FMSXYZ New Version V1.1.0

[lcsaba]

[TreeHugger]

Hi,

some illustrations might help to show the difference between spherical and cylindrical mapping:
imagine you're looking from the side into a sphere or cylinder cut open in the middle. Lets assume in both cases an image covering the lower 45° is mapped onto the surface. How is it different?

The first image shows an equirectangular projection ont a sphere. An equal vertical angle will be projected onto an equal distance on the sphere's surface. The points in 3D-space have to accomodate to match. This projection will sqeeze the image towards the top, that's why spherical projections look so distorted when flat.


The second images shows a projection onto a cylinder with a vertical wall. Now an equal amount of vertical pixels will be projected onto an equal distance in 3D. Important point: In the first case, angle was constant, now distance is constant.


Let's see what we get when we put spherical and cylindrical case on top of each other: Case one and two are NOT equal! Mathematically speaking, an angle and the tangent of that angle are NOT equal - they are only simliar for small angles. An image made for one projection does NOT fit onto the other, you will get the distortions you already noticed. And I hope this will answer your initial question: NO, the images I've used for my sceneries are NOT just flat photos.


If you have any doubts whether the output of autostitch, hugin and emblend really produces a spherical pano, please have a look at any of these:

Look at the curvature of straight features above or below the horizon. Could you produce this with anything else than a fisheye-lens or a pano stitching software? Contact the authors and ask them.

Or better yet, read a workshop:



You'll find a lot of articles on Wikipedia, but they're mostly referring to cartography:


Regards

[lcsaba]

Thanks, for your detailed explanation

it is almost clear fore me but...

As I have already said it was clear for me as far as short range views like halls are concerned but I thought that normal photo could be used if open air landscapes has to be produced and the objects are far enough, because at small angles the two projections gives similar results
and the distorted parts are at sky and cloud level.

Now I it is possible that I have realized something which is worthwhile to mention. A Hungarian fellow modeller said that the the projections are very tricky. The ground level is a transparenent horizontal sheet, the shadow of the model is projected to this sheet.
The landscape below the horizon is projected on the sphere below this gound level sheet. Now, the photos to be projected under the ground level has to be distorted very much by the fisheye lense.
On my panorama attempt the most disturbing is the view of the field near to the pilote. I guess this is the reason.

I have got a glance at the documents but should be studied in details.

I have a feeling that normal photos can be processed by dedicated pano producing firms or one has to buy digital camera and fisheye-lens. I am not going to do this threfore I have to search for pano stitching software or give up this idea.

Anyway this should be known everybody who is willing to use FMSXYZ if it will have good projecting capability.

Regards

Laszlo

[TreeHugger]

Hi,

some more quick illustrations to explain how I map a panorama:

The first image shows the scenery "Dietersdorf" from rc-sim.de I chose for demonstration. I haven't asked for permission to convert, so no upload of the scenery data (I assume the use for demonstration purpose is considered "fair use").

Original image resolution is 8160*3060. The thin gray lines show how it will fit onto the sphere. Equal angle on the source image means equal distance of UV-coordinates, hence the regular square pattern. The orange lines show how I cut the source into patches of 1024*1024px.


This is the middle row I use without any scaling. Since 8*1024 equals 8192, there is an overhead of 32px. I'll distribute this across the images so each texture overlaps the adjacent one by 4px. The UV-coords will have to compensate for this by NOT running from 0 to 255, but rather 0.5 to 254.5, pointing by a small margin inside of the image border. This way you'll avoid the black alias stripes between texture patches.


Third image shows how I'll combine the remaining three quarter sky plus one quarter ground and then scale down by 50%. Several reasons: I want to reduce texture size as much as possible to save performance. Most importantly, in this area there are many more texels (texture pixel) per area in 3D than around the horizon. Since the mapping is more compressed towards the top (check next image), this is the natural place to shave something off. Secondly, most of the time you don't look very high up or low down, so it'll hardly make any difference.


This is how the textures fit onto a sphere, equirectangular projection, very straight forward. I'd consider 32 faces horizontally and 12 vertically as the lower limit for smooth results. It's just one way to do it, there are many others, but this one is a decent compromise between size, work and visual quality.


This is how the result it looks from the outside, the sphere is hollow.


And a screen from within FMS. Notice how the heavily bent runway on the pano gets stretched out in spherical projection. I don't have to stress what kind of projection will not work here, don't I?


I hope this will further clarify the process of panoramic mapping...

Regards

[lcsaba]

Hello Frank,

thanks for your contribution. I guess your postings above can be considered as a good tutorial on panorama projection.

In hope that I understand most of the points mentioned. This is not as important than the fact that other new comers just can read it through.

I think that for Perry this is important either.

I will try to explain why, if I am wrong please correct.

But first of all I have to mention that using the services one of the most popular search engines and searching for the prase: "panorama photo stitching software" one get 439 results.

I have to check some of them.

I have already took a glance at the first two, there are free dowloads for testing and the price is from 20 USD to 60 EURO.
The softwares by the text of the homepages can convert normal digital photos to panorama pictures. I have to check and make trials.

I recommend to take a glance at the second one http://www.ptgui.com/gallery
because tens of various panorama photos are shown and in some cases are animated.

Coming back to the FMSXYZ.

I have seen that You produced at least two pano landscapes downloadable from rc-sim.de: mfv73 and Bad-Oldesloe.

I guess that the difference between them is what you described like this: "in this area there are many more texels (texture pixel) per area in 3D than around the horizon".
With other words, mfv73 has got not very detailed front therefore 8+ four combined photos can cover the sphere.
In the case of Bad-Oldesloe thre are 4 sky pictures and two rows of eight pictures.

Now following your explanation above I can say that to select between this two possible method is the task of the designer. (Of course there could be other solutions.)

First of all digital photos sholud be taken, meeting some important requirements, and using an appropriate software the panorama photo should be produced. Next step is to cut the pano to N photoes.

If the N pieces of 1024 *1024 size are ready the scn file should be created.

FMSXYZ could do this if there were two options for 4+8 and for 4+16 photoes.

Selecting one option, I guess, the text lines of one your scn files, which are ready, should be copied to the "NEW" file, replacing the .bmp file names with the "NEW" one.

The last step coud be, fitting the ground level by moving the "red line" up or down, which will result in the proper value of the "height coordinate".

Anyway, for me the next step is to study and select an appropriate SW and produce a pano.

Regards

Laszlo

[TreeHugger]

[lcsaba]

[lcsaba]

[smcxx66]

I figure out an easy way to do it. and it looks better.
Most important..get the horizon line correct or the model will
crash in the air..lol

make sure the horizon line is above or at the center.
the photos you can get from other links of relex is
8160 X 3000..there about.
Notice those panorama horizon are below the half piont of the photo..

To fix that. I just increase the canvas size to 8160 X 4080.
mmm....360 X 180 panorama.lol
without having to crop I just have to make sure the photo
gose on the top partion of canvas..why ? becuase i don'twant to
stretch the original pciture.

This will add portion to the bottom of the picture and raise
the horizon line..the same problem that you had.

Okay..don't worry about the bottom..becuase you don't really see it.
if you do ...you can write your name on it ..lol

Then I convert it to rectangular panorama.
No more sticth lines and you can actaully repair those funky swirls
on the over head or top of the sky, that the pro leaves.lol

There's plenty of sceneries for FMS with rectangular panmorama.
ratty is one of them and those indoors sceneires.

you can load it into the sphere format if you chose to.

you will notice the ratty scene don't have the crash piont files
without a crash piont file..the "down" bmp. won't get display,
but it'll still works. other scenes has crash piont files in them.
this will get the dowm .bmp to display.
But I don't know how to make crash pionts...oh will

all you need is the .scn file

all you have to do is map those 6 .bmp correclty.
Bixomara has a free trial version you can download to convert
those 360 X 180 into retangular...it bascially spits out 6 image files
for you. Then just resize them to 1024x1024.

having those 6 picture will allow you to fix the stitch line or the sky.
you can alway reformate it back into sphere if you want.

i notice some of those reflex scenes that got converted into FMS
didn't have the top part of the sky or are missing portions.
some have funky stitch lines in them ...what da ?
this can fix that..but i don't botther with them, there's better scene
and you can also download panorama photo by the thousands
on the net..if you get tired of field sceneries.lol

[smcxx66]

why do I not want to stretch the original photos ???
quality...lol
my sceneries comes out perfect.
I set the panorama converter on highest quality.lol

my average scenery files are 18-20 mb...oh well.
each images is 3mb.
cheap PC comes with 200 G hards drives, now..lol

To share those sceneris..just convert them back into Jpg..or what have
ya. it's bascially down load time

I get my panorama photo for Flickr...its a free photo sharing site.
A lot of the photo in 360 X 180 are perfectly made by the artist.
you don't have to add bottom protions and what have ya.

[lcsaba]

Hello smcxx66,

first I will send my first relevant photoes, and in a new posting I will reply to You.

As I can edit my former postings, now 06.10.2007 I am deleting the original reference to a FMSXYZ picture. So far I give up the cylindrical pano Landscape creation.
Meanwhile I have made my first coplete spherical FMS Landscape, now I am working on crash objects.
The pano:


The pano is made by a commertial stitching software.

[lcsaba]

Hello, smcxx66,

thanks for your comments. To tell the truth not everything is clear for me so far.

My goal is to make panorama landscapes based on my own photoes.
As I have said that based on this which is above I have made three. I have no horizon problem now. FMSXYZ has got the red line, the mfv73 scn file can be edited accordingly.

I have some ideas how to produce crash surfaces but first I need an acceptable FMS lanscape.

The pano above was made by a digital camera 5MP, 12*optical zoom.
I made 40 pictures, vertical camera position.
It would be possible to make an other row with twenty sky pictures but in this case possibly manual stitching were necessary.

Transformation is not possible, because if the whole picture is transformed, not keeping the aspect ratio, the distortion will be visible at the buildings.

It is possible to transform the sky only, this is what I did, but in this case the problem is that the contrast and brightness of the sky and the lower parts are not matching.

On the other hand I would like to use FMSXYZ if Perry is willing to develop it further. This is the reasont why I have posted the FMS screen shot.

I know that spherical projection is better but I could live with FMSXYZ if the white stripes problem would be solved, and more UV squares per picture would be defined it would be great.

If you know panorama FMS landscape with 6 pictures I would try it. As I said the five picture scn files are bad, if the "sky" is not homogenous.

I have Rainbow stadium I guess this is a seven pictures but it would be difficult to replace those pictures with cuts from my pano.

Possibly instead of pulling out the sky to be higher, next I will double the sky strip cutted from the pano and the upper one will be mirrored 180 degrees.

[smcxx66]

Icsaba,

I think perry said you might need to overlap your pictures or crop sections by 3-4 pixels..so those lines won't show, if i read it correctly.


i think your picture will work in the cube or box. it looks good to me.
just makesure the horizon is a little bit higher or at center.
I'm not sure how long you photo is..but you can simply increase the
canvas size.

example if your photo is 5000 long..make the canvas to 5000x2500.
bigger is better if you have the original.lol
I just use artweaver, it's a free simple software the allows me to increase
the canvas size. very useful if you like a cyclinder shot..but not overheads.
Just leave your panorama at center.

then just download Bixorama and try it out.
feed bixorama whatever your panoram ,whatever the canvas size may be.
select , horizatal/longiture as input type or source.
then click on view..it'll say it's not responding..but give it time to process.
click on single files to veiw..you'll see 6 single images.
then select those as output...send to a folder.
then just use art weaver or whatever, to resize them to 1024x1024.
okay...now you'll notice...the top part of your panoram...gose in a circle
on the _top or _up image
You might also notice a line..that's from top left and right of portion
of your panorama.
Air brush those in..or use a smear tool to blend everything in.
Artweaver has those tools or brushes....

okay..you'll notice a circle on the _down or _bottom image.
paint a happy face ..lol or stamp your name on it.
that's the picture under your camera pod or under your feet.lol
Some people don't bother doing that...that's a lot of work

okay , you might notice a big stamp assigned to the _ front image
depending how you select as output or rotate in bixorama. In the
trial version. Just assign it to the back and back as front.
left as right, right as left. Then roate the sky and down image
180..You can air brush the cloud section easily..the grass might
be a challenge..Bixorama is $20 but just trying it out..

get a .SCN file from RC-SIM..from the ratty scenery.
Assign all of your 6 images as ratty.
Bixorama dose that for you...just assign ratty as the files name.

a total of 7 files is all that are needed to make it run.
You can get the crash piont files from other sceneries..
this will display the _down image and have a crash piont.
but i don't crash pionts..lol
it bascially set a perimeter or a bondary..when you hit an invisable
crash piont...then you crash..lol
those sceneries are in french ??...not sure.
if you choose to do that..you have to assign your files that same names
and use the .snc file of the scenery.

if you images are a little to blur..trun off the fog and click zoom out
one or two clicks.

make your orginal image as big as you can...cram as many pixels
as you can without freezing your PC.lol
make it 10000 x 5000..lol
make me one...i want one !!!

[TreeHugger]

Hi,

to avoid confusion: I never said sphere projection was better. It's just the only matching projection for an equirectangular panorama, because "angle->pixel" is the principle by which the pano has been made initially.

You can just as well remap to cubical and put the output onto a box, like smcxx66 did. This technique is very common for the distant background in game engines, it's called a "skybox". You'll find plenty of tutorials on the net.

The disadvantage is the low resolution with 1024px textures. Useful panos have a horizontal resolution of at least 8000px. (That's the number of pixel you see in one 360° turn.) If you project this onto a cube of 1024px edgelength, you'll end up with a horizontal resolution of only 4096px, the equivalent of 4 sides of a cube. That's a reduction by one half, seriously pixelating on a normal screen even without zooming in. To see the difference, just make a sketch with measurements.

Iscaba, your pano looks promising, but it doesn't have the necessary aspect ratio. You'll make life much easier if you take another row of images for the sky and ground to produce a proper 360*180 or 360*135.

Regards

[lcsaba]

Hello,

it is nice to hear again about You.

"All flights are test flights".

Unfortunatelly this afternoon I had to "stitch" my Mefisto, because an unbelievable thing happend with me. I lost the propeller with the axis of the brushless motor in the air. The result was, that I had to land very far and the wingend touched the ground first.

As suggested by smcxx66 I have downloaded "Ratty" replaced the front picture and the sky with my own pictures (Tomorrow I will make a new stitching and make a poster type (cubic?) projection to check again.)

With this two inserted pictures one can see how this cubic projection works.
Not only the resolution is the problem. The main problem is the enormous distortion. On my picture there are buildings. If a mountain is distorted it is not disturbing, but if a building is distorted such a way as in reality can never be seen, it is bad.

Therefore next I will fight to improve my pano to meet the requirements of Your method some postings before.

I checked my mfv73 type "Telki" landscape jus now and it is -leaving out the sky problem and checking out the fog box as I have learned reading the instruction to "Ratty" - is reasonably good even if a model is flying in front of the buildings. (Crash objects introduction comes later). As I have already mentioned I have no problem with the ground level besides that the slope feature of the field might be adjusted later.)

I have made several hundred photoes to get this 40. It is not easy to make three rows, I have tried but PTGui left out the middle row. If on the upper row only sky is visible, I guess, manual stitching is necessary because there are not enough recognizable matching pixel groups for the software.

This is the reason I will try to expand the sky somehow.

(I have got some hints from two real photo artists how to use my digital camera, one of those is a real panorama photographer, interesting to see his works. He is one of the Galery artists of PanaVue stitching software, but he is using PTGui, he is D.Varga Tamás)

There is a trivial solution. I have to find a cloudless, sunless situation, before sun rise for instance. In this case the upper pictures should not be stitched.

By the way the grass stripe which is two UV squares wide is OK. even now.

Regards Laszlo