Panoramas which covers a field of view of 360°x180° are a specific class of panoramas as they make us enter into an impressive virtual reality. From those panoramas covering the whole field of view, peculiar geometric transformation can be applied and transformes our way to see the world by creating "small planet", small poetic and or fantastic worlds.
We will explore the different steps which lead to the realization of such images.
The discovery of free performant tools to make those panoramas shall not reduce the importance of choosing the right composition and spot which will awake the artist who were sleeping inside. For my part, I discovered this fascinating universe with the outstanding images on the photo web site Flickr of the Flickrnaute "Gadl".
From links to links, my learning has been made on the net. Real communities of passionates and experts exists around this topic, a new world to explore, different from the one of amateur of Astronomie, but not that much... This page is an introduction page which will propose the links who helped me in my progression. They are put at the beginning of the sections and point to specialized sites which I strongly recommend to explore.
My principal links are:
panoguide.com, includes multiples tutorials and detailed explanantions
Hugin, freeware to assemble and generates the panoramas
How to, sur panoguide.com
The goal is to cover a full field of view of 360°x180°. The number of images will then be function of the horizontal and vertical angle of your lens. The smaller this field will be the more pictures you'll have to take. It is not mandatory to have a fish-eye, we can assemble 20 to 30 images, even more. The assembling will be just longer and less accurate.
I've made panoramas with a small DSLR sony and with a D70 and a zoom at 17mm. I now use a nikkor 10.5mm, a "full frame" fish-eye. With 8 images I cover the field instead of the thirties before.
To cover 360° we understand that you have to turn around a fixed point. But to cover the vertical 180°, you need to include the sky and... the ground. We will name zenith the sky pictures and nadir the pictures of the ground. Take a picture of the ground is not the easiest excercise and during the shooting you'll probably be taken for a nut, but if you want to avoid or reduce the cut/paste with an image processing software you'll need to do it.
The natural reflexe to take a panoram is to hand your camera horizontally. We use to think that the 360° field of view will be covered more rapidly. But it will be atthe expense of the 180° field. The good practice is to hand the camera vertically to cover this direction more easely.
A good panorama shall in in theory have defects at the junction of the images set. But, if you simply turn around yourself, all the pictures will present some parallaxe issues: closest objects will project differently on the background. To eliminate this shifting issue, in fact the turn has to be done around the "nodal point". (See on this site an explanation of this effect)
This nodal point varies among lenses. It is usually inside the lens. You can find tables listing the position for some lenses. You can also determine it by yourself with a method explained on this site.
Once known the position of the nodal point, you have to turn around it.
The ideal solution is to buy a panoramic head, like the head "Nodal Ninja" for some hundreds dollars.
You can also take the panorama without this, just by hand. Some different methods are proposed, they all consist in a way to turn around the nodal point and not around yoursef.
The camera is hold against the chest, turn and shoot as explained here.
Or you can prefer this little "dance" which I practice with good result, but not without having people looking at me:
During the assembling, to avoid the bad junctions due to brightness variation of the different images taken (you'll have certainly one with the sun in it...) you have to take them all at the same exposure time. The scene being heterogenous, you'll have to take an average exposure time for the all set. I use to practice one turn before I really take the pictures, then I choose the time, set the camera in manual exposure mode and record the pictures. I also disable the automatic focus, for sky images the focus can be impossible.
For the experts, you can take the panorams with bracketting, i.e. taking the same picture with 3 or more different exposure time. We call this "HDR" images, and some software exists to process those images (like Hugin/Enfuse), and fuse them to equalize the brigthness, homogenous, without under or over exposition. A another chapter to open and explore...
If you have follwed those steps, you shall be ending with a set like this:
To take sky image, all the orientation are not equal. You have to take the one which wil include significative elements of the background to allow the assembling. Take a picture of a uniform sky on the other hand is useless as it cannot be easely stitched with the other images. For the ground, the challenge is almost the same. It is more easy to stitch ground with a grid or stones than grass. In or other cases, some times there is not other solution than "recreating" the image with cut/paste.
All the place do not worth a panorama 360°x180°. If the region of interest is concentrated on a small region around the horizon, surrounded by large sky or boring ground a classical panorama will be sufficiant and more appropriated to render the place.
For "small planet" effect, here again, the right spot is important. The first idea is to believe that it consist in a finding an elevated spot, with open horizon. In fact, you need elements of the surrounding landscape close enough to produce strange effect by their strucuture and proximity.Using a tripod, you can also adjust the proportion of the sky in your panorama having your camera closer to the ground. In fact this where the art shall take over the technic...
Multiple software exist to stich panorama, some are quiet expensive. The one I use is maybe not the more userfriendly but it is really performant and... free. It is the "suite" Hugin. The word "suite" indicates that this package install, link and exploit several applications, each one being dedicated to a task. Hugin is in fact an interface on window which encapsulate other executable (DOS type like) which executes heavy and complex calculation for you.
You will find all the informations on Hugin's site: http://hugin.sourceforge.net/
And numerous tutorials: http://hugin.sourceforge.net/tutorials/index.shtml
Let's explore the different steps through some screen capture.
I load the images and enter the lens paramaters. For Nikkor 10.5mm: fisheye fullframe, focal 10.5 and multiplication factor x1.43 (CCD sensor is smaller than the taditional 24x36 film, so the resulting focal of the lens is in fact bigger than indicated for digital camera). With experience, you will be able to fine tune the exact focal of your lens and even save the settings in separated file that you can re-use next time.
Then I align the image using the automatic feature
I did not modified the preset of Hgin. Leaving outside of US, I can do this without legal issue on the intellectual property of autopano-sift algorithm.
At the end of the process, it can happen that some images or group of images can not be aligned. This happens quiet often with zenith images.
In this case, in the preview window, you can disable the image (here the image 9) and run an optimisation of the positions (incremental, starting from original position).
The stitched images will form the panorama in the preview window.
You can change the center of the panorama or make the horizon more straight.
You will note here some shiftinn on the right of the composition. You can now add manually control points and run again the optimisation to fine tune the overall result.
You can also run an optimisation asking the software to vary and iterate on the geometric paramaters of the lens like distorsion, field of view.
After few iterations, adding or deleting control points (you cannot neglect this option as all the points constraint the model. Too many control points on a region can prevent you to change the behaviour by adding points in other areas. At the end, you can find the best trade-off which minimise the shifts. It will never be perfect and will be smaller if you use a tripod.
To stitch images of sky of graound, you can get sometimes better results by making the lens parameters different. You can declare in the camera and lens tab that those images were taken with a different lens. Then the software will optimize changing independantly the focal and parameters of those images as well.
And you can run an optimisation only on those parameters separatly.
The result is getting even better, even if you have to do some trial and error.
On the above image, you shall not take into acount the strange effect on the sky. It is an Hugin artefact only for the preview.
Now, all you need is to "render" the image, by choosing the type of projection you want to generate. Either a classical 360°x180° also called "equirectangular projection" or a "stereographic projection" or "small planet" which is in fact a polar projection.
Once stitched, you can create the panorama as a TIFF format image with the assembling application linked by Hugin: Nona and Enblend. Enblend is really powerfull as it takes in charge the borders of the images, smoothing it and making unvisible.
Enblend Specifically it can litterally "delete" objects or people badly stiched over two pictures.
But sometimes you will have to manually help. To do this, you will have to modify the unitary TIFF images which are generated along the process. To generate some intermediate images, you have to click on the checkbox "reformatted image". With photoshop, or equivalent, you need to modify the alpha channel or layer to extend or remove it and then modify the portion of the image which has to be "smoothed" at the border. In this example, I extended the alpha layer to remove a moving person on one of the image to force the sofwtare to include only the portion of the person from one single image.
You need then to create the final panorama using the Enblend application on DOS, or using the "droplets" installed by hugin or your desktop. Put the single TIFF images in a directory then darg and drop the directory on the Enblend icon on your desktop. If you do it correctly you can really control the borders stitching even in difficult situation.
Stitching an optimisation are made in equirectangular mode. But to generate the final view, for the last step, you select the "stereographic projection" in the drop-down list.
In the preview window, the image looks strange... there is one additional paramater to adjust to center the projection on the ground and not on the horizon as previously, the transformation parameter.
Click on the menu item "transformation" and enter 90° in the "tangage" (pitching ?) value (I'm using hugin in french so I do not know how this really translate). This parameter will modify the view and a small planet will now appear. Finally, adjust the zoom cursors.
Here we are, the small planet appears suspended in the deformed sky.
Now, you can render the panorama the same way as seen before for an equirectangular projection. You can modify the orientation (rolling parameter) and complete with some final touch under your familiar image processing software.
if your best production deserves to be printed, keep the the large TIFF format for better resolution. To publish on the net, a reduced version in jpeg is maybe enough, as it will be faster to load. But the real interest of making 360°x180° panorama resides in the possbility to immerge the observer at the center of the place. The Quicktime VR application allows you to do that, you can find plug-in on the net.
If you want to include your panorama as an interactive one on your web pages, you first need to create a .mov movie at QTVR format using your panorama. I use the software "pano2qtvr", from the site http://gardengnomesoftware.com/pano2qtvr.php. It produces .mov movie as below.
you can parameterize the image size of the video, the starting point of view, the resolution, with the software configuration interface. Really practical, reliable and free.
If you own an account on the picture server Flickr, you can access directly to an interactive display "Field Of View": http://fieldofview.com/flickrtools/
In the desciption zone of your equirectangular panorama, add a link to this site with some parameters (see the site above) and the visitor can directly get access to the interactive view of your panorama without having to generate intermediate movie or images.
You can see the result here
A very easy way for your visitors, but linked to the Flickr site.
Some small planet of my production to illustrate some situation, click on the image to access the large format and desciption of the place. From right to left: inside the dome of the 193cm telescope (OHP) - Moonlight at Pic du Midi - Place du Capitole, Toulouse - Paris XVième
As I am astronmy amateur, do not miss the interactive view of the milky way at the summit of Pic du midi, during summer. Click on the image below...
Some outstanding small panet of the flickrnaute "gadl", Alexandre Duret-Lutz.
And from flickrnaute "Seb Przd", Seb Perez-Duarte.
Some examples of interactive movies from the author:
Links to sites or group to further explore some insolite work done:
Private collections from:
My personal collection on flickr: