codebook建模 代码

// 此码元最长不更新时间,用于删除规定时间不更新的码元,精简码本
} code_element;
// 码元的数据结构
typedef struct code_book {
code_element **cb;
// 码元的二维指针,理解为指向码元指针数组的指针,使得添加码元时不需要来回复制码元,只需要
简单的指针赋值即可
//
// RETURN
// codebook index
int cvupdateCodeBook(uchar *p, codeBook &c, unsigned *cbBounds, int numChannels)
{
if(c.numEntries == 0) c.t = 0;
// 码本中码元为零时初始化时间为 0
// This is book keeping to allow us to kill
stale entries
// 此码元最后一次更新的时间,每一帧为一个单位时间,用于计算 stale
int
stale;
// max negative run (biggest period of inactivity)
// Given a pixel and a code book, determine if the pixel is covered by the codebook
//
// p
pixel pointer (YUV interleaved)
// c
codebook reference
// numChannels Number of channels we are testing
/** 比平均背景法性能更加良好的方法,codeBook 模型实现背景减除
核心代码详细解析和实现 by zcube /zcube/
*/
/************************************************************************/
该像素可合并于此码元
uchar max[CHANNELS];
// High side of box boundary
// 属于此码元的像素中各通道的最大值
uchar min[CHANNELS];
// Low side of box boundary
// 属于此码元的像素中各通道的最小值
int
t_last_update;
// 更新新码元各通道数据 {
c.cb[c.numEntries]->learnHigh[n] = high[n]; c.cb[c.numEntries]->learnLow[n] = low[n]; c.cb[c.numEntries]->max[n] = *(p+n); c.cb[c.numEntries]->min[n] = *(p+n); } c.cb[c.numEntries]->t_last_update = c.t; c.cb[c.numEntries]->stale = 0; c.numEntries += 1; }
// 将前 c.numEntries 个指针指向已存在的每个码元 foo[ii] = c.cb[ii];
foo[c.numEntries] = new code_element; // 申请一个新的码元 if(c.numEntries) delete [] c.cb; // 删除 c.cb 指针数组 c.cb = foo; // 把 foo 头指针赋给 c.cb for(n=0; n<numChannels; n++)
// OVERHEAD TO TRACK POTENTIAL STALE ENTRIES for(int s=0; s<c.numEntries; s++) {
// This garbage is to track which codebook entries are going stale int negRun = c.t - c.cb[s]->t_last_update; // 计算该码元的不更新时间 if(c.cb[s]->stale < negRun)
}
break;
}
}
// ENTER A NEW CODE WORD IF NEEDED if(i == c.numEntries) // No existing code word found, make a new one // p 像素不满足此码本中任何一个码元,下面创建一个新码元 {
code_element **foo = new code_element* [c.numEntries+1]; // 申请 c.numEntries+1 个指向码元的指针 for(int ii=0; ii<c.numEntries; ii++)
#include "stdafx.h" #include <cv.h> #include <highgui.h> #include <cxcore.h>
#define CHANNELS 3 // 设置处理的图像通道数,要求小于等于图像本身的通道数
///////////////////////////////////////////////////////////////////////////
/*
A few more thoughts on codebook models
In general, the codebook method works quite well across a wide number of
conditions,
and it is relatively quick to train and to run. It doesn’t deal well with varying
for (n=0; n<numChannels; n++)
//调整该码元各通道最大最小值
{
if (c.cb[i]->max[n] < *(p+n))
c.cb[i]->max[n] = *(p+n);
else if (c.cb[i]->min[n] > *(p+n))
c.cb[i]->min[n] = *(p+n);
}
return(i); }
////////////////////////////////////////////////////////////////////////////
///////
// uchar cvbackgroundDiff(uchar *p, codeBook &c, int minMod, int maxMod)
Codebook for this pixel
// cbBounds
Learning bounds for codebook (Rule of thumb: 10)
// numChannels Number of color channels we're learning
//
// NOTES:
//
cvBounds must be of size cvBounds[numChannels]
patterns of
light — such as morning, noon, and evening sunshine — or with someone turning
lights
on or off indoors. This type of global variability can be taken into account by
// 此码元各通道的阀值上限(学习界限)
uchar learnLow[CHANNELS];
// Low side threshold for learning
// 此码元各通道的阀值下限
// 学习过程中如果一个新像素各通道值 x[i],均有 learnLow[i]<=x[i]<=learnHigh[i],则
//遍历每个通道
{
if((c.cb[i]->learnLow[n] <= *(p+n)) && (*(p+n) <=
c.cb[i]->learnHigh[n])) //Found an entry for this channel
// 如果 p 像素通道数据在该码元阀值上下限之间
{
matchChannel++;
}
}
if (matchChannel == numChannels)
// If an entry was found over all
channels
// 如果 p 像素各通道都满足上面条件
{
c.cb[i]->t_last_update = c.t;
// 更新该码元时间为当前时间
// adjust this codeword for the first channel
///////
// int updateCodeBook(uchar *p, codeBook &c, unsigned cbBounds)
// Updates the codebook entry with a new data point
//
// p
Pointer to a YUV pixel
// c
using
several different codebook models, one for each condition, and then allowing the