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([m n],k)

[mb,nb] = bestblk([m n],k)

举例

siz = bestblk([640 800],72)

siz =

64 50

相关命令:

blkproc

3.blkproc

MATLAB高级应用——图形及影像处理 320

功能:实现图像的显式块操作.

语法:

B = blkproc(A,[m n],fun)

B = blkproc(A,[m n],fun,P1,P2,...)

B = blkproc(A,[m n],[mborder nborder],fun,...)

B = blkproc(A,'indexed',...)

举例

I = imread('alumgrns.tif');

I2 = blkproc(I,[8 8],'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)

[BW2,idx] = bwfill(...)

BW2 = bwfill(x,y,BW1,xi,yi,n)

[x,y,BW2,idx,xi,yi] = bwfill(...)

BW2 = bwfill(BW1,'holes',n)

[BW2,idx] = 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)

[L,num] = 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

[r,c] = find(L==2);

rc = [r c]

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)

[BW2,idx] = bwselect(...)

举例

BW1 = imread('text.tif');

c = [16 90 144];

r = [85 197 247];

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:

[Y,newmap] = cmpermute(X,map)

[Y,newmap] = cmpermute(X,map,index)

举例

To order a colormap by luminance, use:

ntsc = rgb2ntsc(map);

[dum,index] = sort(ntsc(:,1));

[Y,newmap] = cmpermute(X,map,index);

相关命令:

randperm

13.cmunique

功能:查找颜色映像表中特定的颜色及相应的图像.

语法:

[Y,newmap] = cmunique(X,map)

[Y,newmap] = cmunique(RGB)

[Y,newmap] = 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,[m n],[mm nn],block_type)

A = col2im(B,[m n],[mm nn])

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,[m n],block_type,fun)

B = colfilt(A,[m n],block_type,fun,P1,P2,...)

B = colfilt(A,[m n],[mblock nblock],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 = [1 2 1;0 2 0;3 1 3]

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,[m n])

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,[m n])

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)

[BW,thresh] = edge(I,'sobel',...)

BW = edge(I,'prewitt')

BW = edge(I,'prewitt',thresh)

BW = edge(I,'prewitt',thresh,direction)

[BW,thresh] = edge(I,'prewitt',...)

BW = edge(I,'roberts')

BW = edge(I,'roberts',thresh)

[BW,thresh] = edge(I,'roberts',...)

BW = edge(I,'log')

BW = edge(I,'log',thresh)

BW = edge(I,'log',thresh,sigma)

[BW,threshold] = edge(I,'log',...)

BW = edge(I,'zerocross',thresh,h)

[BW,thresh] = 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

[BW,threshold] = 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

29.fftn

功能: 进行n维快速傅里叶变换.

语法:

B = fftn(A)

B = fftn(A,siz)

相关命令:

fft2, ifftn

30.fftshift

MATLAB高级应用——图形及影像处理 334

功能:把快速傅里叶变换的DC组件移到光谱中心.

语法:

B = fftshift(A)

举例

B = fftn(A);

C = fftshift(B);

相关命令:

fft2, fftn, ifftshift

31.filter2

功能:进行二维线性过滤操作.

语法:

B = filter2(h,A)

B = filter2(h,A,shape)

举例

A = magic(6)

A =

35 1 6 26 19 24

3 32 7 21 23 25

31 9 2 22 27 20

8 28 33 17 10 15

30 5 34 12 14 16

4 36 29 13 18 11

h = fspecial('sobel')

h =

1 2 1

0 0 0

-1 -2 -1

B = filter2(h,A,'valid')

B =

-8 4 4 -8

-23 -44 -5 40

-23 -50 1 40

-8 4 4 -8

相关命令:

conv2, roifilt2

32.freqspace

附录 MATLAB图像处理命令 335

功能:确定二维频率响应的频率空间.

语法:

[f1,f2] = freqspace(n)

[f1,f2] = freqspace([m n])

[x1,y1] = freqspace(...,'meshgrid')

f = freqspace(N)

f = freqspace(N,'whole')

相关命令:

fsamp2, fwind1, fwind2

33.freqz2

功能:计算二维频率响应.

语法:

[H,f1,f2] = freqz2(h,n1,n2)

[H,f1,f2] = freqz2(h,[n2 n1])

[H,f1,f2] = freqz2(h,f1,f2)

[H,f1,f2] = freqz2(h)

[...] = freqz2(h,...,[dx dy])

[...] = freqz2(h,...,dx)

freqz2(...)

举例

Hd = zeros(16,16);

Hd(5:12,5:12) = 1;

Hd(7:10,7:10) = 0;

h = fwind1(Hd,bartlett(16));

colormap(jet(64))

freqz2(h,[32 32]); axis ([-1 1 -1 1 0 1])

34.fsamp2

MATLAB高级应用——图形及影像处理 336

功能:用频率采样法设计二维FIR过滤器.

语法:

h = fsamp2(Hd)

h = fsamp2(f1,f2,Hd,[m n])

举例

[f1,f2] = freqspace(21,'meshgrid');

Hd = ones(21);

r = sqrt(f1.^2 + f2.^2);

Hd((r0.5)) = 0;

colormap(jet(64))

mesh(f1,f2,Hd)

相关命令:

conv2, filter2, freqspace, ftrans2, fwind1, fwind2

35.fspecial

功能:创建预定义过滤器.

语法:

h = fspecial(type)

h = fspecial(type,parameters)

举例

I = imread('saturn.tif');

h = fspecial('unsharp',0.5);

I2 = filter2(h,I)/255;

imshow(I)

figure, imshow(I2)

相关命令:

conv2, edge, filter2, fsamp2, fwind1, fwind2

36.ftrans2

功能:通过频率转换设计二维FIR过滤器.

语法:

附录 MATLAB图像处理命令 337

h = ftrans2(b,t)

h = ftrans2(b)

举例

colormap(jet(64))

b = remez(10,[0 0.05 0.15 0.55 0.65 1],[0 0 1 1 0 0]);

[H,w] = freqz(b,1,128,'whole');

plot(w/pi-1,fftshift(abs(H)))

相关命令:

conv2, filter2, fsamp2, fwind1, fwind2

37.fwind1

功能:用一维窗口方法设计二维FIR过滤器.

语法:

h = fwind1(Hd,win)

h = fwind1(Hd,win1,win2)

h = fwind1(f1,f2,Hd,...)

举例

[f1,f2] = freqspace(21,'meshgrid');

Hd = ones(21);

r = sqrt(f1.^2 + f2.^2);

Hd((r0.5)) = 0;

colormap(jet(64))

mesh(f1,f2,Hd)

相关命令:

conv2, filter2, fsamp2, freqspace, ftrans2, fwind2

38.fwind2

功能:用二维窗口方法设计二维FIR过滤器.

语法:

h = fwind2(Hd,win)

h = fwind2(f1,f2,Hd,win)

举例

[f1,f2] = freqspace(21,'meshgrid');

Hd = ones(21);

r = sqrt(f1.^2 + f2.^2);

Hd((r0.5)) = 0;

colormap(jet(64))

mesh(f1,f2,Hd)

MATLAB高级应用——图形及影像处理 338

相关命令:

conv2, filter2, fsamp2, freqspace, ftrans2, fwind1

39.getimage

功能:从坐标轴取得图像数据.

语法:

A = getimage(h)

[x,y,A] = getimage(h)

[...,A,flag] = getimage(h)

[...] = getimage

举例

imshow rice.tif

I = getimage;

40.gray2ind

功能:转换灰度图像为索引图像.

语法:

[X,map] = gray2ind(I,n)

相关命令:

ind2gray

41.grayslice

功能:从灰度图像创建索引图像.

语法:

X = grayslice(I,n)

X = grayslice(I,v)

举例

I = imread('ngc4024m.tif');

X = grayslice(I,16);

imshow(I)

figure, imshow(X,jet(16))

附录 MATLAB图像处理命令 339

相关命令:

gray2ind

42.histeq

功能:用柱状图均等化增强对比.

语法:

J = histeq(I,hgram)

J = histeq(I,n)

[J,T] = histeq(I,...)

举例

I = imread('tire.tif');

J = histeq(I);

imshow(I)

figure, imshow(J)

imhist(I,64)

figure; imhist(J,64)

相关命令:

brighten, imadjust, imhist

43.hsv2rgb

功能: 转换HSV值为RGB颜色空间.

语法:

rgbmap = hsv2rgb(hsvmap)

RGB = hsv2rgb(HSV)

相关命令:

MATLAB高级应用——图形及影像处理 340

rgb2hsv, rgbplot

44.idct2

功能:计算二维离散反余弦变换.

语法:

B = idct2(A)

B = idct2(A,m,n)

B = idct2(A,[m n])

相关命令:

dct2, dctmtx, fft2, ifft2

45.ifft2

功能:计算二维快速傅里叶反变换.

语法:

B = ifft2(A)

B = ifft2(A,m,n)

相关命令:

fft2, fftshift, idct2

46.ifftn

功能: 计算n维快速傅里叶反变换.

语法:

B = ifftn(A)

B = ifftn(A,siz)

相关命令:

fft2, fftn, ifft2

47.sim2bw

功能:转换图像为二进制图像.

语法:

BW = im2bw(I,level)

BW = im2bw(X,map,level)

BW = im2bw(RGB,level)

举例

load trees

BW = im2bw(X,map,0.4);

imshow(X,map)

附录 MATLAB图像处理命令 341

figure, imshow(BW)

相关命令:

ind2gray, rgb2gray

48.im2col

功能:重调图像块为列.

语法:

B = im2col(A,[m n],block_type)

B = im2col(A,[m n])

B = im2col(A,'indexed',...)

相关命令:

blkproc, col2im, colfilt, nlfilter

49.im2double

功能:转换图像矩阵为双精度型.

语法:

I2 = im2double(I1)

RGB2 = im2double(RGB1)

BW2 = im2double(BW1)

X2 = im2double(X1,'indexed')

相关命令:

double, im2uint8, uint8

50.im2uint8

功能:转换图像阵列为8位无符号整型.

语法:

I2 = im2uint8(I1)

RGB2 = im2uint8(RGB1)

BW2 = im2uint8(BW1)

X2 = im2uint8(X1,'indexed')

MATLAB高级应用——图形及影像处理 342

相关命令:

im2uint16, double, im2double, uint8, imapprox, uint16

51.im2uint16

功能:转换图像阵列为16位无符号整型.

语法:

I2 = im2uint16(I1)

RGB2 = im2uint16(RGB1)

X2 = im2uint16(X1,'indexed')

相关命令:

im2uint8, double, im2double, uint8, uint16, imapprox

52.imadjust

功能:调整图像灰度值或颜色映像表.

语法:

J = imadjust(I,[low high],[bottom top],gamma)

newmap = imadjust(map,[low high],[bottom top],gamma)

RGB2 = imadjust(RGB1,...)

举例

I = imread('pout.tif');

J = imadjust(I,[0.3 0.7],[]);

imshow(I)

figure, imshow(J)

相关命令:

brighten, histeq

53.imapprox

功能:对索引图像进行近似处理.

语法:

[Y,newmap] = imapprox(X,map,n)

附录 MATLAB图像处理命令 343

[Y,newmap] = imapprox(X,map,tol)

Y = imapprox(X,map,newmap)

[...] = imapprox(...,dither_option)

相关命令:

cmunique, dither, rgb2ind

54.imcontour

功能:创建图像数据的轮廓图.

语法:

imcontour(I,n)

imcontour(I,v)

imcontour(x,y,...)

imcontour(...,LineSpec)

[C,h] = imcontour(...)

举例

I = imread('ic.tif');

imcontour(I,3)

相关命令:

clabel, contour, LineSpec

55.imcrop

功能:剪切图像.

语法:

I2 = imcrop(I)

X2 = imcrop(X,map)

RGB2 = imcrop(RGB)

I2 = imcrop(I,rect)

X2 = imcrop(X,map,rect)

RGB2 = imcrop(RGB,rect)

MATLAB高级应用——图形及影像处理 344

[...] = imcrop(x,y,...)

[A,rect] = imcrop(...)

[x,y,A,rect] = imcrop(...)

举例

I = imread('ic.tif');

I2 = imcrop(I,[60 40 100 90]);

imshow(I)

figure, imshow(I2)

相关命令:

zoom

56.imfeature

功能:计算图像区域的特征尺寸.

语法:

stats = imfeature(L,measurements)

stats = imfeature(L,measurements,n)

举例

BW = imread('text.tif');

L = bwlabel(BW);

stats = imfeature(L,'all');

stats(23)

ans =

Area: 89

Centroid: [95.6742 192.9775]

BoundingBox: [87.5000 184.5000 16 15]

MajorAxisLength: 19.9127

MinorAxisLength: 14.2953

Eccentricity: 0.6961

Orientation: 9.0845

ConvexHull: [28x2 double]

附录 MATLAB图像处理命令 345

ConvexImage: [15x16 uint8 ]

ConvexArea: 205

Image: [15x16 uint8 ]

FilledImage: [15x16 uint8 ]

FilledArea: 122

EulerNumber: 0

Extrema: [ 8x2 double]

EquivDiameter: 10.6451

Solidity: 0.4341

Extent: 0.3708

PixelList: [89x2 double]

相关命令:

bwlabel

57.imfinfo

功能:返回图形文件信息.

语法:

info = imfinfo(filename,fmt)

info = imfinfo(filename)

举例

info = imfinfo('canoe.tif')

info =

Filename:'canoe.tif'

FileModDate: '25-Oct-1996 22:10:39'

FileSize: 69708

Format: 'tif'

FormatVersion: []

Width: 346

Height: 207

BitDepth: 8

ColorType: 'indexed'

FormatSignature: [73 73 42 0]

ByteOrder: 'little-endian'

NewSubfileType: 0

BitsPerSample: 8

Compression: 'PackBits'

PhotometricInterpretatio n: 'RGB Palette'

MATLAB高级应用——图形及影像处理 346

StripOffsets: [ 9x1 double]

SamplesPerPixel: 1

RowsPerStrip: 23

StripByteCounts: [ 9x1 double]

XResolution: 72

YResolution: 72

ResolutionUnit: 'Inch'

Colormap: [256x3 double]

PlanarConfiguration: 'Chunky'

TileWidth: []

TileLength: []

TileOffsets: []

TileByteCounts: []

Orientation: 1

FillOrder: 1

GrayResponseUnit: 0.0100

MaxSamplue: 255

MinSamplue: 0

Thresholding: 1

相关命令:

imread, imwrite

58.imhist

功能:显示图像数据的柱状图.

语法:

imhist(I,n)

imhist(X,map)

[counts,x] = imhist(...)

举例

I = imread('pout.tif');

imhist(I)

附录 MATLAB图像处理命令 347

相关命令:

histeq

59.immovie

功能:创建多帧索引图的电影动画.

语法:

mov = immovie(X,map)

举例

load mri

mov = immovie(D,map);

相关命令:

montage