Watch 3D Stereoscopic Panoramas on 360Cities.net
360Cities.net, the world's biggest spherical panorama publishing platform, is now hosting 3D stereoscopic panoramas. They can be viewed on phone-based VR devices, or on your PC screen if you have a mirror stereoscope. If you don't select VR mode, they are shown as 2D panoramas, with full range zoom. In VR mode they offer zoom over a smaller range, and static panning (with finger or mouse) in addition to the normal gyro-controlled panning.
What is a Stereoscopic Panorama?
A stereoscopic photo is a pair of images, taken simultaneously with two lenses placed like our eyes, about 65 mm apart and looking in the same direction. When presented to the two eyes by a stereoscope, these images give most people the impression of seeing a 3D space. A stereoscopic panorama is a pair of 360 degree images, which when viewed with synchronized pano viewers presents a stereo pair. The most popular stereoscope for viewing stereo panoramas is a virtual reality headset.
How to Create Stereo panoramas
The most obvious way to make a stereo panorama is to stitch together a series of stereo photos, taken by turning a pair of cameras. But such photos will not easily stitch to two seamless spheres, because each series was taken from a moving viewpoint, not from a single fixed point as assumed by standard stitching software. There are two basic ways to handle this problem:
- Take a large number of closely spaced stereo views. Then the panorama contains just a narrow vertical strip from each photo. If they are narrow enough, the errors between adjacent strips will be too small to see. This method is very reliable but has problems with moving subjects.
- Take a small number of stereo views, as for a regular panorama, and hide the errors by careful composition and masking. Moving subjects can be handled by masking, as in normal panography.
Both methods have single-camera variants, that need a truly static subject because the left and right views are taken at different times. For the “many views” method, the camera is mounted with the pivot axis 35 - 50 mm behind the pupil of a wide fish-eye lens, and a single series of images is taken. Left and right spheres are stitched from narrow strips selected from the right and left sides respectively of the images. For the “few views” method, two series of photos are taken with the camera shifted sideways + or - 35 mm from the normal centered position, and each series is stitched to one sphere. This is often called the “cha-cha” method because of the sideways shift.