threshold_vector

 threshold_vector - performs a threshold on a vector

 Usage: passed = threshold_vector(data, threshold, type)

 Takes an N by 1 or 1 by N vector and thresholds the values based on
 threshold.  Returns the indices of the elements that pass the threshold.
 "type" is one of '-signed' or '-unsigned'.

 This function is part of froi, available from http://froi.sourceforge.net,
 and is governed by the terms of the Artistic License.

 $Id: threshold_vector.m,v 1.3 2003/09/23 15:38:19 nknouf Exp $

0001 function passed = threshold_vector(data, threshold, type)
0002 % threshold_vector - performs a threshold on a vector
0003 %
0004 % Usage: passed = threshold_vector(data, threshold, type)
0005 %
0006 % Takes an N by 1 or 1 by N vector and thresholds the values based on
0007 % threshold.  Returns the indices of the elements that pass the threshold.
0008 % "type" is one of '-signed' or '-unsigned'.
0009 %
0010 % This function is part of froi, available from http://froi.sourceforge.net,
0011 % and is governed by the terms of the Artistic License.
0012 %
0013 % $Id: threshold_vector.m,v 1.3 2003/09/23 15:38:19 nknouf Exp $
0014 
0015 passed = [];
0016 
0017 if (strncmp(type, '-signed', 7))
0018     passed = signed_thresh(data, threshold);
0019 elseif (strncmp(type, '-unsigned', 9))
0020     passed = unsigned_thresh(data, threshold);
0021 end
0022 
0023 return;
0024 
0025 
0026 function passed = signed_thresh(data, threshold)
0027     if (threshold > 0)
0028         passed = find(data>=threshold);
0029     elseif (threshold < 0)
0030         passed = find(data<=threshold);
0031     elseif (threshold == 0)
0032         oops(255);
0033     end
0034 
0035 return;
0036 
0037 
0038 function passed = unsigned_thresh(data, threshold)
0039     passed1 = find(data>=threshold);
0040     passed2 = find(data<=threshold);
0041 
0042     passed = [passed1; passed2];
0043 
0044 return;