101 lines
2.4 KiB
Groff
101 lines
2.4 KiB
Groff
.TH IM_EXPTRA 3 "24 April 1991"
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.SH NAME
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im_exp10tra, im_exptra, im_expntra, im_expntra_vec, im_log10tra, im_logtra,
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im_powtra, im_powtra_vec \- logarithmic, exponential and power transform of an image
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.SH SYNOPSIS
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.B #include <vips/vips.h>
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.B int im_expntra(in, out, base)
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.br
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.B IMAGE *in, *out;
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.br
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.B double base;
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.B int im_expntra_vec(in, out, n, vec)
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.br
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.B IMAGE *in, *out;
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.br
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.B int n;
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.br
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.B double *vec;
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.B int im_exp10tra(in, out)
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.br
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.B IMAGE *in, *out;
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.B int im_exptra(in, out)
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.br
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.B IMAGE *in, *out;
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.B int im_log10tra(in, out)
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.br
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.B IMAGE *in, *out;
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.B int im_logtra(in, out)
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.br
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.B IMAGE *in, *out;
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.B int im_powtra(in, out, exponent)
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.br
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.B IMAGE *in, *out;
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.br
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.B double exponent;
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.B int im_powtra_vec(in, out, n, vec)
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.br
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.B IMAGE *in, *out;
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.br
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.B int n;
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.br
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.B double *vec;
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.SH DESCRIPTION
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Each of the above functions maps in through a log or anti-log
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function of some sort and writes the result to out. The size and number of
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bands are unchanged, the output type is float, unless the input is double, in
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which case the output is double. Non-complex images only!
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.B im_expntra(3)
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transforms element x of input, to pow(base, x) in output. It detects division
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by zero, setting those pixels to zero in the output. Beware: it does this
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silently!
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.B im_expntra_vec(3)
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works as im_expntra(), but lets you specify a constant per band.
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.B im_exp10tra(3)
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transforms element x of input, to pow(10,0, x) in output. Internally, it is
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defined in terms of im_expntra().
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.B im_exptra(3)
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transforms element x of input, to pow(e, x) in output, where e is the
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mathematical constant. Internally, it is defined in terms of im_expntra().
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.B im_log10tra(3)
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transforms element x of input, to log10tra(x) in output.
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.B im_logtra(3)
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transforms element x of input, to logtra(x) in output.
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.B im_powtra(3)
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transforms element x of input, to pow(x, exponent) in output. It detects
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division by zero, setting those pixels to zero in the output. Beware: it does
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this silently!
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.B im_powtra_vec(3)
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works as im_powtra(3), but lets you specify a constant per band.
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.SH BUGS
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None of the functions checks for under/overflow. Overflow is very common for
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many of these functions!
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.SH RETURN VALUE
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Each function returns 0 on success and -1 on error.
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.SH SEE ALSO
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im_add(3), im_multiply(3), im_subtract(3), im_lintra(3),
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im_absim(3), im_mean(3), im_max(3).
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.SH AUTHOR
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N. Dessipris \- 24/04/1991
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.br
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J. Cupitt (rewrite) \- 21/7/93
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