Photoshop图像处理算法—饱和度调整
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
*）Matlab实验程序。
span style="font-size:*8px;"clc;clear all;close all;
Image=imread('Fotor_LomoOrg.bmp');
Image=double(Image);
R=Image(:,:,*);
G=Image(:,:,2);
B=Image(:,:,3);
[row, col] = size(R);
R_new=R;
G_new=G;
B_new=B;
%%%% Increment, 饱和度调整增量（-*00,*00）photoshop的范围
Increment=-50;
%换算成调整比率
Increment=Increment/*00;
%利用HSL模式求得颜色的S和L
for i=*:row
for j=*:col
rgbMax=max(R(i,j),max(G(i,j),B(i,j)));
rgbMin=min(R(i,j),min(G(i,j),B(i,j)));
Delta=(rgbMax-rgbMin)/255;
if(Delta==0) %如果delta=0，则饱和度S=0，所以不能调整饱和度
continue;
end
value = (rgbMax + rgbMin)/255;
L=value/2; %Lightness
if(L0.5) %根据明度L计算饱和度S
S=Delta/value;
else
S =Delta/(2 - value);
end
%具体的饱和度调整，Increment为饱和度增减量
if (Increment=0)
if((Increment+S)=*)
alpha=S;
else
alpha=*-Increment;
end
alpha=*/alpha-*;
R_new(i,j) = R(i,j) + (R(i,j) - L * 255) * alpha;
G_new(i,j) = G(i,j) + (G(i,j) - L * 255) * alpha;
B_new(i,j) = B(i,j) + (B(i,j) - L * 255) * alpha;
else
alpha=Increment;
R_new(i,j) = L*255 + (R(i,j) - L * 255) * (*+alpha);
G_new(i,j) = L*255 + (G(i,j) - L * 255) * (*+alpha);
B_new(i,j) = L*255 + (B(i,j) - L * 255) * (*+alpha);
end
end
end
Image_new(:,:,*)=R_new;
Image_new(:,:,2)=G_new;
Image_new(:,:,3)=B_new;
imshow(Image/255);
figure, imshow(Image_new/255);/spanspan style="font-weight: bold; font-size: *8px;"
/span
2）C程序，此处只贴上关键处理部分，已经把图像变成了数组来处理
span style="font-size:*8px;"void SaturationAdjustRGB(unsigned char *pSrc, unsigned char *pDest, int nWidth, int nHeight,int nParameter)
//局部变量声明
int i = 0;
int t = 0;
int nLength = nHeight * nWidth;
//参数处理
double dPercent= static_cast double (nParameter) / *00;
//RGB颜色通道声明
unsigned char *imgR = new unsigned char[nLength];
unsigned char *imgG = new unsigned char[nLength];
unsigned char *imgB = new unsigned char[nLength];
//局部变量声明
unsigned char rgbMax;
unsigned char rgbMin;
double dDelta;
double dValue;
double dL;
double dS;
double dAlpha;
//分离出RGB通道
for (i = 0; i nLength; i++)
t = 3 * i;
imgB[i] = pSrc[t];
imgG[i] = pSrc[t + *];
imgR[i] = pSrc[t + 2];
for (int i = 0; i nLength; i++)
rgbMax = max(max(imgR[i] , imgG[i]) , imgB[i]);
rgbMin = min(min(imgR[i] , imgG[i]) , imgB[i]);
dDelta = static_castdouble(rgbMax - rgbMin) / 255;
dValue = static_castdouble(rgbMax + rgbMin) / 255;
//如果该像素点是灰色 不处理
if(0 == dDelta)
continue;
//按照公式计算明度L [0,*]
dL = dValue / 2;
//按照公式计算饱和度S [0,*]
if(dL 0.5)
dS = dDelta / dValue;
else
dS = dDelta / (2 - dValue);
//进行饱和度调整
if(dPercent = 0)
if(dPercent + dS = *)
dAlpha = dS;
else
dAlpha = * - dPercent;
dAlpha = * / dAlpha - *;
imgB[i] = imgB[i] + (imgB[i] - dL * 255) * dAlpha;
imgG[i] = imgG[i] + (imgG[i] - dL * 255) * dAlpha;
imgR[i] = imgR[i] + (imgR[i] - dL * 255) * dAlpha;
else
dAlpha = dPercent;
imgB[i] = dL * 255 + (imgB[i] - dL * 255) * (* + dAlpha);
imgG[i] = dL * 255 + (imgG[i] - dL * 255) * (* + dAlpha);
imgR[i] = dL * 255 + (imgR[i] - dL * 255) * (* + dAlpha);
//得到结果
for(i = 0; i nLength; i++)
t = 3 * i;
pDest[t] = imgB[i];
pDest[t + *] = imgG[i];
pDest[t + 2] = imgR[i];
//释放内存
if(!imgR)
delete []imgR;
imgR = NULL;
if(!imgG)
delete []imgG;
imgG = NULL;
if(!imgB)
delete []imgB;
imgB = NULL;
}/span
3、实验结果，与photoshop处理结果一致
图* 原图
02*yin.com/xingyanxiao/article/details/48035537/
