the falling edge of the line valid bit
into account, you must also set the frame grabber to the number of pixels in the area
of interest. For example, when you have an area of interest of 500 pixels, you must
also set the grabber to 500 pixels. Otherwise, the grabber will show no effect.
BASLER L100
k Series
DRAFT
Starting
Pixel
Length in Pixels
Operation and Features
Line of Pixels
in the CCD
3-29