1Pamsummcol User Manual(0) Pamsummcol User Manual(0)
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6 pamsummcol - summarize (sum, average, etc) a Netpbm image by column
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10 pamsummcol { -sum | -mean | -min | -max } [imagefile]
11 All options can be abbreviated to their shortest unique prefix. You
13 may use two hyphens instead of one. You may separate an option name
14 and its value with white space instead of an equals sign.
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18 This program is part of Netpbm(1).
19 pamsummcol reads a Netpbm image (PNM or PAM) and performs a summary
21 function over all the rows in each column (sum, mean, etc.). It pro‐
22 duces an image of the same kind that the same width and depth as the
23 input, and one row high. Its sample values are the result of the sum‐
24 mary.
25 pamsummcol performs the summary operation on each plane independently.
27 pamsummcol performs the operation on the actual sample values, not on
29 the light intensities represented by them in the case that the image is
30 a PGM or PPM image.
31 If you want to summarize by row instead of by column, run the input
33 through pamflip first (and if you want the output to be a single column
34 instead of a single row, use pamflip again).
35 If you want to summarize over the entire image (getting a one-tuple
37 output image), use pamsumm to get a summary row, pamflip to turn that
38 into a column, the pamsumm again to summarize the column.
39 If you want to summarize the individual samples in an entire image,
41 instead of by tuple, use pamsumm.
42 pamsummcol performs the operation on the actual sample values, not on
44 the light intensities represented by them in the case that the image is
45 a PGM or PPM image or PAM equivalent. You can use pnmgamma to convert
46 such an image to one with samples proportional to light intensity, and
47 then use pamsummcol on the result.
48 You can achieve the same thing as pamsummcol -mean with pamscale. Just
50 scale vertically to a single row, without scaling horizontally at all.
51 Use the pixel mixing method.
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56 You must specify exactly one of -sum, -mean, -min, or -max.
57 -sum
61 This option makes the summary function addition.
63 In each column and plane of the output row, the sample
64 value is the
65 sum of all the samples values in the same column and plane
66 of the input.
67 If a result is greater than the image maxval, it is clipped
68 to
69 the maxval.
70 -mean
73 This option makes the summary function arithmetic mean.
75 In each column and plane of the output row, the sample
76 value is the
77 mean of all the samples values in the same column and plane
78 of the input.
79 -min
82 This option makes the summary function arithmetic minimum.
84 In each column and plane of the output row, the sample
85 value is the
86 minimum of all the samples values in the same column and
87 plane of
88 the input.
89 -max
92 This option makes the summary function arithmetic maximum.
94 In each column and plane of the output row, the sample
95 value is
96 the maximum of all the samples values in the same column
97 and
98 plane of the input.
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104 pamsumm(1), pamscale(1), pamfunc(1), pamarith(1), pamscale(1), pam(1),
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108 pamsummcol was added to Netpbm in Release 10.21 (March 2004).
109netpbm documentation 25 January 2009 Pamsummcol User Manual(0)