These programs, which are based on the Carpick Lab Toolbox, are used to extract the data from a NanoScope data file.

The scaled results are placed in the matrix data, an N x M x L matrix, where N is the number of lines, M is the number of points per line (N = M in most cases), and L is the number of simultaneous data channels recorded.  The assumption is that the first data channel is topgraphy and all the other channels are not topography.  The data output is nm for the first channel and V for all subsequent channels.  It has been tested on data files with only one channel (topography) and data files with three channels (topography and LFM forward and back).

usage: data = open_di(file_name)
To use open_di.m, you need get_num.m (included here) and di_header_find.m (in the Carpick Lab Toolbox).

Jennifer R. Hampton  2/16/09



Additional Information on the Scaling in NanoScope Data Files

The scaling of binary data to physical units is based on Appendix B "Data File Format" from the NanoScope Command Reference Manual (Section B.6.3).

The Z scale conversion factors for topography are in the following two header lines:

\@Sens. Zscan: V XXX nm/V
\@2:Z scale: V [Sens. Zscan] (XXX V/LSB) YYY V

There will be one version of the second line for each simultaneous data channel that is recorded.  For example, a for a friction channel, the second header line is:

\@2:Z scale:  V [Sens. Friction] (XXX V/LSB) YYY V

The first header line in this case isn't needed:

\@Sens. Friction: V 1.000000

To convert from binary (LSB) to hardware units (V), the second line is used.  The XXX value in parentheses is the conversion factor that was used when the data were taken.  However, a rescaling is performed when the data are saved to use the full range of the 2-byte binary data.  So the scaling factor to convert saved LSB data to V is

YYY V/2^16 LSB = YYY V/65536 LSB

In the topography case, to convert from hardware units (V) to physical units (nm), the first line is used.  The scaling factor is

XXX nm/V