matlab iread,iread.m · zigzag2015/machinevision-toolbox-matlab - Gitee.com

崔涵亮

2023-12-01

%IREAD Read image from file

% IM = IREAD() presents a file selection GUI from which the user can select

% an image file which is returned as a matrix. On subsequent calls

% the initial folder is as set on the last call.

% IM = IREAD([], OPTIONS) as above but allows options to be specified.

% IM = IREAD(PATH, OPTIONS) as above but the GUI is set to the folder specified

% by PATH. If the path is not absolute it is searched for on the MATLAB search

% path.

% IM = IREAD(FILE, OPTIONS) reads the specified image file and returns a matrix.

% If the path is not absolute it is searched for on MATLAB search path.

% The image can be greyscale or color in any of a wide range of formats

% supported by the MATLAB IMREAD function.

% Wildcards are allowed in file names. If multiple files match a 3D or 4D image

% is returned where the last dimension is the number of images in the sequence.

% Options::

% 'uint8' return an image with 8-bit unsigned integer pixels in

% the range 0 to 255

% 'single' return an image with single precision floating point pixels

% in the range 0 to 1.

% 'double' return an image with double precision floating point pixels

% in the range 0 to 1.

% 'grey' convert image to greyscale, if it's color, using ITU rec 601

% 'grey_709' convert image to greyscale, if it's color, using ITU rec 709

% 'gamma',G apply this gamma correction, either numeric or 'sRGB'

% 'reduce',R decimate image by R in both dimensions

% 'roi',R apply the region of interest R to each image,

% where R=[umin umax; vmin vmax].

% Examples::

% Read a color image and display it

% >> im = iread('lena.png');

% >> about im

% im [uint8] : 512x512x3 (786.4 kB)

% >> idisp(im);

% Read a greyscale image sequence

% >> im = iread('seq/*.png');

% >> about im

% im [uint8] : 512x512x9 (2.4 MB)

% >> ianimate(im, 'loop');

% Notes::

% - A greyscale image is returned as an HxW matrix

% - A color image is returned as an HxWx3 matrix

% - A greyscale image sequence is returned as an HxWxN matrix where N is the

% sequence length

% - A color image sequence is returned as an HxWx3xN matrix where N is the

% sequence length

% See also IDISP, IANIMATE, IMONO, IGAMMA, IMREAD, IMWRITE, PATH.

% This file is part of The Machine Vision Toolbox for Matlab (MVTB).

% MVTB is free software: you can redistribute it and/or modify

% it under the terms of the GNU Lesser General Public License as published by

% the Free Software Foundation, either version 3 of the License, or

% (at your option) any later version.

% MVTB is distributed in the hope that it will be useful,

% but WITHOUT ANY WARRANTY; without even the implied warranty of

% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

% GNU Lesser General Public License for more details.

% You should have received a copy of the GNU Leser General Public License

% along with MVTB. If not, see .

function [I,info] = iread(filename, varargin)

persistent lastPath

% options

% 'float

% 'uint8

% 'grey'

% 'gray'

% 'grey_601'

% 'grey_709'

% 'grey_value'

% 'gray_601'

% 'gray_709'

% 'gray_value'

% 'reduce', n

opt.type = {[], 'double', 'single', 'uint8'};

opt.mkGrey = {[], 'grey', 'gray', 'mono', '601', 'grey_601', 'grey_709'};

opt.gamma = [];

opt.reduce = 1;

opt.roi = [];

opt.disp = [];

opt = tb_optparse(opt, varargin);

im = [];

fileFilter = {

'*.gif;*.png;*.pgm;*.ppm;*.pnm;*.jpg;*.tif;*.GIF;*.PNG;*.PGM;*.PPM;*.PNM;*.JPG;*.TIF;', 'All images';

'*.pgm;*.PGM', 'PGM images';

'*.jpg;*.JPG', 'JPEG images';

'*.pgm;*.ppm;*.pnm;*.PGM;*.PPM;*.PNM', 'PBMplus images';

'*.gif;*.png;*.jpg;*.GIF;*.PNG;*.JPG', 'web images';

'*.*', 'All files';

};

if nargin == 0 || isempty(filename)

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%invoke file browser GUI

if ~isempty(lastPath)

[file, npath] = uigetfile(fileFilter, 'iread', lastPath);

else

[file, npath] = uigetfile(fileFilter, 'iread');

end

if file == 0

fprintf('iread canceled from GUI\n');

return; % cancel button pushed

else

% save the path away for next time

lastPath = npath;

filename = fullfile(lastPath, file);

im = loadimg(filename, opt);

end

elseif exist(filename,'dir') == 7

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% invoke file browser GUI on specified path

[file,npath] = uigetfile(fileFilter, 'iread', filename);

if file == 0

fprintf('iread canceled from GUI\n');

return; % cancel button pushed

else

% save the path away for next time

lastPath = npath;

filename = fullfile(lastPath, file);

im = loadimg(filename, opt);

end

else

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% some kind of wildcard filespec has been given

if ~isempty(strfind(filename, '*')) | ~isempty(strfind(filename, '?')),

% wild card files, eg. 'seq/*.png', we need to look for a folder

% seq somewhere along the path.

[pth,name,ext] = fileparts(filename);

if opt.verbose

fprintf('wildcard lookup: %s %s %s\n', pth, name, ext);

end

% search for the folder name along the path

folderonpath = pth;

if ~(isempty(pth) || pth(1) == '.' || pth(1) == '/')

for p=path2cell(path) % was userpath

if exist( fullfile(p{1}, pth) ) == 7

folderonpath = fullfile(p{1}, pth);

if opt.verbose

fprintf('folder found\n');

end

break;

end

s = dir( fullfile(folderonpath, [name, ext])); % do a wildcard lookup

onserver = false;

if length(s) == 0

% not found locally, try on the server

% try to find it on the server

if ~folderonserver(folderonpath)

error('MVTB:iread:nofile', 'file not found');

end

index = webread(['http://petercorke.com/files/images/' folderonpath]);

index = strrep(index, '
', '');

files = regexp(index, [strrep(name, '*', '.*') strrep(ext, '*', '.*')], 'match');

files = splitlines(files{1});

if length(files) == 0

error('no matching files found');

end

onserver = true;

for i=1:length(files)

s(i).name = files{i};

end

%folderonpath = ['http://petercorke.com/files/images/' folderonpath];

fprintf('downloading from server...')

end

for i=1:length(s)

if onserver

im1 = fetchfromserver( fullfile(folderonpath, s(i).name), opt);

else

im1 = loadimg( fullfile(folderonpath, s(i).name), opt);

end

if i==1

% preallocate storage, much quicker

im = zeros([size(im1) length(s)], class(im1));

end

if ndims(im1) == 2

im(:,:,i) = im1;

elseif ndims(im1) == 3

im(:,:,:,i) = im1;

end

if onserver

fprintf('.')

end

if onserver

fprintf('\n');

end

else

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% simple file, no wildcard

if strncmp(filename, 'http://', 7)

im = loadimg(filename, opt);

elseif exist(filename)

im = loadimg(filename, opt);

else

% % see if it exists on the MATLAB search path

% p=fileparts( which('iread') );

% pth = [ fullfile(p, 'images') path2cell(path)];

% for p=pth

% fname = fullfile(p{1}, filename);

% if exist( fname ) > 0

% im = loadimg(fullfile(p{1}, filename), opt);

% break;

% end

im = fetchfromserver(filename, opt);

if isempty(im)

error('MVTB:iread:nofile', 'file not found');

end

if isempty(im)

error(sprintf('can''t find/open file: %s', filename));

end

if nargout > 0

I = im;

if nargout > 1

info = imfinfo(filename);

end

else

% if no output arguments display the image

if ndims(im) <= 3

idisp(im);

end

% load image from file name and apply options

function im = loadimg(filename, opt)

% now we read the image

im = imread(filename);

if opt.verbose

if ndims(im) == 2

fprintf('loaded %s, %dx%d\n', filename, size(im,2), size(im,1));

elseif ndims(im) == 3

fprintf('loaded %s, %dx%dx%d\n', filename, size(im,2), size(im,1), size(im,3));

end

im = applyoptions(im, opt);

end

% get named file from the server, and process according to options

function im = fetchfromserver(filename, opt)

[pth,fname] = pathlist(filename);

if isempty(pth)

% simple filename

if ~fileonserver(fname)

im = [];

return

end

else

if ~folderonserver(pth{1})

error('MVTB:iread:nofile', 'folder not on server');

end

fprintf('downloading from server...')

im = imread(fullfile('http://petercorke.com/files/images', filename));

fprintf('\n');

% stash a copy away locally

savetocache(im, filename);

im = applyoptions(im, opt);

end

% apply options to image

function im = applyoptions(im, opt)

% optionally convert it to greyscale using specified method

if ~isempty(opt.mkGrey) && (ndims(im) == 3)

im = imono(im, opt.mkGrey);

end

% optionally chop out a roi

if ~isempty(opt.roi)

im = iroi(im, opt.roi);

end

% optionally decimate it

if opt.reduce > 1

im = idecimate(im, opt.reduce);

end

% optionally convert to specified numeric type

if ~isempty(opt.type)

if isempty(findstr(opt.type, 'int'))

im = cast(im, opt.type) / double(intmax(class(im)));

else

im = cast(im, opt.type);

end

% optionally gamma correct it

if ~isempty(opt.gamma)

im = igamm(im, opt.gamma);

end

if opt.disp

idisp(im);

drawnow

end

% return the MATLAB path as a cell array

function c = path2cell(s)

remain = s;

c = {};

while true

[str, remain] = strtok(remain, ':');

if isempty(str), break; end

c = [c str];

end

% works like loadimage

function savetocache(im, filename)

mvtb = fileparts( which('iread') );

mkdir_p(mvtb, fullfile('images', filename) );

filename = fullfile(mvtb, 'images', filename);

fprintf('saving locally to %s\n', filename);

imwrite(im, filename);

end

% works like mkdir -p

% starting at base, it creates all the folders needed for filename

function mkdir_p(base, filename)

[pth,fname] = pathlist(filename);

dir = base;

for i=1:length(pth)

dir = fullfile(dir, pth{i});

if exist( dir ) ~= 7

% folder doesn't exist, create it

mkdir(dir);

end

% convert a file path into a cell array of path components and the filename (with

% extension)

function [pth,fname] = pathlist(filename)

[p,f,e] = fileparts(filename);

fname = [f e];

if isempty(p)

pth = {};

else

pth = strsplit(p, filesep);

end

% test if the first component of the folder is on the server

function v = folderonserver(folder)

folderlist = [

"bridge-l"

"bridge-r"

"campus"

"mosaic"

];

pth = strsplit(folder, filesep);

v = ~isempty( intersect(folderlist, pth{1}) );

end

% test if the file is on the server in root folder

function v = fileonserver(filename)

% list of all the files associated with the toolbox, test here rather than pester my server

filelist = [

"58060.jpg"

"5points.png"

"Image18.tif"

"P2.png"

"adelson.png"

"apriltag12.png"

"bender2.png"

"bouget.mat"

"building2-1.png"

"building2-2.png"

"building2-3.png"

"castle.png"

"castle2.png"

"castle_sign.jpg"

"castle_sign2.png"

"church.png"

"circle_noisy.png"

"eiffel-1.png"

"eiffel-2.png"

"eiffel2-1.jpg"

"eiffel2-2.jpg"

"eye.png"

"fisheye_target.png"

"flowers1.png"

"flowers2.png"

"flowers3.png"

"flowers4.png"

"flowers5.png"

"flowers6.png"

"flowers7.png"

"flowers8.png"

"flowers9.png"

"garden-l.jpg"

"garden-r.jpg"

"garden_big-l.jpg"

"garden_big-r.jpg"

"greenscreen.jpg"

"lena.pgm"

"lena.png"

"lotsblobs.png"

"mb.png"

"monalisa.png"

"morph1.png"

"multiblobs.png"

"notre-dame.jpg"

"parks.jpg"

"penguins.jpg"

"penguins.png"

"road.png"

"rocks2-l.png"

"rocks2-r.png"

"roof.jpg"

"shapes.png"

"shark1.png"

"shark2.png"

"shark2a.png"

"sharks.png"

"street.png"

"tomato_124.jpg"

"tomato_14.jpg"

"tomato_54.jpg"

"traffic_sequence.mpg"

"walls-l.jpg"

"walls-r.jpg"

"wally.png"

"wheres-wally.png"

"yellowtargets.png"

];

v = ~isempty( intersect(filelist, filename) );

end

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matlab iread,iread.m · zigzag2015/machinevision-toolbox-matlab - Gitee.com

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