41 lines
1.2 KiB
Groff
41 lines
1.2 KiB
Groff
.TH IM_CONTRAST_SURFACE 3 "01 May 2006"
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.SH NAME
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im_contrast_surface, im_contrast_surface_raw \- Generate contrast surface
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.SH SYNOPSIS
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.nf
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.B #include <vips/vips.h>
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.sp
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.BI "int im_contrast_surface( IMAGE " "*in" ", IMAGE " "*out" ", int " "half_win_size" ", int " "spacing" " );
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.br
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.BI "int im_contrast_surface_raw( IMAGE " "*in" ", IMAGE " "*out" ", int " "half_win_size" ", int " "spacing" " );
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.fi
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.SH DESCRIPTION
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These functions generate an image where the value of each pixel represents the
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contrast within a square window of size 2 * half_win_size + 1 centred on the
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corresponsing point in the input image.
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.PP
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The output is sub-sampled by a factor of spacing.
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.PP
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Input must be single-band uncoded uchar, WIO or PIO.
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.PP
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Output is single-band uncoded uint, WIO or PIO.
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.PP
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In
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.BR im_contrast_surface(3) ,
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pixels beyond the edges of the input image are considered to be have the value
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of the nearest pixel which is in the image.
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.PP
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Alternatively, in
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.BR im_contrast_surface_raw(3) ,
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pixels within half_win_size of the edge are not calculated, and output is
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smaller accordingly.
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.SH RETURN VALUE
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The functions returns 0 on success and -1 on error.
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.SH COPYRIGHT
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.br
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Copyright 2006, The Nottingham Trent University.
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.SH AUTHOR
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Tom Vajzovic
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