matlab中读取PPM格式的图像程序.docx

matlab中读取PPM格式的图像程序function I,w,h,level = ppmread(path) %* % Title: Ppmread % Input Parameter: path of the ppm file % Description: This file reads .ppm file % open the file in read mode f= fopen(path,'r'); A = 0 ; % Ascii flag % ignore the comments in the file a = fscanf(f,'%s',1); while(a(1)='#') a = fscanf(f,'%s',1); end % check magic number if (strcmp(a,'P3')=0) &(strcmp(a,'P6')=0) while(a(1)='#') a = fscanf(f,'%s',1); end display('its not ppm file'); else display('its ppm file'); if(strcmp(a,'P3') A = 1; end a = fscanf(f,'%s',1); while(a(1) = '#') b = fgets(f); % throw away the comments line a= fscanf(f,'%s',1); % read first character of next line end w = str2num(a); % width of image a= fscanf(f,'%s',1); while(a(1) = '#') b = fgets(f); a= fscanf(f,'%s',1); end h = str2num(a); % hight of image a= fscanf(f,'%s',1); while(a(1) = '#') b = fgets(f); % throw away the comments line a= fscanf(f,'%s',1); end level = str2num(a); % colour levels if (A = 1) for i = 1:h for j = 1:w I(i,j,1) = fscanf(f,'%i',1); % Red I(i,j,2) = fscanf(f,'%i',1); % Green I(i,j,3) = fscanf(f,'%i',1); % Blue end end else % Skip one more char fread(f,1); % Now read the matrix Arr = uint8(fread(f); index = 0; for i = 1:1:h for j = 1:w index = index+1; I(i,j,1) = Arr(index); index = index+1; I(i,j,2) = Arr(index); index = index+1; I(i,j,3) = Arr(index); end end end end