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View Full Version : CG Texture Conservation Help: Videogrammetry To Save The Planet!!!


mattbjerregaard
08-27-2008, 11:50 AM
Hi all,

Intro: I am an editor/compositor and camera director primairily but am currently involved in helping out voluntarily in an underwater conservation project which is unfunded and involves the monitoring of a specific extremely important coral reef in the Philippines. I am also a professional diver with many years experience.

What I am trying to achieve is a massive texture stitch/record of an area of coral. My camera rig consists of a HDV camera with levels mounted so as its Z axis is as fixed as possible, perpendicular to the sea bed, and Y and X remain as level possible also. I have rigged a trio of crossing lasers to give me a fixed distance from the sea bed. Basically I swim or use a propulsion vehicle over a massive area, and record the corals on the bottom in matching, 'stitchable' stripes/strips.

So far I need to repeat this process about every month for the entire area (about 2 square km, it is massive) and I am manually sitching the frames together which takes far too long. This is incredibly time consuming and very inaccurate. The portion of the image I am concerned with is the centre strip. I need to automate the process more... I would look at buying a copy of 2d3 Tacitview but it is $$$

I have had a few ideas... They are probably crazy... Maybe I am barking up the wrong tree but I need to create in Maya something like a slitscan technique (Zbig et al) and bake out the texture.

Basically I can remove lens distortion and what I need to do I think is track the camera in something like Boujou then take the data and bake it to a single surface. I don't know how to do this for a texture using multiple frames from a camera projection.

Or in maya live, track a frame, solve it, bake the centre strip, repeat until the image sequence is completed. In effect you are baking the film back not the sea bed... headache

CONCLUSION

Any offers extremely grateful.

The end product does not need to be at an FX level of realism, the data just needs to be there.

Please excuse my ignorance and remember that this is for an extremely worthy cause.
True environment mapping.

Many thanks for reading...

EricChadwick
09-02-2008, 02:16 AM
Sounds like what they do to extract color data from 3d scanning, by basically stitching together the vertical centerline from each frame of video, into a single wide image.

Some info here:
http://www.sjbaker.org/wiki/index.php?title=A_Simple_3D_Scanner

vsions
09-04-2008, 05:50 PM
If you have multiple images that need to be stitched together, you should use photomerge in photoshop, its quite effective. I created a short tutorial on it for creating a human face texture but its actually designed more for panoramas similar to what you are doing

http://forums.cgsociety.org/showthread.php?f=46&t=671449


hope this helps

Dennis

Marcel
09-05-2008, 12:34 PM
I think it would be useful if you posted a few images from the sequence you want to stitch. (And perhaps the end result) It will make it much easier to understand what you want to achieve.

Have you tried panorama stitchers such as Gigapan or PTGui? They are limited to a 360x180 canvas, but with some cheating it might work. If the footage has enough recognizable patterns then PTGui does a miraculous job stitching it into a seamless whole.

Marcel
09-05-2008, 12:38 PM
I would look at buying a copy of 2d3 Tacitview but it is $$
Maybe you can arrange sponsorship for a license of Tactiview? It sounds like a worthwile project.

softdistortion
09-11-2008, 07:24 PM
My 2 cents :)
Tracking a series of frames like you are shooting I've found you have to stitch manually or the results are not good to very bad. You get better results shooting with a zoom from further back and panning across the large area..

A 10 or 12 megapixel DSLR shooting from a fixed point above the subject and try to keep your pan motion centered around your camera body.

mattbjerregaard
09-11-2008, 09:31 PM
Hi folks and many thanks for all your suggestions so far;

1. I will try to upload some images soon.
2. I glide a HD camera above the seabed with a laser guided rig so as to pan smoothly and with minimal distortion of axes. You should see the rig... its pretty good

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