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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

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,[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: [28×2 double]

附录 MATLAB图像处理命令 345

ConvexImage: [15×16 uint8 ]

ConvexArea: 205

Image: [15×16 uint8 ]

FilledImage: [15×16 uint8 ]

FilledArea: 122

EulerNumber: 0

Extrema: [ 8×2 double]

EquivDiameter: 10.6451

Solidity: 0.4341

Extent: 0.3708

PixelList: [89×2 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’

PhotometricInterpretation: ‘RGB Palette’

MATLAB高级应用——图形及影像处理 346

StripOffsets: [ 9×1 double]

SamplesPerPixel: 1

RowsPerStrip: 23

StripByteCounts: [ 9×1 double]

XResolution: 72

YResolution: 72

ResolutionUnit: ‘Inch’

Colormap: [256×3 double]

PlanarConfiguration: ‘Chunky’

TileWidth: []

TileLength: []

TileOffsets: []

TileByteCounts: []

Orientation: 1

FillOrder: 1

GrayResponseUnit: 0.0100

MaxSampleValue: 255

MinSampleValue: 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

60.imnoise

功能:

增加图像的渲染效果.

语法:

J = imnoise(I,type)

J = imnoise(I,type,parameters)

举例

I = imread(‘eight.tif’);

J = imnoise(I,’salt & pepper’,0.02);

imshow(I)

figure, imshow(J)

相关命令:

rand

61.impixel

功能:

确定像素颜色值.

语法:

MATLAB高级应用——图形及影像处理 348

P = impixel(I)

P = impixel(X,map)

P = impixel(RGB)

P = impixel(I,c,r)

P = impixel(X,map,c,r)

P = impixel(RGB,c,r)

[c,r,P] = impixel(…)

P = impixel(x,y,I,xi,yi)

P = impixel(x,y,X,map,xi,yi)

P = impixel(x,y,RGB,xi,yi)

[xi,yi,P] = impixel(x,y,…)

举例

RGB = imread(‘flowers.tif’);

c = [12 146 410];

r = [104 156 129];

pixels = impixel(RGB,c,r)

pixels =

61 59 101

253 240 0

237 37 44

相关命令:

improfile, pixval

62.improfile

功能:

沿线段计算剖面图的像素值.

语法:

c = improfile

c = improfile(n)

c = improfile(I,xi,yi)

c = improfile(I,xi,yi,n)

[cx,cy,c] = improfile(…)

[cx,cy,c,xi,yi] = improfile(…)

[…] = improfile(x,y,I,xi,yi)

[…] = improfile(x,y,I,xi,yi,n)

附录 MATLAB图像处理命令 349

[…] = improfile(…,method)

举例

I = imread(‘alumgrns.tif’);

x = [35 338 346 103];

y = [253 250 17 148];

improfile(I,x,y), grid on

相关命令:

impixel, pixval

63.imread

功能:

从图形文件中读取图像.

语法:

A = imread(filename,fmt)

[X,map] = imread(filename,fmt)

[…] = imread(filename)

[…] = imread(…,idx) (TIFF only)

[…] = imread(…,ref) (HDF only)

[…] = imread(…,’BackgroundColor’,BG) (PNG only)

[A,map,alpha] = imread(…) (PNG only)

举例

[X,map] = imread(‘flowers.tif’,6);

info = imfinfo(‘skull.hdf’);

[X,map] = imread(‘skull.hdf’,info(4).Reference);

bg = [255 0 0];

A = imread(‘image.png’,’BackgroundColor’,bg);

MATLAB高级应用——图形及影像处理 350

[A,map,alpha] = imread(‘image.png’);

相关命令:

imfinfo, imwrite,fread,double,uint8,uint16

64.imresize

功能:

改变图像大小.

语法:

B = imresize(A,m,method)

B = imresize(A,[mrows ncols],method)

B = imresize(…,method,n)

B = imresize(…,method,h)

65.imrotate

功能:

旋转图像.

语法:

B = imrotate(A,angle,method)

B = imrotate(A,angle,method,’crop’)

举例

I = imread(‘ic.tif’);

J = imrotate(I,-4,’bilinear’,’crop’);

imshow(I)

figure, imshow(J)

相关命令:

imcrop, imresize

66.imshow

功能:

显示图像.

语法:

附录 MATLAB图像处理命令 351

imshow(I,n)

imshow(I,[low high])

imshow(BW)

imshow(X,map)

imshow(RGB)

imshow(…,display_option)

imshow(x,y,A,…)

imshow filename

h = imshow(…)

相关命令:

getimage, imread, iptgetpref, iptsetpref, subimage, truesize, warp

67.imwrite

功能:

把图像写入图形文件中.

语法:

imwrite(A,filename,fmt)

imwrite(X,map,filename,fmt)

imwrite(…,filename)

imwrite(…,Param1,Val1,Param2,Val2…)

举例

imwrite(X,map,’flowers.hdf’,’Compression’,’none’,…

‘WriteMode’,’append’)

相关命令:

imfinfo, imread

68.ind2gray

功能:

把检索图像转化为灰度图像.

语法:

I = ind2gray(X,map)

举例

load trees

I = ind2gray(X,map);

imshow(X,map)

figure,imshow(I)

MATLAB高级应用——图形及影像处理 352

相关命令:

gray2ind, imshow, rgb2ntsc

69.ind2rgb

功能:

转化索引图像为RGB真彩图像.

语法:

RGB = ind2rgb(X,map)

相关命令:

ind2gray, rgb2ind

70.iptgetpref

功能:

获取图像处理工具箱参数设置.

语法:

value = iptgetpref(prefname)

举例

value = iptgetpref(‘ImshowAxesVisible’)

value =

off

相关命令:

imshow, iptsetpref

71.iptsetpref

功能:

设置图像处理工具箱参数.

语法:

iptsetpref(prefname,value)

举例

iptsetpref(‘ImshowBorder’,’tight’)

相关命令:

imshow, iptgetpref, truesize

72.iradon

附录 MATLAB图像处理命令 353

功能:

进行反Radon变换.

语法:

I = iradon(P,theta)

I = iradon(P,theta,interp,filter,d,n)

[I,h] = iradon(…)

举例

P = phantom(128);

R = radon(P,0:179);

I = iradon(R,0:179,’nearest’,’Hann’);

imshow(P)

figure, imshow(I)

相关命令:

radon, phantom

73.isbw

功能:

判断是否为二进制图像.

语法:

flag = isbw(A)

相关命令:

isind, isgray, isrgb

74.isgray

功能:

判断是否为灰度图像.

语法:

flag = isgray(A)

相关命令:

isbw, isind, isrgb

75.isind

MATLAB高级应用——图形及影像处理 354

功能:

判断是否为索引图像.

语法:

flag = isind(A)

相关命令:

isbw, isgray, isrgb

76.isrgb

功能:

判读是否为RGB真彩图像.

语法:

flag = isrgb(A)

相关命令:

isbw, isgray, isind

77.makelut

功能:

创建一个用于applylut函数的lookup表.

语法:

lut = makelut(fun,n)

lut = makelut(fun,n,P1,P2,…)

举例

f = inline(‘sum(x(:)) >= 2’);

lut = makelut(f,2)

lut =

0

0

0

1

0

1

1

1

0

1

1

1

1

1

附录 MATLAB图像处理命令 355

1

1

相关命令:

applylut

78.mat2gray

功能:

转化矩阵为灰度图像.

语法:

I = mat2gray(A,[amin amax])

I = mat2gray(A)

举例

I = imread(‘rice.tif’);

J = filter2(

fspecial

(‘sobel’),I);

K = mat2gray(J);

imshow(I)

figure, imshow(K)

相关命令:

gray2ind

79.mean2

功能:

计算矩阵元素的平均值.

语法:

b = mean2(A)

相关命令:

std2, mean, std

80.medfilt2

功能:

进行二维中值过滤.

语法:

MATLAB高级应用——图形及影像处理 356

B = medfilt2(A,[m n])

B = medfilt2(A)

B = medfilt2(A,’indexed’,…)

举例

I = imread(‘eight.tif’);

J = imnoise(I,’salt & pepper’,0.02);

K = medfilt2(J);

imshow(J)

figure, imshow(K)

相关命令:

filter2, ordfilt2, wiener2

81.montage

功能:

在矩形框中同时显示多幅图像.

语法:

montage(I)

montage(BW)

montage(X,map)

montage(RGB)

h = montage(…)

举例

load mri

montage(D,map)

附录 MATLAB图像处理命令 357

相关命令:

immovie

82.nlfilter

功能:

进行边沿操作.

语法:

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

B = nlfilter(A,[m n],fun,P1,P2,…)

B = nlfilter(A,’indexed’,…)

举例

B = nlfilter(A,[3 3],’median(x(:))’);

相关命令:

blkproc, colfilt

83.ntsc2rgb

功能: 转换NTSC的值为RGB颜色空间.

语法:

rgbmap = ntsc2rgb(yiqmap)

RGB = ntsc2rgb(YIQ)

相关命令:

rgb2ntsc, rgb2ind, ind2rgb, ind2gray

84.ordfilt2

功能:

进行二维统计顺序过滤.

语法:

B = ordfilt2(A,order,domain)

B = ordfilt2(A,order,domain,S)

MATLAB高级应用——图形及影像处理 358

B = ordfilt2(…,padopt)

相关命令:

medfilt2

85.phantom

功能:

产生一个头部幻影图像.

语法:

P = phantom(def,n)

P = phantom(E,n)

[P,E] = phantom(…)

举例

P = phantom(‘Modified Shepp-Logan’,200);

imshow(P)

相关命令:

radon, iradon

86.pixval

功能:

显示图像像素信息.

语法:

pixval on

pixval off

pixval

pixval(fig,option)

相关命令:

impixel, improfile

87.qtdecomp

功能:

进行四叉树分解.

附录 MATLAB图像处理命令 359

语法:

S = qtdecomp(I)

S = qtdecomp(I,threshold)

S = qtdecomp(I,threshold,mindim)

S = qtdecomp(I,threshold,[mindim maxdim])

S = qtdecomp(I,fun)

S = qtdecomp(I,fun,P1,P2,…)

举例

I = [1 1 1 1 2 3 6 6

1 1 2 1 4 5 6 8

1 1 1 1 10 15 7 7

1 1 1 1 20 25 7 7

20 22 20 22 1 2 3 4

20 22 22 20 5 6 7 8

20 22 20 20 9 10 11 12

22 22 20 20 13 14 15 16];

S = qtdecomp(I,5);

full(S)

ans =

4 0 0 0 2 0 2 0

0 0 0 0 0 0 0 0

0 0 0 0 1 1 2 0

0 0 0 0 1 1 0 0

4 0 0 0 2 0 2 0

0 0 0 0 0 0 0 0

0 0 0 0 2 0 2 0

0 0 0 0 0 0 0 0

相关命令:

qtgetblk, qtsetblk

88.qtgetblk

功能:

获取四叉树分解中的块值.

语法:

[vals,r,c] = qtgetblk(I,S,dim)

MATLAB高级应用——图形及影像处理 360

[vals,idx] = qtgetblk(I,S,dim)

举例

[vals,r,c] = qtgetblk(I,S,4)

vals(:,:,1) =

1 1 1 1

1 1 2 1

1 1 1 1

1 1 1 1

vals(:,:,2) =

20 22 20 22

20 22 22 20

20 22 20 20

22 22 20 20

r =

1

5

c =

1

1

相关命令:

qtdecomp, qtsetblk

89.qtsetblk

功能:

设置四叉树分解中的块值.

语法:

J = qtsetblk(I,S,dim,vals)

举例

newvals = cat(3,zeros(4),ones(4));

J = qtsetblk(I,S,4,newvals)

J =

0 0 0 0 2 3 6 6

0 0 0 0 4 5 6 8

0 0 0 0 10 15 7 7

附录 MATLAB图像处理命令 361

0 0 0 0 20 25 7 7

1 1 1 1 1 2 3 4

1 1 1 1 5 6 7 8

1 1 1 1 9 10 11 12

1 1 1 1 13 14 15 16

相关命令:

qtdecomp, qtgetblk

90.radon

功能: 计算Radon变换.

语法:

R = radon(I,theta)

R = radon(I,theta,n)

[R,xp] = radon(…)

举例

iptsetpref(‘ImshowAxesVisible’,’on’)

I = zeros(100,100);

I(25:75,25:75) = 1;

theta = 0:180;

[R,xp] = radon(I,theta);

imshow(theta,xp,R,[]), colormap(hot), colorbar

相关命令:

iradon, phantom

91.rgb2gray

功能: 转换RGB图像或颜色映像表为灰度图像.

语法:

I = rgb2gray(RGB)

newmap = rgb2gray(map)

相关命令:

MATLAB高级应用——图形及影像处理 362

ind2gray, ntsc2rgb, rgb2ind, rgb2ntsc

92.rgb2hsv

功能: 转化RGB值为HSV颜色空间.

语法:

hsvmap = rgb2hsv(rgbmap)

HSV = rgb2hsv(RGB)

相关命令:

hsv2rgb, rgbplot

93.rgb2ind

功能: 转化RGB图像为索引图像.

语法:

[X,map] = rgb2ind(RGB,tol)

[X,map] = rgb2ind(RGB,n)

X = rgb2ind(RGB,map)

[…] = rgb2ind(…,dither_option)

举例

RGB = imread(‘flowers.tif’);

[X,map] = rgb2ind(RGB,128);

imshow(X,map)

相关命令:

cmunique, dither, imapprox, ind2rgb, rgb2gray

94.rgb2ntsc

功能: 转化RGB的值为NTSC颜色空间.

语法:

yiqmap = rgb2ntsc(rgbmap)

YIQ = rgb2ntsc(RGB)

附录 MATLAB图像处理命令 363

相关命令:

ntsc2rgb, rgb2ind, ind2rgb, ind2gray

95.rgb2ycbcr

功能: 转化RGB的值为YcbCr颜色空间.

语法:

ycbcrmap = rgb2ycbcr(rgbmap)

YCBCR = rgb2ycbcr(RGB)

相关命令:

ntsc2rgb, rgb2ntsc, ycbcr2rgb

96.rgbplot

功能:

划分颜色映像表.

语法:

rgbplot(map)

举例

rgbplot(jet)

相关命令:

colormap

97.roicolor

功能:

选择感兴趣的颜色区.

语法:

BW = roicolor(A,low,high)

BW = roicolor(A,v)

举例

I = imread(‘rice.tif’);

BW = roicolor(I,128,255);

imshow(I);

MATLAB高级应用——图形及影像处理 364

figure, imshow(BW)

相关命令:

roifilt2, roipoly

98.roifill

功能:

在图像的任意区域中进行平滑插补.

语法:

J = roifill(I,c,r)

J = roifill(I)

J = roifill(I,BW)

[J,BW] = roifill(…)

J = roifill(x,y,I,xi,yi)

[x,y,J,BW,xi,yi] = roifill(…)

举例

I = imread(‘eight.tif’);

c = [222 272 300 270 221 194];

r = [21 21 75 121 121 75];

J = roifill(I,c,r);

imshow(I)

figure, imshow(J)

附录 MATLAB图像处理命令 365

相关命令:

roifilt2, roipoly

99.roifilt2

功能:

过滤敏感区域.

语法:

J = roifilt2(h,I,BW)

J = roifilt2(I,BW,fun)

J = roifilt2(I,BW,fun,P1,P2,…)

举例

h =

fspecial

(‘unsharp’);

J = roifilt2(h,I,BW);

imshow(J)

相关命令:

filter2, roipoly

100.roipoly

功能:

选择一个敏感的多边形区域.

语法:

BW = roipoly(I,c,r)

BW = roipoly(I)

BW = roipoly(x,y,I,xi,yi)

[BW,xi,yi] = roipoly(…)

[x,y,BW,xi,yi] = roipoly(…)

举例

I = imread(‘eight.tif’);

c = [222 272 300 270 221 194];

r = [21 21 75 121 121 75];

BW = roipoly(I,c,r);

imshow(I)

MATLAB高级应用——图形及影像处理 366

figure, imshow(BW)

相关命令:

roifilt2, roicolor, roifill

101.std2

功能:

计算矩阵元素的标准偏移.

语法:

b = std2(A)

相关命令:

corr2, mean2

102.subimage

功能:

在一幅图中显示多个图像.

语法:

subimage(X,map)

subimage(I)

subimage(BW)

subimage(RGB)

subimage(x,y,…)

h = subimage(…)

举例

load trees

[X2,map2] = imread(‘forest.tif’);

subplot(1,2,1), subimage(X,map)

subplot(1,2,2), subimage(X2,map2)

相关命令:

附录 MATLAB图像处理命令 367

103.truesize

功能:

调整图像显示尺寸.

语法:

truesize(fig,[mrows mcols])

truesize(fig)

相关命令:

imshow, iptsetpref, iptgetpref

104.uint8

功能:

转换数据为8位无符号整型.

语法:

B = uint8(A)

举例

a = [1 3 5];

b = uint8(a);

whos

Name Size Bytes Class

a 1×3 24 doublearray

b 1×3 3 uint8 array

相关命令:

double, im2double, im2uint8

105.uint16

功能:

转换数据为16位无符号整型.

语法:

I = uint16(X)

MATLAB高级应用——图形及影像处理 368

举例

a = [1 3 5];

b = uint16(a);

whos

Name Size Bytes Class

a 1×3 24 double array

b 1×3 6 uint16 array

相关命令:

double, datatypes, uint8, uint32, int8, int16, int32.

106.warp

功能:

将图像显示到纹理映射表面.

语法:

warp(X,map)

warp(I,n)

warp(BW)

warp(RGB)

warp(z,…)

warp(x,y,z,…)

h = warp(…)

举例

[x,y,z] = cylinder;

I = imread(‘testpat1.tif’);

warp(x,y,z,I);

相关命令:

imshow

附录 MATLAB图像处理命令 369

107.wiener2

功能:

进行二维适应性去噪过滤处理.

语法:

J = wiener2(I,[m n],noise)

[J,noise] = wiener2(I,[m n])

举例

I = imread(‘saturn.tif’);

J = imnoise(I,’gaussian’,0,0.005);

K = wiener2(J,[5 5]);

imshow(J)

figure, imshow(K)

相关命令:

filter2, medfilt2

108.ycbcr2rgb

功能: 转化YcbCr值为RGB颜色空间.

语法:

rgbmap = ycbcr2rgb(ycbcrmap)

RGB = ycbcr2rgb(YCBCR)

相关命令:

ntsc2rgb, rgb2ntsc, rgb2ycbcr

109.zoom

功能:

缩放图像.

语法:

zoom on

zoom off

zoom out

MATLAB高级应用——图形及影像处理 370

zoom reset

zoom

zoom xon

zoom yon

zoom(factor)

zoom(fig,option)

相关命令:

imcrop