There are two reasons why your photos might not Stitch correctly : a wrong setting of the nodal point and maybe even more, optical distortions of your lens or zoom lens. It is due to the form of the lens: an aspheric lens. Here is how to know it and correct it..
All the photos of the sphere have been shot and prepared and are ready to be Stitchd by a panorama software on one or several ranges. At that point, it is still not about using a virtual tour creation software like Virtual Tour 3DVista because the panorama isn't Stitchd yet. But this type of software needs a flat image, possibly on 180 x 360°. Few of them offer stitching qualities, flexibility of use, productivity and can thus be considered professional, or at least, top-range. In this page, I'll tell you all about my experience and the qualities of each of them.
When we were trying to stitch a simple panorama to print it for example, we saw in the tutorial dedicated to panorama stitching that the photographer had numerous choices to make in terms of geometric projections in order to convey HIS message. For the creation of virtual tours, only one geometric projection can be used: the spherical geometric projection. Let's see this now..
The key points if you're a beginner.. Here are the key points to remember about panorama stitching. The rest of this page is aimed at those who want to learn more. A virtual tour is realized in two steps: firstly, you need to stitch all the photos together using a panorama software like PTGui. Then the panorama is opened in another software, a virtual tour creation software like Pano2VR in order to create this virtual tour in itself. The only geometric projection to choose when you want to realize a virtual tour is the spherical projection during the stitching. Nowadays, the three best pieces of panorama software are PTGui 11, in English only, its direct competitor and Hugin 2019, very similar to PTGui but available in other languages. Next key points: Final editing of the panorama |
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Basic principles of photo stitching
The panorama software has several things to do, completely automatically:
- Compare the details of two consecutive pictures and and stitch them together, whenever possible automatically;
- Transform and distort them, in the only way that interests us here, meaning in spherical mode.; It is the mode automatically picked by the software.
- >Finally, harmonize shades and/or luminosity differences in accordance with the chosen panorama software.
Geometric transformations are detailed on the page dedicated to geometric projections but we'll see very quickly here that only one interests us: the spherical projection. Indeed, it is the only geometric projection that virtual tour creation software can handle. stitching software, when it's given photos to Stitch a panorama 180 x 360°, stitches them automatically in this geometric projection mode. They'll try to Stitch, for instance in the example here, eight photos shot with a full-format Fisheye, once the nadir corrected, to render a panorama that will look like that:
The central part of the photo is rendered 'classically' but the more we get away from the middle part, the more the image is distorted.. It is especially sensible at the bottom of the panorama.
Panorama softwares
There are many of them and I imagine that most of you already have an opinion on the subject. Each will have its favorite because lots of stitching pieces of software, once mastered, are amazingly efficient. You can also be attracted to one panoramic piece of software but because of your lens and its distortions, have to choose a different panorama software, more powerful in this case.. Firstly, the aim of this tutorial is to introduce a few pieces of software that seem to be reference and I'll complete that list as my reviews go along.
Caution though! It is not a list of virtual tour creation software but of panorama software. Virtual tour creation pieces of software will be detailed in the last page of this tutorial.
