User guide

Page 64 Document No: 11294 LBA-USB User Guide
In 3D, the Reference beam alone appears in the display. It is presented in the
Beam Color choice selected.
 Current-Reference – In 2D, both Cursors and Cursor Profiles must be
enabled for this feature to operate. The Current minus the Reference beam
appears in the display. A second profile, drawn in light gray, appears in the
display. This profile is a projection of the Current beam. All projections are
made from the cursor positions.
In 3D, the Current minus the Reference beam appears in the display. It is
presented in the Beam Color choice selected.
 Current+Reference – In 2D, both Cursors and Cursor Profiles must be
enabled for this feature to operate. The Current plus the Reference beam
appear in the display. A second profile, drawn in light gray, appears in the
display. This profile is a projection of the Current beam. All projections are
made from the cursor positions.
In 3D, the Current plus the Reference beam appears in the display. It is
presented in the Beam Color choice selected.
Note: In all of the above, negative energy results are always drawn in dark gray. The
results computations are only for the Current beam. The displayed image
resulting from adding or subtracting reference frames is not saved in the frame
buffer. However, these images can be printed.
Set Reference Source
Select the type of data to load into the reference frame.
Note: This selection is repeated in the Capture dialog box.
 Current Frame – The data in the currently viewed frame will be copied to the
Reference frame.
 Last Gauss – If the Gauss Fit item in the Computations dialog box is also
checked, then the beam profile resulting from a computed Gaussian fit to the
currently viewed frame will be copied to the Reference frame.
 Auto Gauss – If the Gauss Fit item in the Computations dialog box is also
checked, then the beam profile resulting from a computed Gaussian fit to newly
acquired frames will be automatically copied to the Reference frame. In this
mode, setting a reference frame manually does not make any sense because the
next frame brought into view will automatically update the contents of the
reference frame.
Note: In the last two examples, if the Gauss Fit item is not checked and set to
Whole Beam, then no fit data will be available and therefore nothing will
be copied to the Reference frame.
Display Thresholds
Add Display Thresholds to the beam display that indicates when energy
intensities fall into regions that may be of significance to your application. Both a
Lower and an Upper threshold are available. Setting the Lower threshold to
zero disables its operation. Setting the Upper threshold to its maximum value
likewise disables its operation. If the Energy of Beam setting is set to zero,
then the maximum value is 255 for 8-bit mode and 4095 for 12-bit mode. When
the beam energy is calibrated, then the maximum value will be scaled
accordingly.