Matlab图像读取函数imread用法介绍

%%
%清理工作区与命令区
clc
clear
close all
%%
%图片读取
I1 = imread('0827','jpg'); 
I2 = imread('0827.jpg');
I3 = imread('D:\MATLAB\R2016a\mine\0827.jpg');
figure(1)
imshow(I1)

>> help imread
 imread Read image from graphics file.
    A = imread(FILENAME,FMT) reads a grayscale or color image from the file
    specified by the string FILENAME. FILENAME must be in the current 
    directory, in a directory on the MATLAB path, or include a full or 
    relative path to a file.
    
    The text string FMT specifies the format of the file by its standard
    file extension. For example, specify 'gif' for Graphics Interchange 
    Format files. To see a list of supported formats, with their file 
    extensions, use the IMFORMATS function. If imread cannot find a file 
    named FILENAME, it looks for a file named FILENAME.FMT.
 
    The return value A is an array containing the image data. If the file 
    contains a grayscale image, A is an M-by-N array. If the file contains
    a truecolor image, A is an M-by-N-by-3 array. For TIFF files containing
    color images that use the CMYK color space, A is an M-by-N-by-4 array. 
    See TIFF in the Format-Specific Information section for more
    information.
    
    The class of A depends on the bits-per-sample of the image data,
    rounded to the next byte boundary. For example, imread returns 24-bit
    color data as an array of uint8 data because the sample size for each
    color component is 8 bits. See the Remarks section for a discussion of  
    bitdepths, and see the Format-Specific Information section for more  
    detail about supported bitdepths and sample sizes for a particular
    format.
     
    [X,MAP] = imread(FILENAME,FMT) reads the indexed image in FILENAME into
    X and its associated colormap into MAP. Colormap values in the image 
    file are automatically rescaled into the range [0,1]. 
  
    [...] = imread(FILENAME) attempts to infer the format of the file
    from its content.
  
    [...] = imread(URL,...) reads the image from an Internet URL.  
   
    PPM  --  Portable Pixmap 
    
    Supported        Raw      ASCII (Plain)  Output        
    Bitdepths        Binary   Encoded        Class
    ------------------------------------------------
    up to 16-bit      x            -         uint8
    Arbitrary         -            x     
    
    RAS  --  Sun Raster 
    
    Supported    Output    
    Bitdepths    Class     Notes
    ----------------------------------------------------
     1-bit       logical   Bitmap  
     8-bit       uint8     Indexed
    24-bit       uint8     RGB (8-bit samples)
    32-bit       uint8     RGB with Alpha (8-bit samples)
     
    TIFF  --  Tagged Image File Format
    
    NOTE:  Images with a YCbCr photometric interpretation are converted to
    the RGB colorspace.  
    Please read the file libtiffcopyright.txt for more information.
 
    Example:
 
        imdata = imread('ngc6543a.jpg');
 
    See also imfinfo, imwrite, imformats, fread, image, double, uint8.
    imread 的参考页