彩色图像处理MATLAB函数简介PPT学习课件.ppt

,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,彩色图像处理函数简介,1,1,函数简介,applycform -Apply device-independent color space,transformation.,hsv2rgb -Convert HSV values to RGB color space,(MATLAB Toolbox).,iccread -Read ICC color profile.,lab2double -Convert Lab color values to double.,lab2uint16 -Convert Lab color values to uint16.,lab2uint8 -Convert Lab color values to uint8.,makecform -Create device-independent color,space transform structure.,ntsc2rgb -Convert NTSC values to RGB color space.,2,1,函数简介,rgb2hsv -Convert RGB values to HSV color space,(MATLAB Toolbox).,rgb2ntsc -Convert RGB values to NTSC color space.,rgb2ycbcr -Convert RGB values to YCBCR color,space.,whitepoint -Returns XYZ values of standard,illuminants.,xyz2double -Convert XYZ color values to double.,xyz2uint16 -Convert XYZ color values to uint16.,ycbcr2rgb -Convert YCBCR values to RGB color,space.,3,1,函数简介,dither -Convert image using dithering.,gray2ind -Convert intensity image to indexed image.,grayslice -Create indexed image from intensity image,by thresholding.,graythresh -Compute global image threshold using,Otsus method.,im2bw -Convert image to binary image by,thresholding.,im2double -Convert image array to double precision.,4,1,函数简介,ind2gray -Convert indexed image to intensity image.,ind2rgb -Convert indexed image to RGB image,(MATLAB Toolbox).,mat2gray -Convert matrix to intensity image.,rgb2gray -Convert RGB image or colormap to,grayscale.,rgb2ind -Convert RGB image to indexed image.,5,2,颜色空间转换矩阵的创建与应用,makecform,Create a color transformation structure,Syntax,C=makecform(type),creates the color transformation structure C that defines the color space conversion specified by type.To perform the transformation,pass the color transformation structure as an argument to the applycform function.,6,type,参数,7,type,参数,8,颜色空间,9,应用,rgb=imread(peppers.png);,cform=makecform(srgb2lab);,lab=applycform(rgb,cform);,10,3,颜色空间转换函数举例,rgb2hsv,Convert RGB colormap to HSV colormap,cmap=rgb2hsv(M),Description,converts an RGB colormap M to an HSV colormap cmap.Both colormaps are m-by-3 matrices.The elements of both colormaps are in the range 0 to 1.The columns of the input matrix M represent intensities of red,green,and blue,respectively.The columns of the output matrix cmap represent hue,saturation,and value,respectively.,11,3,颜色空间转换函数举例,hsv2rgb,Convert HSV colormap to RGB colormap,M=hsv2rgb(H),Description,converts a hue-saturation-value(HSV)colormap to a red-green-blue(RGB)colormap.H is an m-by-3 matrix,where m is the number of colors in the colormap.The columns of H represent hue,saturation,and value,respectively.M is an m-by-3 matrix.Its columns are intensities of red,green,and blue,respectively.,12,编程应用,fc=imread(peppers.png);,%,提取,RGB,分量,fr=fc(:,:,1);,fg=fc(:,:,2);,fb=fc(:,:,3);,figure(1),imshow(f),title(rgb image),13,编程应用,figure(2),imshow(fr),title(red component),figure(3),imshow(fg),title(green component),figure(4),imshow(fb),title(blue component),14,编程应用,%,将,RGB,转换成,HSV,hc=rgb2hsv(fc);,%,提取,HSV,分量,h=hc(:,:,1);,s=hc(:,:,2);,v=hc(:,:,3);,figure(5),imshow(hsv2rgb(hc),title(hsv image),15,编程应用,%,显示,HSV,分量图像,figure(6),imshow(h),title(hue component),figure(7),imshow(s),title(saturation component),figure(8),imshow(v),title(value component),16,编程应用,%,产生均值滤波器,w=fspecial(average,5);,%,对,RGB,图像滤波,rgb_filtered=imfilter(fc,w,replicate);,figure(9),imshow(rgb_filtered),title(filtered RGB image),17,编程应用,%,仅对,HSV,图像的,v,分量滤波,v_filtered=imfilter(v,w,replicate);,h=cat(3,h,s,v_filtered);,f_filtered=hsv2rgb(h);,f_filtered=min(f_filtered,1);,figure(10),imshow(f_filtered),title(filtered hsv image),18,编程应用,%,对,h,s,v,同时滤波,h_filtered=imfilter(h,w,replicate);,s_filtered=imfilter(s,w,replicate);,v_filtered=imfilter(v,w,replicate);,h=cat(3,h_filtered,s_filtered,v_filtered);,f_filtered=hsv2rgb(h);,f_filtered=min(f_filtered,1);,figure(11),imshow(f_filtered),19,4,颜色空间转换函数的编写,function hsi=rgb2hsi(rgb),%,将,RGB,图像转换成,HSI,图像,rgb=im2double(rgb);,r=rgb(:,:,1);,g=rgb(:,:,2);,b=rgb(:,:,3);,20,4,颜色空间转换函数的编写,%,将,RGB,转换,HSI,num=0.5*(r-g)+(r-b);,den=sqrt(r-g).2+(r-b).*(g-b);,theta=acos(num./(den+eps);,H=theta;,h(bg)=2*pi-H(bg);,H=H/(2*pi);,num=min(min(r,g),b);,den=r+g+b;,den(den=0)=eps;,S=1-3.*num./den;,I=(r+g+b)/3;,hsi=cat(3,H,S,I);,21,4,颜色空间转换函数的编写,function rgb=hsi2rgb(hsi),%,将,HSI,图像转换成,RGB,图像,H=hsi(:,:,1)*2*pi;,S=hsi(:,:,2);,I=hsi(:,:,3);,%,初始化,R=zeros(size(hsi,1),size(hsi,2);,G=zeros(size(hsi,1),size(hsi,2);,B=zeros(size(hsi,1),size(hsi,2);,22,4,颜色空间转换函数的编写,%,分区转换,%RB,区间（,0-120,）,idx=find(0=H),B(idx)=I(idx).*(1-S(idx);,R(idx)=I(idx).*(1+S(idx).*cos(H(idx)./cos(pi/3-H(idx);,G(idx)=3*I(idx)-(R(idx)+B(idx);,23,4,颜色空间转换函数的编写,%GB,区间（,120-240,）,idx=find(2*pi/3=H),R(idx)=I(idx).*(1-S(idx);,G(idx)=I(idx).*(1+S(idx).*cos(H(idx)-2*pi/3)./cos(pi-H(idx);,B(idx)=3*I(idx)-(R(idx)+G(idx);,24,4,颜色空间转换函数的编写,%BR,区间（,240-360,）,idx=find(4*pi/3=H),G(idx)=I(idx).*(1-S(idx);,R(idx)=I(idx).*(1+S(idx).*cos(H(idx)-4*pi/3)./cos(5*pi/3-H(idx);,G(idx)=3*I(idx)-(G(idx)+B(idx);,%,组合成,RGB,图像,rgb=cat(3,R,G,B);,rgb=max(min(rgb,1),0);,25,5,灰度条与彩条产生函数,function graybar(h,w,l,map),%h,w,为一个小条带图像的高度和宽度,%l,为条带的灰度级或颜色数，,map,为调色板,c=;,if nargin=0,h=64;w=8;l=16;,elseif nargin=4,error(wrong number of inputs.),end,26,5,灰度条与彩条产生函数,X=ones(h,w);,l=256/l;,for k=0:l:256,Y=k*X;,c=cat(2,c,Y);,end,if isempty(map),map=0:1/256:1*ones(1,3);,end,figure,imshow(c,map),27,6,彩色，索引，灰度图像的转换,x,map=gray2ind(gray_image,n);,gray_image=ind2gray(x,map);,x,map=rgb2ind(rgb_image,n,dither_option);,rgb_image=ind2rgb(x,map);,gray_image=rgb2gray(rgb_image);,28,6,彩色，索引，灰度图像的转换,f=imread(peppers.png);x1,map1=rgb2ind(f,8,nodither);,figure(1),imshow(f),x2,map2=rgb2ind(f,8,dither);,figure(2),imshow(x1,map1),figure(3),imshow(x2,map2),g=rgb2gray(f);,g1=dither(g);,figure(4),imshow(g);,figure(5),imshow(g1);,29,