An example of image processing using matlab

function [imgdatadb,mymask]=rgb2whiteblack(ImgFileName,mymask) %  To show some basic image processing (percentage of some colors) %  using matlab. Also shows how to create a mask using mouse. %  Copyright: http://scriptdemo.blogspot.com IsFig=0; IsFinalFig=1; % read image if nargin==0     ImgFileName='8x.JPG'; end if ~exist(ImgFileName,'file')     disp(['image file: ',ImgFileName,' cannot be found!!! return nothing'])     imgdatadb=[];mymask=[];     return end % assume input image is in rgb mode imgrgb=imread(ImgFileName); % Be more accurate or professional, consider operations with rgb channels if ~exist('mymask','var')    %create the mask    mask1=roipoly(imgrgb);    mask2=roipoly(imgrgb);    mask3=roipoly(imgrgb);    mymask=mask1+mask2+mask3;    close; end if IsFig % show rgb channels of the image    figure;    for N=1:4        subplot(2,2,N);        if N~=4           imagesc(imgrgb(:,:,N));        else           imagesc(imgrgb);        end    end end % convert data into gray scale [intensity image] imgdata=rgb2gray(imgrgb); % or maybe consider rgb2bw %convert to double imgdatadb=double(imgdata); % convert dark part to black imgdatadb(imgdatadb<100)=0; % ..      light part to white imgdatadb(imgdatadb>=100)=255; % set mask region to specified value, e.g., 90 imgdatadb(mymask==1)=90; % statistics NumOfMaskP=length(find(mymask==1)); NumOfEffectiveP=length(imgdatadb(:))-NumOfMaskP; PerEffective=NumOfEffectiveP/(NumOfMaskP+NumOfEffectiveP)*100; PerBlack=length(find(imgdatadb==0))/NumOfEffectiveP*100; % show percentage disp(['Percentage of Effective  pixels (%): ',num2str(PerEffective)]) disp(['Percentage of black region (%): ',num2str(PerBlack)]) % show image if IsFinalFig    figure;    title('Origin Gray image');imagesc(imgdata);    figure;    title('Black and White'); imagesc(uint8(imgdatadb)); end