Why "imshow" function in GUI so slow?

I have a GUI program which shows 10 images using "axes(handles.axes1);" and "imshow(f);" function. But when I run it, the 10 images appear sequentially but not at the same time. There's a delay between each image showing. What's wrong within it?

Answer 1

[Walter Roberson]

If you must use imshow(), then skip the axes() call and use

imshow(f, 'Parent', handles.axes1);

However, if you do not need imshow() specifically (e.g., you do not need the tools that it adds), then use

imagesc(f, 'Parent', handles.axes1);

[Yang]

yes. your suggestion is quite good!! but one more question, the image shown by imagesc is by blue and red. My image is binary image 0 and 1. How can I convert blue and red to black and white?

[Yang]

and also, imagesc shows the axis. I can't let it not show by using axis off. how to solve it?

[Yang]

problem solved. thank you!

[Image Analyst]

You likely had a grayscale image and for some strange reason imagesc, unlike imshow, applies some weird colormap. To undo that you also need to call colormap(gray(256)) right after you call imagesc.

Answer 2

[Image Analyst]

Call "cla reset" before each call to imshow. Otherwise all the images "stack up" in the control and it will slow down each additional time imshow is called. cla reset clears out any prior images.

[Yang]

I tried "cla reset" before each imshow but the result is still slow.

[Image Analyst]

I'm still not sure what your question is. Is it that you want all 10 images to flash by sequentially and almost instantaneously (because you say it's too slow), OR is it that they appear sequentially instead of at the same time? If you want them all at the same time, use the montage() function in the Image Processing Toolbox to make a mosaic of all your images in one huge single image.

[Gerald]

Thank you so much for your "cla reset" answer!! Images are now displayed much faster without truncation!! Thx!

[Image Analyst]

You're welcome. Glad my suggestion was helpful to you. Can you go ahead and "Vote" for my answer then?

[DEBANJAN DEBNATH]

I want it to look like a vedio with high frame per second. Can u help?

[Image Analyst]

@DEBANJAN DEBNATH - not enough information. You want what to "look like" a video? Please explain in your own, new discussion thread (not here).

Answer 3

[Jan]

Nothing is wrong. Displaying an image needs some time.

You can use image and let drawnow trigger the screen update of the figure after all images have been inserted.

I assume posting the relevant part of the code and the size of the images might reveal other problems.

[Yang]

yes but my image is binary image, how can I show it by using image

[Jan]

Please post a code which reproduces the problem. I do not see a problem for using IMAGE for a binary image. But perhaps I do not know exactly, what a binary image is...