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Range Finding - Parallax Calculations
helvick
post Dec 3 2005, 02:46 PM
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Just setting this up as a topic.

Rodolfo (RNeuhaus) has pointed out that he gets hard to interpret results when using Joe Knapp's online Parallax Calculator.

I don't know the formulas behind this calculator but have been trying to work out my own.

Taking (for now) that the geometries are as follows:
Pancam, 16deg FOV, 300mm separation between L and R and a 1deg toe in.
Navcam, 45deg FOV 200mm separation between L and R and no toe in.

Parallax formula - Distance to object=half the Camera Separation/Tan angle between the point in the L+R images. (I don't think this is 100% correct for parallel cameras but it should be good to a close first approximation provided things aren't too close).

Sticking with the Navcam which doesn't have any toe in my gut feel for things is that distant objects should be affected less by parallax. So taking Joe Knapps sample calculation for Navcam. Left Camera 512 pixels, right camera 500 pixels.
Separation is 12 pixels so the parallax angle is 12 * (45deg/1024pixels) = 0.527344 degrees.
The distance should then be (100mm/tan(0.527344 deg).
That gives me 108m.
Joe Knapps calculator gives me 20.3m.

The Pancam is a bit trickier because of the toe in angle, I need to think a bit more about whether my default assumption that it can be compensated for by simply subtracting 64 pixels from the right image position is valid or not.

Anyway - something is amiss in either my numbers or Joe Knapp's calculator. Anyone out there able to throw some light on this.
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djellison
post Mar 3 2006, 11:58 AM
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Alternatively, just write a convertor for the released data which includes meshes smile.gif

Oh yeah- hint hint smile.gif

Doug
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Posts in this topic
- helvick   Range Finding - Parallax Calculations   Dec 3 2005, 02:46 PM
- - RNeuhaus   Good to hear from you. I have already written a no...   Dec 5 2005, 03:47 PM
- - helvick   Rodolfo, The author (Joe Knapp) posts here as jmk...   Dec 5 2005, 07:53 PM
- - mars_armer   QUOTE (helvick @ Dec 3 2005, 06:46 AM)Taking ...   Dec 5 2005, 11:40 PM
- - RNeuhaus   Helvick, Thanks for the response. However I still ...   Dec 6 2005, 03:17 AM
|- - jamescanvin   Just jumping in as I'm mentioned: QUOTE (RNeu...   Dec 6 2005, 04:24 AM
|- - helvick   QUOTE (jamescanvin @ Dec 6 2005, 05:24 AM)Jus...   Dec 6 2005, 10:31 AM
|- - jmknapp   My parallax calculator could sure use some improve...   Dec 6 2005, 11:57 AM
|- - algorimancer   QUOTE (jmknapp @ Dec 6 2005, 06:57 AM)... The...   Feb 11 2006, 04:02 PM
|- - jmknapp   Interesting that taking all the rotations into acc...   Feb 14 2006, 09:49 PM
- - Tesheiner   Rodolfo, just an additional reminder: You will se...   Dec 6 2005, 07:40 AM
- - algorimancer   I have just completed a new 3D MER RangeFinder: ...   Mar 2 2006, 01:51 AM
|- - jmknapp   QUOTE (algorimancer @ Mar 1 2006, 08:51 P...   Mar 2 2006, 12:21 PM
|- - algorimancer   QUOTE (jmknapp @ Mar 2 2006, 06:21 AM) Ve...   Mar 2 2006, 01:31 PM
- - djellison   I know JB's out the office at the moment, but ...   Mar 2 2006, 01:50 PM
|- - algorimancer   QUOTE (djellison @ Mar 2 2006, 07:50 AM) ...   Mar 2 2006, 03:29 PM
- - MaxSt   Thanks, algorimancer. I was using these simple fo...   Mar 2 2006, 10:14 PM
|- - algorimancer   QUOTE (MaxSt @ Mar 2 2006, 04:14 PM) Than...   Mar 3 2006, 01:48 AM
- - algorimancer   While it's only a day since the initial announ...   Mar 3 2006, 02:02 AM
|- - Tesheiner   Thanks for this new tool, algorimancer. QUOTE (al...   Mar 3 2006, 08:36 AM
- - MaxSt   Batch Process seems to work fine, that's very ...   Mar 3 2006, 03:59 AM
|- - algorimancer   QUOTE (MaxSt @ Mar 2 2006, 09:59 PM) Batc...   Mar 3 2006, 12:15 PM
|- - jmknapp   QUOTE (algorimancer @ Mar 3 2006, 07:15 A...   Mar 3 2006, 02:42 PM
||- - algorimancer   QUOTE (jmknapp @ Mar 3 2006, 08:42 AM) .....   Mar 3 2006, 04:53 PM
||- - jmknapp   QUOTE (algorimancer @ Mar 3 2006, 11:53 A...   Mar 4 2006, 02:05 PM
|- - MaxSt   QUOTE (algorimancer @ Mar 3 2006, 07:15 A...   Mar 3 2006, 07:10 PM
||- - algorimancer   QUOTE (MaxSt @ Mar 3 2006, 01:10 PM) That...   Mar 3 2006, 08:44 PM
||- - MaxSt   QUOTE (algorimancer @ Mar 3 2006, 03:44 P...   Mar 3 2006, 10:23 PM
||- - algorimancer   QUOTE (MaxSt @ Mar 3 2006, 04:23 PM) That...   Mar 3 2006, 10:55 PM
|- - Tesheiner   QUOTE (algorimancer @ Mar 3 2006, 01:15 P...   Mar 3 2006, 08:55 PM
|- - MaxSt   QUOTE (Tesheiner @ Mar 3 2006, 03:55 PM) ...   Mar 3 2006, 11:12 PM
|- - algorimancer   QUOTE (MaxSt @ Mar 3 2006, 05:12 PM) That...   Mar 4 2006, 12:31 AM
- - djellison   Then once you have a fairly populated array of val...   Mar 3 2006, 08:40 AM
- - MaxSt   Actually, that's exactly what I'm playing ...   Mar 3 2006, 10:23 AM
- - djellison   Alternatively, just write a convertor for the rele...   Mar 3 2006, 11:58 AM
- - MaxSt   No, I'm still using my simple formulas, I...   Mar 4 2006, 03:01 AM
|- - algorimancer   QUOTE (MaxSt @ Mar 3 2006, 10:01 PM) I...   Mar 4 2006, 04:02 PM
- - CosmicRocker   Holy Moses! I wasn't expecting the synerg...   Mar 4 2006, 06:58 AM
- - djellison   I've been waiting 2 years for files like that....   Mar 4 2006, 07:49 AM
|- - helvick   I started this thread just looking to get a slight...   Mar 4 2006, 08:35 AM
- - djellison   15MB 720p WMV-HD movie of it http://www.unmannedsp...   Mar 4 2006, 11:40 AM
|- - helvick   QUOTE (djellison @ Mar 4 2006, 11:40 AM) ...   Mar 4 2006, 11:54 AM
|- - algorimancer   QUOTE (djellison @ Mar 4 2006, 06:40 AM) ...   Mar 4 2006, 03:40 PM
|- - djellison   QUOTE (algorimancer @ Mar 4 2006, 03:40 P...   Mar 4 2006, 04:11 PM
- - djellison   Now extrapolate to the complete traverse from the ...   Mar 4 2006, 12:00 PM
- - algorimancer   Soliciting opinions for additional development ......   Mar 4 2006, 04:45 PM
- - MaxSt   Nice video, Doug. Gives me confidence that automat...   Mar 4 2006, 08:49 PM
|- - algorimancer   QUOTE (MaxSt @ Mar 4 2006, 03:49 PM) algo...   Mar 4 2006, 11:43 PM
- - algorimancer   For those of you into that whole command line thin...   Mar 8 2006, 03:18 AM
- - Tesheiner   Great tool, algorimancer. One feature I would rea...   Mar 8 2006, 02:24 PM
|- - djellison   QUOTE (Tesheiner @ Mar 8 2006, 02:24 PM) ...   Mar 8 2006, 03:01 PM
|- - algorimancer   QUOTE (Tesheiner @ Mar 8 2006, 08:24 AM) ...   Mar 8 2006, 08:21 PM
- - algorimancer   Okay, the MER RangeFinder and Photogrammetry appli...   Mar 9 2006, 02:35 AM
- - algorimancer   Here is a significant new version of the MER Photo...   Mar 15 2006, 03:12 AM
- - algorimancer   Updated AlgorimancerPG photogrammetry and rangefin...   Mar 16 2006, 05:29 PM
|- - dilo   Nice software. However, I have impression that err...   Mar 16 2006, 11:10 PM
|- - algorimancer   QUOTE (dilo @ Mar 16 2006, 05:10 PM) Nice...   Mar 16 2006, 11:47 PM
|- - helvick   QUOTE (algorimancer @ Mar 16 2006, 11:47 ...   Mar 17 2006, 01:34 AM
|- - dilo   Thanks for the infos, algorimancer. About the err...   Mar 17 2006, 06:56 AM
|- - algorimancer   QUOTE (dilo @ Mar 17 2006, 12:56 AM) Your...   Mar 17 2006, 01:58 PM
- - algorimancer   Okay, per dilo's suggestions, here is an updat...   Mar 18 2006, 03:22 PM
|- - dilo   Very good job, algorimancer! Cross pointer is...   Mar 18 2006, 07:16 PM
|- - algorimancer   QUOTE (dilo @ Mar 18 2006, 01:16 PM) A sm...   Mar 18 2006, 08:49 PM
- - MaxSt   Very very nice program. And very easy to use. One...   Mar 18 2006, 08:01 PM
|- - algorimancer   QUOTE (MaxSt @ Mar 18 2006, 02:01 PM) Ver...   Mar 18 2006, 08:59 PM
- - algorimancer   Here it is, per MaxSt's and Dilo's suggest...   Mar 18 2006, 11:35 PM
|- - dilo   GREAT! You do not waste time... I was reading ...   Mar 19 2006, 07:30 AM
- - Tesheiner   Thanks a lot, algorimancer! I didn't have...   Mar 19 2006, 11:25 AM
- - CosmicRocker   This really is a sweet application. I had always...   Mar 21 2006, 06:21 AM
- - algorimancer   I just posted the next AlgorimancerPG update (vers...   Mar 24 2006, 03:45 AM
- - Tesheiner   Thanks for this new update! And here is somet...   Mar 24 2006, 09:17 AM
|- - algorimancer   QUOTE (Tesheiner @ Mar 24 2006, 03:17 AM)...   Mar 24 2006, 01:44 PM
- - MaxSt   I understand that left and right rays only in theo...   Mar 25 2006, 06:12 AM
|- - algorimancer   QUOTE (MaxSt @ Mar 25 2006, 12:12 AM) I u...   Mar 25 2006, 02:57 PM
|- - MaxSt   QUOTE (algorimancer @ Mar 25 2006, 09:57 ...   Mar 25 2006, 09:56 PM
|- - algorimancer   QUOTE (MaxSt @ Mar 25 2006, 03:56 PM) Oh,...   Mar 26 2006, 12:59 AM
|- - MaxSt   QUOTE (algorimancer @ Mar 25 2006, 07:59 ...   Mar 26 2006, 02:31 AM
|- - algorimancer   QUOTE (MaxSt @ Mar 25 2006, 08:31 PM) No,...   Mar 26 2006, 04:11 PM
|- - MaxSt   QUOTE (algorimancer @ Mar 26 2006, 11:11 ...   Mar 26 2006, 08:21 PM
|- - algorimancer   QUOTE (MaxSt @ Mar 26 2006, 02:21 PM) Tru...   Mar 26 2006, 09:00 PM
|- - Steve   QUOTE (algorimancer @ Mar 26 2006, 05:00 ...   Apr 22 2006, 10:31 PM
|- - algorimancer   QUOTE (Steve @ Apr 22 2006, 05:31 PM) I s...   Apr 24 2006, 01:48 PM
- - Tesheiner   Algorimacer, Speaking of "improvements...   Apr 22 2006, 07:55 PM
- - algorimancer   QUOTE (Tesheiner @ Apr 22 2006, 02:55 PM)...   Apr 26 2006, 12:44 AM
- - mhoward   Actually MMB doesn't access the SQL server dir...   Apr 26 2006, 01:43 AM
|- - algorimancer   QUOTE (mhoward @ Apr 25 2006, 08:43 PM) ....   Apr 26 2006, 01:49 AM
|- - helvick   QUOTE (algorimancer @ Apr 26 2006, 01:49 ...   Apr 26 2006, 02:47 PM
- - Tesheiner   QUOTE (algorimancer @ Apr 26 2006, 02:44 ...   Apr 26 2006, 08:58 PM


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