Alternatively, bisect the segment S2 and draw a line from alpha to that point.
--- Frank C. Wimberly 140 Calle Ojo Feliz, Santa Fe, NM 87505 505 670-9918 Santa Fe, NM On Fri, Jul 22, 2022, 2:38 PM Stephen Guerin <stephen.gue...@simtable.com> wrote: > Yes, that's what I was calling "splitting the slanted face" this morning. > Keep going... :-) > _______________________________________________________________________ > stephen.gue...@simtable.com <stephen.gue...@simtable.com> > CEO, https://www.simtable.com <http://www.simtable.com/> > 1600 Lena St #D1, Santa Fe, NM 87505 > office: (505)995-0206 mobile: (505)577-5828 > > > On Fri, Jul 22, 2022 at 2:29 PM Frank Wimberly <wimber...@gmail.com> > wrote: > >> Drop a perpendicular from the alpha vertex to S2. >> >> --- >> Frank C. Wimberly >> 140 Calle Ojo Feliz, >> Santa Fe, NM 87505 >> >> 505 670-9918 >> Santa Fe, NM >> >> On Fri, Jul 22, 2022, 1:34 PM Stephen Guerin <stephen.gue...@simtable.com> >> wrote: >> >>> Today at Friam, I showed a small problem I was working on in >>> photogrammetry. Attached is a Netlogo visualization of the geometry of the >>> system. >>> >>> The problem is: given an image where we know two star coordinates (RA, >>> DEC), solve for the field of view of the image. We can get the spherical >>> angle between the stars (alpha) and we know the principal point and two UV >>> coordinates in the image. These create a right triangle pyramid and I want >>> to solve for the height X (focal length). Here's a diagram. >>> >>> [image: rightTrianglePyramid.jpg] >>> Law of Cosines can get all the interior angles of the bases with S1, S2, >>> S3. >>> >>> >>> >>> _______________________________________________________________________ >>> stephen.gue...@simtable.com <stephen.gue...@simtable.com> >>> CEO, https://www.simtable.com <http://www.simtable.com/> >>> 1600 Lena St #D1, Santa Fe, NM 87505 >>> office: (505)995-0206 mobile: (505)577-5828 >>> >>
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