Differences between imshow() and image() ?

Hi everyone,

As long as I know, there are two ways of displaying an image on matlab.

One way is by using imshow

imshow('image.png')

And the other one is by using imread() and image()

d=imread('image.png')
image(d)

What are the main differences and pro/cons between them? I do not see much difference but I can not tell.

The only differences I have noticed is that when I use imread() and then image(), the image (or images theirselves if I have putted overlaped) appear upside down

Thanks very much.

Answer 1

[Walter Roberson]

• imshow() detects whether the image is RGB or not. If it is not, then it detects the datatype and uses that to load a colormap (e.g., gray(2) for binary images)
• if the current axes is in its default position that it would get if it were the only axes, then imshow deletes the axes and creates a new one and resizes the figure to be just big enough for the image. I repeat, deletes the axes, not changes properties of the axes. You will lose all customizations you have done on the axes
• imshow() adds some tools to the window
• imshow() does not permit Alpha to be configured in the imshow() call: you need to record the handle and set the alpha properties for it
• image() does not resize the axes -- so if you have a small image in a larger axes, the image will end up magnified
• image() does not set any particular colormap -- so you get whatever colormap was in effect, which is often parula()
• image() when Hold is not on, will reset some axes properties, but will not delete the axes
• image() does not add tools to the window, and so is better suited for cases where the image is being used for text or logos or any carefully constructed user interface
• image() permits you to configure AlphaData during the image() call

[ErikJon Pérez Mardaras]

Thanks a lot for your reply.

That reply has led me to another related question:

What are the main differences between those and poping up an image with uifgiure?

I guess that with uifigure I can include more elements inside the window such as buttons, other windows, other images, and so on.

Am I right? There is more?

Thanks

[Walter Roberson]

uifigure() is very similar to figure() but with a different implementation technology. It does not display any graphics by itself: it only creates a window that you can use to draw inside.

[ErikJon Pérez Mardaras]

Thanks

[cui,xingxing]

I add a point for compare:

imshow is a high-level function with relatively large overhead and is generally not used inside loops, whereas image is a low-level function with better performance.