signdata.mex.c

这是图像识别方法bag of feature 的matlab源代码

/* file:        signdata.mex.c
** description: MEX weighted signdata 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>

int
powi(int x, int i)
{
  int j,z ;
  if(i == 0) return 1 ;
  if(i == 1) return x ;
  j = i >> 1 ;
  z = powi(x,j) ;
  return (i - j - j) ? z*z*x : z*z ; 
}

/* pairs are used to generate random permutations of data */
typedef struct {int w ; int j ;} pair_t ; 

int 
cmp_pair(void const* a, void const* b) 
{
  pair_t* pa = (pair_t*) a;
  pair_t* pb = (pair_t*) b;
  return pa->w - pb->w ;
}

/* 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 ;
  idx_t*  signature_pt ;
  
  /*  mxClassID data_class = mxINT8_CLASS ;*/
  enum {IN_K=0,IN_DEPTH,IN_ASGN} ;
  enum {OUT_SIGNATURE=0} ;
  int M,N,L,K=0 ;
  int depth=0 ;

  /** -----------------------------------------------------------------
   **                                               Check the arguments
   ** -------------------------------------------------------------- */
  if (nin != 3) {
    mexErrMsgTxt("Three arguments required.") ;
  } else if (nout > 2) {
    mexErrMsgTxt("Too many output arguments.");
  }
  
  if(mxGetClassID(in[IN_ASGN]) != mxUINT32_CLASS) {
    mexErrMsgTxt("ASGN must be of class uint32") ;
  }

  if(uIsRealScalar(in[IN_K])) {
    K = (int) *mxGetPr(in[IN_K]) ;
    if(K > 0) goto K_is_ok ;
  }
  mexErrMsgTxt("K must be a positive integer.") ;
 K_is_ok:
  
  if(uIsRealScalar(in[IN_DEPTH])) {
    depth = (int) *mxGetPr(in[IN_DEPTH]) ;
    if(depth > 0) goto depth_is_ok ;
  }
  mexErrMsgTxt("DEPTH must be a positive integer.") ;
 depth_is_ok:
  
  M = mxGetM(in[IN_ASGN]) ; /* n of components */
  N = mxGetN(in[IN_ASGN]) ; /* n of elements */

  L = (powi(K,depth+1) - 1) / (K - 1) ;
  
  {
    int dims [2] ; 
    dims[0] = L ; 
    dims[1] = 1 ;
    out[OUT_SIGNATURE] = mxCreateNumericArray(2,dims,mxUINT32_CLASS, mxREAL) ;
  }
  
  asgn_pt      = (idx_t*) mxGetPr(in[IN_ASGN]) ;
  signature_pt = (idx_t*) mxGetPr(out[OUT_SIGNATURE]) ;
  
  /** -----------------------------------------------------------------
   **                                                                Go
   ** -------------------------------------------------------------- */
  {    
    int d,j ;

    /*
      branch_offset                   |  level_offset
      --------------------------------+-----------------
      s(0) K^0                        |  1           
      s(0) K^1 + s(1)*K^0             |  1 + K       
      s(0) K^2 + s(1)*K^1 + s(2)*K^0  |  1 + K + K^2
      ...                             |  ...
    */

    for(j = 0 ; j < N ; ++j) {

      int level_offset   = 0 ;
      int branch_offset  = 0 ;
      for(d = 0 ; d < depth ; ++d) {
        int s = asgn_pt[depth*j + d] - 1 ;
        level_offset  = K * level_offset  + 1 ;
        branch_offset = K * branch_offset + s ;
        
        /* -1 because we do not have the root */
        ++ signature_pt[ level_offset + branch_offset - 1] ;
      }
    }
  }
}