lib/src/jp/nyatla/nyartoolkit/core/analyzer/histogram/NyARHistogramAnalyzer_KittlerThreshold.java

   1 /* \r
   2  * PROJECT: NyARToolkit(Extension)\r
   3  * --------------------------------------------------------------------------------\r
   4  * The NyARToolkit is Java edition ARToolKit class library.\r
   5  * Copyright (C)2008-2009 Ryo Iizuka\r
   6  *\r
   7  * This program is free software: you can redistribute it and/or modify\r
   8  * it under the terms of the GNU General Public License as published by\r
   9  * the Free Software Foundation, either version 3 of the License, or\r
  10  * (at your option) any later version.\r
  11  * \r
  12  * This program is distributed in the hope that it will be useful,\r
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  15  * GNU General Public License for more details.\r
  16  *\r
  17  * You should have received a copy of the GNU General Public License\r
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.\r
  19  * \r
  20  * For further information please contact.\r
  21  *      http://nyatla.jp/nyatoolkit/\r
  22  *      <airmail(at)ebony.plala.or.jp> or <nyatla(at)nyatla.jp>\r
  23  * \r
  24  */\r
  25 package jp.nyatla.nyartoolkit.core.analyzer.histogram;\r
  26 \r
  27 import jp.nyatla.nyartoolkit.core.types.NyARHistogram;\r
  28 \r
  29 \r
  30 /**\r
  31  * このクラスは、kittlerThresholdを用いて敷居値を求める機能を提供します。\r
  32  */\r
  33 public class NyARHistogramAnalyzer_KittlerThreshold implements INyARHistogramAnalyzer_Threshold\r
  34 {\r
  35         /**\r
  36          * この関数は、kittlerThresholdを用いて敷居値を1個求めます。敷居値の範囲は、i_histogram引数の範囲と同じです。\r
  37          */\r
  38         public int getThreshold(NyARHistogram i_histogram)\r
  39         {\r
  40                 int i;          \r
  41                 double min=Double.MAX_VALUE;\r
  42                 int th=0;\r
  43                 int da,sa,db,sb,pa,pb;\r
  44                 double oa,ob;\r
  45                 \r
  46                 int[] hist=i_histogram.data;\r
  47                 int n=i_histogram.length;\r
  48                 //Low側\r
  49                 da=pa=0;\r
  50                 int h;\r
  51                 for(i=0;i<n;i++){\r
  52                         h=hist[i];\r
  53                         da+=h*i;        //i*h[i]\r
  54                         pa+=h*i*i;      //i*i*h[i]\r
  55                 }\r
  56                 sa=i_histogram.total_of_data;\r
  57                 //High側(i=n-1)\r
  58                 db=0;\r
  59                 sb=0;\r
  60                 pb=0;\r
  61                 \r
  62                 \r
  63                 for(i=n-1;i>0;i--){\r
  64                         //次のヒストグラムを計算\r
  65                         int hist_count=hist[i];//h[i]\r
  66                         int hist_val =hist_count*i;  //h[i]*i\r
  67                         int hist_val2=hist_val*i;    //h[i]*i*i\r
  68                         da-=hist_val;\r
  69                         sa-=hist_count;\r
  70                         pa-=hist_val2;\r
  71                         db+=hist_val;\r
  72                         sb+=hist_count;                 \r
  73                         pb+=hist_val2;\r
  74 \r
  75                         //初期化\r
  76                         double wa=(double)sa/(sa+sb);\r
  77                         double wb=(double)sb/(sa+sb);\r
  78                         if(wa==0 || wb==0){\r
  79                                 continue;\r
  80                         }\r
  81 \r
  82                         oa=ob=0;\r
  83                         double ma=sa!=0?(double)da/sa:0;\r
  84                         //Σ(i-ma)^2*h[i]=Σ(i^2*h[i])+Σ(ma^2*h[i])-Σ(2*i*ma*h[i])\r
  85                         oa=((double)(pa+ma*ma*sa-2*ma*da))/sa;\r
  86 \r
  87                         double mb=sb!=0?(double)db/sb:0;\r
  88                         //Σ(i-mb)^2*h[i]=Σ(i^2*h[i])+Σ(mb^2*h[i])-Σ(2*i*mb*h[i])\r
  89                         ob=((double)(pb+mb*mb*sb-2*mb*db))/sb;\r
  90 \r
  91                         double kai=wa*Math.log(oa/wa)+wb*Math.log(ob/wb);\r
  92                         if(kai>0 && min>kai){\r
  93                                 min=kai;\r
  94                                 th=i;\r
  95                         }\r
  96                         //System.out.println(kai);\r
  97 \r
  98                 }\r
  99                 return th;//129//7.506713872738873\r
 100         }\r
 101         /**\r
 102          * デバック用関数\r
 103          * @param args\r
 104          * main関数引数\r
 105          */     \r
 106         public static void main(String[] args)\r
 107         {\r
 108                 NyARHistogram data=new NyARHistogram(256);\r
 109                 for(int i=0;i<256;i++){\r
 110                         data.data[i]=128-i>0?128-i:i-128;\r
 111                 }\r
 112                 data.total_of_data=data.getTotal(0,255);\r
 113                 NyARHistogramAnalyzer_KittlerThreshold an=new NyARHistogramAnalyzer_KittlerThreshold();\r
 114                 int th=an.getThreshold(data);\r
 115                 System.out.print(th);\r
 116                 return;\r
 117         }\r
 118 }\r