Saving Image on Axes component to File

Is there a reason why an image that is displayed on an axes1 is not saving to file via:

I=double(getimage(handles.axes1));
class I
figure
imshow(I,[])
imwrite(I,'C:\mtf.bmp')

the class of I is returning char?

Thanks

Answer 1

[Jan]

class I

is the short form of:

class('I')

so it is the character array containing an uppercase 'I'. Try:

class(I)

Now the problem, that the file is not written. Do you get an error message? Perhaps the one, that you do not have write permissions in C:\ ? Then try to save the file to another folder you have write permissions to.

[Jason]

Hi, it saves to disk OK, but its just blank as attached.

<<

>>

[Jan]

Blanks?! It is an image file filled with one single color. Where do you see "blanks" - which are characters. And what do you expect? What does the image contain? Are you sure, that the conversion to double is useful?

[Jason]

This is the picture that 'Im trying to save.

Its a tiff image (uint16), and you are correct I don't need the double.

When I save it as a tif it works, but if I try to save as jpg or bmp it gives the blank image shown earlier.

I was getting an error that to save as jpg or bmp, the data needs to be double. After converting, I still only save an "empty" image as shown previously.

I=double(I);
imwrite(I,'C:\mtf.bmp')
imwrite(I,'C:\mtf.jpg')

[Jan]

The image is not empty, but white - correct? Converting the UINT16 values to doubles means for an image, that all values > 1 are clipped to 1.0, which means a white pixel. Try:

I = double(I/max(I(:)));

or

I = double(I / maxint('uint16'));

Using im2double considers the scaling also.

[Jason]

Hi Jan, only the im2double worked.for the other two:

I = double(I/max(I(:)));

Gave the white image again, and

I = double(I / maxint('uint16'));

Gave an error that no maxint exists. thanks jason