【转】MATLAB图像处理函数汇总（一）

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' PhotometricInterpretation: '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