8) Stereo stitching

  1. Intro.
  2. Historical review.
  3. The Stereography.
  4. The Stereopanography.
  5. Research and development.
  6. Stereoscopic panorama capture.
  7. Capture templates.
  8. Stereo stitching.
  9. Prosumer
  10. Publication.

8.0) Intro.
8.1) PTGui
8.2) Autopano Giga.
8.3) Mistika VR.
8.4) Stereo Comparative.
8.4) Presets for Nodal Ninja.

8.0) Intro.

 

The software designed for the stiching of panoramic photographs is based on a nodal capture, but still has a certain tolerance that minimizes the alignment errors of our input pupil with respect to the NPP of the RIG.  For this use interpolators that act during the render, these interpolators can correct nodal mismatches of millimeters, but can not eliminate the errors that occur in captures in which the nodal misalignment is several centimeters.

TYRREL 1.0So that these interpolators can reduce the errors, it is necessary to distribute the parallax error among many photographs, so the more photos we make the less visible will be these small jumps, and if we use a single row rotation base of (15 º) that are 24 photos with each camera, the errors come to be close to invisible.

The VR video software has been designed to align non-nodal images, since in a video RIG, all the entrance pupils are misaligned, but these “softs” work in a different way, there is really no stitching as such, but all the images are part of a whole thanks to the interpolation.

In the following points we will see how to stitch in stereo using the  “softs” that currently exist on the market and make a comparison. For these exercises we are going to use the same material, a capture of two rows of (60º) and an optics of 10mm- In total there are 26 images, 12 for each panorama plus two photos of the nadir, one with tripod and one without.

 


 

8.1   PTGui.

 

ptguiIn PTGui we will proceed in a habitual way, taking into consideration that we are going to stitch all the images together as much those of the right as those of the left at the same time.

 

 

1

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Once the panorama is finished, the only thing we have to do before the render is to deactivate the frames/images on the left side to save the panorama on the right and then proceed in reverse order to export the image on the left.

3.jpeg

In the image below we see the result having used the “Spline 64 in which the Parallax/Stitching errors are really small.

ptgui


8.2)   Autopano Giga.

 

If you are an Autopano Giga user and you are still using it, I have using version 4.4. Just like using PTGui, let’s proceed as usual but using left and rigth pics and finally deactivate the right or left layers.

5.jpeg

Once finished, the easiest way to export right and left is to create two folders, one for each view, and when activating or deactivating the whole group, we will obtain the image of the right or left.

6.jpeg

As in PTGui, the stitching saws are minimal, even smaller using once again the interpolator “Spline 64″.

autopano.jpg


8.2)   Mistika VR 8.8.8.

 

Mistika VR is a “soft” designed for VR video, but after a few slight adjustments such as increasing the size of the output files, or being able to use up to 64 cameras has allowed its use for photography.

This software is based on the “presets” made by the S.G.O. team, and already includes the positioning in the space of the cameras,  the interpolation, the correction of the off-set of the cameras, the adjustment the angulation of each camera, the application of the “Optical Flow” in its just and minimal measure, the perfect (R/L) alignment and the colour correction.

Captura4

In the image below we see the right and left views made with Mistika VR where it is not possible to find parallax/stitching errors.

mistik


 

8.1)   Stereo comparative.

 

But a Stereopanography is not only to eliminate the stitching errors, we also look for a correct alignment and in the three lower images we can see the final result using these three softwares.

These photos must be viewed in WEB VR mode, as it is very important that the stereoscopic works are checked on the same screen on which they are going to be exhibited, as the size of the screen will influence both,  positive and negative parallaxes.

2_0000   PTGui

2_0000    Autopano

2_0000   Mistika VR


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