Virtual tour

Stitching photographs

There are several ways of stitching virtual tours together.

Rectilinear stitching

This involves the rotation of a digital camera, typically in the portrait (up and down) position and centered directly over the tripod. As the operator manually rotates the camera clockwise, the camera stops or clicks into a detent at regular intervals, such as every 30° of rotation. The rotator can be adjusted by changing the position of "detent ring or bolt," into another slot, to alter the interval of rotation: 40°, 60°, 90° etc.

If a given camera lens supports a wider view, one could select a larger detent value (for example, 60° instead of 30°). With a larger detent interval, fewer images are needed to capture a complete panoramic scene. The photographer may only need to take 6 shots as opposed to 10 shots to capture the same panorama. The combination of a precision rotator and a digital camera allows the photographer to take rectangular "slices" of any scene (indoors or outdoors). With a typical point and shoot digital camera, the photographer will snap 8, 10, 12 or 14 slices of a scene. Using specialized "photo stitching" software, the operator then assembles the "slices" into a single rectangular image, typically 4,500 pixels to 6,000 pixels wide. This technique, while extremely time consuming, has remained popular even through today as the required equipment, rotator heads and software are relatively inexpensive and easy to learn. A stitched panoramic view is also called "cylindrical"—as the resulting stitched panorama allows panning in a complete 360°, but offers a limited vertical field of about 50° degrees above or below the horizon line.

Spherical stitching

This method requires the use of a "Fisheye lens" lens equipped digital SLR camera. The 2-shot fish eye camera system was made popular by IPiX in the mid-1990s and a two-shot rotator head that rotated and locked into 0° and 180° positions only. The camera was an Olympus or Nikon CoolPix camera and the lenses used were the Nikon FC-E8 or FC-E9 fish-eye lens. The IPiX 360 camera system enabled photographers to capture a full 360 X 360 floor to ceiling view of any scene with just 4 shots as opposed to the more time consuming 8, 10, or 12-shot rectilinear produced panoramas described above. This type of virtual tour required more expensive virtual tour camera equipment including (for example) a Sigma 8mm f/3.5 lens which allowed photographers to set their rotator heads to 90° and capture a complete virtual tour of any scene in just 4 shots (0°, 90°, 180°, 270°).

Cubical stitching

This technique was one of the first forms of immersive, floor to ceiling virtual tours. Apple Computer pioneered this with the release of Apple's QuickTime VR in the early 1990s. Free utility software such as Cubic Converter and others allowed photographers to stitch and convert their panoramas into a "cube" like box to achieve a complete 360 X 360 view. Today, this technique is considered rather "old school," and spherical stitching has become more mainstream for producing these types of tours.

One-shot optics

Using one-shot panoramic optics one can create quick and easy panoramic videos and images such as the type used on the iPhone.

While programs such as Adobe Photoshop have new features that allow users to stitch images together, they only support "rectilinear" types of stitching. Photoshop cannot produce them as quickly or accurately as stitching software programs can such as Autodesk Stitcher. This is because there is sophisticated math and camera-lens profiles that are needed to create the desired panorama image which is based on your camera's depth of field (FOV) and the type of lens used. Cameras such as the Nikon D3 or D700 have a full frame digital SLR cameras, whereas the Nikon D90 or Canon T2i (Rebel line of Digital EOS cameras) have a smaller sensor. When full frame digital SLR cameras are used with a fish eye lens such as a Sigma 8mm F/3.5, a full circular image is captured. This allows you to shoot 2 or 3 shots per view to create a 360 X 360 stitched panoramic image. When used with a non full frame digital SLR camera like the Nikon D90 or Canon digital Rebel and similar cameras, 4-shots are required with the camera in the portrait position. The resulting image will have the left and right sides cropped off each of the 4 images and each of the four corners, creating a rounded image.

Video-based virtual tours

With the expansion of video on the internet, video-based virtual tours are growing in popularity. Video cameras are used to pan and walk-through real subject properties. The benefit of this method is that the point of view is constantly changing throughout a pan. However, capturing high-quality video requires significantly more technical skill and equipment than taking digital still pictures. Video also eliminates viewer control of the tour. Therefore, the tour is the same for all viewers and subject matter is chosen by the videographer. Editing digital video requires proficiency with video editing software and has higher computer hardware requirements. Also, displaying video over the internet requires more bandwidth. Due to these difficulties, the task of creating video-based tours is often left to professionals.

Recently different groups have been using Google's system to provide access to private areas, which were previously unavailable to the general public.^[5]

Specialized software

Various software products can be used to create virtual tours.

Web-based or online

For most business purposes, a virtual tour must be accessible from everywhere. The major solution is a web-based virtual tour. In addition, a rich and useful virtual tour is not just a series of panoramic pictures. A better experience can be obtained by viewing a variety of materials such as that obtained from videos, texts, and still pictures in an interactive web content. There are many ways to gather data in a mixed web content, such as using rich content builders (Java applet or Adobe Flash being two examples) or a Web content management system.

Flash-based tours are becoming very popular today. A study done by the PEW Research Group showed that more than 5 million Americans watched virtual tours every day in 2004. PEW's research data which showed that Americans watching virtual tours rose from 54 million people in 2004 to 72 million people by August 2006, a two-year increase of 18 million.

Thanks in part to the recent explosion of many Internet devices, such as Apple's iPad, iPhone and other tablet computing platforms powered entirely by Google's Android 3 operating systems such as Motorola's Xoom, it can be predicted that consumption of virtual tour content, through the use of Adobe Flash and HTML5/CSS3 driven virtual tours will only increase over time.

Real estate

Virtual tours are very popular in the real estate industry. Several types of such tours exist, including simple options such as interactive floor plans, and more sophisticated options such as full-service virtual tours. An interactive floor plan shows photographs of a property with the aid of a floor plan and arrows to indicate where each photograph was taken. Clicking on arrows shows the user where the camera was and which way the camera was pointing. Full service virtual tours are usually created by a professional photographer who will visit the property being sold, take several photos, and run them through stitching software. Matterport offers 3D camera services to create virtual tours. Full service virtual tours are usually more expensive than interactive floor plans because of the expense of the photographer, higher-end equipment used, such as a digital SLR camera, and specialized software. Real estate virtual tours are typically linked to the listing in the Multiple Listing Service.

Historic Preservation

3D virtual tour technology has been increasingly used in the documentation and preservation of historic properties that are at risk of being razed or undergoing restricted public access. 3D virtual models using standard file formats, such as the Object file (.obj) format, can be stored in digital archives for future academic research and exploration.^[6]

Hospitality

Virtual tours are also popular in the hospitality industry. Hotels are increasingly offering online tours on their websites, ranging from "360" stitched photos to professionally produced video tours. These tours are typically offered by hotels in an effort to increase booking revenue by providing online viewers with an immersive view of the property and its amenities.

Virtual walks

Virtual walk videos are documentary motion pictures shot as the camera continuously moves forward through an urban or natural area. The effect is to allow viewers to experience the sights they would see and the sounds they would hear were they actually traveling along a particular route at the same pace as the camera. Virtual walks based on real-world photography typically do not require the use of virtual reality goggles or headsets of the kind used by gamers.

In realistically simulating the experience of moving through space, virtual walks—or virtual runs or bicycle rides—differ from conventional travel videos, which typically consist of a sequence of mostly static camera setups along a particular route or within a given area. The advantage of the conventional travel video is that one or more narrators or on-screen guides can provide insights into the geographical, historical, political, military, cultural, geological, or architectural aspects of the area.

Virtual walks appeal to those who want to experience the sights and sounds of particular places in the country or the world, but who may not have the time or the financial or physical resources to actually travel there. They also appeal to treadmill or elliptical trainer users, for whom walking or running while watching these videos enhances the reality of the experience (and, at a minimum, reduce the boredom of the exercise).

Some feature-length narrative motion pictures have made use of the virtual walk technique for dramatic purposes. These include the opening sequences of Orson Welles’ Touch of Evil and Robert Altman’s The Player, the famous tracking shot through the Copacabana in Martin Scorcese’s Goodfellas, Alexander Sokurov’s Russian Ark (which consists of a single 96-minute Steadicam take), and, more recently Alfonso Cuarón’s long tracking shots in Gravity, and almost the entire narrative structure of Alejandro Gonzáles Iñárrito’s Birdman.