RE: [Vxl-maintainers] Re: Vxl-maintainers digest, Vol 1 #150 - 4 msgs

[Joseph M. <mu...@le...>]

I agree with Brendan that that reusing blocks of image memory is a good
idea in interfacing directly with live video cameras.  There is no
reason to copy the data into a second image buffer, but merely have the
image be a "view" of the data.
Joe 
-----Original Message-----
From: vxl...@li...
[mailto:vxl...@li...] On Behalf Of
Brendan McCane
Sent: Sunday, September 22, 2002 4:44 PM
To: vxl...@li...
Subject: [Vxl-maintainers] Re: Vxl-maintainers digest, Vol 1 #150 - 4
msgs



> Most usage of vil_image does not go further than vil_load(),
vil_save(),
> i.width(), i.height(), i.get_section() and i.put_section().
> There should (and will) be backward compatibility for those.
> 
> So the question is rather: who is using or assuming more than that?
> E.g., who is assuming an image loaded with vil_load() cannot have more
than
> 1 plane *and* more than 1 component?  Who is using some sort of pixel
> "pointer arithmetic" and assuming that e.g. pixel i(1,0) has address
> which is 1 more than pixel (0,0)?
> 
> 
> 	Peter.

G'day,

I assume that the underlying representation is in fact contiguous,
especially in relation to vil_memory_image_of's. This is important when
dealing with frame grabbers for example. To get a frame grabbed image
into memory quickly, I want to be able to directly access the memory so
the frame grabber can simply write straight to that memory. In fact, I
did modify vil_memory_image_of and the impl version so that one of these
images could be created with previously allocated memory. Check out
oul/oufgl/* for some examples of how this gets used.

-- 
Cheers,

Brendan.
------------------------------------------------------------------------
----
Brendan McCane                            Email:  mc...@cs...
Department of Computer Science            Phone:  +64 3 479 8588/8578.
University of Otago                       Fax:    +64 3 479 8529
Box 56, Dunedin, New Zealand.             There's only one catch - Catch
22.




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