strong barrel distortion on imported rendered pano

[Bobski]

Hi, just tried pano2vr today but Ive a problem with barrel distortion. Ive rendered out a scene in my 3D app with a spherical camera with a resolution of 4000 x 2000px and imported it in to pano2vr. There is quite strong barrel distortion in the editor and also in the html 5 export. Ive tried adjusting the filed of view but that just seems to zoom in and out but the distortion remains. Any ideas what im doing wrong? It was a fresh scene with default settings and the export is just a spherical cam 160cm from the ground - so hopefully eye height.

Thanks for any help.

[360Texas]

My experience with spherical imaging and barrel distortion.
I found by setting:

Degrees are angle of view from left to right on the horizon

Max zoom out to 110° prevents barrel distortion
Initial Field of view to 50° initial
Max zoom in to 40° prevents excessive pixelation by zooming in so far that no real object definition is seen visitor gets lost.

[Bobski]

Thanks, I'll give those figures a go tomorrow in the office.

[Bobski]

Unless Im doing this wrong, its not seemed to work for me. Ive attached the example. This street is supposed to be level but as you can see the distortion is way too much. No matter what my fov settings are it is always bent - I just seem to get closer or further away. Its like there is some base level calibration that is wrong. The render engine has no settings in the spherical camera and all is modelled at real world scale. So I cant think there would be an issue there as it should give the perfect image.

Its just the demo so fortunately I've not sunk any cash in yet but hoping someone can set me straight otherwise its back to the drawing board on VR.

[360Texas]

lets discuss your image and how was it taken?

Normal spherical panorama images
For example: your camera is a standard aDSLR with a full 35mm sensor and you are using a full circle 180 x 180° fisheye lens. Sigma 8mm Fisheye lens. You took 4 images around the horizon and stitched it with software like PTGUI to create an equi rectangular image that is 4000 x 2000 px.

This produced panorama that contains distorted vertical and horizontal lines. The Pano2vr spherical viewer than displays an adjusted view where it shows horizontal lines corrected.

Normal cylinder panorama image A cylinder panorama is like the vegetable tin label wrapper. It is called a cylinder panorama.
For example: your camera is a standard aDSLR with a wide angle lens like a Canon EF 10 -22mm taken at say 10mm. You take multiple images around the horizon and stitch it with software like PTGUI to create a wider than normal angle of view. Then you crop the image to 4000 x 2000 px.

This produced panorama that contains distorted vertical and horizontal lines. The Pano2vr spherical viewer than displays an adjusted view where it shows horizontal lines NOT corrected properly. It would be necessary in Pano2vr to load the image as a cylinder. Then the cylinder viewer should display objects horizontal lines in the image level properly.

Also you now have a FLAT panorama which when using autorotation will rotate to far right and bounce slowly back to the left in a cycle. You still can mouse around / zoom in/out but you can not rotate full 360°

Just a thought while looking at your sample image.

[Bobski]

Thanks. It is a rendered image using a virtual sphere camera. 4000x2000 which I have seen in other examples as the way to go for a rectilinear image. Maybe I need to render 4000 square? The only examples I have seen are 2:1 rectangular though.

I have attached the base image if you fancied a closer look?

Cheers

[360Texas]

Thanks for letting me use your image for testing. Did open it in Photoshop CS6 and PTgui to look under your image bonnet. Finally used your test image in Pano2vr and found:

After you load your image mouse up to the upper left corner "Image Type" click to find

Spherical
Cylinder
Flat <---- select Similar to Cylinder regarding mousing around. Sorry still can't rotate full 360° on the horizon. But skins, hotspot links should still work.

Now save the project, and click the GEAR to generate an HTML 5 project. It should then generate and display in your browser with the barrel distortion removed.

I really thought this was a real stitched photograph until I zoomed in and did not see any People things.... streets too clean. Than realized your virtual camera is really a computer aided drawing or Cad. Great stuff so realistic.

Hope this helps.

flat.jpg (130.06 KiB) Viewed 4776 times

[Bobski]

Thanks for the compliments. This was just really a test to dip my toe in to VR.

The flat projection doesnt really work for me. The whole idea is that it can be used with goggles as an immersive environment like the pano tours on the pano2vr website. I know this is possible but had no idea it would not just be a simple automated process. I might try a competitors demo to see if it works in that but I do like the pano2vrs features and price point so its a shame its not working for me.

[360Texas]

Ok... it appears that your CAD graphic is 2:1 image ratio and is 4000 x2000 px and .jpg file format

I personally do not quite understand why your image does not work with the spherical projection viewer.

It has all the correct vertical and horizontal lines. I will ask Hopki to look in and do additional tests on your image.

Stay around for few more days... lets see what Martin has to say

TIA

[Bobski]

Totally my fault Dave, so sorry for wasting your time and thanks for your help. The problem was indeed the initial rendering. I had a film offset on the image which works like a shift lens and so distorts the spherical cam. I had just converted a previous camera in the scene to a spherical cam and forgot about the offset. All works great now. Will definitely be purchasing.

Now the next thing is official support for occulus rift? from my forum searches I gather its not supported for multiple node / tours, only single panos at a time is that right?

Sorry again

[360Texas]

No ones fault.

Think of it as a learning experience. A good one at that to add to our Lessons Learned book.

Thanks for the feedback.