MAN page from Mandrake Other XITE-3.3-3.i386.rpm
LOGARITHM
Section: User Commands (1)
Updated: 16 Mar 1998
Index
NAME
logarithm, fftDisplay - Take logarithm of BIFF band (compressdynamic range)
SYNTAX
logarithm [<option>...] <inimage> <outimage>
DESCRIPTION
Takes the logarithm of the magnitude of the pixelvalues of areal or complex band according to the formula
out_pix = (log10(eps + |in_pix|) + offset) * scale
This mapping will compress the dynamic range of an image andmake small pixelvalues better visible (e.g. used to displayFourier transform magnitude).
All pixeltypes are accepted in inimage.For an integraloutput pixeltype, the resulting pixel-values are rounded. Thepixelvalues are limited to fit within the range of the outputpixeltype.
fftDisplayis retained for compatibility with previousXITE versions. It is a script which invokes logarithmwith the option -shift.
OPTIONS
- -eps eps
- Default value: 1 / (10 * xsize * ysize)
- -offset offset
- Default value: -log10(eps)
- -scale scale
- Default value: 20.0
- -min minimum
- Default: No minimum (only limited by the data type)
- -pt pixtyp
- Determines pixeltype of bands in outimage.Legal values forpixtypare
ub or 3 : unsigned byte
r or 8 : real
d or 10 : double
Default: unsigned byte
- -shift
- The resulting bands are shifted horizontally xsize/2,vertically ysize/2. This is convenient to be able to centerthe (0,0) frequency of a Fourier transform image.
RETURN VALUE
0 - ok
1 - Illegal pixeltype for 'outimage'.
2 - Error in logarithm function.
SEE ALSO
logarithm(3),
power(1),
phase(1),
real(1),
imag(1),
absValue(1)
AUTHOR
Trond Sørensen.
ID
$Id: logarithm.c,v 1.42 1997/05/27 14:44:03 svein Exp $
Index
- NAME
- SYNTAX
- DESCRIPTION
- OPTIONS
- RETURN VALUE
- SEE ALSO
- AUTHOR
- ID
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