pic = imread('1.jpg');
figure(1)
imshow(pic)
graypic=rgb2gray(pic);
noisepic=imnoise(graypic,'gaussian',0,0.01);
figure(2)
imshow(noisepic),title('添加均值为0，方差为0.01的高斯噪声');
x=-0.5*pi:0.1:0.5*pi;
y1=sin(2*x).*sin(9*x);
y2=real(exp(3.*sqrt(x)));
y3=(0.8+(3*cos(x))./(1+x.^3)).*sin(x);
y4=0.6*exp(-0.5*x).*sin(10*x);
hold on
plot(x,y1,'k-')
plot(x,y2,'b*')
plot(x,y3,'r--')
plot(x,y4,'mx')
xlabel('x')
ylabel('y')
legend('y1','y2','y3','y4')
text(-1,3,'y1=sin(2x)sin(9x)')
text(1,15,'y2=e^{3\surdx}')
text(-0.9,-10,'y3=[0.8+(3cosx)/(1+x^{3})]sin(x)')
text(0.5,-3,'y4=0.6e^{-0.5x}sin10x')
