M-File Help: iread View code for iread

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

See also

idisp, ianimate, imono, igamma, imread, imwrite, path


 

© 1990-2012 Peter Corke.