计算RGB、YUV文件的熵值

news/2024/7/21 7:11:37 标签: 图像处理

对课程中的down.rgb和down.yuv分析三个通道的概率分布，并计算各自的熵。（编程实现）

个文件的分辨率均为256*256，yuv为4:2:0采样空间，存储格式为：rgb文件按每个像素BGR分量依次存放；YUV格式按照全部像素的Y数据块、U数据块和V数据块依次存放。

对于down.rgb及分配率，数据量为0-256*256

int main(void)
{
//定义指针、分量数组、读入数据输出数据
 FILE *picture_rgb=NULL; 
 FILE *R=NULL;  
 FILE *G=NULL;
 FILE *B=NULL;

//定义各分量数组
unsigned char *RGB_buffer = NULL;
RGB_buffer=(unsigned char *)malloc(sizeof(unsigned char)*3*width*height);
unsigned char Rr[width*height]={0};  
unsigned char Gg[width*height]={0};
unsigned char Bb[width*height]={0};

int data1;
data1=fopen_s(&picture_rgb,"C:\\Users\\16203\\Desktop\\down.rgb","rb"); //open down.rgb
fopen_s(&R,"C:\\Users\\16203\\Desktop\\R_out.txt","w");
fopen_s(&G,"C:\\Users\\16203\\Desktop\\G_out.txt","w");
fopen_s(&B,"C:\\Users\\16203\\Desktop\\B_out.txt","w");
fread(RGB_buffer,sizeof(unsigned char),3*width*height,picture_rgb);

//读取文件值：
 int a=0;
 int r=0;
 int g=0;
 int b=0;

 for(a;a<3*width*height;a++)
 {
  if(a%3==0)
  {
   Bb[b]=*(RGB_buffer+a);
   b++;
  }
  else if(a%3==1)
  {
   Gg[g]=*(RGB_buffer+a);
   g++;
  }
  else  if(a%3==2)
  {
   Rr[r]=*(RGB_buffer+a);
   r++;
  }
 }

 //计算分量熵值
double H_R=0;
double H_G=0;
double H_B=0;
 for(int i=0;i<256;i++)
 {
  if(Rre[i]!=0)
  {
   H_R=H_R-Rre[i]*(log(Rre[i])/log(double(2)));
  }
  //以2为底对数熵公式
  if(Gre[i]!=0)
  {
   H_G=H_G-Gre[i]*(log(Gre[i])/log(double(2)));
  }
  if(Bre[i]!=0)
  {
   H_B=H_B-Bre[i]*(log(Bre[i])/log(double(2)));
  }
 }
 printf("熵R=%f\n",H_R);
 printf("熵G=%f\n",H_G);
 printf("熵B=%f\n",H_B);

YUV文件

//定义指针、分量数组、读入数据输出数据
int main(void)
{
	FILE *picture_yuv=NULL;
	FILE *Y;
	FILE *U;
	FILE *V;
//定义各分量数组
unsigned char *YUV_buffer = (unsigned char *)malloc(sizeof(unsigned char) *1.5*width*height); 
unsigned char Yy[width*height]={0};
unsigned char Uu[width*height/4]={0};
unsigned char Vv[width*height/4]={0};

fopen_s(&picture_yuv,"down.yuv","rb");
fopen_s(&Y,"Y_out.txt","w");
fopen_s(&U,"U_out.txt","w");
fopen_s(&V,"V_out.txt","w");
fread(YUV_buffer,sizeof(unsigned char),1.5*width*height,picture_yuv);

//读取文件值
int y=0;
int u=0;
int v=0;
for(int a=0,b=0;a<width*height;a++,b++)
	{
		Yy[b]=YUV_buffer[a];
	}
for(int a=width*height, b=0;a<width*height*1.25;a++,b++)
	{
		Uu[a]=YUV_buffer[a];
	}
	for(int a=width*height*1.25, b=0;a<width*height*1.5;a++,b++)
	{
		Vv[b]=YUV_buffer[a];
	}

//计算分量熵值
double H_Y=0;
double H_U=0;
double H_V=0;
	for(int i=0;i<256;i++)
	{
		if(Yre[i]!=0)
		{
			H_Y=H_Y-Yre[i]*(log(Yre[i])/log(double(2)));
		}
		if(Ure[i]!=0)
		{
			H_U=H_U-Ure[i]*(log(Ure[i])/log(double(2)));
		}
		if(Vre[i]!=0)
		{
			H_V=H_V-Vre[i]*(log(Vre[i])/log(double(2)));
		}
	}
	printf("熵Y=%f\n",H_Y);
	printf("熵U=%f\n",H_U);
	printf("熵V=%f\n",H_V);