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Depth-of-field
The depth of field (DOF) is the distance between the nearest and the furthest objects that are in acceptably sharp focus in an image captured with a camera. Factors affecting depth of field For cameras that can only focus on one object distance at a time, depth of field is the distance between the nearest and the farthest objects that are in acceptably sharp focus. "Acceptably sharp focus" is defined using a property called the "circle of confusion". The depth of field can be determined by focal length, distance to subject, the acceptable circle of confusion size, and aperture. Limitations of depth of field can sometimes be overcome with various techniques and equipment. The approximate depth of field can be given by: : \text \approx \frac for a given circle of confusion (c), focal length (f), f-number (N), and distance to subject (u). As distance or the size of the acceptable circle of confusion increases, the depth of field increases; however, increasing the size of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plenoptic Camera
A light field camera, also known as a plenoptic camera, is a camera that captures information about the '' light field'' emanating from a scene; that is, the intensity of light in a scene, and also the precise direction that the light rays are traveling in space. This contrasts with conventional cameras, which record only light intensity at various wavelengths. One type uses an array of micro-lenses placed in front of an otherwise conventional image sensor to sense intensity, color, and directional information. Multi-camera arrays are another type. Holograms are a type of film-based light field image. History Early research The first light field camera was proposed by Gabriel Lippmann in 1908. He called his concept " integral photography". Lippmann's experimental results included crude integral photographs made by using a plastic sheet embossed with a regular array of microlenses, or by partially embedding small glass beads, closely packed in a random pattern, into the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F-number
In optics, the f-number of an optical system such as a camera lens is the ratio of the system's focal length to the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical Engineering'', 4th Ed., 2007 McGraw-Hill Professional, p. 183. It is also known as the focal ratio, f-ratio, or f-stop, and is very important in photography. It is a dimensionless number that is a quantitative measure of lens speed; increasing the f-number is referred to as '' stopping down''. The f-number is commonly indicated using a lower-case hooked f with the format ''N'', where ''N'' is the f-number. The f-number is the reciprocal of the relative aperture (the aperture diameter divided by focal length). Notation The f-number is given by: N = \frac \ where f is the focal length, and D is the diameter of the entrance pupil (''effective aperture''). It is customary to write f-numbers preceded by "", which forms a mathematical expression of the entrance pupil diameter i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apodization
In signal processing, apodization (from Greek "removing the foot") is the modification of the shape of a mathematical function. The function may represent an electrical signal, an optical transmission or a mechanical structure. In optics, it is primarily used to remove Airy disks caused by diffraction around an intensity peak, improving the focus. Apodization in electronics Apodization in signal processing The term apodization is used frequently in publications on Fourier-transform infrared (FTIR) signal processing. An example of apodization is the use of the Hann window in the fast Fourier transform analyzer to smooth the discontinuities at the beginning and end of the sampled time record. Apodization in digital audio An apodizing filter can be used in digital audio processing instead of the more common brickwall filters, in order to avoid the pre-ringing that the latter introduces. Apodization in mass spectrometry During oscillation within an Orbitrap, ion tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperfocal Distance
In optics and photography, hyperfocal distance is a distance beyond which all objects can be brought into an "acceptable" focus. As the hyperfocal distance is the focus distance giving the maximum depth of field, it is the most desirable distance to set the focus of a fixed-focus camera. The hyperfocal distance is entirely dependent upon what level of sharpness is considered to be acceptable. The hyperfocal distance has a property called "consecutive depths of field", where a lens focused at an object whose distance is at the hyperfocal distance ''H'' will hold a depth of field from ''H''/2 to infinity, if the lens is focused to ''H''/2, the depth of field will extend from ''H''/3 to ''H''; if the lens is then focused to ''H''/3, the depth of field will extend from ''H''/4 to ''H''/2, etc. Thomas Sutton and George Dawson first wrote about hyperfocal distance (or "focal range") in 1867. Louis Derr in 1906 may have been the first to derive a formula for hyperfocal distance. Ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3D Reconstruction
In computer vision and computer graphics, 3D reconstruction is the process of capturing the shape and appearance of real objects. This process can be accomplished either by active or passive methods. If the model is allowed to change its shape in time, this is referred to as non-rigid or spatio-temporal reconstruction. Motivation and applications The research of 3D reconstruction has always been a difficult goal. By Using 3D reconstruction one can determine any object's 3D profile, as well as knowing the 3D coordinate of any point on the profile. The 3D reconstruction of objects is a generally scientific problem and core technology of a wide variety of fields, such as Computer Aided Geometric Design ( CAGD), computer graphics, computer animation, computer vision, medical imaging, computational science, virtual reality, digital media, etc. For instance, the lesion information of the patients can be presented in 3D on the computer, which offers a new and accurate approach in d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contessa Hyperfocal
Contessa may refer to: __NOTOC__ Entertainment * ''Contessa'' (film), a 2018 Indian film * ''Contessa'' (TV series), a 2018 Philippine television series * The Contessa, a character in the game show '' Where in the World Is Carmen Sandiego?'' * The Contessa, a villain from the ''Sly Cooper'' video game franchise; see '' Sly 2: Band of Thieves'' * ''Contessa'', a fictional ship the TV series ''Chuck''; see "Chuck Versus the Push Mix" Transportation * Contessa 26, a GRP yacht in a range of yachts built by Jeremy Rogers Ltd. and J. J. Taylor & Sons Ltd. * Contessa 32, a design in a range of GRP yachts built by Jeremy Rogers Ltd. * Hino Contessa, a 1960s car made by Hino Motors * Hindustan Contessa, an Indian car made by Hindustan Motors Other uses * Polina (singer) or Contessa, American-Russian singer See also * Barefoot Contessa (other) * Conte (other) * Contes (other) Contes may refer to: * Contes, Alpes-Maritimes, a commune in the Alpes-Maritime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DOF Scale Detail
DOF may stand for: Science * Depth of field, in photography a measurement of depth of acceptable sharpness in the object space, or subject space * Depth of focus, in lens optics describes the tolerance of placement of the image plane to the lens * Digital obstacle file, in aviation contains data on man-made obstacles * 2,5-Dimethoxy-4-fluoroamphetamine (DOF), a psychedelic drug. * Distance-of-Flight, a mass spectrometry technology. * Degrees of freedom, used in mechanics, statistics, as well as physics and chemistry. Music * Deeds of Flesh, a Death Metal band * Deutsch-Österreichisches Feingefühl or DÖF, a 1980s Austrian-German Neue Deutsche Welle pop band. Other * Dansk Ornitologisk Forening, Danish Ornithological Society * Department of Finance (Philippines), an executive department in the Philippines * Department of Finance (Northern Ireland), a government department in Northern Ireland * Diario Oficial de la Federación The (DOF; translated variously as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modulation Transfer Function
The optical transfer function (OTF) of an optical system such as a camera, microscope, human eye, or projector specifies how different spatial frequencies are captured or transmitted. It is used by optical engineers to describe how the optics project light from the object or scene onto a photographic film, detector array, retina, screen, or simply the next item in the optical transmission chain. A variant, the modulation transfer function (MTF), neglects phase effects, but is equivalent to the OTF in many situations. Either transfer function specifies the response to a periodic sine-wave pattern passing through the lens system, as a function of its spatial frequency or period, and its orientation. Formally, the OTF is defined as the Fourier transform of the point spread function (PSF, that is, the impulse response of the optics, the image of a point source). As a Fourier transform, the OTF is complex-valued; but it will be real-valued in the common case of a PSF that is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motion Blur
Motion blur is the apparent streaking of moving objects in a photograph or a sequence of frames, such as a film or animation. It results when the image being recorded changes during the recording of a single exposure, due to rapid movement or long exposure. Usages / Effects of motion blur Photography When a camera creates an image, that image does not represent a single instant of time. Because of technological constraints or artistic requirements, the image may represent the scene over a period of time. Most often this exposure time is brief enough that the image captured by the camera appears to capture an instantaneous moment, but this is not always so, and a fast moving object or a longer exposure time may result in blurring artifacts which make this apparent. As objects in a scene move, an image of that scene must represent an integration of all positions of those objects, as well as the camera's viewpoint, over the period of exposure determined by the shutter speed. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
