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Re: Quaternions to Euler Angles [message #39340] Thu, 13 May 2004 23:00
Craig Markwardt is currently offline  Craig Markwardt
Messages: 1869
Registered: November 1996
Senior Member
"Rick Towler" <tsehai@comcast.net> writes:
> "Graham" wrote...
>
>> I was trying to use Rick's quaternion code which pitch about x, yaw
>> about y, and roll about z but x and z are swapped. My naive was to
>> simply swap the pitch and roll on input/output but I cannot seem to
>> reproduce the given tables:
>
> Hi Graham,
>
> Yeah, my quaternion code was written specifically for my camera and I'm not
> too surprised it didn't work out. :(
>
> Have you tried Craig Markwardt's quaternion routines?
>
> http://astrog.physics.wisc.edu/~craigm/idl/idl.html

Thanks for the plug. However, I don't have any specialized routines
for roll pitch and yaw. In fact, these are defined so many ways, and
with so many sign conventions, that I believe it's nearly impossible
get the one that Graham is interested in. Unfortunately I have the
forward transformation (QTEULER) but not the inverse.

One possibility is is for Graham to make a direction cosine matrix
(with QTMAT) and then decide how to decompose it from there.

Good luck!
Craig

--
------------------------------------------------------------ --------------
Craig B. Markwardt, Ph.D. EMAIL: craigmnet@REMOVEcow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
------------------------------------------------------------ --------------
Re: Quaternions to Euler Angles [message #39341 is a reply to message #39340] Thu, 13 May 2004 21:25 Go to previous message
Rick Towler is currently offline  Rick Towler
Messages: 821
Registered: August 1998
Senior Member
"Graham" wrote...

> I was trying to use Rick's quaternion code which pitch about x, yaw
> about y, and roll about z but x and z are swapped. My naive was to
> simply swap the pitch and roll on input/output but I cannot seem to
> reproduce the given tables:

Hi Graham,

Yeah, my quaternion code was written specifically for my camera and I'm not
too surprised it didn't work out. :(

Have you tried Craig Markwardt's quaternion routines?

http://astrog.physics.wisc.edu/~craigm/idl/idl.html

-Rick
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