PanoTools:
Re: {HTML} New tutorial - running the optimizer
John Houghton 2004-May-13 08:36:05
Thanks for your comments. I deliberately did not go into details
about projections because this is generally covered in beginners'
tutorials already. I did consider that having a table listing their
straight line preservation characteristics might be helpful. I think
I will probably do that. Thanks for the interesting observation that
straight lines in rectilinear images are projections of great
circles. This is obvious when you realise that the lines correspond
to the intersection of two planes, but I had not thought of it in
those terms.
John
--- In #removed#, JD Smith <#removed#> wrote:
> Very nice tutorial. A couple of issues and questions:
>
> I had forgotten that t1/t2 attempts to make lines straight in the
image
> space of the final panorama, rather than fixing them as lines of
> longitude/latitude when mapped onto the sphere. It might be worth
> pointing out sooner that the rectilinear output, while restricted to
> <180 degrees (and <100 degrees in practice) has the nice feature
that
> straight lines (well, actually great circles) are preserved as
straight
> in the final image output, and thus even the "t3+" lines should
work for
> these projections, and t2 lines on any horizontal feature should
work as
> well. For cylindrical projections, any vertical line will be
preserved,
> but only the central horizontal will remain flat (this is usually
chosen
> to be the horizon, as you point out, but it doesn't have to be: the
main
> point is there can be only one). It's all in there if you dig, but
an
> earlier, separate section comparing the projections would be useful.
>
> I'd actually like to see someday an area-preserving projection for
full
> 360x180 panoramas, like the Lambert cylindrical equal-area
projection,
> which I think would look nicer than straight cylindrical (which is
> rarely used in map projections).
>
> JD
------------------------ Yahoo! Groups Sponsor ---------------------~-->
Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar.
Now with Pop-Up Blocker. Get it for free!
http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/.Cr1lB/TM
---------------------------------------------------------------------~->
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/PanoTools/
<*> To unsubscribe from this group, send an email to:
#removed#
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/