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Image stabilization is a family of techniques to increase the stability of an image. It is used in image-stabilized binoculars, photography, videography, and astronomical telescopes. With still cameras, camera shake is particularly problematic at slow shutter speeds or with long focal length (telephoto) lenses. With video cameras, camera shake causes visible frame-to-frame jittering in the video recorded. With astronomy, these problems are compounded by variations in the atmosphere over time, which causes the apparent position of objects to move.
Techniques of image stabilization
Optical Image Stabilization
An Optical Image Stabilizer, often abbreviated as OIS, is a mechanism used in a digital still camera or video camera that stabilizes the recorded image by varying the optical path to the sensor.What is Optical Image Stabilizer?, Technology FAQ, Canon Broadcast Equipment It works by having a floating lens element that is moved relative to the rest of the lens, typically by using gyroscopes.Glossary : Optical : Image Stabilization, Vincent Bockaert, Digital Photography ReviewMoving the image sensor
The sensor capturing the image may be moved in such a way as to counteract the motion of the camera. Konica Minolta used a technique called "anti-shake" now marketed as steadyshot in the Sony α line, which relies on a very precise angle speed sensor to detect camera motion.Dynax 7D Anti-Shake Technology, Konica Minolta Other manufacturers use DSPs to analyze the image on the fly and then move the sensor appropriately.Digital image stabilization
Digital image stabilization is used in some video cameras. This technique shifts the electronic image from frame to frame of video, enough to counteract the motion. It uses pixels outside the border of the visible frame to provide a buffer for the motion.Orthogonal Transfer CCD
Used in astronomy, an orthogonal transfer CCD (OTCCD) actually shifts the image within the CCD itself while the image is being captured, based on analysis of the apparent motion of bright stars. This is a rare example of digital stabilization for still pictures. An example of this is in the upcoming gigapixel telescope Pan-STARRS being constructed in Hawaii.Pan-STARRS Orthogonal Transfer CCD Camera Design, Gareth Wynn-Williams, Institute for AstronomyReferences
- gyroscopic stabilization in aerial photography, Multimedia: Use Image Stabilization, Andy King, Web Site Optimization, 2004
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