Several image processing techniques, such as unsharp masking, can increase the acutance in real images. Unprocessed, slight unsharp masking, then strong unsharp masking.
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Unsharp masking does not increase the actual sharpness, as it cannot recover details lost to blurring. Unprocessed, slight unsharp masking, then strong unsharp masking.
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Unsharp masking applied to lower part of image Unsharp masking (USM) is an image sharpening technique, often available in digital image processing software. Its name derives from the fact that the technique uses a blurred, or "unsharp", negative image to create a mask of the original image. The unsharp mask is then combined with the original positive image, creating an image that is less blurry than the original. The resulting image, although clearer, may be a less accurate representation of the image's subject.
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Unsharp masking allows the photographer to sharpen areas that have become blurred in the original negative, due to long shutter speed/exposure time, or from using a wide aperture/"fast" lens. When creating the unsharp mask, extra space or diffusing material is added between the image and the mask to produce the necessary blur.
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In the photographic procedure, the amount of blurring can be controlled by changing the "softness" or "hardness" (from point source to fully diffuse) of the light source used for the initial unsharp mask exposure, while the strength of the effect can be controlled by changing the contrast and density (i.e., exposure and development) of the unsharp mask. For traditional photography, unsharp masking is usually used on monochrome materials; special panchromatic soft-working black-and-white films have been available for masking photographic colour transparencies. This has been especially useful to control the density range of a transparency intended for photomechanical reproduction.
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In the context of signal processing, an unsharp mask is generally a linear or nonlinear filter that amplifies the high-frequency components of a signal.
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Unsharp masking has become automated in digital editing, with higher-end suites offering the process as a "tool" or "filter" in their standard sharpening kits—the actual creation of a mask is bypassed in favor of calculations that represent the mask's effect. The process depends on three factors: the radius of the blur, the strength of the effect, and the threshold degree of contrast above which the effect will be applied. (Adjusting the threshold allows the editor to apply the effect selectively upon moderately defined edges and ignore image noise.) Unsharp masking is computationally more complex than other sharpening algorithms, but results in a higher-quality remedy. Deconvolution allows for truer sharpening, but is much more complex than unsharp masking.
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A derivative of contrast masking is unsharp masking, an unusual term for a process intended to increase the apparent sharpness (acutance) of an image. Unsharp masking uses a blurred form of the image to increase contrast along regions of moderate contrast difference. Around edges, the blur region causes highlights to overexpose and shadows to underexpose. Taken to an extreme, the edges become overly visible and detract from the quality of the image—this is referred to as halation.
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Historically, acutance was enhanced chemically during development of a negative (high acutance developers), or by optical means in printing (unsharp masking). In digital photography, onboard camera software and image postprocessing tools such as Photoshop or GIMP offer various sharpening facilities, the most widely used of which is known as "unsharp mask" because the algorithm is derived from the eponymous analog processing method. In the example image, two light gray lines were drawn on a gray background. As the transition is instantaneous, the line is as sharp as can be represented at this resolution.
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The Unsharp Mask tool is considered to give more targeted results for photographs than a normal sharpening filter. The Selective Gaussian Blur tool works in a similar way, except it blurs areas of an image with little detail.
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Some of these cameras are quite small and still hold appeal to subminiature-photography enthusiasts. The small negative size of 110 film makes it difficult to enlarge successfully. For these reasons, the 110 format is associated with prints that are often rather grainy and unsharp.
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These include (but are not limited to) entanglement, noncommutativity of measurements, teleportation, interference, the no-cloning and no-broadcasting theorems, and unsharp measurements. The toy model cannot, however, reproduce quantum nonlocality and quantum contextuality, as it is a local and non-contextual hidden-variable theory.
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This contrast between the light and dark creates a sharper image. (Compare unsharp masking in digital processing). This mechanism also creates the Mach band visual effect. Visual lateral inhibition is the process in which photoreceptor cells aid the brain in perceiving contrast within an image.
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Figure 4 This aberration is quite distinct from that of the sharpness of reproduction; in unsharp, reproduction, the question of distortion arises if only parts of the object can be recognized in the figure. If, in an unsharp image, a patch of light corresponds to an object point, the center of gravity of the patch may be regarded as the image point, this being the point where the plane receiving the image, e.g., a focusing screen, intersects the ray passing through the middle of the stop. This assumption is justified if a poor image on the focusing screen remains stationary when the aperture is diminished; in practice, this generally occurs.
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Priyanka Kaushal, Neeraj Mohan and Parvinder S. Sandhu, "Relevancy of Fuzzy Concept in Mathematics". International Journal of Innovation, Management and Technology, Vol. 1, No. 3, August 2010. Across at least two and a half millennia, all of them had something to say about graded concepts with unsharp boundaries.
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The ink colors are not uniform and have specular reflections that put light pixels within the lines. The pencil lines also have interior defects due to the roughness (tooth) of the paper. The scan also has some unsharp masking artifacts. There are many different image styles and possibilities, and no single vectorization method works well on all images.
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For image processing, deconvolution is the process of approximately inverting the process that caused an image to be blurred. Specifically, unsharp masking is a simple linear image operation—a convolution by a kernel that is the Dirac delta minus a gaussian blur kernel. Deconvolution, on the other hand, is generally considered an ill-posed inverse problem that is best solved by nonlinear approaches. While unsharp masking increases the apparent sharpness of an image in ignorance of the manner in which the image was acquired, deconvolution increases the apparent sharpness of an image, but is based on information describing some of the likely origins of the distortions of the light path used in capturing the image; it may therefore sometimes be preferred, where the cost in preparation time and per-image computation time are offset by the increase in image clarity.
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More advanced functionalities include video tracking and egomotion estimation. Based on the internal representation that VCA generates in the machine, it is possible to build other functionalities, such as identification, behavior analysis or other forms of situation awareness. VCA relies on good input video, so it is often combined with video enhancement technologies such as video denoising, image stabilization, unsharp masking and super-resolution.
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This algorithm formulates the face hallucination as an image decomposition problem and propose a Morphological Component Analysis (MCA)) Yan Liang, Xiaohua Xie, Jian-Huang Lai based method. The method is presented in three-step framework. Firstly, a low-resolution input image is up-sampled by an interpolation. The interpolated image can be represented as a superposition of the global high- resolution image and an “unsharp mask”.
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The most highly cited of Foulis's research papers is "Effect algebras and unsharp quantum logics" (Foundations of Physics, 1994) which he wrote with his former student and later University of Massachusetts colleague Mary K. Bennett. Foulis is also the author of seven undergraduate textbooks in mathematics. One of his texts, a large red book on calculus, was used as a prop in the 1985 romantic comedy movie The Sure Thing.
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This application allowed the use of Chasys Draw IES in processing digital negatives, which are popular with professional photographers. Chasys Draw IES 3.24 was released with a re-designed user interface, powered by a higher performance graphics core and better memory management. A history palette was introduced, as was a new screen capture function with video capability. The layer palette received drag-drop capability and unsharp masking got yet another upgrade.
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The blue separation negative was exposed through the green unsharp mask. The purpose of the contrast reducing masks was to reduce the contrast range of the original transparencies to a level that could be handled by reflected copy material. By swapping the masks, colour correction was achieved to compensate for deficiencies in the dyes. The 8 x 10 separation negatives were placed in an enlarger to expose the printing matrices.
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An early result of these explorations was the Minolta Varisoft Rokkor-X 85mm f/2.8 (Japan) of 1978 for Minolta 35mm SLRs. It used floating elements to allow the photographer to deliberately under-correct the spherical aberration of the lens system and render unsharp specular highlights as smoothly fuzzy blobs without affecting focus or other aberrations.Shuji Ogino, et al, Variable Soft Focus Lens System. United States Patent #4,214,814; granted 29 July 1980.
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Yet it can at least make explicit, what exactly the variations are in the applicability of a concept which has unsharp boundaries. If one always had perfectly crisp concepts available, perhaps no fuzzy expressions would be necessary. In reality though, one often does not have all the crisp concepts to start off with. One might not have them yet for a long time, or ever - or, several successive "fuzzy" approximations might be needed, to get there.
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With some physical processes this threshold is relatively easy to identify. For example, water turns into steam at 100 °C or 212 °F (the boiling point depends partly on atmospheric pressure, which decreases at higher altitudes). With many other processes and gradations, however, the point of change is much more difficult to locate, and remains somewhat vague. Thus, the boundaries between qualitatively different things may be unsharp: we know that there are boundaries, but we cannot define them exactly.
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Kreitsek's screenplay is unsharp, without focus, working into and out of the hallucinations with great awkwardness." Canby found the film to have "moments of eerie beauty" but believed that the director was limited by the screenplay. The critic said, "Everything remains foetus-like and underdeveloped, although shrouded in misty pretensions of grandeur." Echoing Canby, Roger Ebert of the Chicago Sun-Times wrote, "Smight's confused, wandering film never does quite come to terms with what it wants to be.
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In quantum mechanics (and computation & information), weak measurements are a type of quantum measurement that results in an observer obtaining very little information about the system on average, but also disturbs the state very little. From Busch's theorem the system is necessarily disturbed by the measurement. In the literature weak measurements are also known as unsharp, fuzzy, dull, noisy, approximate, and gentle measurements. Additionally weak measurements are often confused with the distinct but related concept of the weak value.
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Usually this involves the use of software with unsharp masking, a filtering algorithm that removes out-of- focus portions of each exposure. The in-focus portions are then "stacked"; combined into a single image. Focus stacking is challenging, in that the subject (as in all brackets) must stay still and that as the focal point changes, the magnification (and position) of the images change. This must then be corrected in a suitable application by transforming the image.
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Because the positive has been blurred intentionally, only the low-frequency (blurred) information is cancelled. In addition, the mask effectively reduces the dynamic range of the original negative. Thus, if the resulting enlarged image is recorded on contrasty photographic paper, the partial cancellation emphasizes the high-spatial- frequency information (fine detail) in the original, without loss of highlight or shadow detail. The resulting print appears more acute than one made without the unsharp mask: its acutance is increased.
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All songs written by Farin Urlaub. Großes Album (Büffelherde) (Big album (Buffalo herd)) # "Nichimgriff" (Notundercontrol) – 2:46 # "Unscharf" (Fuzzy, lit. Unsharp) – 2:55 # "Gobi Todič" – 2:32 # "Seltsam" (Odd) – 2:51 # "Krieg" (War) – 3:15 # "Pakistan" – 2:50 # "Niemals" (Never) – 3:31 # "Die Leiche" (The corpse) – 3:45 # "Monster" – 3:28 # "Atem" (Breath) – 4:09 # "Karten" (Cards) – 4:21 Kleines Album (Ponyhof) (Small album (Pony ranch)) # "I.F.D.G." (short for "Ich find' das gut" (I like that, lit.
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This is a photo from Emerson's album "The Hunters" depicting a hunter and his dog sourced from Nancy Newhall's book "P.H. Emerson" Emerson also believed that the photograph should be a true representation of that which the eye saw. Following contemporary optical theories, he produced photographs with one area of sharp focus while the remainder was unsharp. He vehemently pursued this argument about the nature of seeing and its representation in photography, to the discomfort of the photographic establishment.
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Stroebel, 1976 With tilt, the depth of field is wedge shaped. As noted above, using a large amount of tilt and a small f-number gives a small angular DoF. This can be useful if the objective is to provide selective focus to different objects at essentially the same distance from the camera. But in many cases, effective use of tilt for selective focus requires a careful choice of what is sharp as well as what is unsharp, as Vincent Laforet has noted.
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An image with artificially increased acutance overshoot caused by using unsharp masking to sharpen the image (bottom half) increases acutance. In photography, the term "acutance" describes a subjective perception of sharpness that is related to the edge contrast of an image. Acutance is related to the amplitude of the derivative of brightness with respect to space. Due to the nature of the human visual system, an image with higher acutance appears sharper even though an increase in acutance does not increase real resolution.
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New features can be added to GIMP not only by changing program code (GIMP core), but also by creating plug-ins. These are external programs that are executed and controlled by the main GIMP program. MathMap is an example of a plug-in written in C. There is support for several methods of sharpening and blurring images, including the blur and sharpen tool. The unsharp mask tool is used to sharpen an image selectively — it sharpens only those areas of an image that are sufficiently detailed.
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The double-CD edition of Live aus Berlin containing all 24 songs of the Columbiahalle concert was favourably reviewed by Linus Schwanke of German music magazine laut.de, who felt that the album faithfully captured the live performance. Felix Kosel of German music magazine bloom was also impressed with the double-CD album, commenting that it reflected the feelings and atmosphere in the Columbiahalle. However, he was less impressed with the video recording on the DVD album, criticizing the unsharp pictures, the editing and the cinematography.
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Graphics programs can be used to both sharpen and blur images in a number of ways, such as unsharp masking or deconvolution.Implementations include FocusMagic, and Photoshop Portraits often appear more pleasing when selectively softened (particularly the skin and the background) to better make the subject stand out. This can be achieved with a camera by using a large aperture, or in the image editor by making a selection and then blurring it. Edge enhancement is an extremely common technique used to make images appear sharper, although purists frown on the result as appearing unnatural.
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A simple depth map Depth map is the term used in Adobe Photoshop for indicating distance from the camera with varying levels of gray when using the Lens Blur filter. consisting of a linear gradient can be edited to give uniform sharpness to objects at the same distance from the camera. This effect cannot be achieved using lens tilt. Even simple digital techniques afford greater flexibility than optical techniques, including the ability to choose the region of sharpness and the amount of blur for the unsharp areas after the photograph has been taken.
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Overshoot (bottom of image), caused by using unsharp masking to sharpen an image The sine integral, which is the step response of an ideal low-pass filter. The sinc function, which is the impulse response of an ideal low-pass filter. In signal processing, overshoot is when the output of a filter has a higher maximum value than the input, specifically for the step response, and frequently yields the related phenomenon of ringing artifacts. This occurs for instance in using the sinc filter as an ideal (brick-wall) low-pass filter.
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Picture Manager lacks several image editing features of its predecessor, Photo Editor, including emboss, noise reduction, RGB gamma correction options, smudge, and unsharp mask features. The following effects of Photo Editor are not included in Picture Manager: Chalk and Charcoal, Edge, Graphic Pen, Negative, Notepaper, Posterize, Sharpen, Soften, Stained Glass, Stamp, Texturizer, and Watercolor. Picture Manager also cannot create new images from a digital camera or from a scanner. Microsoft stated that this feature is native to Windows Explorer in Windows XP and that users are not required to import images to manage them.
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Example of high-pass filter applied to the right half of a photograph. Left side is unmodified, Right side is with a high-pass filter applied (in this case, with a radius of 4.9) High-pass and low-pass filters are also used in digital image processing to perform image modifications, enhancements, noise reduction, etc., using designs done in either the spatial domain or the frequency domain. The unsharp masking, or sharpening, operation used in image editing software is a high-boost filter, a generalization of high-pass.
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An important issue within radiology today is how to reduce the radiation dose during CT examinations without compromising the image quality. In general, higher radiation doses result in higher-resolution images, while lower doses lead to increased image noise and unsharp images. However, increased dosage raises the adverse side effects, including the risk of radiation-induced cancer – a four-phase abdominal CT gives the same radiation dose as 300 chest X-rays (See the Scan dose section). Several methods that can reduce the exposure to ionizing radiation during a CT scan exist.
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The matrices, which are relief gelatine images on a film support (one for each subtractive primary color) absorb dye in proportion to the optical densities of the gelatin relief image. Successive placement of the dyed film matrices, one at a time, "transfers" each primary dye by physical contact from the matrix to a mordanted, gelatin-coated paper. It took a technician one whole day to produce one print. Firstly, three colour separation negatives were made using three high contrast highlight masks to produce three contrast reducing and colour correction unsharp masks.
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Such lenses designed for the EF-S mount can be made smaller, lighter (containing less glass), faster (larger aperture) and less expensive. Although not all Canon EF-S lenses use this short back focal length, they cannot be mounted on DSLRs with sensors larger than APS-C. However, some lenses produced by third-party manufacturers may feature the standard EF mount if they do not have the shorter back focal length but only have a small image circle. Such lenses will give noticeable vignetting or unsharp outer areas if used on a 35mm film or full frame sensor cameras.
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Simplified principle of unsharp masking For the photographic darkroom process, a large-format glass plate negative is contact- copied onto a low-contrast film or plate to create a positive image. However, the positive copy is made with the copy material in contact with the back of the original, rather than emulsion-to-emulsion, so it is blurred. After processing this blurred positive is replaced in contact with the back of the original negative. When light is passed through both negative and in-register positive (in an enlarger, for example), the positive partially cancels some of the information in the negative.
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Unsharp masking may also be used with a large radius and a small amount (such as 30–100 pixel radius and 5–20% amountLocal Contrast Enhancement, Cambridge in Color.), which yields increased local contrast, a technique termed local contrast enhancement.Understanding Local Contrast Enhancement, The Luminous Landscape. USM can increase either sharpness or (local) contrast because these are both forms of increasing differences between values, increasing slope—sharpness referring to very small-scale (high-frequency) differences, and contrast referring to larger- scale (low-frequency) differences. More powerful techniques for improving tonality are referred to as tone mapping.
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Each photographic plate is a special black and white emulsion designed for low light conditions and is further enhanced for low light sensitivity by baking in a nitrogen and hydrogen atmosphere. The exposure times are relatively long, varying between 5–60 minutes for each colour, depending on the luminosity of the object. The colour image is re-assembled in the darkroom, where further techniques such as unsharp masking to enhance fine detail might also be applied. In 1986 he discovered Malin 1, a giant spiral galaxy located away in the constellation Coma Berenices, near the North Galactic Pole.
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Miniature simulation using digital post processing Selective focus via tilt is often used to simulate a miniature scene, so much that "tilt-and-shift effect" has been used as a general term for some miniature faking techniques. Basic digital post-processing techniques can give results similar to those achieved with tilt, and afford greater flexibility and control, such as choosing the region that is sharp and the amount of blur for the unsharp regions. Moreover, these choices can be made after the photograph is taken. One advanced technique, Smallgantics, is used for motion-pictures; it was first seen in the 2006 Thom Yorke music video "Harrowdown Hill", directed by Chel White.
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Unsharp masking has been applied to lower part of image, creating overshoot and undershoot and increasing acutance. Edge enhancement is an image processing filter that enhances the edge contrast of an image or video in an attempt to improve its acutance (apparent sharpness). The filter works by identifying sharp edge boundaries in the image, such as the edge between a subject and a background of a contrasting color, and increasing the image contrast in the area immediately around the edge. This has the effect of creating subtle bright and dark highlights on either side of any edges in the image, called overshoot and undershoot, leading the edge to look more defined when viewed from a typical viewing distance.
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The term "gobo" also is used to describe black panels of different sizes or shapes placed between a light source and photographic subject (such as between sun light and a portrait model) to control the modeling effect of the existing light. It is the opposite of a photographer using a "reflector" to redirect light into a shadow, which is "additive" lighting and most commonly used. Use of a gobo subtracts light from a portion of an overall shaded subject and creates a contrast between one side of the face and another. It allows the photographer to expose with wider open apertures giving soft natural transitions between the sharp subject and unsharp background, called bokeh.
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