C语言实现二值图像模拟灰值图像显示效果

本文实例为大家分享了C语言实现二值图像模拟灰值图像显示效果的具体代码，供大家参考，具体内容如下

图案法

图案法(patterning)是指灰度可以用一定比例的黑白点组成的区域表示，从而达到整体图象的灰度感。黑白点的位置选择称为图案化。

下面介绍的一种设计标准图案的算法，是由Limb在1969年提出的。

先以一个2×2的矩阵开始：

通过递归关系有：

其中Mn和Un均为2n×2n的方阵，Un的所有元素都是1。
根据这个算法M2如下，为16级灰度的标准图案：

M3(8×8阵)比较特殊，称为Bayer抖动表。M4是一个16×16的矩阵。

M3 表模拟灰值图像显示效果：

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#pragma pack(1)   //全紧凑模式

typedef struct {
 unsigned char bfType[2];
 unsigned long bfSize;
 unsigned short bfReserved1;
 unsigned short bfReserved2;
 unsigned long bfOffBits;
}bitmapFileHeader;

typedef struct {
 unsigned long biSize;
 unsigned long biWidth;
 unsigned long biHeight;
 unsigned short biPlanes;
 unsigned short biBitCount;
 unsigned long biCompression;
 unsigned long biSizeImage;
 long biXPixPerMeter;
 long biYPixPerMeter;
 unsigned long biClrUsed;
 unsigned long biClrImportant;
}bitmapInfoHeader;

typedef struct{
 unsigned char rgbBlue;
 unsigned char rgbGreen;
 unsigned char rgbRed;
 unsigned char rgbReserved;

}rgbQUAD;

typedef struct{
 bitmapFileHeader bfHeader;
 bitmapInfoHeader biHeader;
 rgbQUAD palette[256];
 unsigned char *imgData;
}bmp;

int main(){
 FILE *fp;
 if((fp=fopen("d:\Temp\\test_gray.bmp","rb"))==NULL){
  perror("can not open file!");
  return -1;
 }
 //读入彩色bmp图像文件头，信息头和图像数据
 bitmapFileHeader bfHeader;
 fread(&bfHeader,14,1,fp);
 bitmapInfoHeader biHeader;
 fread(&biHeader,40,1,fp);
 int imSize=biHeader.biSizeImage;
 int width=biHeader.biWidth;
 int height=biHeader.biHeight;
 int bitCount=biHeader.biBitCount;
 int lineBytes=(width*bitCount+31)/32*4;

 fseek(fp,bfHeader.bfOffBits,SEEK_SET);
 unsigned char*imageData=(unsigned char*)malloc(imSize*sizeof(unsigned char));
 fread(imageData,imSize*sizeof(unsigned char),1,fp);
 fclose(fp);

 bmp b;
 memcpy(&(b.bfHeader),&bfHeader,sizeof(bfHeader));
 memcpy(&(b.biHeader),&biHeader,sizeof(biHeader));
 b.imgData=(unsigned char*)malloc(sizeof(unsigned char)*imSize);
 memset(b.imgData,0,sizeof(unsigned char)*imSize);
 for(int i=0;i<256;i++){
  b.palette[i].rgbBlue=i;
  b.palette[i].rgbGreen=i;
  b.palette[i].rgbRed=i;
 }

 int i,j,temp;
 unsigned char bayer[8][8]={
  0,32,8,40,2,34,10,42,
  48,16,56,24,50,18,58,26,
  12,44,4,36,14,46,6,38,
  60,28,52,20,62,30,54,22,
  3,35,11,43,1,33,9,41,
        51,19,59,27,49,17,57,25,
  15,47,7,39,13,45,5,37,
        63,31,55,23,61,29,53,21
 };
 for(i=0;i<height;i++){
  for(j=0;j<width;j++){
   temp=imageData[lineBytes*i+j];
   if((temp>>2)>bayer[i&7][j&7])
    b.imgData[lineBytes*i+j]=255;
   else
    b.imgData[lineBytes*i+j]=0;
  }
 }

 char savePath[]="D:\Temp\\save_test.bmp";
 FILE *f_save=fopen(savePath,"wb");
 if(f_save==NULL){
  perror("can not open file!");
  return -2;
 }

 fwrite(&b.bfHeader,sizeof(bitmapFileHeader),1,f_save);
 fwrite(&b.biHeader,sizeof(bitmapInfoHeader),1,f_save);
 fwrite(&b.palette,1024,1,f_save);
 fwrite(b.imgData,sizeof(unsigned char)*b.biHeader.biSizeImage,1,f_save);
 fclose(f_save);

 free(imageData);
 free(b.imgData);
 getchar();
 return 0;
}

代码效果：

抖动法

假设灰度级别的范围从b(black)到w(white)，中间值t为(b+w)/2，对应256级灰度，b=0,w=255,t=127.5。设原图中象素的灰度为g，误差值为e，则新图中对应象素的值用如下的方法得到：

if g > t then
  打白点
  e=g-w
else
  打黑点
  e=g-b
 3/8 × e 加到右边的象素
 3/8 × e 加到上边的象素
 1/4 × e 加到右上方的象素

实现代码：

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#pragma pack(1)   //全紧凑模式

typedef struct {
 unsigned char bfType[2];
 unsigned long bfSize;
 unsigned short bfReserved1;
 unsigned short bfReserved2;
 unsigned long bfOffBits;
}bitmapFileHeader;

typedef struct {
 unsigned long biSize;
 unsigned long biWidth;
 unsigned long biHeight;
 unsigned short biPlanes;
 unsigned short biBitCount;
 unsigned long biCompression;
 unsigned long biSizeImage;
 long biXPixPerMeter;
 long biYPixPerMeter;
 unsigned long biClrUsed;
 unsigned long biClrImportant;
}bitmapInfoHeader;

typedef struct{
 unsigned char rgbBlue;
 unsigned char rgbGreen;
 unsigned char rgbRed;
 unsigned char rgbReserved;

}rgbQUAD;

typedef struct{
 bitmapFileHeader bfHeader;
 bitmapInfoHeader biHeader;
 rgbQUAD palette[256];
 unsigned char *imgData;
}bmp;

int main(){
 FILE *fp;
 if((fp=fopen("d:\Temp\\test_gray.bmp","rb"))==NULL){
  perror("can not open file!");
  return -1;
 }
 //读入彩色bmp图像文件头，信息头和图像数据
 bitmapFileHeader bfHeader;
 fread(&bfHeader,14,1,fp);
 bitmapInfoHeader biHeader;
 fread(&biHeader,40,1,fp);
 int imSize=biHeader.biSizeImage;
 int width=biHeader.biWidth;
 int height=biHeader.biHeight;
 int bitCount=biHeader.biBitCount;
 int lineBytes=(width*bitCount+31)/32*4;

 fseek(fp,bfHeader.bfOffBits,SEEK_SET);
 unsigned char*imageData=(unsigned char*)malloc(imSize*sizeof(unsigned char));
 fread(imageData,imSize*sizeof(unsigned char),1,fp);
 fclose(fp);

 bmp b;
 memcpy(&(b.bfHeader),&bfHeader,sizeof(bfHeader));
 memcpy(&(b.biHeader),&biHeader,sizeof(biHeader));
 b.imgData=(unsigned char*)malloc(sizeof(unsigned char)*imSize);
 memset(b.imgData,0,sizeof(unsigned char)*imSize);
 for(int i=0;i<256;i++){
  b.palette[i].rgbBlue=i;
  b.palette[i].rgbGreen=i;
  b.palette[i].rgbRed=i;
 }

 int i,j,temp;
 double e,f;
 for(i=0;i<height;i++){
  for(j=0;j<width;j++){
   b.imgData[lineBytes*i+j]=imageData[lineBytes*i+j]; //拷贝数据
  }
 }

 for(i=0;i<height;i++){
  for(j=0;j<width;j++){
   temp=b.imgData[lineBytes*i+j];
   if(temp>128){
    b.imgData[lineBytes*i+j]=255;
    e=(float)(temp-255);
   }
   else{
    b.imgData[lineBytes*i+j]=0;
    e=(float)temp;
   }
   if(j<width-1){
    f=b.imgData[lineBytes*i+j+1];
    f+=3.0/8.0*e;
    b.imgData[lineBytes*i+j+1]=(unsigned char)f; //向右传播
   }
   if(i<height-1){
    f=b.imgData[lineBytes*(i+1)+j];
    f+=3.0/8.0*e;
    b.imgData[lineBytes*(i+1)+j]=(unsigned char)f; //向上传播
    f=b.imgData[lineBytes*(i+1)+j+1];
    f+=1.0/4.0*e;
    b.imgData[lineBytes*(i+1)+j+1]=(unsigned char)f; //向右上传播
   }
  }
 }

 char savePath[]="D:\Temp\\save_test.bmp";
 FILE *f_save=fopen(savePath,"wb");
 if(f_save==NULL){
  perror("can not open file!");
  return -2;
 }

 fwrite(&b.bfHeader,sizeof(bitmapFileHeader),1,f_save);
 fwrite(&b.biHeader,sizeof(bitmapInfoHeader),1,f_save);
 fwrite(&b.palette,1024,1,f_save);
 fwrite(b.imgData,sizeof(unsigned char)*b.biHeader.biSizeImage,1,f_save);
 fclose(f_save);

 free(imageData);
 free(b.imgData);
 getchar();
 return 0;
}

代码效果：

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