PS 滤镜——素描算法（二）

利用另外一种算法完成素描特效的生成。

%%% Sketch

clc;

clear all;

Image=imread(‘4.jpg‘);

Image=double(Image);

[row,col,layer]=size(Image);

Filter_size=30;

sigma=Filter_size/6;

F_gaussian=fspecial(‘gaussian‘, Filter_size, sigma);

for i=1:row

for j=1:col

I(i,j)=max(Image(i,j));

end

end

I=I/255;

p=1;

Gradient_X=[-1 -p -1

0   0  0

1   p  1];

Gradient_Y=[-1 0 1

-p 0 p

-1 0 1];

Image_y=imfilter(I, Gradient_Y, ‘conv‘);

Image_x=imfilter(I, Gradient_X, ‘conv‘);

alpha=0.5;

% Image_edge=(abs(Image_x)*alpha+(1-alpha)*abs(Image_y));

Image_edge=(abs(Image_x)+abs(Image_y));

F_image=imfilter(Image,F_gaussian,‘conv‘);

[L,a,b]=Rgb2Lab(F_image);

I=sqrt(L.*L+a.*a+b.*b);

I_mean=mean(mean(I));

F_S=I;

for i=1:row

for j=1:col

if(I(i,j)<I_mean)

F_S(i,j)=(1-I(i,j)/I_mean).^2;

else

F_S(i,j)=0;

end

end

end

Image_out=(1-Image_edge).*(0.8-F_S);

%% 设置底色层

Image_Dodge(:,:,1)=Image_out;

Image_Dodge(:,:,2)=Image_out;

Image_Dodge(:,:,3)=Image_out;

Base_layer=Image_out;

Base_layer(:,:,1)=210/255;

Base_layer(:,:,2)=225/255;

Base_layer(:,:,3)=105/255;

alpha=0.7;

Image1=alpha*Image_Dodge+(1-alpha)*Base_layer;

Image3=Image_Dodge.*Image1;

figure, imshow(Image3);

%%%  Rgb2Lab

%%%

function [L,a,b]=Rgb2Lab(Image)

Image=double(Image)/255;

R=Image(:,:,1);

G=Image(:,:,2);

B=Image(:,:,3);

X=0.5767309*R + 0.1855540*G + 0.1881852*B;

Y=0.2973769*R + 0.6273491*G + 0.0752741*B;

Z=0.0270343*R + 0.0706872*G + 0.9911085*B;

[row, col]=size(R);

L=R;

a=R;

b=R;

for i=1:row

for j=1:col

L(i,j)=116*F_Correction(Y(i,j))-16;

a(i,j)=500*(F_Correction(X(i,j))-F_Correction(Y(i,j)));

b(i,j)=200*(F_Correction(Y(i,j))-F_Correction(Z(i,j)));

end

end

原图

效果图