Making a spherical panorama by Google

Three days ago (April 16, 2014) the Google Camera application, previously available only to Nexus owners, was published on Google Play. The day before yesterday (April 17), I read about it on AndroidInsider.ru, downloaded, tried to make a spherical panorama. Succeeded.

I share my impressions.

First of all, I will say that the application (which, for simplicity, I will call Googlekamera), is installed only on KitKat (Android 4.4). Yesterday I tried to install it on one of last year’s Galaxy Tab models still working on Jelly Bean (Android 4.2) - this attempt failed. However, on the HTC One mobile phone (even on the first model, not this year), the Google Camera is installed smoothly.
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When you start Google Camera opens full screen:



A menu of photo and video modes appears on the left, of which I have selected the top one (“Photo Sphere”). Pay attention also to the gear in the right corner of the screen (in the upper corner for landscape and in the lower for portrait orientation): this gear serves to access additional settings. After selecting the mode (or just after a second), the menu hides to the left (from where you can later pull it out with your finger), and the translucent dark background of the menu disappears, fully opening the spherical photographing interface.

However, even without that (in the previous screenshot) you can see that the background for such an interface is a virtual “ floor ” consisting of square “tiles”, the corners of which are shown with light cross-shaped marks. The position of this floor responds only to the accelerometer readings, that is, it does not rotate when the device turns around a vertical axis parallel to the action of gravity. Above the floor is a virtual sphere , on which are placed the photographs from which the spherical panorama will be composed.

The production of individual photographs takes place semi-automatically according to the principle, which is explained by the hint “for a start, put a dot in a circle” (“to start, keep dot inside circle”). In the center of the field of view there is a circle that needs to “catch” points located on the sphere’s parallels at an equal distance from each other (moreover, on the equator of the sphere, which corresponds to the photographer’s horizon , there are more such points, and on the remaining point parallels the smaller the closer to the zenith above the head of the photographer or to the nadir under his feet); at such and such moments, the camera, which is precisely aimed at the next point, takes a photograph.

The first such point is always located at the equator and in the place where the “line of sight” of the apparatus crosses the equator for the first time. After the first picture was taken, the google camera calculates that the remaining pictures will be taken in the same orientation (portrait or landscape) and arrange the corresponding number of points on the parallels of the sphere; in addition, the background "floor" begins to react to rotation around the vertical axis; in addition, it is the point of the first image that becomes the central one in the rectangle, which ultimately turns out - after the sphere has been turned into a plane.

If the device is skewed or if you rotate it too quickly (so that the image is blurred), the Google camera will warn you about it. In general, I noticed that the picture is obtained the more qualitatively, the slower to bring the circle to the point, especially at night.

Points on a sphere can be “caught at sight” in a different order. For example, that Google Maps video recommends moving along parallels: first make a full circle along the horizon, and then a few more circles parallel to it. But I noticed, to my regret, that with such behavior it is very difficult to tread, standing completely in the same place - and in fact a step to the side is inevitably fraught with the appearance of parallax distortions when docking neighboring photos on the sphere. Therefore, I prefer, on the contrary, first of all to walk along one “meridian” (from the horizon to the zenith and nadir, if necessary, deviating aside to take into account an unequal number of points on adjacent parallels), and only then turn and continue.

You can interrupt the compilation of a set of photographs on a sphere (and proceed to their automatic docking) at any time (and not only when the sphere has been completely photographed). If the photosphere is not completed, then all non-photographed parts of it will be black on the final photo panorama. The docking progress is displayed (both in percent and in a creeping completion line) on the system-wide notification bar in Android.

I will cite for example a photo panorama made by me (and a google block) the day before yesterday. It completely (360 ° × 180 °) depicts the Gelendzhik embankment at sunset near the entrance to the Laguna Grill.



This photo panorama has a size of 9728 × 4860 pixels and occupies 5 914 774 bytes. It can be seen that the automatic docking everywhere was tolerable, except for a couple of places on the pavement and the parapet of the embankment.

When viewing, one inevitably faces the fact that the Nexus googlomer lacks the Nexus viewer of spherical photopans. After: there is such .

A big problem is also the publication of a photo panorama on the Internet: many image hosting sites are simply not suitable for storing such a whopper. For example, hostingkartinok.com does not accept photos of more than 3 megabytes, and FastPic refuses to accept more than 25 megapixels (whereas the picture has more than 47 megapixels). Twitter, however, accepts meekly, but shrinks the image up to 1024 pixels (exactly 9½ times) and, at the same time , drastically reduces its JPEG quality, so it’s completely impossible to look at the small details of it (which is, in fact, the main pleasure of looking at the photo pan). As a result, for Habrakhabr , I posted a photo panorama on PicShare ; nevertheless, I have to admit that I still haven’t found such a photo hosting service that would not only accept photos of substantial size, but also support Twitter Cards for a miniature preview on Twitter.