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Old May 20, 2005, 09:22 PM
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Panorama Pictures for Reflex XTR scenery.

Has anybody here created a panorama bmp for Reflex XTR scenery? How did you do it (equipment, software, etc)?

Producing an 8120x3060 pixel .bmp file isn't much of a problem. It's taking good pictures to make it that seems to be the real problem. Has anybody been successful using ordinary cameras instead of the specialized panorama variety?

Let's see your 82x31 thumnail.

Hank

HOW TO :

When Reflex XTR is installed, it creates a set of folders. The top folder is named RefleXTR. One of the sub folders is called WLP. WLP contains the sceneries used by XTR. If you want to add your own scenery, create a new folder within the WLP folder.

Locate the WLP/Modellflugverein Grosse Heide 73.eV scenery folder and open it. Copy the files: S2.wlp and S2_1a.bmp into the new scenery folder you just created. These files define the 3D geometry of the scenery. Until we get a scenery editor from Reflex, we have to use an existing 3D definition. This particular set is reasonably flat. Using a graphics program, you can make the S2_1a.bmp file all black. It represents the objects which mask a vehicle flying behind them.

Create a .jpg or .bmp image file precisely 8160 pixels wide by 3060 pixels high and put it into your new scenery folder. Name it S2.jpg or S2.bmp. The horizon line in this image file should be at precisely 2040 pixels from the top. 8160 pixels represents 360 degrees of horizontal view, 3060 represents 135 degrees of view down from the zenith, and 2040 represents 90 degrees down from the zenith.

When you run XTR, the new scenery folder’s name should appear in the scenery list when selecting scenery. Click on the new scenery and XTR will create a panorama of the S2.jpg or bmp file which will then appear as the background.
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Old May 21, 2005, 02:49 AM
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[ o ] cap's Avatar
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Hey HankF,

My brother and i dove into it deeply about 5 months ago. We released one with our new web site and are working on a couple more right now. Through alot of trial and error we have figured out all the secrets to making top quality pans. there are certain tools that make it alot easier ,mainly a steady tripod and a panaramic head for the tripod ( which i made from seeing pics of them online). as far as the camera goes, we did them using a 5000 dollar, 12 meg camera (mothers a proffessional photographer) and we did them using 500 dollar, 4 meg cameras and there wasn't really any gain using the higher meg camera because of the scaling down you have to do anyway. so with the right tools, a "good" camera and a LOT of patience , you can do extremely good pans. We'll be putting up a good english tutorial on our site as soon as we have time to put everything we've learned in type. web site- http://w3.wehner.cc

-Chris

W3 Group


Heres a pic of the pan head i made for our tripod. It allows you to take pictures in exact degrees and at different angles so all 400-500 pics line up as close as possible.
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Old May 21, 2005, 12:42 PM
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Hi Chris,

That's a nice site you have. It looks like you guys have settled on the process of stitching multiple pictures rather than using specialized equipment like fisheye lenses or convex parabolic mirrors to take a minimum of pictures. Of course there is an incentive to keep the costs as low as possible. BTW, what sort of software are you using?

I ran across an interesting expeiment on the Panoguide forum you might be interested in. It used a Christmas tree ornament as a mirror - which is certainly cheap enough:

http://www.panoguide.com/forums/tipsntricks/25/

If used horizontally with the camera in portrait position, you could get a 360x180 panorama with just 3 shots. Any distortion caused by being spherical would occur down low or up high and may be acceptable. I'd like to hear your opinion.

Hank
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Old May 23, 2005, 01:55 PM
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RE: Panorama Pictures for Reflex XTR scenery

Hey Hank,

After quite a bit of experimentation, we settled on the process of (as you mentioned) stitching multiple pics together. We did not have an opportunity to use a "one-shot" solution such as a 360 lens. I'm not entirely sure how well they would work for this application, however. I suspect that they would likely be very dependent on camera quality and capability.

Digital cameras only truely support one resolution (the resolution of the ccd). This is the resolution at which the camera takes "RAW" pictures. When we used wide angle zoom factors (thereby getting more real world coverage in a single picture), we found that the camera, even at its highest, raw, resolution) did not give us the "crisp" quality we wanted in our pictures. There was a noticable amount of vignetting and blurriness around the edges. It seems to me that when using a one-shot lens, which of course has to warp the scene into a single pic, that you would not be getting an equal amount of "pixel-coverage" for any given part of the scene. That is to say, that as the scene is compressed around the edges (or maybe even the center, depending on the lens), you essentially get fewer ccd pixels to devote to what amounts to more real-world degrees of space.

We also found that, although we could technically shoot a reasonably acceptable scene with very few photographs (about 15 pics per horizontal row - wide angle), the depth perspective was quite skewed. The human eye sees the world at about a 50mm "zoom". Our camera could zoom out to 7mm, which let us get a full 360 degrees with only 15 pictures per row. However, once we stitched those together, objects close to the camera seemed fine, but objects far from the camera seemed *very* far away.

So, we reshot a particular scene at 7mm and again at 21mm and again at 50mm. We stitched them all up and found that the 21mm and 50mm looked way better than the 7mm, both in perspective and image quality. The latter was due to a couple of factors. First, being zoomed in to a higher zoom factor produces less distortion in pictures. This has the benefit of more equally distributing real world space over the ccd, as well as making the stitching software's life much easier. Second, being zoomed in also means you have to take a lot more pictures to cover a given amount of real space - (at 7mm we could get away with 15 pics/row, at 21mm or better we had to use 36 pics/row...every ten degrees). This meant that much more data had been captured going into the stitch process, assuming we were still shooting pictures at our camera's highest resolution.

The downside to more pictures is that the stitch (and especially the blend) took much much longer to run. So, we decided that we would still take pictures every 10 degrees, but we would lower the resolution of the camera so we wouldn't have so much extraneous data to stitch. After all, if the camera was shooting at 2500 pixels wide, that meant that 36 pictures (with 30% overlap) was generating a master stitch size of 30000 pixels wide...and we would have to scale that down to 8160 pixels wide for Reflex XTR. This turned out to be a not-so-beneficial move. In fact, it completely obliterated the crisp clean look we were trying for. It turns out that the camera's scaling algorithms were not stellar. Thinking about it, its probably a little much to expect the small processor in the camera to do on the fly with the speed we demand while shooting pics (particularly panorama shooting where speed is of the essence...clouds moving, etc).

Because of the real time scaling problems, we submitted to using full ccd resolution for the pictures, and letting the stitcher deal with the large pictures sizes. At first we let the stitcher handle the scaling down to 8160 (in Hugin, we set the output size to 8160 wide). As it turns out, hugin (and other stitching packages we tried) are even worse at scaling down. The interpolators included do a great job of scaling up, but as is not the intent of an "In"terpolator, they are either not used in the scale down operation or they are really really bad at it. Letting the stitcher scale the 30000 down to 8160 produced an image with really bad jaggies and a pixelated feel.

So, we ultimately decided on letting the sticher and blender process the images at full resolution, thereby producing a final stitch at 30000 pixels wide (this takes many days to run, so do some test runs at lower resolutions to get the stiching right). We then take the final image into photoshop, which does a phenomenal job of down-scaling/resampling, to get the the final 8160 wide resolution we need.

These stitches always seem to have problems at the "top" of the world, so you'll probably have to edit them in photoshop (we just do a small gradient blend from a sampled blue color to transparent over the top few - say 50 - pixels on the top of the picture). Reflex doesn't show the ground all the way to the feet so you dont have to take pictures all the way down. If you end up with any unfilled areas at the bottom just clone-stamp them in using photoshop or similar tool).

As for getting the panoramas into reflex, you'll need to find one that closely matches the physical layout and lighting you want. Open up the original you're copying from and notice the vertical position of the horizon and horizontal position of the sun. You'll need to match these in your panorama. You shouldn't need to do any stretching or scaling of your stitch after it comes out of the stitch/blend step. Just crop them vertically as necessary to make sure they are 8160 x 3060, and paint in whatever is missing.

As Chris mentioned, we use a panorama head so we can get more accurate spacing and leveling of our pictures. This pan head requires the camera to be in portrait mode, and we shoot at 1200x1600 (actually not the full ccd res, but plenty of detail given the number of pics taken and a requirement for us as Photoshop cant open images larger than 30k pixels wide) which gives us an "optimal stitch" size of about 30000 pixels when shooting 36 pics / row. We shoot rows at 10 degree vertical increments from about 80 degrees up down to 60 degrees down (considering the horizon as 0 degrees)

Hope this rather long-winded summary helps,

Ted
The W3 Group

P.S. we use the following freeware tools and Adobe Photoshop

http://hugin.sourceforge.net
http://enblend.sourceforge.net/
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Old May 23, 2005, 02:35 PM
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oh, and btw

we'll take a look at the christmas ball technique...looks fun if nothing else
We'll try using the 12 meg camera with it...
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Old May 23, 2005, 03:14 PM
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Augsburg, Germany
Joined Sep 2004
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Hi Ted,

please allow me an interposed question, since I just tried panorama myself last weekend. I used hugin too, and now I wonder what stitcher program you used. If I understand correctly, hugin is more or less a frontend for panorama tools, both common and the Panorama Tools (by Helmut Dersch). I found the standard stitcher of hugin ("nona", for no name?) pretty bad compared to the PTStitcher program (one of the Panorama Tools), especially with the Sinc interpolation method. What's your experience?

Burkhard
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Old May 23, 2005, 07:57 PM
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We actually experimented with both the Hugin frontend and PTStitcher...and used the nona-stitcher as well as PT with each interpolator. We re-stitched the same pan with each interpolator (specifically looking to confirm or deny our theory that the interpolators simply arent used or are not effective when scaling down - or not scaling at all.) We indeed found that the interpolator chosen seemed to have no visible effect on a scaled down image - they all looked bad, which is why we eventually opted to not scale down at all in the stitching software (in Hugin just select "optimal size").

As for the hugin front-end versus the PTStitcher front-end, the only reason we chose Hugin is that we could not find any way in PTStitcher to define true vertical and horizontal lines - particularly necessary in roll correction for those without a good leveling pan head. PTStitcher allowed us to define lines as a series of points, but we could not find a way to call those lines "vertical" or "horizontal".

So, to specifically answer your question, we just used nona as it gave us the option to render to a single tif image using enblend (and save a manual step...course this all went out the window anyway when our pans started consisting of 400+ pictures and hugin could shell out to enblend anyway because of command-line length limitations).

Ted
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Old May 23, 2005, 08:08 PM
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One other point of interest:

After Chris built the pan head shown above, we no longer had to rely so much on the optimization phase. Because we knew the exact coordinates of each picture in the sequences (say 20 degree yaw by 10 degree pitch and 0 degree roll), we were able to key in those positions manually to hugin. After doing this, a preview will yield an ok stitch without any optimization. Then we could run the optimization (p/b/r i think...went very fast as the images were already very near their correct position) and get a perfect stitch with no seams out the other end. I eventually wrote a small command line program to modify the .oto files before we even opened them in hugin. We create the oto from command line with autopano, then run our utility to auto-key in the basic positions (it just takes a starting pitch and ending pitch as arguments and assumes the rows are in sequence and have 36 pics each). We then open the .oto in hugin and run the optimize and generate the stitch. We were able to run our last stitch (the football field) without even previewing - stupid yes considering the render time, but it worked .
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Old May 23, 2005, 08:20 PM
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Wow! my head hurts.

I tried a test panorama using my digital (low res) camera with protrait mode vertical at my widest angle (about 35mm equivalent). The series was in two rows with overlaping both horizontally and vertically. I did 8 pictures per row. I got about a 360x140 degree coverage.

I then tried a free stitching program without any correction to the images. The scene included a parking lot with stall markings. As you could expect, the stall markings did not match after the stitching. The method worked but was of very low quality.

Several things I learned with this simple experiment: you need a camera with manual exposure controls, you need a panning tripod, you need to correct the (keyhole?) distortion caused by tilting the camera before stitching. You need a good stitching program.

My question is this: Do you correct the individual images for distortion before stitching and when the images are corrected for distortion, they are no longer rectilinear. How does the stitcher handle the resulting images considering that Reflex needs a rectilinear image?

Hank
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Old May 23, 2005, 10:46 PM
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Actually, the stitching software will correct for barrel distortion during the optimization (it does a decent job of calculating this using the control points that autopano finds). I'm having trouble figuring out how you were able to get 360 degrees out of 8 pictures 35 mm should be pretty zoomed in and should probably not represent more than about 10 degrees in portrait orientation (no math here...just guessing based on myexperience).
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Old May 24, 2005, 03:25 AM
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someone really needs to figure out the deal with the colision file

they should have made a scenery maker like they made the rmk model maker.

mike
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Old May 24, 2005, 04:02 AM
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Quote:
Originally Posted by [ o ] cap
so all 400-500 pics line up as close as possible.
Ehhh... 400-500 pictures? are you kidding. I can take 32 or so with REALVIZ Stitcher and get good results.
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Old May 24, 2005, 09:35 AM
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We did plenty of sub-100 pic scenes...then we did 400 pic scenes. The sub-100 scenes invariably had stitch errors that had to be corrected manually. The 400 pic scene stitched up waaaaay better than the 40 pic scenes. Shooting at 50 mm means very little image distortion. The scenes stitch up with no manual intervention. Then we put the two stitched scenes side by side to compare image quality and perpective. The image quality on the 400 pic scene was hands down better than the sub-100 - and what we were after, above all, was super clean, crisp image quality. And as I mentioned above, shooting a sub-100 scene requires a wide angle while shooting. This leads to major perspective problems. At 7mm zoom, objects past 20 feet will appear way to far away.

Ted
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Old May 24, 2005, 09:39 AM
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mhale71,

Amen! We found mention a few months ago of an RSK (reflex scenery kit) that was supposed to come out this year. Of course, after repeated attempts to contact wolfgang on the subject (with no response) we are still left with only questions and a lot of frustration. We've got some really good scenes in the can that just don't work with borrowed geometry (small-space scenes good for 3d flying) and borrowed lighting. Really wish we could edit those files....

Ted
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Old May 24, 2005, 01:07 PM
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Quote:
I'm having trouble figuring out how you were able to get 360 degrees out of 8 pictures 35 mm should be pretty zoomed in
The camera was an old (in digital terms) Olympus D-620L (1280x1024 CCD). The manual claims it's a 36 - 110, 35 mm equivalent. I had it zoomed out to the widest angled setting and insured that there was overlap as required by the stitcher. It's not what I'd use for a final panorama and might give me an excuse to upgrade.

Can you tell me what functions the sticher and blender do (besides the obvious) and what functions you do with your imager (Photoshop)?

On rereading your treatise, a question occured to me: How much overlap is there between pictures and could you use Photoshop to reduce that as much as possible to speed things up rather than let the stitcher do the cropping?

Lastly, to me the problem seems to be in getting decent vertical coverage - as close to 180 degrees as possible. How many rows of pictures do you deal with?

Hank
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