panorama software,virtual tour software
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2003-06-02
#1

+s and -s to shooting more than 2FEs

Hi Forum,

   Can anybody explain to me the benefits to shooting and stitching more than two fe's. Go ahead Smooth let me have it.
I was just curious if there were any quality comparisons out there?
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2003-06-02
#2

Hi Jack,

Well the main benefit is that the stitching with Panoweaver 3.1 using 3 FEs is the stitching error rate is very small should you have the correct nodel point.

The other is 183 degree fisheye lense x 2 shot = 366 gives you only 6 maximum degree of overlap because we are making 360 degree shots! Right?, where as 3 shot x 183 degree = 549 of which we are going to use only 360. So the overlap is much greater. Thus giving greater control of the stitch.

Hope this make some sense? I have tried to explain it as I see it! 

If someone has a better view on this or can explain it better, please have a go!

Regards, Smooth


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2003-06-03
#3
Hi Smooth,


      I think that is a perfectly exceptable answer. But is this the only benifit? The fact your more likely to be able to stitch three FE pano because you have more margin for error? I have heard of four FE panos mentioned as well. You must have to really have to have your nodal point off to need that much overlap! But why go to 4 when you should certainly be able to stitch a three FE. I really don't know guys. I mean I'm not playing devils advocate here I really don't know . We kinda had this discussion because when your shooting in a crowd it seems that a one shot or donut system would be the tool to use. Are there more benefits other thyan the extra margin for stitching error that smooth mentioned?
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2003-06-03
#4
One of the real advantages of using three instead of two (besides the much easier stitching) is that the final panorama has much less data coming from the regions near the edge of the image. The portion of the image near the edges has, by far, the greatest amount of chromatic aberration. I may be off on this, but I also think that the pixel/degree resolution of the image is greatest near the center. Thus, by having a large overlap so that only the regions close to the top and bottom of the panorama come from portions of the images near the edges, you decrease the aberrations and increase the resolution of the images.

John Riley
Assoc. Prof. of Physics
U. of SC Spartanburg
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2003-06-03
#5

I use Remote Reality's One Shot 360, The 360 Plus and I use Panoweaver with 3 FE's.  The Panoweaver has the best quality.   The One shot 360 is great for crowds that are moving, or shots where you cannot take the time to take 2 or more photos. But, the quality of the single shot is not that great.  The mirror that is used scratches easily, and reflection of lights and the sun can be a problem. There is no stitching required but you are only working with the resolution of one image, compared to resolution of multiple images.

The 360 Plus option uses 4 donut images to make a complete 360 spherical pano like Panoweaver.  The quality is not bad, but it uses the same mirror which in my opinion is not that great.

 

Scott

 


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2003-06-03
#6

I changed from 2 to 3 panos to.

One reason is that if your tripod and camera are not 100 % leveled it realy gets hard to fix. As mentioned above, more overlap to work with.

Outdoor Panos with 3 FE's are mostly stiched correct on automode (no manuall intervention necessairy)

If I had a indoor pano to do with lots of lines like floor tile I would try both. Use a 3 FE and also do a 2 FE on the same room.

Why, because if you get lucky and the 2 panos are properly leveled stiching is less a problem and you have only one seam to worry about and therefore manual stiching is a bit easier. But would defenitely do both 3 and 2 shots.

I allways have a hard time on manual stiching to find out wich hemisphere will effect which seam.

Also on 2 panos i find that sometimes you will still see a colordifference on the seam because of the black around the FE shot, while in 3 FE they blend more.

Long reply short answer.

3 hemispheres gives you  more margin of error.

 Set up your camera and just try it and you will soon find out which you like better.


Nikon D70s, Sigma 8 mm, 4 to 12 shots, Agnos MrotatorTShort, PTGui, PS CS3, and lots of other software :-)
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2003-06-04
#7
Forum,

      Thanks for this input. All very valid concepts that make sense. I had heard of the increase in resolution but I had never been able to track down an explination of how it was increased.
    John or forum for that matter could you point me in the direction of any technical papers of any kind on the subject. John you mentioned the pixel/degree resolution. I'm curious about that because I have observed that on some panos not all there seems to be a "pinching" artifact that occurs. I'm sure you all have seen it. It looks like the pixels actually get stretched and it looks like the image is being sucked into the poles. Is this a result of less resolution or the chromatic aberration at the edges?

Thanks all for your responses!
Jack
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2003-06-04
#8
I am not sure I have observed the pinching effect you mention. If you give me a URL of an example, it would be interesting to look at. Are you speaking of when you view it in equirectangular form or when you look at it as a sphere?


On pixels/degree: The best source of knowledge on that subject is the QTVR guru Ken Turkowski. He was, until being layed off recently, the go-to guy on QTVR at Apple. He even has a resolution calculation do-it-all thingie on his site, along with much else. Find it at:

http://www.worldserver.com/turk/quicktimevr/

His explanations can be complicated and terse at times, but if you stick to it, you can learn a lot from his stuff. A good place to communicate with him is on the QuickTime VR mailing list from Apple. Always search the archives of the list before asking, just in case the question has been answered a hundred times    Don't wanna get flamed as a newbie.

http://lists.apple.com/mailman/listinfo/quicktime-vr

John

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2003-06-06
#9
Hi John

    Thanks for the referances. Boy there is a lot of that going around these days. People being "let go" as it were. It makes me appreciate being self motivated and above all self employed! The pinching artifact I was refering to is in the viewer sphere mode. Its why I believe the ceiling cap was invented as well as its another good place to advertise it would cover up the artifact. I just got administrative control to my web site so I hope to be able to post some or at least one example. As soon as I get that done I'll post one. Stay tuned!

Jack