SIGMA LBA-708 - Manual (Page 65)

• Ultracal processing cannot be a part of a post processing operation.
Gamma Correction is also a type of processing. Gamma Correction is controlled from the
Camera dialog box, as it relates to a specific camera’s characteristics. Gamma correction can
be part of a post processing operation.
3.2.4.6 Frame Summing
Click on this item if you want the LBA to sum frames. Specify the Number of Frames that you
want to sum into each frame placed in the frame buffer. Frames are always summed in the
order that they are input. Frame summing can be used to increase the apparent size of low-level
signals. Fixed pattern noise will unfortunately grow linearly with each summed frame, but
temporal noise will increase at approximately the square root of the number of frames summed,
thus the resulting signal to noise ratio will be improved.
3.2.4.7 Frame Average
Check on this item if you want the LBA to average frames. Specify the Number of Frames that
you want to average into each frame placed in the frame buffer. Frames are always averaged in
the order that they are input. Frame averaging will improve the signal to noise ratio by
approximately the square root of the number of frames averaged.
Note: If the frame that you are averaging has poor pointing stability, then the reliability of the computed results of
an averaged frame may not be very good.
3.2.4.8 Gain Correction
Check on this item if you want to apply Gain Correction. You must have Generated or Loaded
a gain correction table, before you can apply gain correction processing to newly acquired or post
processed frames of data. See 3.1.8 Generate Gain, for further details.
3.2.4.9 Reference Subtraction
Check on this item if you want to subtract the reference frame from newly acquired or post
processed frames of data. The reference frame is location 0 (zero) in the frame buffer. This
location is always reserved for the reference frame. The content of frame 0 will be subtracted
from the results of all other processing operations. Associated with creating and saving a
reference frame is the Set Reference Source edit control (shown above), and the Set
Reference action item in the Files menu, and the set reference toolbar button. See Set
Reference for further details.
The Set Reference Source edit control allows you to select what type of data will be loaded
into the reference frame.
Using this feature with the four-camera option will cause the reference frame to be subtracted
from the input of each camera. It does not discriminate between camera selections.
Operator’s Manual LBA-PC
Doc. No. 10654-001, Rev 4.10
65