tags/2.5.0/src/jp/nyatla/nyartoolkit/core/analyzer/histogram/NyARHistogramAnalyzer_KittlerThreshold.java

   1 package jp.nyatla.nyartoolkit.core.analyzer.histogram;\r
   2 \r
   3 import jp.nyatla.nyartoolkit.core.types.NyARHistogram;\r
   4 \r
   5 \r
   6 /**\r
   7  * kittlerThresholdの方式で閾値を求めます。\r
   8  * @param i_histogram\r
   9  * @return\r
  10  */\r
  11 public class NyARHistogramAnalyzer_KittlerThreshold implements INyARHistogramAnalyzer_Threshold\r
  12 {\r
  13         public int getThreshold(NyARHistogram i_histogram)\r
  14         {\r
  15                 int i;          \r
  16                 double min=Double.MAX_VALUE;\r
  17                 int th=0;\r
  18                 int da,sa,db,sb,pa,pb;\r
  19                 double oa,ob;\r
  20                 \r
  21                 int[] hist=i_histogram.data;\r
  22                 int n=i_histogram.length;\r
  23                 //Low側\r
  24                 da=pa=0;\r
  25                 int h;\r
  26                 for(i=0;i<n;i++){\r
  27                         h=hist[i];\r
  28                         da+=h*i;        //i*h[i]\r
  29                         pa+=h*i*i;      //i*i*h[i]\r
  30                 }\r
  31                 sa=i_histogram.total_of_data;\r
  32                 //High側(i=n-1)\r
  33                 db=0;\r
  34                 sb=0;\r
  35                 pb=0;\r
  36                 \r
  37                 \r
  38                 for(i=n-1;i>0;i--){\r
  39                         //次のヒストグラムを計算\r
  40                         int hist_count=hist[i];//h[i]\r
  41                         int hist_val =hist_count*i;  //h[i]*i\r
  42                         int hist_val2=hist_val*i;    //h[i]*i*i\r
  43                         da-=hist_val;\r
  44                         sa-=hist_count;\r
  45                         pa-=hist_val2;\r
  46                         db+=hist_val;\r
  47                         sb+=hist_count;                 \r
  48                         pb+=hist_val2;\r
  49 \r
  50                         //初期化\r
  51                         double wa=(double)sa/(sa+sb);\r
  52                         double wb=(double)sb/(sa+sb);\r
  53                         if(wa==0 || wb==0){\r
  54                                 continue;\r
  55                         }\r
  56 \r
  57                         oa=ob=0;\r
  58                         double ma=sa!=0?(double)da/sa:0;\r
  59                         //Σ(i-ma)^2*h[i]=Σ(i^2*h[i])+Σ(ma^2*h[i])-Σ(2*i*ma*h[i])\r
  60                         oa=((double)(pa+ma*ma*sa-2*ma*da))/sa;\r
  61 \r
  62                         double mb=sb!=0?(double)db/sb:0;\r
  63                         //Σ(i-mb)^2*h[i]=Σ(i^2*h[i])+Σ(mb^2*h[i])-Σ(2*i*mb*h[i])\r
  64                         ob=((double)(pb+mb*mb*sb-2*mb*db))/sb;\r
  65 \r
  66                         double kai=wa*Math.log(oa/wa)+wb*Math.log(ob/wb);\r
  67                         if(kai>0 && min>kai){\r
  68                                 min=kai;\r
  69                                 th=i;\r
  70                         }\r
  71                         //System.out.println(kai);\r
  72 \r
  73                 }\r
  74                 return th;//129//7.506713872738873\r
  75         }\r
  76         public static void main(String[] args)\r
  77         {\r
  78                 NyARHistogram data=new NyARHistogram(256);\r
  79                 for(int i=0;i<256;i++){\r
  80                         data.data[i]=128-i>0?128-i:i-128;\r
  81                 }\r
  82                 data.total_of_data=data.getTotal(0,255);\r
  83                 NyARHistogramAnalyzer_KittlerThreshold an=new NyARHistogramAnalyzer_KittlerThreshold();\r
  84                 int th=an.getThreshold(data);\r
  85                 System.out.print(th);\r
  86                 return;\r
  87         }\r
  88 }\r