Re: Displaying an animation / "movie"

[Jeff Miller]

Robert,
When I do imshow on a matrix, it displays an image where each number in
the matrix corresponds to the intensity (or color) of the pixel in the
image with the corresponding indices (e.g. (0,0), (0,1), ...). So, this
would display a square:

x = [0 0 0 0 0
     0 1 1 1 0
     0 1 0 1 0
     0 1 1 1 0
     0 0 0 0 0];
imshow(x);

What I'd like to do is take a series of such matrices that represent
moving objects and display them sequentially like a movie. For example,
this would show that square moving downward (looping around the edges):

for i=1:100
    x = shift(x, 1);
    imshow(x);
end


This works in Matlab, but I can't seem to make it work in Octave. I
could probably use the approach that the other Robert mentioned (saving
all images to files, making a movie from the files, then displaying the
movie) but I'm hoping there's a simpler way.

(By the way, I'm using this for computer vision stuff, so I can visualize what's going on...)

Thanks for your help,
Jeff

On 5/4/06, Robert A. Macy <address@hidden> wrote:

Jeff,

I don't know what imshow does.  On both my machines it does
strange things [Win 98 and WinXP ]
>> imshow(rand(50,50));drawnow;

However try
>> gsplot rand(100,100);

That plots a matrix and you can move it around with your
mouse forbetter viewing.

but doubt that's what you were after

             - Robert -

On Wed, 3 May 2006 21:04:50 -0400
"Jeff Miller" <address@hidden > wrote:
> Robert,
> Thanks for the function. It works great for animated line
> plots, but I
> still can't figure out how to show a series of images.
>
> You said in the for loop I could use:
> gsplot matrix
>
> I have to admit I'm not very familiar with gnuplot, but I
> couldn't
> find any references to such a command that would display
> an image.
> What would be the exact command?
>
> I have Gnuplot 4.0 ... maybe I need 4.1 to support the
> functionality
> you're describing?
>
> Thanks,
> Jeff
>
> On 5/2/06, Robert A. Macy < address@hidden> wrote:
> > Jeff,
> >
> > I ran across just such a need and wrote this function
> for
> > plotting...
> >   plotmovie.m
> >
> > but you could modify it inserting
> > >> gsplot matrix;
> > in the for loop and get the same effect for displaying
> a
> > matrix.
> >
> >             - Robert -
> >
> > On Tue, 2 May 2006 16:46:50 -0400
> >  "Jeff Miller" <address@hidden> wrote:
> > > Hi,
> > > I would really like to use Octave, but there is an
> > > important feature I need,
> > > which so far I haven't figured out how to do:
> > >
> > > In Matlab I can do:
> > > for i=1:100; imshow(rand(100,100)); drawnow; end;
> > >
> > > ...and it rapidly displays a series of matrices in
> the
> > > same window, like an
> > > animated movie. In Octave, when I try this, it opens
> 100
> > > ImageMagick
> > > windows, with each one containing a separate image.
> > >
> > > Is there a way to get the desired behavior in Octave?
> (or
> > > any other
> > > open-source numerical computation package?)
> > >
> > > Thanks for any help!
> > > Jeff
> >
> >
> >