Dalsa Falcon 4-CLHS Series, User Manual

Page: 45 / 93

Falcon ™ 4 -CLHS Series Operational Reference • 43
Width and Height Features for Partial Scan Control
Width and Height controls along with their respective offsets, allow the Falcon4-CLHS to grab a
region of interest (ROI) within the full image frame. Besides eliminating post acquisition image
cropping done by software in the host computer, a windowed ROI grab reduces the bandwidth
required since fewer pixels are transmitted.
Important: Any reduction of the camera ’s acquisition area from its maximum must be matched by
the same reduction in the frame grabber’s buffer dimensions. The Teledyne DALSA CLHS frame
grabber will generate “Buffer Incomplete” errors when the buffer dimensions do not match the
cropped acquisition.
Vertical Cropping (Partial Scan)
The Height and Vertical Offset features, used for vertical cropping, reduce the number of video
lines grabbed for a frame. By not scanning the full height of the sensor, the maximum possible
acquisition frame rate is proportionately increased, up to the model maximum.
The following figure is an example of a partial scan acquisition using both Height and Vertical Offset
controls. The Vertical Offset feature defines at what line number from the sensor origin to acquire
the image. The Height feature defines the number of lines to acquire (to a maximum of the
remaining frame height). Note that only the partial scan image (ROI) is transmitted to the host
computer.
Vertical Offset
Height
Partial Image Grab
Partial Scan Illustration