图像RGB格式与YUV格式互转

// rgb2yuv.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"


#define Level 256   //直方图bin数 
#define SIZEX 176   //image列尺寸
#define SIZEY 256   //image列尺寸
#define READ 0
#define WRITE 1

unsigned char image_in[SIZEY*SIZEX*3];
unsigned char image_out[SIZEY*SIZEX*3];
float Y[SIZEX*SIZEY], U[SIZEX*SIZEY], V[SIZEX*SIZEY];
float Y_out[SIZEX*SIZEY];


void GetFileName(char *name , char *message)
{
    if((NULL == name) || (NULL == message))
    {
        return ;
    }

    printf("%s" , message);
    scanf("%s" , name);
}

FILE * FileOpen(char *fileName , int mode)
{
    FILE *filePoint ;
    char *option = "" ;

    if(mode == READ)
    {
        option = "r+b";
    }
    else if(mode == WRITE)
    {
        option = "w+b";
    }

    if(NULL == (filePoint = fopen(fileName , option)))
    {
        printf("File Open Fail!
");
    }

    return filePoint ;
}

void ReadImageData(FILE *filePoint)
{
    if(filePoint == NULL)
    {
        return ;
    }

    int y_count ;
    unsigned char temp = 0 ;

    for(y_count = 0 ; y_count < SIZEX*SIZEY ; y_count++)
    {
        fscanf(filePoint , "%c" , &temp);
        image_in[y_count] = temp ;
    }
}

void Histogram(long *hist)
{
    int i , num ;

    for(num = 0 ; num < Level ; num++)
    {
        hist[num] = 0 ;
    }

    for(i = 0 ; i < SIZEX*SIZEY ; i++)
    {
        num = Y[i];
        hist[num]++;
    }
    
    for(num = 0 ; num < Level ; num++)
    {
        printf("%d 
" , hist[num]);
    }
}

void Equalization(long *hist ,long *q)
{
    int i,n;
    long sum=0;

    for(i=0;i<256;i++)
    {
        sum += hist[i];   /* find distribution */
        q[i]=(int) (sum*Level/((float)SIZEY*SIZEX));
    }
}

void Calculate(long *q)
{
     int i, y, data;
   
      for(i=0;i<SIZEX*SIZEY;i++){
            data = Y[SIZEX*SIZEY];
            Y_out[SIZEX*SIZEY] = q[data];
         }
}

void WriteImageData(FILE *file_p)
{
    int Y_Count;
  
    for(Y_Count = 0; Y_Count < SIZEX*SIZEY*3; Y_Count++)
    {
             fprintf(file_p, "%c", image_out[Y_Count]);
    }
}

int _tmain(int argc, _TCHAR* argv[])
{
    FILE *in , *out;

    char source[20],destin[20];
    char *message1="Input  Data File Name : " ;
    char *message2="Output Data File Name : " ;

    int i ;
    long hist[Level] = {0} ; 
    long q[Level]    = {0} ;
    unsigned char Red[SIZEX*SIZEY] = {0} ;
    unsigned char Green[SIZEX*SIZEY] = {0} ;
    unsigned char Blue[SIZEX*SIZEY] = {0} ;

    /*读取源文件名*/
    GetFileName(source , message1);
    GetFileName(destin , message2);

    /*打开源文件/目的文件*/
    in  = FileOpen(source , READ);
    out = FileOpen(destin , WRITE);

    /*读取源文件数据*/
    ReadImageData(in);

    /*RGB2YUV*/
    for(i = 0 ; i < SIZEX*SIZEY; i++)
    {
        /*Get RGB Data*/
        Red[i]   = image_in[i*3] ; 
        Green[i] = image_in[i*3+1] ; 
        Blue[i]  = image_in[i*3+2] ; 

        /*RGB to YUV*/
        Y[i] = 0.3*Red[i] + 0.59*Green[i] + 0.11*Blue[i] ;
        U[i] = (Blue[i]-Y[i]) * 0.493;
        V[i] = (Red[i]-Y[i]) * 0.877;
    }

    /*直方图信息统计*/
    Histogram(hist);

    /*直方图均衡*/
    Equalization(hist , q);

    /*直方图计算*/
    Calculate(q); 

    for(i=0; i < SIZEX*SIZEY; i++)
    { 
        Red[i] = Y_out[i] + 0.956*U[i] + 0.621*V[i];
        Green[i] = Y_out[i] + 0.272*U[i] + 0.647*V[i];
        Blue[i] = Y_out[i] + 1.1061*U[i] + 1.703*V[i];
    }

    for(i=0; i < SIZEY*SIZEX; i++)
    {   

        image_out[i*3] = Red[i];
        image_out[i*3+1] = Green[i];
        image_out[i*3+2] = Blue[i];
    }
        
    WriteImageData(out);
    fcloseall();

    return 0;
}

示例图片：

sample.jpg:                     UV分量：