How can I solve that imshow don't show image ?

I just find out that imshow shows nothing in my Matlab. I used imwrite to save the same data as .jpg, then check it by opening it in the folder, the result is correct. What happened to imshow and how to fix it?

[Jan]

The question is far too general to be answered. Please explain any details: 1. Did it work before? 2. If it did, what has happend since it worked? 3. Did you modify the code of imshow on purpose or by accident? 4. Did you shadow and important built-in function, such that your imshow fails? 5. What exactly does "shows nothing" mean? An empty window? No Window? A transparent window?

For a suggestion of a fixing, you have to find out at first, what broke it.

[Cody Chan]

1.Yes, it worked really normally 2.It worked when the following command

fig=imread('hw3_img.jpg');imshow(fig);

3.I didn't modify the imshow code.

4.Sorry I don't get it.

5.The picture

is "shows nothing", and the left half is the same data imwrite works.

[Geoff Hayes]

Cody - your code is reading a file named hw3_img.jpg but you are showing the a picture for a file named face.png. What does hw3_img.jpg look like outside of MATLAB? Can you attach that file to this question?

[Jan]

"Shadowing a builtin function" means, that you create a function, which has the same name as a builtin function. E.g.:

function imshow(varargin)
a = 1+2;

Afterwards calling imshow will not work anymore. And this problem can concern any other function, which is called inside imshow. Shadowing builtin functions can have arbitrary effects, so if you observe a strange behavior, check if you caused this by shadowing.

[Cody Chan]

Sorry for confusing, "imshow" worked well last time. After few days when I started the other project, "imshow" shows nothing. No matter what picture for imread.

I understand what shadowing means, but I didn't have the same function named "imshow".

[Jan]

@Cody: It need not be imshow directly, but it can matter all other functions, which are called from imshow.

Answer 1

[Image Analyst]

Like Jan said, you're probably overwriting a function in one of your scripts. I believe imshow() calls image() internally, and lots of beginners call their image variable "image" which might prevent imshow from working because it will try to use your variable rather than the function.

Like Geoff said, attach your if you need more help.

[Cody Chan]

Ok, but I'm not sure where the problem is. Is installing MATLAB again the only way out?

[Image Analyst]

No. You could call tech support. What does this say?

>> which -all image
>> which -all imshow

[Cody Chan]

>> which -all image
built-in (C:\Program Files\MATLAB\R2017b\toolbox\matlab\specgraph\image)

>> which -all imshow
C:\Program Files\MATLAB\R2017b\toolbox\matlab\images\imshow.m

[Image Analyst]

Your functions are not shadowed. The only way to solve it now is if you give us your image and code, or to call tech support.

[Arusha cse]

Hi, have you found a solution to this? I am facing the same issue and my functions are not shadowed.

[Image Analyst]

Arusha, start your own question but only after you read this link so we don't waste time going back and forth to get all the info we need to solve your situation. For example, here you dodn't show any error messages or screenshots of what your call to imshow() actually shows. Maybe you have a floating point image outside the range of 0-1 and it's just all black or white because you forgot to use [] when you called imshow.

imshow(doubleImage, []);

I have no idea because you didn't give us enough information to help you. You only asked Cody who hasn't been seen here in over 2 years.