Photoshop图像处理算法—对比度调整（老版功能）

标签：图像处理   算法   颜色空间   对比度调整   photoshop   

前言：之前在公司做项目的用到photoshop颜色空间的一些相关方法，在此总结一下。下面原理部分是从我的总结文档里截取来的。需要复制的童鞋自己手写一下~

2、程序部分

1）Matlab实验程序

<span style="font-size:18px;">clc;clear;close all;
Image=imread('Fotor_LomoOrg.bmp');
figure(1);
imshow(Image);
Image=double(Image);

R=Image(:,:,1);
G=Image(:,:,2);
B=Image(:,:,3);

Average=127;
%调整参数[-100,100]
Contrast=50;

Contrast=Contrast/100*255;
Percent=Contrast/255;
if(Contrast>0)
    R = Average + (R - Average) * 1 / (1 - Percent) ;
    G = Average + (G - Average) * 1 / (1 - Percent) ;
    B = Average + (B - Average) * 1 / (1 - Percent) ;
else
    R= Average + (R - Average) * (1 + Percent);
    G= Average + (G - Average) * (1 + Percent);
    B= Average + (B - Average) * (1 + Percent);
    
end

img(:,:,1)=R;
img(:,:,2)=G;
img(:,:,3)=B;

figure(2);
imshow(uint8(img));</span><strong style="font-size: 18px;">
</strong>

<span style="font-size:18px;">void  ContrastAdjustRGB(unsigned char *pSrc, unsigned char *pDest, int nWidth, int nHeight,int nParameter)
{
	//局部变量声明
	int nAverage = 127;
	int i = 0;
	int nLength = nWidth * nHeight;
	double dTemp;

	//将参数范围由[-100,100]变换到[-1,1]
	double dPercent =static_cast<double>(nParameter) / 100;

	if(nParameter >= 0)
	{
	   for(i = 0;i < 3 * nLength;i++)
	   {
		   dTemp=nAverage + (pSrc[i] - nAverage) * 1/(1 - dPercent);
		   pDest[i] = CLIP8(static_cast<int>(dTemp));
	   }
	}
	else
	{
           for(i = 0;i < 3 * nLength;i++)
	   {
		   pDest[i] = nAverage + (pSrc[i] - nAverage) * (1 + dPercent);
	   }
	}
}</span>

图1 原图

图2 参数为50结果

图3 参数为-50结果

Photoshop图像处理算法—对比度调整（老版功能）

标签：图像处理   算法   颜色空间   对比度调整   photoshop   

原文地址：http://blog.csdn.net/xingyanxiao/article/details/48035237