[MATLAB GUI] 求助：图像装载不出来怎么办？

[cathjj05]

用了一个显示图像的界面，按下按钮后应该显示图像，运行后显示
Error using ==> imread
Unable to determine the file format
该如何改imread函数？

以下是该函数：

function varargout = LoadPush_Callback(h, eventdata, handles, varargin)%回调函数


global im_original im_noised im_filtered %global:定义全局变量
[filename, pathname] = uigetfile('*.bmp;*.pgm;*.tif;*.jpg;*.*', 'Load input image');%读取文件
if isequal(filename,0) | isequal(pathname,0)
disp('User pressed cancel')%disp：显示
else
disp(['User selected ', fullfile(pathname, filename)])
end
im_original=imread(filename);
set(handles.Or_image,'HandleVisibility','OFF');%handles:句柄
set(handles.Out_image,'HandleVisibility','OFF');
%set(handles.Denoised_image,'HandleVisibility','OFF');
set(handles.Or_image,'HandleVisibility','ON');
axes(handles.Or_image);
imshow(im_original);
colormap(gray(256));
axis equal;%让图像的大小与框架吻合
axis tight;%同上
axis off;%把数轴关掉
set(handles.Or_image,'HandleVisibility','OFF');
set(handles.Or_image,'XTickLabel',' ','YTickLabel',' ');