Realización de un panorama cúbico

Some weeks ago we tested Stitcher version 3.0, a panorama creation software from the french company Realviz (http://www.realviz.com), at our Macuarium labs. Version 3.1 is out now. Given the small differences with respect to version 3.0 in the interface interaction, we will try to analyze new features that didn't make to the last article.

First thing, this software is totally native under Mac OS X. The installation is very simple and does not pose any problem at all.

The application consists basically in a desktop where the images are dragged manually until they do fit. Once the panorama's perimeter is completed, it is then closed on itself and several types of panoramas can be rendered.

The greatest advantage of this application is its versatility. It allows for the creation of VR, Cubic VR or spheric panoramas, planar images, exporting the sides of the cubic or VR panorama in order to edit them and add a logo or doing image retouching for instance. All these features make this application an ideal tool for creating web or CD-ROM content.

Let us show now how to create a cubic panorama step by step.

Starting at the beginning

The first step is takings the photos. These photos can be made with a film or a digital camera, we will have to scan the film (negatives or slides) in case we don't make use of a digital camera. Given how time consuming the scanning process is, it is clear for us that a digital camera, although not mandatory, is highly desirable for a smooth work flow with this software. Any digital camera will do the job, although we do prefer one that can make use of wideangle lenses. For a cubic panorama it is advisable the use of at least 24 mm lens, as with a lesser focal lenght the number of photos would be excessive. The photos employed in this article were made with a Nikon Coolpix 990, 24 mm wideangle lens and at a resolution of 1024 x 768 pixels.

A great advantage of Stitcher over other applications is that the images can be placed manually at any position, which allows for taking the pictures without a tripod and then correcting the errors. But this procedure has to be taken only as an emergency case: to obtain the "perfect" panorama it is highly desirable to use a tripod, which should have a pivoting arm, specially with objects close to the camera.

In Spain these kind of accessories can be found at: http://www.todopanoramas.com or in the U.S.A. at http://www.kaidan.com

For the panorama shown in this test we made 12 photos at 0 degrees, 12 at -50 degrees, 12 at +50 degrees and one of the zenith for a total of 37 takes. The place chosen for taking the photos is the Cerro de Santa Catalina in Gijon (Asturias, Spain).

We have to download the photos now, we can use iPhoto for this task. This nice application (free from Apple) allows us to preview the photos and discard the defective or repeated ones. All the valid ones are put together in a folder.

Now we can open Stitcher and import them. Once the photos are imported they appear in a floating window. We just apply a turn to put them in vertical position

Image 1

Now we can drag the first photo to the desktop that the utility presents us with. Next we drag the second image and make it fit approximately. Press the Enter key and the software does the rest.

We can change the size of the image or move around the working desktop by pressing Command (or Option) + clicking with the mouse. We can see this behaviour in this screen capture.

Image 2

When we have completed the first 11 photos we have to adjust the view point to see the start.

Image 3

Finally we "stitch" the last photo at the beginning of the panorama and select a choice in the "close panorama" menu. The desktop turns blue and we only have to drag the last photo into place and press "Enter" to close the circle.

Image 4

Now we have to "stitch" the photos we shot at -50 degrees. The procedure is similar to the one already described with the first row except that now we can pivot the images around its center (pressing Shift + Ctrl) in order to place them properly with more ease. Of course, the images already glued together can be unstitched doing a Ctrl + click and using the Contextual menu if we detect some mistake.

Image 5

We perform the same operation with the sky, the photos taken at +50 degrees. This task is particularly difficult in this panorama as the sky is covered with diffuse cirrus and there are not many points of reference. In the case of a completely open sky this task can be really complicated. In fact, when we try the auto stitching of the images, the software is not able to perform it automatically given the absence of points of reference. To solve this problem we have no other option than doing the fitting manually and without stitching. This task demands some practise so we should start with an easier panorama (like the one in the tutorial, an interior with a lot of details) if we are beginners with the software. In the next screen capture we can observe how the photos are tilted.

Image 6

We will see a hole in the zenith if everything went ok. We do have to put here the photo we took for the zenith.
Finally, let's see what can we do with the hole we are left with in the floor in the next image.

Image 7

We do have two options, namely: when we are taking the photos we can just displace the tripod and make a photo of the ground, the other option is retouching the panorama. The first option has its own difficulty if the ground presents details, so that when we change the perspective it is not very likely to match perfectly . The second option is the most logical one. We have to render a cube to achieve it.

In the rendering options of the application we can see an option named "Cubic", we choose TIFF as the output format. Before performing the rendering it is advisable to equalize the images to avoid tone differences and noticeable transitions in the stitches. Once the cube is rendered we will find 6 TIFF files, one for each side of the cube, which we can alter with our preferred graphics tool to amend possible errors, rectify the stitches or fill the hole in the floor of the panorama. We decided to put the Macuarium and Realviz logos in this one although, of course, you can choose any image you want.

Final render

We save all the files and turn into Stitcher again. We click in the "Panorama Conversion" menu and choose the cube archives. Now we can make the final rendering. We have lots of possibilities to play with, from a cubic VR to conventional (spheric) panoramas all with different compression algorithms and view options. These are among the best features of the application and make it shine above its competitors. The final result can be viewed in the following example.

The QuickTime file

Click to see the results

The rendering time in a Powermac G4/400 with 1,1 Gb of RAM is 4 min. for the sides of the cube and 40 seconds for the QuickTime file. The complete time we used in building the panorama is slightly higher than half an hour, although the first ones take considerably more due to the lack of expertise with the software. The application has got a Help in HTML format and a tutorial that we would say is a mandatory read before starting to use the program.

All in all we can affirm that Stitcher is a great panorama utility and if we have to pick one, this is the most versatile in the market. We have found very few defects, although we would like to see support for nodes within the QuickTime movies.