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Spoke Target
A Siemens star, or spoke target, is a device used to test the resolution of optical instruments, printers, and displays. It consists of a pattern of bright "spokes" on a dark background that radiate from a common center and become wider as they get further from it. In concept, the spokes only meet at the exact center of the star – the spokes, and the gaps between them, become narrower the closer to the center one looks, but they never touch except at the center. When printed or displayed on a device with limited resolution, however, the spokes touch at some distance from the center. The smallest gap visible is limited by the smallest dot of ink the printer can produce, making the Siemens star a useful tool for comparing two printers' resolutions (DPI). Similarly, it can be applied to a camera's optical resolution by taking photographs of a Siemens star printed at high resolution and comparing photographs from different cameras, to see which retained the center detail the cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siemens Star
A Siemens star, or spoke target, is a device used to test the resolution of optical instruments, printers, and displays. It consists of a pattern of bright "spokes" on a dark background that radiate from a common center and become wider as they get further from it. In concept, the spokes only meet at the exact center of the star – the spokes, and the gaps between them, become narrower the closer to the center one looks, but they never touch except at the center. When printed or displayed on a device with limited resolution, however, the spokes touch at some distance from the center. The smallest gap visible is limited by the smallest dot of ink the printer can produce, making the Siemens star a useful tool for comparing two printers' resolutions (DPI). Similarly, it can be applied to a camera's optical resolution by taking photographs of a Siemens star printed at high resolution and comparing photographs from different cameras, to see which retained the center detail the clos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russian Air Force
" Air March" , mascot = , anniversaries = 12 August , equipment = , equipment_label = , battles = , decorations = , battle_honours = , battle_honours_label = , flying_hours = , website = , commander1 = President Vladimir Putin , commander1_label = Supreme Commander-in-Chief of the Russian Defence Forces , commander2 = Army General Sergei Surovikin , commander2_label = Commander-in-Chief of the Aerospace Forces , commander3 = Lieutenant general , commander3_label = Commander-in-Chief of the Russian Air Force , notable_commanders = , identification_symbol = , identification_symbol_label = Flag , identification_symbol_2 = , identification_symbol_4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vector Graphics
Vector graphics is a form of computer graphics in which visual images are created directly from geometric shapes defined on a Cartesian plane, such as points, lines, curves and polygons. The associated mechanisms may include vector display and printing ''hardware'', vector ''data models'' and file formats, as well as the ''software'' based on these data models (especially graphic design software, computer-aided design, and geographic information systems). Vector graphics is an alternative to raster or bitmap graphics, with each having advantages and disadvantages in specific situations. While vector hardware has largely disappeared in favor of raster-based monitors and printers, vector data and software continues to be widely used, especially when a high degree of geometric precision is required, and when complex information can be decomposed into simple geometric primitives. Thus, it is the preferred model for domains such as engineering, architecture, surveying, 3D render ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secchi Disk
The Secchi disk (or Secchi disc), as created in 1865 by Angelo Secchi, is a plain white, circular disk in diameter used to measure water transparency or turbidity in bodies of water. The disc is mounted on a pole or line, and lowered slowly down in the water. The depth at which the disk is no longer visible is taken as a measure of the transparency of the water. This measure is known as the Secchi depth and is related to water turbidity. Since its invention, the disk has also been used in a modified, smaller diameter, black and white design to measure freshwater transparency. Similar disks, with a black-and-yellow pattern, are used as fiducial markers on vehicles in crash tests, crash-test dummies, and other kinetic experiments. History The original Secchi disk was a plain white disk and was used in the Mediterranean Sea. Today, a plain white, diameter Secchi disk remains the standard design used in marine studies. In 1899 George C. Whipple modified the original all-white Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siemens
Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad. The principal divisions of the corporation are ''Industry'', ''Energy'', ''Healthcare'' (Siemens Healthineers), and ''Infrastructure & Cities'', which represent the main activities of the corporation. The corporation is a prominent maker of medical diagnostics equipment and its medical health-care division, which generates about 12 percent of the corporation's total sales, is its second-most profitable unit, after the industrial automation division. In this area, it is regarded as a pioneer and the company with the highest revenue in the world. The corporation is a component of the Euro Stoxx 50 stock market index. Siemens and its subsidiaries employ approximately 303,000 people worldwide and reported global revenue of around €62 billion in 2021 according to its earnings release. History 1847 to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical 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 symmet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aliasing
In signal processing and related disciplines, aliasing is an effect that causes different signals to become indistinguishable (or ''aliases'' of one another) when sampled. It also often refers to the distortion or artifact that results when a signal reconstructed from samples is different from the original continuous signal. Aliasing can occur in signals sampled in time, for instance digital audio, or the stroboscopic effect, and is referred to as temporal aliasing. It can also occur in spatially sampled signals (e.g. moiré patterns in digital images); this type of aliasing is called spatial aliasing. Aliasing is generally avoided by applying low-pass filters or anti-aliasing filters (AAF) to the input signal before sampling and when converting a signal from a higher to a lower sampling rate. Suitable reconstruction filtering should then be used when restoring the sampled signal to the continuous domain or converting a signal from a lower to a higher sampling rate. For spa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defocus
In optics, defocus is the aberration in which an image is simply out of focus. This aberration is familiar to anyone who has used a camera, videocamera, microscope, telescope, or binoculars. Optically, defocus refers to a translation of the focus along the optical axis away from the detection surface. In general, defocus reduces the sharpness and contrast of the image. What should be sharp, high-contrast edges in a scene become gradual transitions. Fine detail in the scene is blurred or even becomes invisible. Nearly all image-forming optical devices incorporate some form of focus adjustment to minimize defocus and maximize image quality. In optics and photography The degree of image blurring for a given amount of focus shift depends inversely on the lens f-number. Low f-numbers, such as to 2.8, are very sensitive to defocus and have very shallow depths of focus. High f-numbers, in the 16 to 32 range, are highly tolerant of defocus, and consequently have large depth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for by using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siemens Star (128 Spokes) & Matlab Code
A Siemens star, or spoke target, is a device used to test the resolution of optical instruments, printers, and displays. It consists of a pattern of bright "spokes" on a dark background that radiate from a common center and become wider as they get further from it. In concept, the spokes only meet at the exact center of the star – the spokes, and the gaps between them, become narrower the closer to the center one looks, but they never touch except at the center. When printed or displayed on a device with limited resolution, however, the spokes touch at some distance from the center. The smallest gap visible is limited by the smallest dot of ink the printer can produce, making the Siemens star a useful tool for comparing two printers' resolutions (DPI). Similarly, it can be applied to a camera's optical resolution by taking photographs of a Siemens star printed at high resolution and comparing photographs from different cameras, to see which retained the center detail the clo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flag Of Jordan
The flag of Jordan, officially adopted on 16 April 1928, is based on the 1916 flag of the Arab Revolt against the Ottoman Empire during World War I. The flag consists of horizontal black, white, and green bands that are connected by a red chevron. The colours are the Pan-Arab Colors, respectively representing the Abbasid (black band), Umayyad (white band), and Fatimid or Rashidun caliphates (green band). The red chevron is for the Hashemite dynasty, and the Arab Revolt. Features In addition to the bands and chevron, a white star with seven points is featured on the hoist side of the red chevron. The star stands for the unity of the Arab people; its seven points refer to the seven verses of Al-Fatiha as well as the seven hills Amman was built on. History File:Flag of Hejaz 1920.svg, First flag (1921–1928) File:Flag of the Emirate of Transjordan.svg, Second flag (1928–1939) Interpretation of the colors Colours scheme Construction Sheet Historical flag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flag Of Japan
The national flag of Japan is a rectangular white banner bearing a crimson-red circle at its center. This flag is officially called the , but is more commonly known in Japan as the . It embodies the country's sobriquet: the Land of the Rising Sun. The ''Nisshoki'' flag is designated as the national flag in the Act on National Flag and Anthem, which was promulgated and became effective on 13 August 1999. Although no earlier legislation had specified a national flag, the sun-disc flag had already become the ''de facto'' national flag of Japan. Two proclamations issued in 1870 by the Daijō-kan, the governmental body of the early Meiji period, each had a provision for a design of the national flag. A sun-disc flag was adopted as the national flag for merchant ships under Proclamation No. 57 of Meiji 3 (issued on 27 February 1870), and as the national flag used by the Navy under Proclamation No. 651 of Meiji 3 (issued on 27 October 1870). Use of the ''Hinomaru'' was severely restric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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