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Constant force mapping capabilities in SPIP™
For a deflection value interactively chosen by the user SPIP™ looks up and interpolates
the corresponding height values in all force curves in the data-set and produces
the resulting height map. This height map corresponds to what would be the expected
result of performing a real time scan with the chosen deflection value as set-point.
An example is given in Figure 1. The top-left image represents the topography
image recorded using a set-point equal to the maximudfgm deflection value in the
Deflection-Height curve. The top-right image is when the set-point has been reduced
to the level indicated by the blue marker in the deflection-height curve. The
graph in the middle shows a section profile from the two images in green and red,
respectively. It is seen that the structure in the image appear higher in the
low set-point image than in the high set-point image indicating that it is softer
than the background.
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Figure 1
Constant force images.
Left:
Force equal to the acquisition set-point.
Right:
Setpoint corresponding to the blue marker in the Deflection-Height curve (Figure
2). |
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Section profiles
Note that the structure appears higher for the lower post-acquisition setpoint
(red curve). |
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| Figure 2
Representative force curve (deflection vs. height) from the force volume data
set.
The setpoint deflection level at the blue marker position has been used to generate
the image with the red section profile (Fig. 1 top-right). |
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As a specialty SPIP™ can add a topography image to the generated height image
on the fly. This is particularly useful when the force volume data is off-set
by the height found at a certain trigger level, which for example is the case
in the NanoScope acquisition software by Veeco
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Image data has kindly been provided by Dr. Terry McMaster, , Dr. David Sheppard
and Jo Evangelides, University of Bristol, UK. The structure visible in the images is
a Primary Cilium from epithelial kidney cells.
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