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    <h1>classify_spectra help</h1>
<p>
<ul>
 <li><a href="#overview">Overview of classify_spectra</a></li>
 <li><a href="#load">Loading segments from a directory</a></li>
    <ul>
        <li>Prerequisite: wave_browser generated "*.seg.txt" file</li>
        <li>Selecting a directory</li>
        <li>Loading a directory</li>
     </ul>
 <li><a href="#navigate">Navigating the segments</a></li>
    <ul>
        <li>Previous and Next buttons</li>
        <li>Browsing all segments</li>
        <li>Selecting a class member</li>
    </ul>
 <li><a href="#classify">Classifying a segment</a></li>
 <ul>
  <li> Defining a new class</li>
  <li> Selecting a defined class</li>
  <li> Declassifying a segment</li>
  <li> Quick mode</li>
  <li> Auto-classifying</li>
 </ul>
 <li><a href="#classview">Class view</a></li>
 <ul>
  <li> Viewing members of a class</li>
  <li> Removing a class</li>
  
 </ul>
 <li><a href="#compare">Comparison mode</a></li>
 <ul>
     <li>Entering comparison mode</li>
     <li>Exiting comparison mode</li>
     <li>Zooming spectra</li>
 </ul>
 <li><a href="#classmembers">Class members view</a></li>
 <ul>
  <li>Typifying a class</li>
  <li>Renaming a class</li>
  <li>Merging two classes</li>
  <li>Navigating to next class</li>
 </ul>
 <li><a href="#configure">Configuring classify_spectra</a></li>
 <ul>
  <li>View parameters</li>
  <li>Parameters for computing spectra</li>
 </ul>
 </ul>
 <hr>

<h2><a name="overview"/>Overview of classify_spectra</h2>

<h2><a name="load"/>Loading segments from a directory</a></h2>

<p>The first task in classifying segments is to load predefined
segments in a directory using the <b>Load</b> button. Segments are
predefined by the wave_browser software which generates "*.seg.txt"
files. If you have just "*.wav" files in a directory and no
"*.seg.txt" files then no segments will be loaded. A directory to load
can be selected using the "<b>...</b>" button. Classify_spectra will
load all defined segments from a directory. Each directory should be
considered as a separate database.</p>

<p>If you are successful loading a directory a progress bar will
appear.  Depending on the number of segments and the speed of the
processor computing all the spectragrams for the segments can take a
considerable amount of time. When one is finished precomputing the
segments click the <b>Save</b> button. This will make it unnecessary to
recompute the spectra the next time the directory is loaded.</p>

<h2><a name="navigate"/>Navigating the segments</h2>

<p>There are several methods to navigate the segments in a
directory. The current selected segment is shown on the left. To
change the current segment use can use the <b>Next</b> and
<b>Previous</b> buttons. Segments are ordered time sequentially and
are grouped by the wave file they originated from. Above the larger
view of the segment is information about the current segment. The
information gives the current segment number, the wav file the segment
comes from, and the segment length.</p>

<p>For directories with a large number of segments navigating with the
<b>Next</b> and <b>Previous</b> buttons can be slow. By selecting
<b>all</b> from the <b>View</b> drop-down menu all segments in the
directory are shown on the right axes. Clicking on the icon of the
spectragram will make the selected segment the current segment. If
there are large number of segments in a directory all the defined
segments will not be shown. One can navigate the segments in a
directory by clicking the <b>Next row</b> and <b>Previous row</b>
buttons.
</p>

<p>A third method exists for navigating segments is in the <b>class
members</b> view in the <b>View</b> drop-down menu. For a defined
class you can click on a class member on the right axes. </p>

<img width="768" height="570" src="opening_view-scaled.png"/>
<h2><a name="classify"/>Classifying a segment</h2>

<p>There are several methods for classifying a segments. The most
direct way of classifying the current segment on the left is to use
the <b>Classify</b> button.  A <b>New Class</b> button appears
adjacent to the disabled <b>Classify</b> button. If no classes have
 been defined, the axes on the right are blank, clicking <b>New
Class</b>. By generating a new class will bring you into the <b>class
view</b>. Notice that the classify button has been changed to a
Declassify button.  If you choose not to define a class clicking
anywhere on the blank axes will reenable the <b>Classify</b> button and
hide the <b>New Class</b> button.</p>

<p>If you already have classes defined click on the class on right
will classify the segment. By default the classes on the right are
organized in descending segment length. If there are more classes than
fit on the current axes the closest matching size segment
automatically will be placed in the middle of the axes.  Using the
<b>Sort</b> drop-down menu you can also sort the classes <b>by
popularity</b> or by the <b>original</b> order of the defined classes.
Popularity is defined by the number of members which belong to that
class.</p>

By clicking on the <b>Declassify</b> button will remove the
classification for the current segment. The current segment can now be
reclassified or skipped. While navigating through the segments you can
see whether a segment is classified by the label
<b>Declassify</b>. Unclassified segments will have the label
<b>Classify</b>. To view all unclassified segments select from the
<b>View</b> drop-down menu <b>unclassified</b>.</p>

<p>By clicking the <b>Save</b> button along the way your
classification will be saved. </P>


<p>An alternative and faster method for classifying exists. By
clicking on the <b>Quick mode</b> toggle button the quick mode for
classification is entered. Quick mode will automatically forward to
the next unclassified segment. Three buttons will appear on the top
right to facilitate faster classification. The <b>New</b> button
generates a new class, the <b>Skip</b> button advances to the the next
unclassified segment, and <b>Review last</b> takes you out of quick
mode and back to the last classified segment. To classify in quick
mode just click a class on the right. After each classification the
next unclassified segment will appear. At any time quick mode can be
exited by clicking the <b>Quick mode</b> toggle button. If all
segments are classified quick mode will be automatically exited. </p>

<p>An additional method for classification exists when in comparison
mode. By clicking on the enabled <b>Classify</b> button the user will
classify the current segment as the class that is being compared
to. This will skip the normal classify view.</p>

<p>The final method for classifying is to click the <b>Auto Classify</b>
Button which will allow the classification to be made automatically.</p>


<img width="217" height="449" src="auto_classify-scaled.png"/>

<h2><a name="classview"/>Class view</h2>

<p>Class view allows you to view all defined classes on the right
axes. Class view is entered by selecting <b>class view</b> from the
<b>View</b> drop-down menu. By clicking on a class you can view all
members of the class. This view is known as class members mode.  In
class view mode one can also remove a defined class and declassify all
class members. By clicking the <b>Remove Class</b> button and
selecting a class on the right a prompt will appear about whether you
want to remove the class and and all its members. By selecting
<b>Yes</b> the class will be removed.</p> 

<img width="768" height="570" src="class_view-scaled.png"/>

<h2><a name="compare">Comparison mode</h2>

<p>To compare a segment against a class click on the <b>Compare</b>
toggle button. The user will be presented with a class view. By
clicking on a class on the right axes the current segment will be
compared to the selected class. The current segment will be the first
segment and the class being compared to will be the second class. If
the current segment is unclassified you can classify it by clicking
the <b>Classify</b> button on the lower left.</p>

<p>When comparing the current segment clicking the <b>Compare</b>
toggle button will not take you entirely out of the comparison
mode. Rather you will be brought back to the class view where you can
select another class to compare the current segment against. If the
user wants to exit the comparison mode click the <b>Compare</b> toggle
button a second time.</p>

<p>In order to make a comparison more carefully it is useful to zoom
in on a specific frequency range of the spectragram. The <b>Zoom
in</b> button will zoom into the specified frequency.  The first time
the the <b>Zoom in</b> button is hit the precomputed spectragram are
resampled. The frequency range for the zoom can be set in the
Configuration window.</p>


<img width="768" height="570" src="comparison_mode-scaled.png"/>

<h2><a name="classmembers"/>Class members view</h2>

<p>There are two ways to view all members of a specific class. The
first is by selecting the class in the class view. The second is to
select <b>class members</b> from the <b>View</b> drop-down menu. When
this is done all members belonging to the the same class as the
currently selected segment are shown on the right. </p>

<p>When a new class is defined the spectra of the first member of the
class is used to represent or typify the class. The spectra of the
typified segment is used in the class view and when making a
comparison.  The segment which typifies the class can be changed in
the class members view. By clicking the <b>Typify</b> button and
selecting a class member on the right. When a member is successfully
selected to typify a class the <b>Typify</b> button is reenabled. By
clicking in the area between the class members the typifying class is
not changed and the <b>Typify</b> button is reenabled. </p>


<p>Each class is automatically assigned a name when a new class is
created. The class name can be changed by clicking <b>Rename
Class</b>. A dialog box will appear titled Edit class name where the
name can be changed. By clicking <b>Ok</b> the name change will be
accepted. If the name is already assigned a second dialog box will appear
asking if you want to merge the two classes with the same name. By
clicking <b>Yes</b> the classes will be merged.</p>

<p>The next class button allows you to forward to the next class
without leaving the class members view.</p>

<img width="768" height="576" src="class_members-scaled.png"/>
<h2><a name="configure"/>Configuring classify_spectra</h2>

<p>Classify_spectra can be configured by the user. The first set of
configuration is for how the software view manipulates spectra.</p>  

<ul>

<li><b>Zoom lower frequency</b> and <b>Zoom upper frequency</b> sets
the frequency range used to resample the spectra when  <b>Zoom in</b>
is clicked. The values should be contained within the <b>Minimum
Frequency</b> and <b>Maximum Frequency</b> that is used to compute the
spectragram.</li>

<li><b>Classified Axes Width</b> and <b>Classified Axes Height</b>
are resolution used for plotting the spectragrams of the segments on
the right axes. Each spectragram is a fixed height of 100 pixels while
the width will vary with time. The higher the numbers the more spectra
that can appear on the axes. </li>

<li><b>Fixed Scaling:</b> Normally when you resize a window the size
of the spectragram stays constant. By enlarging the window you can
view more spectragrams. When fixed scaling is enabled rather than keep
the size constant when you enlarge the spectragram also increases in size.</li>
</ul>


<p>A spectragram is a visual representation of how the intensity of
sound frequencies change over time. Classify_spectra uses a multitaper
approach to compute the spectragram. The log transformed intensities
are plotted. Parameters used to compute the spectragram can be
modified by the user. If these parameters are changed the spectragrams
for all the segments will need to be recomputed.</p>

<ul>

<li><b>Sampling Frequency:</b>  is the frequency that sound is
sampled at in Hertz. Audio on a digital compact disc is sampled 44100
time per second.  It is assumed that all wav files in a directory are
sampled at the same frequency.</li>

<li><b>Moving window (ms)</b> is the window size in milliseconds for
which the intensity of the frequencies is computed by the multitaper
based Fourier transform.</li>

<li><b>Step size (ms)</b> is the step size for the moving window. The
smaller the step size the greater the resolution of the spectragram.</li>

<li><b>Smooth Parameter TW</b> is used to smooth the
spectragram. The parameter is an integer above 1.</li>

<li><b>Minimum Frequency</b> and <b>Maximum Frequency</b> is the
frequency in Hertz range for which the intensity of the audio is
computed. Generally this value is set between 0 and half the sampling
frequency.
</li>

</ul>


<img width="460" height="382" src="configure_classify-scaled.png"/>
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<!-- Created: Mon May 15 15:30:19 EDT 2006 -->
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Last modified: Tue May 23 10:52:39 EDT 2006
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