ondetecthmm.txt

信息隐藏中用于数字隐写的常用算法:LSB替换LSB匹配,包括随机的和排序的,以及对文件和文件夹进行操作,用CxImage类能快速读取各种格式的图象

void CLSBAnalysisDoc::OnDetectHmm() 
{
	//确保打开文件不为空
	ASSERT(m_strPathName != _T(""));

//................得到图像基本信息....................
	DWORD dwHeight = image->GetHeight();           //高
	DWORD dwWidth = image->GetWidth();             //宽
	DWORD dwEffWidth  = image->GetEffWidth();      //实际宽度，对灰度图象为4倍数后的宽度;对彩色图像，为灰度图象宽度的3倍
	DWORD dwImgSize  = dwHeight * dwEffWidth;      //图像数据大小
	DWORD dwColors = image->GetNumColors();        //颜色数
	WORD  wBpp = image->GetBpp();                  //位数


	BYTE* pImg  = NULL;                 //图像数据指针
	pImg = image->GetBits();             

	// HMM 估计LSB替换的嵌入率
	int 	T;
	HMM  	hmm;
	int	N;
	int	M;
	double 	**alpha; 
	double	**beta;
	double	**gamma;
	int	*O;
//	int	c;
	int	seed; /* seed for random number generator */
	int	niter;
	double	logprobinit, logprobfinal;
 

 	/* you can initialize the hmm model three ways:
           i) with a model stored in a file, which also sets 
	      the number of states N and number of symbols M.
           ii) with a random model by just specifyin N and M
              on the command line.
           iii) with a specific random model by specifying N, M
              and seed on the command line. 
        */

		
	/* read the observed sequence */
	T = 64;
	O = new int[dwWidth];
	O = O - 1;
	for (DWORD i = 0; i < dwWidth; i++)
	{
		O[i+1] = (int)pImg[i];  
//		O[i+1] = (int)(pImg[i] + 1);    
	}
	

	/* initialize the hmm model */
	N = 256;
	M = 256;
	seed = hmmgetseed();
//	WienerFilt(pImg, dwWidth, dwHeight, 3, 3, 0.5);
//	InitHMM2(pImg, dwWidth, dwHeight, &hmm, N, M, seed);
	InitHMM(&hmm, N, M, seed);

	/* allocate memory */
	alpha = dmatrix(1, T, 1, hmm.N);
	beta = dmatrix(1, T, 1, hmm.N);
	gamma = dmatrix(1, T, 1, hmm.N);

	/* call Baum Welch2 */
	double theita = BaumWelch2(&hmm, T, O, alpha, beta, gamma, &niter, 
		&logprobinit, &logprobfinal);


	/* free memory */
//	free_ivector(O, 1, T);
	FreeHMM(&hmm);
	free_dmatrix(alpha, 1, T, 1, hmm.N);
	free_dmatrix(beta, 1, T, 1, hmm.N);
	free_dmatrix(gamma, 1, T, 1, hmm.N);
	delete image;	image = NULL;

	if (O != NULL)
	{
		delete [](char*)(O+1);	
		O = NULL;
	}
}