Lens settings for Tikee 3 Pro

[Matthias Güntert]

Hi 

I am looking for the proper lens settings for my Tikee 3 Pro, which contains two sensors. 

Unfortunately, the exif information seems to get cleaned/censored. Here are two EXIF outputs that might help a pro:

https://pastebin.com/YjVBHUEb
https://pastebin.com/NtRSYQSd

This is what I've found by reading through the specs. 

* Tikee view angle 220 deg
* Size of sensors 1/2.3" = 7.67mm
* Max resolution of sensors 16 Mpx
* Sony Exmor R 16 Mpx
* F2.8 HFOV 149 deg

PTGui automatically detects the sensor size and a crop factor of 5.64x. However, if I set the HFOV to 149 deg, it calculates a focal length of 0.85 mm which then doesn't find a single control point anymore. 

I don't even know which type I should start with. I'd have guessed it's a rectilinear type of lens, but had the impression I ended up with "better" results when going with cylindrical and set HFOV to 149 deg. 

I had some decent success with a 2.2mm focal length and 108.77 deg. But still, I get some artifacts, as shown in the (partly obfuscated) panorama. 

https://i.imgur.com/XM5RUsb.jpg

What is the best way to approach this situation when the lens details are not known? 

Thanks in advance! 

[John Houghton]

On Saturday, August 13, 2022 at 10:09:25 PM UTC+1 matthias...@gmail.com wrote:

I am looking for the proper lens settings for my Tikee 3 Pro, which contains two sensors. 

What is the best way to approach this situation when the lens details are not known?

Mattias, With such a wide separation of the two lenses, it's inevitable that you will have parallax issues at the image overlap with nearby features in the scene.  These can compromise attempts to evaluate lens parameters. I suggest you go to an open landscape location where things are generally far way and shoot a full 360 degree panorama, rotating the camera for two or three shots (rotation increment 120 or 180). Three would probably be best, with more overlap.  Then do your stitch, with control points only on the more distant features that are largely unaffected by parallax.  If using PTGui Pro, the Find Optimum Seams blending option will help to hide misalignments in the overlap.  Post the sample images here if you need further help.

John  

[HDouris]

Matthias,

As a user of Tikee camera, after what John said to obtain good lens-settings, you have to accept that parallax is so important that  every time you change the place of your camera you will have to create a new template.

In case of video, you must avoid to use Find-Optimum-Seams. And of course also avoid close foreground, at least 5 meters.

FYI, with a Tikee 2, I start a new place with those datas :

Type full frame fisheye

Focal 17,45mm

H fov 124,2

a -0,04

b 0,11

(ptgui pro 10)

The viewing angle of the panorama is not of great help if the camera is tilted up or down because you’ll have to correct the perspective and crop the result image.

hdrv

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[John Houghton]

Given that there are two separate lenses, it may be beneficial to assign individual lens shift parameters to one of them on the Lens settings tab to get the best result from the optimizer.  (The lens shift parameters are used to compensate for the lens axis not being precisely aligned with the centre of the image sensor).

John

[Matthias Güntert]

Dear all, hdrv

Thanks for sharing your parameters. A couple of additional questions: 

1. When I set the HFOV to 124.2 deg, I can't set the focal length to 17.45mm, as they are "linked" together. Should I make use of the "theoretical" input field?

2. Which type of projection are you using in the panorama editor? Cylindric seems to gives the best results when setting the lens type to "full frame fisheye". If I set the projection as well to "full frame fisheye" the panorama looks quite distorted. 

3. When running the optimizer, do you enable "Optimize lens focal length"?

Best regards, Matthias

P.S. I am running PTGui Pro 12.13 

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[PTGui Support]

20-08-2022 13:44, Matthias Güntert wrote:
> Dear all, hdrv
>
> Thanks for sharing your parameters. A couple of additional questions:
>
> 1. When I set the HFOV to 124.2 deg, I can't set the focal length to
> 17.45mm, as they are "linked" together. Should I make use of the
> "theoretical" input field?

PTGui 12 uses a different lens model, with an extra parameter called
'fisheye factor'.

To repeat Romuald's PTGui 10 settings, set the fisheye factor to 0 and
the sensor size to full frame (36x24mm).

But I think it's better to just do a full optimization in PTGui 12. Load
a pair of images, generate control points. Inspect the control points
and delete control points on nearby objects (these will suffer from
parallax). Optimize and save the project.

The camera has some parallax, so nearby objects will have stitching
errors. This can only be avoided by using a single camera on a panoramic
tripod head.

> 2. Which type of projection are you using in the panorama editor?
> Cylindric seems to gives the best results when setting the lens type to
> "full frame fisheye". If I set the projection as well to "full frame
> fisheye" the panorama looks quite distorted.

The source lens type and the panorama projection are independent. You
can use any panoramic projection, this is mostly a matter of taste.

> 3. When running the optimizer, do you enable "Optimize lens focal length"?

If you use already optimized lens parameters, you can disable this
setting. If you want PTGui to optimize them, enable this setting.

Joost