48 lines
1.2 KiB
Groff
48 lines
1.2 KiB
Groff
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.TH IM_MEASURE 3 "24 October 1992"
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.SH NAME
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im_measure \- measure colour patches off images
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.SH SYNOPSIS
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#include <vips/vips.h>
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DOUBLEMASK *im_measure(in, box, h, v, sel, nsel, name)
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.br
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IMAGE *in;
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.br
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IMAGE_BOX *box;
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.br
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int h, v;
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.br
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int *sel;
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.br
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int nsel;
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.br
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char *name;
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.SH DESCRIPTION
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Analyse a grid of colour patches, producing a DOUBLEMASK of averages.
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Pass an IMAGE, an IMAGE_BOX, the number of horizontal and vertical
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patches, an array giving the numbers of the patches to measure (patches
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are numbered left-to-right, top-to-bottom, starting with 1) and the name we
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should give the output mask. Return a DOUBLEMASK in which rows are patches and
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columns are bands. Only the central 50% of each patch is averaged.
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Example: 6 band image of 4x2 block of colour patches.
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+---+---+---+---+
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| 1 | 2 | 3 | 4 |
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+---+---+---+---+
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| 5 | 6 | 7 | 8 |
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+---+---+---+---+
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Then call im_measure( im, box, 4, 2, { 2, 4 }, 2, "fred" ) makes a mask
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"fred" which has 6 columns, two rows. The first row contains the averages
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for patch 2, the second for patch 4.
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Output warnings: a warning is issued if the standard deviation of any patch is
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greater than 20% of the mean of that patch.
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.SH RETURN VALUE
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NULL on error.
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.SH SEE ALSO
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im_avg(3), im_deviate(3), im_stats(3).
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