PanoTools:
Re: {HTML} New tutorial - running the optimizer
JD Smith 2004-May-13 00:25:13
On Wed, 2004-05-12 at 13:40, John Houghton wrote:
> I've made a stab at producing a tutorial to help beginners understand
> the optimizer a bit better. It's especially aimed at helping those
> who have so far relied on PTAssembler's auto-optimize option or
> PTGui's wizard for getting their projects stitched successfully. In
> particular, some people seem to have great difficulty in
> understanding how t1 and t2 points work. It has turned out a bit
> longer than I planned, but I hope the background information provided
> will go some way to helping people on their way to being fully
> fledged stitchers. Any comments welcomed.
>
> http://homepage.ntlworld.com/j.houghton/optitute.htm
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 ---------------------~-->
Yahoo! Domains - Claim yours for only $14.70
http://us.click.yahoo.com/Z1wmxD/DREIAA/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/