Offline Operation
Rev. F
Scanning Probe Microscope Training Notebook
51
Extreme variations in the sample topography can alter the planefit, leaving a slight tilt in the image.
This can be remedied by only selecting flat portions of the image to determine the planefit. The
calculation is performed only using the chosen areas, and the planefit is extrapolated on to rest of
the image.
The areas are chosen to be part of the planefit calculation by drawing a box or boxes on the image.
An example of this is shown below.
Examples of 2nd and 3rd order bow removal can be seen in the Typical Image Artifacts section of
this manual.
Figure 18.3e
1st Order Planefit using Selected Areas of AFM Image of Cells on a Smooth Glass Substrate
Other Commonly Used Filters
Planefit Manual
: Similar to Planefit Auto except that the planefit is calculated from a manually
positioned line drawn across the image in X and/or Y.
Erase Scan Lines
: Removes scan lines from image due to skips, noise, etc. This routine replaces
the selected scan line with the average of the two scan lines adjacent to it.
Zoom
: Expands a selected portion of the captured image to fill the display screen.
Note:
This does not increase the resolution or fine detail of the captured image.
Lowpass
: Removes high frequency data from the image by replacing each data point with a 3x3
weighted average of points surrounding each point. This feature may be useful for removing noise
if the gain settings were set too high or if the SPM was in a noisy environment when the image was
captured.
Spectrum 2D
: Two-dimensional fast Fourier transform (2D FFT) filter which allows the inclusion
or removal of specific spatial frequencies (or wavelengths) from the image.
Image before Planefit
Use cursor to select areas to
be included in planefit calcu-
lation
Image after 1st order planefit
in X and Y using selected
areas