#include <stdio.h>  
#include <stdlib.h>  
#include <memory.h>
#define height  600  
#define width   800
typedef unsigned char  BYTE;    // 定義BYTE類型，占1個字節(jié)

int main(void)
{
    FILE *fp = NULL;
    //BYTE Pic[height][width];
    BYTE *ptr;
    BYTE **Pic = new BYTE *[height];
    for (int i = 0; i != height; ++i)
    {
        Pic[i] = new BYTE[width];
    }
    fp = fopen("weiminglake_huidu.raw", "rb");       
    ptr = (BYTE*)malloc(width * height * sizeof(BYTE));//創(chuàng)建內(nèi)存
    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            fread(ptr, 1, 1, fp);
            Pic[i][j] = *ptr;  // 把圖像輸入到2維數(shù)組中,變成矩陣型式  
            ptr++;
        }
    }
    fclose(fp);
    
    int hist[256];
    float  fpHist[256];
    float eqHistTemp[256];
    int eqHist[256];
    int size = height *width;
    int i, j;
    memset(&hist, 0x00, sizeof(int) * 256);
    memset(&fpHist, 0x00, sizeof(float) * 256);
    memset(&eqHistTemp, 0x00, sizeof(float) * 256);
    
    for (i = 0; i < height; i++) //計算差分矩陣直方圖  直方圖  統(tǒng)計每個灰度級像素點的個數(shù)
    {
        for (j = 0; j < width; j++)
        {
            unsigned char GrayIndex = Pic[i][j];
            hist[GrayIndex] ++;
        }
    }
    for (i = 0; i< 256; i++)  // 計算灰度分布密度
    {
        fpHist[i] = (float)hist[i] / (float)size;
    }
    for (i = 0; i< 256; i++)  // 計算累計直方圖分布
    {
        if (i == 0)
        {
            eqHistTemp[i] = fpHist[i];
        }
        else
        {
            eqHistTemp[i] = eqHistTemp[i - 1] + fpHist[i];
        }
    }
    //累計分布取整，保存計算出來的灰度映射關(guān)系
    for (i = 0; i< 256; i++)
    {
        eqHist[i] = (int)(255.0 * eqHistTemp[i] + 0.5);
    }
    for (i = 0; i < height; i++) //進行灰度映射均衡化
    {
        for (j = 0; j < width; j++)
        {
            unsigned char GrayIndex = Pic[i][j];
            Pic[i][j] = eqHist[GrayIndex];
        }
    }
    fp = fopen("output.raw", "wb");
    for (i = 0; i < height; i++)
    {
        for (j = 0; j < width; j++)
        {
            fwrite(&Pic[i][j], 1, 1, fp);
        }
    }
    fclose(fp);
    return 0;
}