Stereo camera

Sputnik stereo camera. The two lower lenses are used for the photograph, while the third lens is used for composition.

A stereo camera is a type of camera with two or more lenses with a separate image sensor or film frame for each lens. This allows the camera to simulate human binocular vision, and therefore gives it the ability to capture three-dimensional images, a process known as stereo photography. Stereo cameras may be used for making stereoviews and 3D pictures for movies, or for range imaging. The distance between the lenses in a typical stereo camera (the intra-axial distance) is about the distance between one's eyes (known as the intra-ocular distance) and is about 6.35 cm, though a longer base line (greater inter-camera distance) produces more extreme 3-dimensionality.

In the 1950s, stereo cameras gained some popularity with the Stereo Realist and similar cameras that employed 135 film to make stereo slides.

3D pictures following the theory behind stereo cameras can also be made more inexpensively by taking two pictures with the same camera, but moving the camera a few inches either left or right. If the image is edited so that each eye sees a different image, then the image will appear to be 3D. This method has problems with objects moving in the different views, though works well with still life.

Stereo cameras are sometimes mounted in cars to detect the lane's width and the proximity of an object on the road.

Not all two-lens cameras are used for taking stereoscopic photos. A twin-lens reflex camera uses one lens to image to a focusing/composition screen and the other to capture the image on film. These are usually in a vertical configuration. Examples include would be a vintage Rolleiflex or a modern twin lens like a Mamiya C330.

Nimslo quadralens lenticular

Types of stereo cameras

Vérascope 40
A Kodak stereo camera
A View-Master Personal stereo camera

There have been many types of cameras that take stereo images, most of which are no longer manufactured. The most notable types are:

In 2009, 3D technologies experienced a resurgence,[3][4][5] including stereo cameras, with continuing developments in plenoptic camera technologies, as well as the emergence of stereo digital camera products such as the Fujifilm FinePix Real 3D series[6] and the Minoru 3D Webcam.[7]

Since 2014, computer vision developments and increasing embedded GPU computing power have opened up new applications for stereo cameras. These can be used to calculate a depth map through advanced image processing techniques. In April 2015, Intel has revealed a camera that can fit in a smartphone to serve various depth sensing applications such as changing the focus of a photo after it has been taken, 3D scanning and gesture control.[8] Other recent stereo cameras include the ZED Camera,[9] Tara - Stereo Camera[10] and the Duo 3D Sensor [11]

Digital stereo bases (baselines)

There are different cameras with different stereo bases (distances between the two camera lenses) in the nonprofessional market of 3D digital cameras used for stills and video:

Use of multiple cameras

Dual cameras

Modern low cost digital cameras, and even DSLR cameras, can be mounted in pairs, with both triggered simultaneously. For nonmoving images this can be done by pressing both camera actuating buttons simultaneously, but this is not sufficiently accurate for moving objects. Certain camera models can accept modified programming from an image chip, and the software to trigger a slave camera from a master has been developed as open source software. A popular example of this technology is in the Samsung Galaxy S4, which allows photo capture simultaneously.[12]

Use of one camera and one lens

In late 2012, Samsung announced its NX300 camera. Using just one (optional) lens, this camera can take 2D photos, 3D photos, or Full HD movies, simply by changing the mode. The optional lens is a proprietary, 45mm f/1.8 prime lens. The NX300 has two LCD screens in the optical path which are used to "black out" their respective half of the lens, sending a slightly different image to the sensor.[13]

Another method is used by Sony and Panasonic. With burst captures, the camera should be shifted sideways about 10 centimeters and the camera will choose the two best images with which to create a 3D MPO file. The depth is not as good, but can certainly allow the differentiation of what is in front and what is behind.[14]

See also

References

  1. "Discontinuation of RBT cameras". Stereoworld. 36: 2, 26–27. 2011.
  2. "RBT-Raumbildtechnik GmbH". Rbt-3d.de. Retrieved 2016-06-05.
  3. "Archived copy". Archived from the original on August 13, 2011. Retrieved July 26, 2009.
  4. Sieberg, Daniel (2009-01-08). "Buzzwords Fly At Consumer Electronics Show". CBS News. Retrieved 2016-06-05.
  5. "V-Screen turns PSP into 3D". Coolest Gadgets. 2009-11-13. Retrieved 2016-06-05.
  6. "Archived copy". Archived from the original on July 26, 2009. Retrieved July 26, 2009.
  7. "Minoru 3D Webcam Launches at CES Las Vegas". Minoru3D.com. Retrieved 2016-06-05.
  8. "Intel RealSense 3D depth camera fitted into smartphone". BBC News. Retrieved 2016-06-05.
  9. "ZED - Stereo Camera for Depth Sensing". Stereolabs.com. Retrieved 2016-06-05.
  10. "Tara - USB stereo camera". Retrieved 2016-07-27.
  11. "DUO - A compact USB camera for sensing space". Duo3d.com. Retrieved 2016-06-05.
  12. "Archived copy". Archived from the original on March 26, 2013. Retrieved April 4, 2013.
  13. "Samsung announces NX300 - 3D-capable 20MP mirrorless camera". January 3, 2013.
  14. Ken McMahon. "Panasonic Lumix FZ70 / FZ72 review". Retrieved January 24, 2015.

External links

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