ikmeanspush.mex.c

这是图像识别方法bag of feature 的matlab源代码

/* file:        ikmeanspush.c
** description: MEX weighted ikmeanspush function.
** author:      Andrea Vedaldi
**/

/* AUTORIGHTS
Copyright (C) 2006 Regents of the University of California
All rights reserved

Written by Andrea Vedaldi (UCLA VisionLab).

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of the University of California, Berkeley nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include<mexutils.c>
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<string.h>
#include<assert.h>

/* driver */
void
mexFunction(int nout, mxArray *out[], 
            int nin, const mxArray *in[])
{
  typedef unsigned char data_t ;
  typedef int           acc_t ;
  typedef unsigned int  idx_t ;
  idx_t*    asgn_pt ;
  acc_t*    centers_pt ;
  data_t*   data_pt ;
  /*  mxClassID data_class = mxINT8_CLASS ;*/
  enum {IN_DATA=0,IN_CENTERS} ;
  enum {OUT_ASGN} ;
  int M,N ;
  int K=0 ;
  
  /** -----------------------------------------------------------------
   **                                               Check the arguments
   ** -------------------------------------------------------------- */
  if (nin != 2) {
    mexErrMsgTxt("Two arguments required.") ;
  } else if (nout > 2) {
    mexErrMsgTxt("Too many output arguments.") ;
  }
  
  if(mxGetClassID(in[IN_DATA]) != mxUINT8_CLASS) {
    mexErrMsgTxt("DATA must be of class uint8") ;
  }

  if(mxGetClassID(in[IN_CENTERS]) != mxINT32_CLASS) {
    mexErrMsgTxt("DATA must be of class int32") ;
  }

  M = mxGetM(in[IN_DATA]) ;     /* n of components */
  N = mxGetN(in[IN_DATA]) ;     /* n of elements */
  K = mxGetN(in[IN_CENTERS]) ;  /* n of centers */
  
  if( mxGetM(in[IN_CENTERS]) != M ) {
    mexErrMsgTxt("DATA and CENTERS must have the same number of columns.") ;
  }

  {
    int dims[2] ;
    dims[0] = 1 ;
    dims[1] = N ;
    out[OUT_ASGN] = mxCreateNumericArray(2,dims,mxUINT32_CLASS,mxREAL);
  }

  data_pt    = (data_t*) mxGetPr(in[IN_DATA]) ;
  centers_pt = (acc_t*)  mxGetPr(in[IN_CENTERS]) ;
  asgn_pt    = (idx_t*)  mxGetPr(out[OUT_ASGN]) ;
  
  /** -----------------------------------------------------------------
   **                                                                Go
   ** -------------------------------------------------------------- */
  {    
    int i,j,k ;

    /* assign data to centers */
    for(j=0 ; j < N ; ++j) {
      acc_t best_dist = 0 ;
      idx_t best = (idx_t)-1 ;
      
      for(k = 0 ; k < K ; ++k) {
        acc_t dist = 0 ;
        
        /* compute distance with this center */
        for(i = 0 ; i < M ; ++i) {
          acc_t delta = data_pt[ j*M + i ] - centers_pt[ k*M + i ] ;
          dist += delta*delta ;
        }
        
        /* compare with current best */
        if( best == (idx_t)-1 || dist < best_dist ) {
          best = k  ;
          best_dist = dist ;
        }
      }
      asgn_pt[j] = best ;
    }
    for(j = 0 ; j < N ; ++j) ++ asgn_pt[j] ;
  }
}