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<td class="title">Operations</td>
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<h1>mmsubm
<br>
<span class="subtitle">Subtraction of two images, with saturation.
</span>
</h1>
<div class="synopsis">
<H2>Synopsis</H2>
<div class="H2">
<div class="prototype">y =
<span class="fun">mmsubm</span>(
<span class="par">f1</span>,
<span class="par">f2</span>
)
</div>
<p>Implemented in
<b>Python.</b>
</p>
<div class="input">
<H3>Input</H3>
<div class="H3">
<table class="deflist">
<tbody valign="baseline">
<tr>
<td class="term"><span class="par">f1</span></td>
<td class="def"><span class="type"><a href="../mmtypes/mmImage.html">Image</a></span> Unsigned gray-scale (uint8 or uint16), signed (int32) or binary image.
</td>
</tr>
<tr>
<td class="term"><span class="par">f2</span></td>
<td class="def"><span class="type"><a href="../mmtypes/mmImage.html">Image</a></span> Unsigned gray-scale (uint8 or uint16), signed (int32) or binary image.
<p>Or constant.</p></td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="output">
<H3>Output</H3>
<div class="H3">
<table class="deflist">
<tbody valign="baseline">
<tr>
<td class="term"><span class="par">y</span></td>
<td class="def"><span class="type"><a href="../mmtypes/mmImage.html">Image</a></span> Unsigned gray-scale (uint8 or uint16), signed (int32) or binary image.
</td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</div>
<div class="descr">
<H2>Description</H2>
<div class="H2">
<p>
<span class="fun">mmsubm</span> creates the image
<code>y</code> by pixelwise subtraction of the image
<code>f2</code> from the image
<code>f1</code>. When the subtraction of the values of two pixels is negative, 0 is taken as the result of the subtraction. When
<code>f1</code> and
<code>f2</code> are binary images,
<code>y</code> represents the set subtraction of
<code>f2</code> from
<code>f1</code>.
</p>
</div>
</div>
<div class="examples">
<H2>Examples</H2>
<div class="H2">
<p>
<div class="example">
<div class="listing">
<pre class="user">>>> f = uint8([255, 255, 0, 10, 20, 10, 0, 255, 255])</pre>
<pre class="computer"></pre>
<pre class="user">>>> g = uint8([10, 20, 30, 40, 50, 40, 30, 20, 10])</pre>
<pre class="computer"></pre>
<pre class="user">>>> print mmsubm(f, g)</pre>
<pre class="computer">[245 235 0 0 0 0 0 235 245]</pre>
<pre class="user">>>> print mmsubm(f, 100)</pre>
<pre class="computer">Warning: Converting input image from int32 to uint8.
[155 155 0 0 0 0 0 155 155]</pre>
<pre class="user">>>> print mmsubm(100, f)</pre>
<pre class="computer">Warning: Converting input image from uint8 to int32.
[-155 -155 100 90 80 90 100 -155 -155]</pre>
</div>
</div>
<div class="bridge">Gray scale image:</div>
<div class="example">
<div class="listing">
<pre class="user">>>> a = mmreadgray('boxdrill-C.tif')</pre>
<pre class="computer"></pre>
<pre class="user">>>> b = mmreadgray('boxdrill-B.tif')</pre>
<pre class="computer"></pre>
<pre class="user">>>> c = mmsubm(a,b)</pre>
<pre class="computer"></pre>
<pre class="user">>>> mmshow(a)</pre>
<pre class="computer"></pre>
<pre class="user">>>> mmshow(b)</pre>
<pre class="computer"></pre>
<pre class="user">>>> mmshow(c)</pre>
<pre class="computer"></pre>
</div>
<table class="images">
<tbody align="center">
<tr class="image" valign="bottom">
<td><img width="185" src="../images/img_mmsubm_001.jpg"></td>
<td><img width="185" src="../images/img_mmsubm_002.jpg"></td>
<td><img width="185" src="../images/img_mmsubm_003.jpg"></td>
<td class="spare"></td>
</tr>
<tr class="title" valign="baseline">
<td><a href="../images/img_mmsubm_001.jpg">a</a></td>
<td><a href="../images/img_mmsubm_002.jpg">b</a></td>
<td><a href="../images/img_mmsubm_003.jpg">c</a></td>
<td class="spare"></td>
</tr>
</tbody>
</table>
</div>
</p>
</div>
</div>
<div class="equation">
<H2>Equation</H2>
<div class="H2">
<p>
<div class="eqfig">
<img src="../images/eq_mmsubm001.png">
</div>
</p>
</div>
</div>
<div class="sourcecode">
<H2>Source Code</H2>
<div class="H2">
<pre class="listing">
def mmsubm(f1, f2):
from Numeric import array, minimum, maximum
if type(f2) is array:
assert f1.typecode() == f2.typecode(), 'Cannot have different datatypes:'
y = minimum(maximum(f1.astype('d')-f2, mmlimits(f1)[0]), mmlimits(f1)[1])
y = y.astype(f1.typecode())
return y
</pre>
</div>
</div>
<div class="seealso">
<H2>See also</H2>
<div class="H2">
<table class="deflist">
<tbody valign="baseline">
<tr>
<td class="term"><a href="../morph/mmfreedom.html">mmfreedom</a></td>
<td class="def">Control automatic data type conversion.</td>
</tr>
<tr>
<td class="term"><a href="../morph/mmaddm.html">mmaddm</a></td>
<td class="def">Addition of two images, with saturation.</td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="seealso">
<H2>See also</H2>
<div class="H2">
<table class="deflist">
<tbody valign="baseline">
<tr>
<td class="term"><a href="../morph/mmfreedom.html">mmfreedom</a></td>
<td class="def">Control automatic data type conversion.</td>
</tr>
<tr>
<td class="term"><a href="../morph/mmaddm.html">mmaddm</a></td>
<td class="def">Addition of two images, with saturation.</td>
</tr>
<tr>
<td class="term"><a href="../morph/mmlimits.html">mmlimits</a></td>
<td class="def">Get the possible minimum and maximum of an image.</td>
</tr>
</tbody>
</table>
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<td class="copyright">Copyright (c) 2003, Roberto A. Lotufo, UNICAMP-University of Campinas; Rubens C. Machado, CenPRA-Renato Archer Research Center.</td>
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distrib
>
Mandriva
>
2010.0
>
i586
>
media
>
contrib-release
>
by-pkgid
>
4a71d9984febeb5a206904a5a379841a
>
files
>
747
