在MATLAB环境下图像直方图均匀化代码实现

pulbieup

至于图像直方图均匀化的概念我就不说了，下面直接给出直方图均匀化的代码吧。

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• function om=myhisteq(im,a,b,flag)
• % HISTOGRAM EQUALIZATION
• %
• % input parameters
• % im (must): input grayscale image, can be double, uint8, uint16 and int16
• % a,b (must): piecewise linear stretching parameters, must be a vector between [0 1],
• % a and b must have the same length
• % flag (optional): 1 meaning plot the result, otherwise don't plot
• %
• % output parameters
• % om: output grayscale image after histogram equalization, have the same
• % class with im
• %
• % example
• % close all
• % im=imread('darklena.gif');
• % a=[0 0.1 0.2 1];
• % b=[0 0.8 0.95 1];
• % % 关于myhisteq的使用说明参见myhisteq.m内部
• % om=myhisteq(im,a,b,1);
• %
• % By LaterComer of MATLAB技术论坛
• % See also http://www.matlabsky.com
• % Contact me matlabsky@gmail.com
• % Modifid at 2010-10-13 12:52:53
• %
• % close all
• if nargin<3
•     error('Input parameters must have im, a, b at least!');
• elseif nargin==3
•     flag=0;
• elseif nargin>4
•     error('Too many input parameters, the function have 4 arguments at most!');
• end
• if flag==1
•     figure('name','Piecewise Linear Function')
•     plot(a,b,'o-')
•     xlabel('Input')
•     ylabel('Output')
•     title('Piecewise Linear Function')
•     saveas(gcf,'_Piecewise Linear Function.jpg')
• end
• dataclass=class(im);
• switch dataclass
•     case {'double','sigle'}
•         if ~all(im<=1 & im>=0)
•             error('If input image is double, then the data "im" must be between [0 1]!');
•         end
•     case {'uint8','uint16','int16'}
•         vmin=double(intmin(dataclass));
•         vmax=double(intmax(dataclass));
•         a=a*(vmax-vmin)+vmin;
•         b=b*(vmax-vmin)+vmin;
• end
• om=zeros(size(im),dataclass);
• for i=1:length(a)-1
•     pix = im>=a(i) & im<a(i+1);
•     om(pix)=(b(i+1)-b(i))/(a(i+1)-a(i))*(im(pix)-a(i))+b(i);
• end
• if flag==1
•     figure('name','Input Image')
•     imshow(im)
•     title('Input Image')
•     imwrite(im,'_Input Image.jpg');
•     figure('name','Histogram of Input Image')
•     imhist(im)
•     title('Histogram of Input Image')
•     saveas(gcf,'_Histogram of Input Image.jpg');
•     figure('name','Oput Image')
•     imshow(om)
•     title('Oput Image')
•     imwrite(om,'_Oput Image.jpg')
•     figure('name','Histogram of Output Image')
•     imhist(om)
•     title('Histogram of Output Image')
•     saveas(gcf,'_Histogram of Output Image.jpg')
• end
  

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在MATLAB环境下图像直方图均匀化代码实现