60.imnoise

功能:增加影象的渲染效果.

語法:

J = imnoise(I,type)

J = imnoise(I,type,parameters)

舉例

I = imread('eight.tif');

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

imshow(I)

figure, imshow(J)

相關命令:

rand

61.impixel

功能:確定畫素顏色值.

語法:

MATLAB高階應用——圖形及影像處理 348

P = impixel(I)

P = impixel(X,map)

P = impixel(RGB)

P = impixel(Incur)

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

P = impixel(RGB,c,r)

[carp] = 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,...)

舉例

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

相關命令:

improfile, pixval

62.improfile

功能:沿線段計算剖面圖的畫素值.

語法:

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)

附錄 MATLAB影象處理命令 349

[...] = improfile(...,method)

舉例

I = imread('alumgrns.tif');

x = [35 338 346 103];

y = [253 250 17 148];

improfile(I,x,y), grid on

相關命令:

impixel, pixval

63.imread

功能:從圖形檔案中讀取影象.

語法:

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)

舉例

[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高階應用——圖形及影像處理 350

[A,map,alpha] = imread('image.png');

相關命令:

imfinfo, imwrite,fread,double,uint8,uint16

64.imresize

功能:改變影象大小.

語法:

B = imresize(A,m,method)

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

B = imresize(...,method,n)

B = imresize(...,method,h)

65.imrotate

功能:旋轉影象.

語法:

B = imrotate(A,angle,method)

B = imrotate(A,angle,method,'crop')

舉例

I = imread('ic.tif');

J = imrotate(I,-4,'bilinear','crop');

imshow(I)

figure, imshow(J)

相關命令:

imcrop, imresize

66.imshow

功能:顯示影象.

語法:

附錄 MATLAB影象處理命令 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(...)

相關命令:

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

67.imwrite

功能:把影象寫入圖形檔案中.

語法:

imwrite(A,filename,fmt)

imwrite(X,map,filename,fmt)

imwrite(...,filename)

imwrite(...,Param1,Val1,Param2,Val2...)

舉例

imwrite(X,map,'flowers.hdf','Compression','none',...

'WriteMode','append')

相關命令:

imfinfo, imread

68.ind2gray

功能:把檢索影象轉化為灰度影象.

語法:

I = ind2gray(X,map)

舉例

load trees

I = ind2gray(X,map);

imshow(X,map)

figure,imshow(I)

MATLAB高階應用——圖形及影像處理 352

相關命令:

gray2ind, imshow, rgb2ntsc

69.ind2rgb

功能:轉化索引影象為RGB真彩圖像.

語法:

RGB = ind2rgb(X,map)

相關命令:

ind2gray, rgb2ind

70.iptgetpref

功能:獲取影象處理工具箱引數設定.

語法:

value = iptgetpref(prefname)

舉例

value = iptgetpref('ImshowAxesVisible')

value =

off

相關命令:

imshow, iptsetpref

71.iptsetpref

功能:設定影象處理工具箱引數.

語法:

iptsetpref(prefname,value)

舉例

iptsetpref('ImshowBorder','tight')

相關命令:

imshow, iptgetpref, truesize

72.iradon

附錄 MATLAB影象處理命令 353

功能:進行反Radon變換.

語法:

I = iradon(P,theta)

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

[I,h] = iradon(...)

舉例

P = phantom(128);

R = radon(P,0:179);

I = iradon(R,0:179,'nearest','Hann');

imshow(P)

figure, imshow(I)

相關命令:

radon, phantom

73.isbw

功能:判斷是否為二進位制影象.

語法:

flag = isbw(A)

相關命令:

isind, isgray, isrgb

74.isgray

功能:判斷是否為灰度影象.

語法:

flag = isgray(A)

相關命令:

isbw, isind, isrgb

75.isind

MATLAB高階應用——圖形及影像處理 354

功能:判斷是否為索引影象.

語法:

flag = isind(A)

相關命令:

isbw, isgray, isrgb

76.isrgb

功能:判讀是否為RGB真彩圖像.

語法:

flag = isrgb(A)

相關命令:

isbw, isgray, isind

77.makelut

功能:建立一個用於applylut函式的lookup表.

語法:

lut = makelut(fun,n)

lut = makelut(fun,n,P1,P2,...)

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