空域、频域图像增强举例

MATLAB图像增强程序举例

1.灰度变换增强程序：

% GRAY TRANSFORM

clc;

I=imread('pout.tif');

imshow(I);

J=imadjust(I,[0.3 0.7],[0 1],1); %transforms the walues in the

%intensity image I to values in J by linealy mapping values

% between 0.3 and 0.7 to values between 0 and 1.

figure;

imshow(J);

J=imadjust(I,[0.3 0.7],[0 1],0.5); % if GAMMA is less than 1,the % mapping si weighted toward higher (brighter) output values. figure;

imshow(J);

J=imadjust(I,[0.3 0.7],[0 1],1.5); % if GAMMA is greater than

% 1,the mapping si weighted toward lower (darker) output values. figure;

imshow(J)

J=imadjust(I,[0.3 0.7],[0 1],1); % If TOP

% image is reversed,as in a photographic negative.

figure;

imshow(J);

2.直方图灰度变换

%直方图灰度变换

[X,map]=imread('forest.tif');

I=ind2gray(X,map);%把索引图像转换为灰度图像

imshow(I);

title('原图像');

improfile%用鼠标选择一条对角线，显示线段的灰度值

figure;subplot(121)

plot(0:0.01:1,sqrt(0:0.01:1))

axis square

title('平方根灰度变换函数')

subplot(122)

maxnum=double(max(max(I)));%取得二维数组最大值

J=sqrt(double(I)/maxnum);%把数据类型转换成double,然后进行平方根变换%sqrt函数不支持uint8类型

J=uint8(J*maxnum);%把数据类型转换成uint8类型

imshow(J)

title('平方根变换后的图像')

3.直方图均衡化程序举例

% HISTGRAM EAQUALIZATION

clc;

% Clear command window

I=imread('tire.tif');

% reads the image in tire.tif into I

imshow(I);

% displays the intensity image I with 256 gray levels figure;

%creates a new figure window

imhist(I);

% displays a histogram for the intensity image I

J=histeq(I,64);

% transforms the intensity image I,returning J an intensity figure;

%image with 64 discrete levels

imshow(J);

figure;

imhist(J);

J=histeq(I,32);

%transforms the intensity image ,returning in % J an intensity figure;

%image with 32 discrete levels

imshow(J);

figure;

imhist(J);

4.直方图规定化程序举例

% HISTGRAM REGULIZATION

clc;

%Clear command window

I=imread('tire.tif');

%reads the image in tire.tif into I

J=histeq(I,32);

%transforms the intensity image I,returning in

%J an intensity image with 32 discrete levels

[counts,x]=imhist(J);

%displays a histogram for the intensity image I

Q=imread('pout.tif');

%reads the image in tire.tif into I

figure;

imshow(Q);

figure;

imhist(Q);

M=histeq(Q,counts);

%transforms the intensity image Q so that the

%histogram of the output image M approximately matches counts

figure;

imshow(M);

figure;

imhist(M);

空域滤波增强部分程序

1.线性平滑滤波

I=imread('eight.tif');

J=imnoise(I,'salt & pepper',0.02);

subplot(221),imshow(I)

title('原图像')

subplot(222),imshow(J)

title('添加椒盐噪声图像')

K1=filter2(fspecial('average',3),J)/255;%应用3*3邻域窗口法subplot(223),imshow(K1)

title('3x3窗的邻域平均滤波图像')

K2=filter2(fspecial('average',7),J)/255;%应用7*7邻域窗口法subplot(224),imshow(K2)