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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 transie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bokeh
In photography, bokeh ( or ; ) is the aesthetic quality of the blur produced in out-of-focus parts of an image. Bokeh has also been defined as "the way the lens renders out-of-focus points of light". Differences in lens aberrations and aperture shape cause very different bokeh effects. Some lens designs blur the image in a way that is pleasing to the eye, while others produce distracting or unpleasant blurring ("good" and "bad" bokeh, respectively). Photographers may deliberately use a shallow focus technique to create images with prominent out-of-focus regions, accentuating their lens's bokeh. Bokeh is often most visible around small background highlights, such as specular reflections and light sources, which is why it is often associated with such areas. However, bokeh is not limited to highlights; blur occurs in all regions of an image which are outside the depth of field. The opposite of bokeh—an image in which multiple distances are visible and all are in focu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Window Function
In signal processing and statistics, a window function (also known as an apodization function or tapering function) is a mathematical function that is zero-valued outside of some chosen interval, normally symmetric around the middle of the interval, usually near a maximum in the middle, and usually tapering away from the middle. Mathematically, when another function or waveform/data-sequence is "multiplied" by a window function, the product is also zero-valued outside the interval: all that is left is the part where they overlap, the "view through the window". Equivalently, and in actual practice, the segment of data within the window is first isolated, and then only that data is multiplied by the window function values. Thus, tapering, not segmentation, is the main purpose of window functions. The reasons for examining segments of a longer function include detection of transient events and time-averaging of frequency spectra. The duration of the segments is determined in ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fourier-transform Infrared Spectroscopy
Fourier-transform infrared spectroscopy (FTIR) is a technique used to obtain an infrared spectrum of absorption or emission of a solid, liquid, or gas. An FTIR spectrometer simultaneously collects high-resolution spectral data over a wide spectral range. This confers a significant advantage over a dispersive spectrometer, which measures intensity over a narrow range of wavelengths at a time. The term ''Fourier-transform infrared spectroscopy'' originates from the fact that a Fourier transform (a mathematical process) is required to convert the raw data into the actual spectrum. Conceptual introduction The goal of absorption spectroscopy techniques (FTIR, ultraviolet-visible ("UV-vis") spectroscopy, etc.) is to measure how much light a sample absorbs at each wavelength. The most straightforward way to do this, the "dispersive spectroscopy" technique, is to shine a monochromatic light beam at a sample, measure how much of the light is absorbed, and repeat for each different ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depth-of-field Bracketing
In photography, bracketing is the general technique of taking several shots of the same subject using different camera settings. Bracketing is useful and often recommended in situations that make it difficult to obtain a satisfactory image with a single shot, especially when a small variation in exposure parameters has a comparatively large effect on the resulting image. Given the time it takes to accomplish multiple shots, it is typically, but not always, used for static subjects. Autobracketing is a feature of many modern cameras. When set, it will automatically take several bracketed shots, rather than the photographer altering the settings by hand between each shot. Types of bracketing Exposure bracketing Image:StLouisArchMultExpEV-4.72.JPG, –4 stops Image:StLouisArchMultExpEV-1.82.JPG, –2 stops Image:StLouisArchMultExpEV+1.51.JPG, +2 stops Image:StLouisArchMultExpEV+4.09.JPG, +4 stops Without further qualifications, the term ''bracketing'' usually refers to expos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diaphragm (optics)
In optics, a diaphragm is a thin opaque structure with an opening (aperture) at its center. The role of the diaphragm is to ''stop'' the passage of light, except for the light passing through the ''aperture''. Thus it is also called a stop (an aperture stop, if it limits the brightness of light reaching the focal plane, or a field stop or flare stop for other uses of diaphragms in lenses). The diaphragm is placed in the light path of a lens or objective, and the size of the aperture regulates the amount of light that passes through the lens. The centre of the diaphragm's aperture coincides with the optical axis of the lens system. Most modern cameras use a type of adjustable diaphragm known as an iris diaphragm, and often referred to simply as an iris. See the articles on aperture and f-number for the photographic effect and system of quantification of varying the opening in the diaphragm. Iris diaphragms versus other types A natural optical system that has a diaphragm an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffraction Disc Calculated
Diffraction is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a secondary source of the propagating wave. Italian scientist Francesco Maria Grimaldi coined the word ''diffraction'' and was the first to record accurate observations of the phenomenon in 1660. In classical physics, the diffraction phenomenon is described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets. The characteristic bending pattern is most pronounced when a wave from a coherent source (such as a laser) encounters a slit/aperture that is comparable in size to its wavelength, as shown in the inserted image. This is due to the addition, or interference, of different points on the wavefront (or, equivalently, each wavelet) that travel by paths of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Ultrasonography
Medical ultrasound includes diagnostic techniques (mainly medical imaging, imaging techniques) using ultrasound, as well as therapeutic ultrasound, therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g. distances and velocities) or to generate an informative audible sound. Its aim is usually to find a source of disease or to exclude pathology. The usage of ultrasound to produce visual images for medicine is called medical ultrasonography or simply sonography. The practice of examining pregnant women using ultrasound is called obstetric ultrasonography, and was an early development of clinical ultrasonography. Ultrasound is composed of sound waves with frequency, frequencies which are significantly higher than the range of human hearing (>20,000 Hz). Ultrasonic images, also known as sonograms, are created by se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sony
, commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional electronic products, the largest video game console company and the largest video game publisher. Through Sony Entertainment Inc, it is one of the largest music companies (largest music publisher and second largest record label) and the third largest film studio, making it one of the most comprehensive media companies. It is the largest technology and media conglomerate in Japan. It is also recognized as the most cash-rich Japanese company, with net cash reserves of ¥2 trillion. Sony, with its 55 percent market share in the image sensor market, is the largest manufacturer of image sensors, the second largest camera manufacturer, and is among the semiconductor sales leaders. It is the world's largest player in the premium TV market for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fujinon XF 56mm F1
Fujinon is a brand of optical lenses made by Fuji Photo Film Co., Ltd, now known as Fujifilm. Fujifilm's Fujinon lenses have been used by professional photographers and broadcast stations as well as cinematography. Fujifilm started manufacture of optical glass in its Odawara Factory in Japan in 1940, which was the start of the Fujinon brand. They were proud of their use of expensive Platinum crucibles to get the purest glass achievable at the time. Fujifilm also pioneered Electron Beam Coating (EBC) which according to Fujifilm, represented a new high in lens precision and performance. The EBC process was significantly different from other coating processes by the number of coating, the thinness of the coating, and the materials used for coating. Fujifilm claimed they were able to have as much as 14 layers of coating and used materials such as zirconium oxide, and cerium fluoride, which could not be used for coating in the conventional coating process. The first lens to offer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fujifilm
, trading as Fujifilm, or simply Fuji, is a Japanese multinational conglomerate headquartered in Tokyo, Japan, operating in the realms of photography, optics, office and medical electronics, biotechnology, and chemicals. The offerings from the company that started as a manufacturer of photographic films, which it still produces, include: document solutions, medical imaging and diagnostics equipment, cosmetics, pharmaceutical drugs, regenerative medicine, stem cells, biologics manufacturing, magnetic tape data storage, optical films for flat-panel displays, optical devices, photocopiers and printers, digital cameras, color films, color paper, photofinishing and graphic arts equipment and materials. Fujifilm is part of the Sumitomo Mitsui Financial Group financial conglomerate (''keiretsu''). History 20th century Fuji Photo Film Co., Ltd. was established in 1934 as a subsidiary of Daicel with the aim of producing photographic films. Over the following 10 years, the comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STF Function
Autobracketing is a feature of some more advanced cameras, whether film or digital cameras, particularly single-lens reflex cameras, where the camera will take several successive shots (often three) with slightly different settings. The images may be automatically combined, for example into one high-dynamic-range image, or they may be stored separately so the best-looking pictures can be picked later from the batch. When the photographer achieves the same result by changing the camera settings between each shot, this is simply called bracketing. Parameter altered The bracketing is typically for one specific parameter: Exposure Exposure autobracketing (often abbreviated to ''AEB'' for ''automatic exposure bracketing'' or ''BR'' for ''Bracketing'') is the most common form. In this, the camera is set to capture the same image several times with different exposure settings, both over-exposed and under-exposed (lighter and darker) compared to the current setting on the camera, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minolta Maxxum 7
The Minolta A-mount camera system was a line of photographic equipment from Minolta introduced in 1985 with the world's first integrated autofocus system in the camera body with interchangeable lenses. The system used a lens mount called A-mount, with a flange focal distance 44.50 mm, one millimeter longer, 43.5 mm, than the previous SR mount from 1958. The new mount was wider, 49.7 mm vs. 44.97 mm, than the older SR-mount and had a longer flange focal distance making old manual lenses incompatible with the new system. Minolta bought the autofocus technology of Leica Correfot camera which was partly used on the a-mount autofocus technology. The mount is now used by Sony, who bought the SLR camera division from Konica Minolta, Konica and Minolta having merged a few years before. The Minolta A-mount system was at first marketed as Maxxum in North America and α (Alpha) in Japan and the rest of Asia. In Europe, early Minolta A-mount cameras were initially ident ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
