matlab傅里叶变换图像增强（matlab 调用图像放大命令）

本文目录

• matlab 调用图像放大命令
• 用matlab进行图像的傅里叶变换

matlab 调用图像放大命令

Matlab图像处理函数 汇总1
1.applylut
功能:
在二进制图像中利用lookup表进行边沿操作.
语法:
A = applylut(BW,lut)
举例
lut = makelut(’sum(x(:)) == 4’,2);
BW1 = imread(’text.tif’);
BW2 = applylut(BW1,lut);
imshow(BW1)
figure, imshow(BW2)
相关命令:
makelut
2.bestblk
功能:
确定进行块操作的块大小.
语法:
siz = bestblk(,k)
,k)
举例
siz = bestblk(,72)
siz =
64 50
相关命令:
blkproc
3.blkproc
功能:
MATLAB高级应用——图形及影像处理 320
实现图像的显式块操作.
语法:
B = blkproc(A,,fun)
B = blkproc(A,,fun,P1,P2,...)
B = blkproc(A,,fun,...)
B = blkproc(A,’indexed’,...)
举例
I = imread(’alumgrns.tif’);
I2 = blkproc(I,,’std2(x)*ones(size(x))’);
imshow(I)
figure, imshow(I2,);
相关命令:
colfilt, nlfilter,inline
4.brighten
功能:
增加或降低颜色映像表的亮度.
语法:
brighten(beta)
newmap = brighten(beta)
newmap = brighten(map,beta)
brighten(fig,beta)
相关命令:
imadjust, rgbplot
5.bwarea
功能:
计算二进制图像对象的面积.
语法:
total = bwarea(BW)
举例
BW = imread(’circles.tif’);
imshow(BW);
附录 MATLAB图像处理命令 321
bwarea(BW)
ans =
15799
相关命令:
bweuler, bwperim
6.bweuler.
功能:
计算二进制图像的欧拉数.
语法:
eul = bweuler(BW,n)
举例
BW = imread(’circles.tif’);
imshow(BW);
bweuler(BW)
ans =
-2
相关命令:
bwmorph, bwperim
7.bwfill
功能:
填充二进制图像的背景色.
语法:
BW2 = bwfill(BW1,c,r,n)
BW2 = bwfill(BW1,n)
= bwfill(...)
BW2 = bwfill(x,y,BW1,xi,yi,n)
= bwfill(...)
BW2 = bwfill(BW1,’holes’,n)
= bwfill(BW1,’holes’,n)
举例
MATLAB高级应用——图形及影像处理 322
BW1 =[1 0 0 0 0 0 0 0
1 1 1 1 1 0 0 0
1 0 0 0 1 0 1 0
1 0 0 0 1 1 1 0
1 1 1 1 0 1 1 1
1 0 0 1 1 0 1 0
1 0 0 0 1 0 1 0
1 0 0 0 1 1 1 0]
BW2 = bwfill(BW1,3,3,8)
BW2 =
1 0 0 0 0 0 0 0
1 1 1 1 1 0 0 0
1 1 1 1 1 0 1 0
1 1 1 1 1 1 1 0
1 1 1 1 0 1 1 1
1 0 0 1 1 0 1 0
1 0 0 0 1 0 1 0
1 0 0 0 1 1 1 0
I = imread(’blood1.tif’);
BW3 = ~im2bw(I);
BW4 = bwfill(BW3,’holes’);
imshow(BW3)
figure, imshow(BW4)
相关命令:
bwselect, roifill
8.bwlabel
功能:
标注二进制图像中已连接的部分.
语法:
附录 MATLAB图像处理命令 323
L = bwlabel(BW,n)
= bwlabel(BW,n)
举例
BW = [1 1 1 0 0 0 0 0
1 1 1 0 1 1 0 0
1 1 1 0 1 1 0 0
1 1 1 0 0 0 1 0
1 1 1 0 0 0 1 0
1 1 1 0 0 0 1 0
1 1 1 0 0 1 1 0
1 1 1 0 0 0 0 0]
L = bwlabel(BW,4)
L =
1 1 1 0 0 0 0 0
1 1 1 0 2 2 0 0
1 1 1 0 2 2 0 0
1 1 1 0 0 0 3 0
1 1 1 0 0 0 3 0
1 1 1 0 0 0 3 0
1 1 1 0 0 3 3 0
1 1 1 0 0 0 0 0
= find(L==2);
rc =
rc =
2 5
3 5
2 6
3 6
相关命令:
bweuler, bwselect
9.bwmorph
功能:
提取二进制图像的轮廓.
语法:
BW2 = bwmorph(BW1,operation)
BW2 = bwmorph(BW1,operation,n)
举例
BW1 = imread(’circles.tif’);
MATLAB高级应用——图形及影像处理 324
imshow(BW1);
BW2 = bwmorph(BW1,’remove’);
BW3 = bwmorph(BW1,’skel’,Inf);
imshow(BW2)
figure, imshow(BW3)
相关命令:
bweuler, bwperim, dilate, erode
10.bwperim
功能:
计算二进制图像中对象的周长.
语法:
BW2 = bwperim(BW1,n)
举例
BW1 = imread(’circbw.tif’);
BW2 = bwperim(BW1,8);
imshow(BW1)
figure, imshow(BW2)
附录 MATLAB图像处理命令 325
相关命令:
bwarea, bweuler, bwfill
11.bwselect
功能:
在二进制图像中选择对象.
语法:
BW2 = bwselect(BW1,c,r,n)
BW2 = bwselect(BW1,n)
= bwselect(...)
举例
BW1 = imread(’text.tif’);
c = ;
r = ;
BW2 = bwselect(BW1,c,r,4);
imshow(BW1)
figure, imshow(BW2)
相关命令:
bwfill, bwlabel, impixel, roipoly, roifill
12.cmpermute
MATLAB高级应用——图形及影像处理 326
功能:
调整颜色映像表中的颜色.
语法:
= cmpermute(X,map)
= cmpermute(X,map,index)
举例
To order a colormap by luminance, use:
ntsc = rgb2ntsc(map);
= sort(ntsc(:,1));
= cmpermute(X,map,index);
相关命令:
randperm
13.cmunique
功能:
查找颜色映像表**定的颜色及相应的图像.
语法:
= cmunique(X,map)
= cmunique(RGB)
= cmunique(I)
相关命令:
gray2ind, rgb2ind
14.col2im
功能:
将矩阵的列重新组织到块中.
语法:
A = col2im(B,,block_type)
A = col2im(B,)
相关命令:
blkproc, colfilt, im2col, nlfilter
15.colfilt
功能:
利用列相关函数进行边沿操作.
语法:
B = colfilt(A,,block_type,fun)
B = colfilt(A,,block_type,fun,P1,P2,...)
B = colfilt(A,,block_type,fun,...)
B = colfilt(A,’indexed’,...)
附录 MATLAB图像处理命令 327
相关命令:
blkproc, col2im, im2col, nlfilter
16.colorbar
功能:
显示颜色条.
语法:
colorbar(’vert’)
colorbar(’horiz’)
colorbar(h)
colorbar
h = colorbar(...)
举例
I = imread(’blood1.tif’);
h = fspecial(’log’);
I2 = filter2(h,I);
imshow(I2,), colormap(jet(64)), colorbar
17.conv2
功能:
进行二维卷积操作.
语法:
C = conv2(A,B)
C = conv2(hcol,hrow,A)
C = conv2(...,shape)
举例
A = magic(5)
A =
17 24 1 8 15
23 5 7 14 16
4 6 13 20 22
MATLAB高级应用——图形及影像处理 328
10 12 19 21 3
11 18 25 2 9
B =
B =
1 2 1
0 2 0
3 1 3
C = conv2(A,B)
C =
17 58 66 34 32 38 15
23 85 88 35 67 76 16
55 149 117 163 159 135 67
79 78 160 161 187 129 51
23 82 153 199 205 108 75
30 68 135 168 91 84 9
33 65 126 85 104 15 27
相关命令:
filter2
18.convmtx2
功能:
计算二维卷积矩阵.
语法:
T = convmtx2(H,m,n)
T = convmtx2(H,)
相关命令:
conv2
19.convn
功能: 计算n维卷积.
语法:
C = convn(A,B)
C = convn(A,B,shape)
相关命令:
conv2
20.corr2
功能:
计算两个矩阵的二维相关系数.
附录 MATLAB图像处理命令 329
语法:
r = corr2(A,B)
相关命令:
std2
21.dct2
功能:
进行二维离散余弦变换.
语法:
B = dct2(A)
B = dct2(A,m,n)
B = dct2(A,)
举例
RGB = imread(’autumn.tif’);
I = rgb2gray(RGB);
J = dct2(I);
imshow(log(abs(J)),), colormap(jet(64)), colorbar
J(abs(J) 《 10) = 0;
K = idct2(J)/255;
imshow(K)
相关命令:
fft2, idct2, ifft2
22.dctmtx
功能:
MATLAB高级应用——图形及影像处理 330
计算离散余弦变换矩阵.
语法:
D = dctmtx(n)
相关命令:
dct2
23.dilate
功能:
放大二进制图像.
语法:
BW2 = dilate(BW1,SE)
BW2 = dilate(BW1,SE,alg)
BW2 = dilate(BW1,SE,...,n)
举例
BW1 = imread(’text.tif’);
SE = ones(6,2);
BW2 = dilate(BW1,SE);
imshow(BW1)
figure, imshow(BW2)
相关命令:
bwmorph, erode
24.dither
功能:
通过抖动增加外观颜色分辨率,转换图像.
语法:
X = dither(RGB,map)
BW = dither(I)
相关命令:
rgb2ind
25.double
附录 MATLAB图像处理命令 331
功能:
转换数据为双精度型.
语法:
B = double(A)
举例
A = imread(’saturn.tif’);
B = sqrt(double(A));
相关命令:
im2double, im2uint, uint8
26.edge
功能:
识别强度图像中的边界.
语法:
BW = edge(I,’sobel’)
BW = edge(I,’sobel’,thresh)
BW = edge(I,’sobel’,thresh,direction)
= edge(I,’sobel’,...)
BW = edge(I,’prewitt’)
BW = edge(I,’prewitt’,thresh)
BW = edge(I,’prewitt’,thresh,direction)
= edge(I,’prewitt’,...)
BW = edge(I,’roberts’)
BW = edge(I,’roberts’,thresh)
= edge(I,’roberts’,...)
BW = edge(I,’log’)
BW = edge(I,’log’,thresh)
BW = edge(I,’log’,thresh,sigma)
= edge(I,’log’,...)
BW = edge(I,’zerocross’,thresh,h)
= edge(I,’zerocross’,...)
BW = edge(I,’canny’)
BW = edge(I,’canny’,thresh)
BW = edge(I,’canny’,thresh,sigma)
MATLAB高级应用——图形及影像处理 332
= edge(I,’canny’,...)
举例
I = imread(’rice.tif’);
BW1 = edge(I,’prewitt’);
BW2 = edge(I,’canny’);
imshow(BW1);
figure, imshow(BW2)
27.erode
功能:
弱化二进制图像的边界.
语法:
BW2 = erode(BW1,SE)
BW2 = erode(BW1,SE,alg)
BW2 = erode(BW1,SE,...,n)
举例
BW1 = imread(’text.tif’);
SE = ones(3,1);
BW2 = erode(BW1,SE);
imshow(BW1)
figure, imshow(BW2)
相关命令:
bwmorph, dilate
附录 MATLAB图像处理命令 333
28.fft2
功能:
进行二维快速傅里叶变换.
语法:
B = fft2(A)
B = fft2(A,m,n)
举例
load imdemos saturn2
imshow(saturn2)
B = fftshift(fft2(saturn2));
imshow(log(abs(B)),), colormap(jet(64)), colorbar
相关命令:
dct2, fftshift, idct2, ifft2

用matlab进行图像的傅里叶变换

除了最后一句化为0~255之外
用abs求出复数的模
和先求实部，虚部，再用两者平方和再开方求的复数模，本质上没有区别
只是第一中，方法多得到了实部信号和虚部信号