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<!DOCTYPE document PUBLIC "-//CNX//DTD CNXML 0.5 plus MathML//EN" "http://cnx.rice.edu/cnxml/0.5/DTD/cnxml_mathml.dtd">
<document xmlns="http://cnx.rice.edu/cnxml" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:bib="http://bibtexml.sf.net/" id="m10476">

  <name xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">The Scaling Equation</name>

  <metadata xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">
  <md:version xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">2.6</md:version>
  <md:created xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">2002/01/31</md:created>
  <md:revised xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">2004/08/04 13:01:38.088 GMT-5</md:revised>
  <md:authorlist xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">
      <md:author xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="schniter">
      <md:firstname xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Phil</md:firstname>
      
      <md:surname xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Schniter</md:surname>
      <md:email xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">schniter@ee.eng.ohio-state.edu</md:email>
    </md:author>
  </md:authorlist>

  <md:maintainerlist xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">
    <md:maintainer xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="charlet">
      <md:firstname xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Charlet</md:firstname>
      
      <md:surname xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Reedstrom</md:surname>
      <md:email xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">charlet@rice.edu</md:email>
    </md:maintainer>
    <md:maintainer xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="schniter">
      <md:firstname xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Phil</md:firstname>
      
      <md:surname xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Schniter</md:surname>
      <md:email xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">schniter@ee.eng.ohio-state.edu</md:email>
    </md:maintainer>
  </md:maintainerlist>
  
  <md:keywordlist xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">
    <md:keyword xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Scaling equation</md:keyword>
    <md:keyword xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">wavelet scaling equation</md:keyword>
    <md:keyword xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">wavelet coefficients</md:keyword>
    <md:keyword xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">mother wavelet</md:keyword>
    <md:keyword xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Haar wavelet</md:keyword>
    <md:keyword xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">DWT</md:keyword>
    <md:keyword xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Perfect Reconstruction Filterbanks</md:keyword>
    <md:keyword xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Power symmetry</md:keyword>
  </md:keywordlist>

  <md:abstract xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">This module covers scaling equations and coefficients for the discrete wavelet transform.
</md:abstract>
</metadata>

  <content xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">
    <para xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="sec1para1">
      Consider the level-1 subspace and its orthonormal basis:

      <equation xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="eq01">
	<m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	  <m:apply>
	    <m:eq/>
	    <m:ci><m:msub>
		<m:mi>V</m:mi>
		<m:mn>1</m:mn>
	      </m:msub></m:ci>
	    <m:apply>
	      <m:ci type="fn">span</m:ci>
	      <m:set>
		<m:bvar>
		  <m:apply>
		    <m:ci type="fn"><m:msub>
			<m:mi>φ</m:mi>
			<m:mrow>
			  <m:mn>1</m:mn>
			  <m:mo>,</m:mo>
			  <m:mi>n</m:mi>
			</m:mrow>
		      </m:msub></m:ci>
		    <m:ci>t</m:ci>
		  </m:apply>
		</m:bvar>
		<m:condition>
		  <m:apply>
		    <m:in/>
		    <m:ci>n</m:ci>
		    <m:integers/>
		  </m:apply>
		</m:condition>
	      </m:set>
	    </m:apply>
	  </m:apply>
	</m:math>
      </equation>

      <equation xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="eq02">
	<m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	  <m:apply>
	    <m:eq/>
	    <m:apply>
	      <m:ci type="fn"><m:msub>
		  <m:mi>φ</m:mi>
		  <m:mrow>
		    <m:mn>1</m:mn>
		    <m:mo>,</m:mo>
		    <m:mi>n</m:mi>
		  </m:mrow>
		</m:msub></m:ci>
	      <m:ci>t</m:ci>
	    </m:apply>
	    <m:apply>
	      <m:times/>
	      <m:apply>
		<m:divide/>
		<m:cn>1</m:cn>
		<m:apply>
		  <m:root/>
		  <m:cn>2</m:cn>
		</m:apply>
	      </m:apply>
	      <m:apply>
		<m:ci type="fn">φ</m:ci>
		<m:apply>
		  <m:minus/>
		  <m:apply>
		    <m:times/>
		    <m:apply>
		      <m:divide/>
		      <m:cn>1</m:cn>
		      <m:cn>2</m:cn>
		    </m:apply>
		    <m:ci>t</m:ci>
		  </m:apply>
		  <m:ci>n</m:ci>
		</m:apply>
	      </m:apply>
	    </m:apply>
	  </m:apply>
	</m:math>
      </equation>

      Since 
      <m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	<m:apply>
	  <m:prsubset/>
	  <m:ci><m:msub><m:mi>V</m:mi><m:mn>1</m:mn></m:msub></m:ci>
	  <m:ci><m:msub><m:mi>V</m:mi><m:mn>0</m:mn></m:msub></m:ci>
	</m:apply>
      </m:math> (<foreign xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">i.e.</foreign>,
      <m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	<m:ci><m:msub>
	    <m:mi>V</m:mi>
	    <m:mn>0</m:mn>
	  </m:msub></m:ci>
      </m:math>
      is more detailed than
      <m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	<m:ci><m:msub>
	    <m:mi>V</m:mi>
	    <m:mn>1</m:mn>
	  </m:msub></m:ci>
      </m:math>
      ) and since
      <m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	<m:apply>
	  <m:in/>
	  <m:apply>
	    <m:ci type="fn"><m:msub>
		<m:mi>φ</m:mi>
		<m:mrow>
		  <m:mn>1</m:mn>
		  <m:mo>,</m:mo>
		  <m:mn>0</m:mn>
		</m:mrow>
	      </m:msub></m:ci>
	    <m:ci>t</m:ci>
	  </m:apply>
	  <m:ci><m:msub>
	      <m:mi>V</m:mi>
	      <m:mn>0</m:mn>
	    </m:msub></m:ci>
	</m:apply>
      </m:math>
      , there must exist coefficients

      <m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	<m:set>
	  <m:bvar>
	    <m:apply>
	      <m:ci type="fn" class="discrete">h</m:ci>
	      <m:ci>n</m:ci>
	    </m:apply>
	  </m:bvar>
	  <m:condition>
	    <m:apply>
	      <m:in/>
	      <m:ci>n</m:ci>
	      <m:integers/>
	    </m:apply>
	  </m:condition>
	</m:set>
      </m:math> such that

      <equation xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="eq03">
	<m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	  <m:apply>
	    <m:eq/>
	    <m:apply>
	      <m:ci type="fn"><m:msub>
		  <m:mi>φ</m:mi>
		  <m:mrow>
		    <m:mn>1</m:mn>
		    <m:mo>,</m:mo>
		    <m:mn>0</m:mn>
		  </m:mrow>
		</m:msub></m:ci>
	      <m:ci>t</m:ci>
	    </m:apply>
	    <m:apply>
	      <m:sum/>
	      <m:bvar><m:ci>n</m:ci></m:bvar>
	      <m:lowlimit>
		<m:apply>
		  <m:minus/>
		  <m:infinity/>
		</m:apply>
	      </m:lowlimit>
	      <m:uplimit><m:infinity/></m:uplimit>
	      <m:apply>
		<m:times/>
		<m:apply>
		  <m:ci type="fn" class="discrete">h</m:ci>
		  <m:ci>n</m:ci>
		</m:apply>
		<m:apply>
		  <m:ci type="fn"><m:msub>
		      <m:mi>φ</m:mi>
		      <m:mrow>
			<m:mn>0</m:mn>
			<m:mo>,</m:mo>
			<m:mi>n</m:mi>
		      </m:mrow>
		    </m:msub></m:ci>
		  <m:ci>t</m:ci>
		</m:apply>
	      </m:apply>
	    </m:apply>
	  </m:apply>
	</m:math>
      </equation> 

      <equation xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="eq04">
	<m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	  <m:apply>
	    <m:mo>⇔</m:mo>
	  </m:apply>
	  <m:apply>
	    <m:eq/>
	    <m:apply>
	      <m:times/>
	      <m:apply>
		<m:divide/>
		<m:cn>1</m:cn>
		<m:apply>
		  <m:root/>
		  <m:cn>2</m:cn>
		</m:apply>
	      </m:apply>
	      <m:apply>
		<m:ci type="fn">φ</m:ci>
		<m:apply>
		  <m:times/>
		  <m:apply>
		    <m:divide/>
		    <m:cn>1</m:cn>
		    <m:cn>2</m:cn>
		  </m:apply>
		  <m:ci>t</m:ci>
		</m:apply>
	      </m:apply>
	    </m:apply>

	    <m:apply>
	      <m:sum/>
	      <m:bvar><m:ci>n</m:ci></m:bvar>
	      <m:lowlimit>
		<m:apply>
		  <m:minus/>
		  <m:infinity/>
		</m:apply>
	      </m:lowlimit>
	      <m:uplimit><m:infinity/></m:uplimit>
	      <m:apply>
		<m:times/>
		<m:apply>
		  <m:ci type="fn" class="discrete">h</m:ci>
		  <m:ci>n</m:ci>
		</m:apply>
		<m:apply>
		  <m:ci type="fn">φ</m:ci>
		  <m:apply>
		    <m:minus/>
		    <m:ci>t</m:ci>
		    <m:ci>n</m:ci>
		  </m:apply>
		</m:apply>
	      </m:apply>
	    </m:apply>
	  </m:apply>
	</m:math>
      </equation>

      <equation xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="eq05">
	<name xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/">Scaling Equation</name>
	<m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	  <m:apply>
	    <m:eq/>
	    <m:apply>
	      <m:ci type="fn">φ</m:ci>
	      <m:ci>t</m:ci>
	    </m:apply>
	    <m:apply>
	      <m:times/>
	      <m:apply>
		<m:root/>
		<m:cn>2</m:cn>
	      </m:apply>
	      <m:apply>
		<m:sum/>
		<m:bvar><m:ci>n</m:ci></m:bvar>
		<m:lowlimit>
		  <m:apply>
		    <m:minus/>
		    <m:infinity/>
		  </m:apply>
		</m:lowlimit>
		<m:uplimit><m:infinity/></m:uplimit>
		<m:apply>
		  <m:times/>
		  <m:apply>
		    <m:ci type="fn" class="discrete">h</m:ci>
		    <m:ci>n</m:ci>
		  </m:apply>
		  <m:apply>
		    <m:ci type="fn">φ</m:ci>
		    <m:apply>
		      <m:minus/>
		      <m:apply>
			<m:times/>
			<m:cn>2</m:cn>
			<m:ci>t</m:ci>
		      </m:apply>
		      <m:ci>n</m:ci>
		    </m:apply>
		  </m:apply>
		</m:apply>
	      </m:apply>
	    </m:apply>
	  </m:apply>
	</m:math>
      </equation>
      To be a valid scaling function,
      <m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	<m:apply>
	  <m:ci type="fn">φ</m:ci>
	  <m:ci>t</m:ci>
	</m:apply>
      </m:math> must obey the scaling equation for some coefficient
      set 
      <m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
	<m:set>
	  <m:apply>
	    <m:ci type="fn" class="discrete">h</m:ci>
	    <m:ci>n</m:ci>
	  </m:apply>
	</m:set>
      </m:math>.
    </para>

  </content>
</document>
