Gigapan: hosting for photopans + technical means of their creation

It is not difficult to see that some habra people have recently been keen on the merits of a software called Photosynth , which is produced by Microsoft and allows you to look at the same scene from different points of view, using photos taken from different sides. Search in Habrahabru finds two whole pages with Habratopics about Photosynth ( first page , second page ).

However, for some reason, no one has yet created a story about Gigapan in Habrahabr (the search does not detect anything ). The topic is completely new. Meanwhile, fans of Photosynth (and indeed, in general, of all photography lovers) will surely like the story of Gigapan. After all, Photosynth and Gigapan to a certain extent complement each other. Or rather, they are approximately like parallels and meridians - and they complement, but they are also perpendicular in meaning.

But this is a metaphor. And to compare Photosynth and Gigapan is most appropriate with an example.
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We will have an example at the highest shtatovskom level.

At the level of the president.

Those who looked at the main page of Photosynth.net , certainly remember the photosynthetic scene of Barack Obama’s inauguration, glued together from many images.

Now look at the Gigapan website , what the scene of the inauguration of Barack Obama looks like, also glued together from many images.

Immediately it becomes clear how well different tools.

Photosynth stores three-dimensional scenes with the ability to look at one object (object, scene) from different points, in one word - to inspect. The main thing in such a scene is volume (the ability to see any visible object from different sides).

Gigapan stores photo panoramas with the ability to look from one point to different directions, in a word - look around. The main thing in this panorama - detail (the ability to see any visible object under high magnification).

This is an ideological difference. And there is also a software: Photosynth is made by Microsoft and requires the installation of a special plug-in that works only on Microsoft operating systems (and even then not in all). Gigapan is not made by Microsoft, it does not require any special plug-in, it works in normal Flash and in all those operating systems and browsers for which Flash exists. In addition, Gigapan photo panoramas can also be viewed in Google Earth, and in exactly the same way as you view the spherical panoramas of Google Street View in the same place.

This is the end of the Photosynth and Gigapan comparison; more will go on a more detailed story about the origin and possibilities of Gigapan.

Gigapan is a joint project of Carnegie Mellon University and NASA and Google, born on the basis of a kind of "bringing down from heaven to earth" of one of NASA's space technologies, namely, such a robot arm , which allowed every rover there to automatically roll a relatively low megapixel camera in different directions consistently do it several dozens and even hundreds of photographs, then docking them and getting a large-scale (multi-megapixel, even multi-megapixel!) photo panorama of the entire surrounding space.

On Earth, this turned out to be a product called Gigapan Epic - a relatively inexpensive (slightly less than 380 bucks) robotic photo stand, in which an ordinary digital camera is inserted so that the “finger” of the robot can press the camera's trigger. Then the photographer sets the left upper and right lower position of the “arm” of the robot, and the robot does the rest, that is, methodically and quickly “shares” the entire space given to it, and makes adjacent frames “overlap” for subsequent stitching together for common joints.

Along with a tripod and sold a special program docker.

Tripod robot looks like this:



But the reverse side of it:



The resulting multi-megapixel panoramas can be uploaded to Gigapan.org site for free, after which they can be viewed as a flash viewer. If you additionally specify the coordinates (and the azimuth of the rotation) of such a photo-panorama, then it will be visible in Google Earth as well - the view will be “from the inside of the sphere”, as in the Street View mode. If the panorama is not quite spherical (that is, not all 360 ° turns around the vertical axis, and (or) not all 180 ° from top to bottom from the zenith to the nadir), then the panorama will take only a part of the sphere - the rest will be transparent, displaying located behind the sphere Google Earth's landscape model, created by snapping satellite photography onto an elevation map.

In addition to the coordinates and azimuth of the photo-panorama, you can also set the diameter of the sphere and the height of its center over the earth in Google Earth. (If the sphere intersects with the earth, then the lower part of the sphere will turn out to be naturally invisible.)

And now the main and most beautiful feature: Gigapan photohosting accepts and places not only those photo panoramas that are made with its own equipment. It is not necessary to first order the sending of Gigapan Epic from the States, and then use Gigapan Epic to make and upload your photo panorama to Gigapan.org, give it to your friends and to the entire Web, and to Flash, and to Google Earth.

FAQ Gigapan clearly states that you can use your own tripod, you can use any means of automated gluing photos (for example, PTGui or Autopano Pro ), the only limitation is the detail of the photo panorama: at least fifty megapixels.

From myself, I’ll add one more to the information from this FAQ: there is also a third useful dock, called hugin . Useful by the fact that cross-platform.

The sequence of actions for the manual manufacture of a photo panorama (without any Gigapan Epic) is what it is:

1) Acquire (or take an existing) photographic stand of the type on which the parrots sit :



2) Place the photo stand at the point of shooting and fasten the camera so that the camera turns (around its center), but the center of the camera does not move, or near objects on neighboring frames (for example, bushes or hedges) will block distant objects (for example, buildings or mountains) in different ways, so that the joining of such neighboring frames will not work (or it will turn out so bad that it would be better not get).

3) Make a series of frames, a rectangular grid covering the space and overlap joined to each other. At the same time, try not to allow moving objects to appear at the joints (passers-by, vehicles, clouds, animals, tree branches in the wind).

4) Take the camera home, set up an automatic docking system on a series of shots, enjoy the result.

5) Upload a photo panorama into Gigapan, drag it in the same place in Google Earth onto a meter or two meter diameter sphere located above the ground at the height of its diameter (for reliability) and located geographically accurately.

In general, that's all.

The photo panorama automatically replenishes the KML file with the coordinates of all Gigapan photo panoramas . (Download with caution: this monster weighs more than thirteen megabytes.) If Google thinks that the photo panorama is worthy of their Google , then they will also include it in a special “Gigapan” layer available to all Google Earth users. So you can observe some of the streets and buildings of Moscow, St. Petersburg and many other cities, to which Google Street View cars have not yet reached (and are unlikely to get there in a short time), as well as the space away from the roads.

A few simple practical tips:

1) If the angle of rotation around the vertical axis during shooting is 360 °, then you know its exact value, not the approximate one: it will not be possible to under-extend or overgrow the panorama when it is pulled onto a sphere, and this is good. And then the horizon will also not be overwhelmed by a straight line — at worst, a sine wave that completely encompasses a 360 ° horizontal rotation with its own sine period.

2) If you are shooting in the shade, then the sun will not strike directly into the lens wherever you turn it. It's good.

3) Leave to the horizon sections of streets, bridges and other directions of movement leave in the center of the frame, and not on the edge, otherwise the movement of objects will create a difference between adjacent frames at the junction. For the same reason, it is appropriate to place the horizon in the center of the frame.

4) Try not to change the magnitude of the exposure between adjacent frames, or the splicer will involuntarily make bright objects at the junction of frames (or near such a junction) “lit”, adjusting the brightness of adjacent frames to each other.

Finally, I note that Gigapan is not the only hosting for photo-panoramas. For example, there is the 360 Cities project, which, however, is more fastidious, taking only fully spherical panoramas, not partial ones. The approach of the Gigapan site seems to me more far-sighted, because it is better not to be able to look at the skies or under our feet, rather than not having a photo of a certain place at all.