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| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2023-09-07 16:26:28 +0000 |
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| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2023-09-07 16:26:28 +0000 |
| commit | 851f8a113827e42ae618423fdab09cb0a67dc4e4 (patch) | |
| tree | c7975f26f69fa817d5de575a5c97d0a585b4e999 | |
| parent | 3195997e71a1ad9686da91a1d14cda2d81d3eb52 (diff) | |
| download | netpbm-mirror-851f8a113827e42ae618423fdab09cb0a67dc4e4.tar.gz netpbm-mirror-851f8a113827e42ae618423fdab09cb0a67dc4e4.tar.xz netpbm-mirror-851f8a113827e42ae618423fdab09cb0a67dc4e4.zip | |
miscellaneous update
git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@4637 9d0c8265-081b-0410-96cb-a4ca84ce46f8
| -rw-r--r-- | pamaddnoise.html | 99 | ||||
| -rw-r--r-- | pbmmake.html | 9 | ||||
| -rw-r--r-- | ppmrough.html | 86 |
3 files changed, 108 insertions, 86 deletions
diff --git a/pamaddnoise.html b/pamaddnoise.html index 3a0f3903..0d1609bd 100644 --- a/pamaddnoise.html +++ b/pamaddnoise.html @@ -2,7 +2,7 @@ <html><head><title>Pamaddnoise User Manual</title></head> <body> <h1>pamaddnoise</h1> -Updated: 12 December 2020 +Updated: 21 August 2023 <br> <a href="#index">Table Of Contents</a> @@ -81,60 +81,97 @@ Common Options</a>), <b>pamaddnoise</b> recognizes the following command line options: <dl compact> -<dt><b>-lambda</b> <i>value</i> +<dt><b>-type</b> <i>noise_type</i> + +<dd> +Select type of noise by name. The following noise types are +available: gaussian, multiplicative_gaussian, impulse, laplacian, +poisson. Only enough letters to be unique are required for the noise +type option. The default noise type is <b>gaussian</b>. + +<dl> +<dt><b>gaussian</b> + <dd>To each sample value is added the value of a two Gaussian random variables. + The variance of one is independent of the sample value, while the variance + of the other is proportional to the sample value. You control these + variances with options <b>-sigma1</b> and <b>-sigma2</b> (and can eliminate + either by setting the variance to 0). The mean of the Gaussian + distributions is 0. + +<dt><b>multiplicative_gaussian</b> +<dt><b>impulse</b> + <dd>This is "salt and pepper" noise. Samples are changed randomly + to zero or full brightness or left alone. This is also know as salt and + pepper noise, as in a grayscale picture, it adds white pixels and black + pixels, which look like salt and pepper, respectively. Control this with + options <b>-tolerance</b> and <b>-salt</b>. + +<dt><b>laplacian</b> + +<dt><b>poisson</b> +</dl> -<dd>This is the expected value of the Poisson distribution for a sample value - of mximum intensity. The expected value for other intensities is - proportional; e.g. for half intensity, it is half this value. +<dt><b>-lambda</b> <i>value</i> -<p>This is meaningful only with <b>-type=poisson</b>. +<dd> +This is valid only with <b>-type=poisson</b>. It is the expected value +of the Poisson distribution for a sample value of mximum intensity. The +expected value for other intensities is proportional; e.g. for half intensity, +it is half this value. <p>The default value is 12. <dt><b>-lsigma</b> <i>value</i> -<dd>Used for laplacian noise only. The default value is 10.0. +<dd>This is menaingful only for laplacian noise. + +<p>The default value is 10.0. <dt><b>-mgsigma</b> <i>value</i> -<dd>Used for multiplicative gaussian noise only. The default value is -0.5. +<dd>This is valid only for multiplicative gaussian noise. + +<p>The default value is 0.5. <dt><b>-seed</b> <i>int</i> -<dd>Used for all noise types. Set the initial random number generator -seed value. +<dd>This is the random number generator seed value. Use this to get + repeatable results. <dt><b>-sigma1</b> <i>value</i> -<dd>Used for gaussian noise only. The default value is 4.0. +<dd>This is valid only for gaussian noise. It is the standard deviation + of the Gaussian random variable that is multiplied by the square root of + each sample value and added to that sample value. +<p> + The default value is 4.0. <dt><b>-sigma2</b> <i>value</i> -<dd>Used for gaussian noise only. The default value is 20.0. +<dd>This is valid only for gaussian noise. + It is the standard deviation of the Gaussian random variable that is + added directly to each sample value. +<p> +The default value is 20.0. -<dt><b>-tolerance</b> <i>ratio</i> +<dt><b>-tolerance</b> <i>fraction</i> -<dd> -Used for impulse noise only. The default value is 0.10. This means -that 5% of all pixel values will be set to 0 and 5% will be set to -the maxval +<dd>This is valid only for impulse noise. + <i>fraction</i> is the fraction of samples that are changed + in the output. Whether each is changed to salt or pepper is controlled by + <b>-salt</b>. -<dt><b>-type</b> <i>noise_type</i> +<p>The default value is 0.10. -<dd> -Select type of noise by name. The following noise types are -available: gaussian, multiplicative_gaussian, impulse, laplacian, -poisson. Only enough letters to be unique are required for the noise -type option. The default noise type is <b>gaussian</b>. +<dt><b>-salt=<i>fraction</i></b> + <dd>This is valid only for impulse noise. <i>fraction</i> is the + fraction of the pixels that are changed that are changed to salt (maxval); + the rest are changed to pepper (0). -<ul> -<li><b>gaussian</b> -<li><b>multiplicative_gaussian</b> -<li><b>impulse</b> -<li><b>laplacian</b> -<li><b>poisson</b> -</ul> +<p>The default is 0.5 (half salt, half pepper). + +<p>This option was new in Netpbm 11.04 (September 2023). Before that, the + noise is always half salt and half pepper. </dl> diff --git a/pbmmake.html b/pbmmake.html index 06afbb73..4ed8358b 100644 --- a/pbmmake.html +++ b/pbmmake.html @@ -40,12 +40,11 @@ command line options: <dt><b>-black</b> <dt><b>-gray</b> -<p>In addition to the usual <b>-white</b> and <b>-black</b>, this -program implements <b>-gray</b>. This gives a simple 50% gray pattern -with 1's and 0's alternating. +<p>These options specify the color of the output. <b>-white</b> means +all pixels are white. <b>-black</b> means all pixels are black. +<b>-gray</b> means black and white pixels alternate. -<p>With none of the above specified, the output image will be entirely -white. +<p>You may specify only one of these. The default is all white. </dl> diff --git a/ppmrough.html b/ppmrough.html index 7ecc343d..e31c4221 100644 --- a/ppmrough.html +++ b/ppmrough.html @@ -2,12 +2,13 @@ <html><head><title>Ppmrough User Manual</title></head> <body> <h1>ppmrough</h1> -Updated: 28 January 2022 +Updated: 20 August 2023 <br> <a href="#index">Table Of Contents</a> <h2>NAME</h2> -ppmrough - create PPM image of two colors with a ragged border between them +ppmrough - create PPM image of a single color rectangle with ragged edges on a +different color background <h2 id="synopsis">SYNOPSIS</h2> @@ -43,37 +44,27 @@ name and its value with white space instead of an equals sign. <p>This program is part of <a href="index.html">Netpbm</a>. -<p><b>ppmrough</b> generates a PPM image of the specified width, height, and -colors. <b>ppmrough</b> tiles the image into semi-rectangular regions with a -ragged borders between them. It calculates the fluctuations with -pseudo-random numbers. +<p><b>ppmrough</b> generates a PPM image of the specified width and height. + The image consists of a rectangle of the specified foreground color + surrounded by borders of the specified size and background color, except + that the boundary between the foreground rectangle and the borders is + ragged. The ragged effect is random. <p><b>ppmrough</b> writes the PPM image to Standard Output. <p>The maxval of the output image is 255 (You can change this with <b>pamdepth</b>). -<p>Use the options <b>-left</b> or <b>-right</b>, respectively, to -make vertical borders, and <b>-top</b> or <b>-bottom</b>, -respectively, to generate horizontal borders inside the image. Each of -these options needs an integer value <i>pixels</i> that determines the -average distance of the interior border to the related edge of the -image. You may combine the <b>-left</b>, <b>-right</b>, <b>-top</b>, -and <b>-bottom</b> options to generate an image with more than one -border. The algorithm ensures that you can concatenate two images -produced with the same (i.e. <b>-left</b>) value without dislocations. - -<p>You specify the dimensions of the generated image with the -<b>-width</b> and <b>-height</b> options. - -<p>Use the <b>-bg</b> and <b>-fg</b> options to set the background -(margin) color and the foreground (interior) color, respectively. If -you don't specify any of the <b>-left</b>, <b>-right</b>, <b>-top</b>, -and <b>-bottom</b> options, all pixels are set to foreground color. -The defaults are white foreground and black background. +<p>Use the options <b>-left</b> or <b>-right</b>, respectively, to make +vertical borders, and <b>-top</b> or <b>-bottom</b>, respectively, to generate +horizontal borders inside the image. The value of each of these options is +the minimum width of the border on that edge. Beyond that minimum, the width +at any given location on that edge is random, varying along the edge in a +fractal kind of way. + <p>Use the <b>-var</b> option to control the "raggedness" of -the border. The less its value is the smoother the border is. You +the border. The lower its value, the smoother the border is. You can initialize the pseudo-random generator with the <b>-init</b> option. @@ -88,51 +79,46 @@ Common Options</a>), <b>ppmrough</b> recognizes the following command line options: <dl compact> -<dt><b>-left=</b><i>pixels</i> - -<dd> Specifies the mean distance of the border from the left margin -(default: no border). -<dt><b>-right=</b><i>pixels</i> +<dt><b>-width=</b><i>pixels</i> -<dd>Specifies the mean distance of the border from the right margin -(default: no border). +<dd>This specifies the width of the image in pixels (default: 100). -<dt><b>-top=</b><i>pixels</i> +<dt><b>-height=</b><i>pixels</i> -<dd>Specifies the mean distance of the border from the top margin -(default: no border). +<dd>This specifies the height of the image in pixels (default: 100). +<dt><b>-left=</b><i>pixels</i> +<dt><b>-right=</b><i>pixels</i> +<dt><b>-top=</b><i>pixels</i> <dt><b>-bottom=</b><i>pixels</i> -<dd>Specifies the mean distance of the border from the bottom margin -(default: no border). - -<dt><b>-width=</b><i>pixels</i> - -<dd>Specifies the width of the image (default: 100). - -<dt><b>-height=</b><i>pixels</i> - -<dd>Specifies the height of the image (default: 100). +<dd>This option causes the program to create a left, right, top, or bottom +border, respectively, at least <i>pixels</i> pixels wide, varying randomly +beyond that. You may specify any combination of these. <dt><b>-bg=</b><i>colorspec</i> -<dd>Background color. <i>colorspec</i> is as described for the +<dd>This is the background color, i.e. the color of the +borders. <i>colorspec</i> is as described for the <a href="libnetpbm_image.html#colorname">argument of the <b>pnm_parsecolor()</b> library routine</a>. Default is black. <dt><b>-fg=</b><i>color</i> -<dd>Foreground color. <i>colorspec</i> is as described for the +<dd>This specifies the foreground color, i.e. the color of the center of the +mage -- everything but the borders. <i>colorspec</i> is as described for the <a href="libnetpbm_image.html#colorname">argument of the <b>pnm_parsecolor()</b> library routine</a>. Default is white. <dt><b>-var=</b><i>pixels</i> -<dd> Specifies the variance of the ragged border (default: 10). Must -be a positive integer. Set <i>pixels</i> to 1 to get a straight -border. +<dd>This specifies how ragged the borders are -- how much and how quickly its +width varies along the image edge. Its specific meaning is complex, but the +larger it is, the more the border varies. Zero means it does not vary at all +-- the edge of the foreground is straight. + +<p>This must be a nonnegative integer. The default is 10. <dt><b>-randomseed=</b><i>seed</i> |