User guide

Page 48 Document No: 11294 LBA-USB User Guide
When enabled, the precedence for all processing and post processing operations
occurs in the following order:
1. Ultracal! Processing (cannot be post processed)
2. Gain Correction
3. Gamma Correction
4. Frame Summing
5. Frame Averaging
6. Reference Subtraction
7. Convolution
Although Ultracal! is a processing step, it is important to note the following about
Ultracal!:
 Processing of newly acquired video is not an option in the dialog above.
 Processing must be enabled from the main screen Menu bar.
 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.
 Frame Summing –
Activate this option to sum frames and then specify the
Number of Frames to be placed in the frame buffer. Frames are always
summed in the order received. 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
overall signal to noise ratio typically improves.
 Frame Average –
Activate this option to average frames and then specify
the Number of Frames to be placed in the frame buffer. Frames are always
averaged in the order received. Frame averaging improves the signal to noise
ratio by approximately the square root of the number of frames averaged.
Note: If the frame being averaging has poor pointing stability, then the reliability
of the computed results of an averaged frame may also result in a poor
image.
 Gain Correction –
Activate this option to apply Gain Correction. A
correction table must be generated or loaded prior to applying a gain correction
process to newly acquired or post processed frames of data. See section 2.1.7,
for further details.
 Reference Subtraction –
Activate this option to subtract the reference
frame from newly acquired or post processed frames of data. The reference
frame location is at 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 File menu (see section 2.1.6), and the set
reference toolbar button.
The Set Reference Source control provides a selection for the type of data to
be loaded into the reference frame.