Matlab常用图像处理命令108例（五）

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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) 
[...] = 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]
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'

PhotometricInterpretation: 'RGB Palette' 
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
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)

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：

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)
[...] = 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); 
[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

参考文献：

[1] Rafael C. Gonzalez, Richard E. Woods, and Steven L. Eddins. 2003. Digital Image Processing Using MATLAB. Prentice-Hall, Inc., USA.

[2] 阮秋琦. 数字图像处理（MATLAB版）[M]. 北京：电子工业出版社, 2014.

[3] 冈萨雷斯. 数字图像处理（第三版）[M]. 北京：电子工业出版社, 2011.