User guide

Page 36 Document No: 11294 LBA-USB User Guide
Set a Custom ROI (Region of Interest)
(LBA-USB-Lxxx model specific)
Select this Format option to either further reduce the amount of data collected
(thus allowing for faster frame capture rates) or to focus in on a specific region
of interest. The format x and y Offsets and Width/Height settings from the
previous selection are retained as the starting point for the custom ROI.
To set a custom ROI, modify the x and y Offsets to establish the new location
of the top left pixel of the ROI. Next, define the size of the ROI in pixels by
Width and Height. Finally, select an appropriate Frame Rate calculated for
the application. The available rates are dependent on the size of the region, the
pixel format, and the shutter setting.
Note: The Resolution parameter remains fixed at x1.
Number of Frames (LBA-USB-Lxxx model specific)
The Number of Frames or Size, Kb setting determines the buffer size, or the
total amount of system memory allocated to the temporary storage of digitized
video frames. There are two ways to set frame buffer size.
 Enter a specific amount of memory to allocate in the Size, Kb field
 Specify the Number of Frames available to the buffer
We recommend setting the number of Frames, rather than the amount of
memory allocated to the Buffer Size.
What is the Frame Buffer?
The frame buffer is an allocated block of the PC’s system memory. It receives
and temporarily retains frames of digitized video data. The frames in the frame
buffer are numbered from 1 to N, where N is the maximum number of frames
allocated. At least one frame must be allocated in the frame buffer.
The frame buffer is loaded in a sequential round robin fashion. Frames of data
can be placed into the frame buffer by:
 Transferring data from a digital camera
 Loading data from a file
 Post processing data already in the frame buffer
 Post processing data from a file
In the far lower right hand corner of the main screen display is a Frame edit and
spin control:
The number visible in the edit control indicates frame number currently
displayed. Edit this number by double-clicking and entering a new value, or use
the spin control to increment or decrement to the desired frame.
We recommend setting the frame buffer to contain as many frames as your
Windows environment allows in real memory. This will prevent LBA-USB from
attempting to use virtual memory (hard drive space) as frame buffer space. A