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High-dynamic-range
High dynamic range (HDR) is a dynamic range higher than usual, synonyms are wide dynamic range, extended dynamic range, expanded dynamic range. The term is often used in discussing the dynamic range of various signals such as images, videos, audio or radio. It may apply to the means of recording, processing, and reproducing such signals including analog and digitized signals. The term is also the name of some of the technologies or techniques allowing to achieve high dynamic range images, videos, or audio. Imaging In this context, the term ''high dynamic range'' means there is a lot of variation in light levels within a scene or an image. The ''dynamic range'' refers to the range of luminosity between the brightest area and the darkest area of that scene or image. (HDRI) refers to the set of imaging technologies and techniques that allow to increase the dynamic range of images or videos. It covers the acquisition, creation, storage, distribution and display of images an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi-exposure HDR Capture
In photography and videography, multi-exposure HDR capture is a technique that creates extended or high dynamic range (HDR) images by taking and combining multiple exposures of the same subject matter at different exposure levels. Combining multiple images in this way results in an image with a greater dynamic range than what would be possible by taking one single image. The technique can also be used to capture video by taking and combining multiple exposures for each frame of the video. The term "HDR" is used frequently to refer to the process of creating HDR images from multiple exposures. Many smartphones have an automated HDR feature that relies on computational imaging techniques to capture and combine multiple exposures. A single image captured by a camera provides a finite range of luminosity inherent to the medium, whether it is a digital sensor or film. Outside this range, tonal information is lost and no features are visible; tones that exceed the range are "burned o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Range
Dynamic range (abbreviated DR, DNR, or DYR) is the ratio between the largest and smallest values that a certain quantity can assume. It is often used in the context of signals, like sound and light. It is measured either as a ratio or as a base-10 ( decibel) or base-2 (doublings, bits or stops) logarithmic value of the difference between the smallest and largest signal values. Electronically reproduced audio and video is often processed to fit the original material with a wide dynamic range into a narrower recorded dynamic range that can more easily be stored and reproduced; this processing is called dynamic range compression. Human perception The human senses of sight and hearing have a relatively high dynamic range. However, a human cannot perform these feats of perception at both extremes of the scale at the same time. The human eye takes time to adjust to different light levels, and its dynamic range in a given scene is actually quite limited due to optical glare. The ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transfer Functions In Imaging
This article is about the Transfer function, transfer functions used in Image, pictures and Video, videos and describing the relationship between Signal, electrical signal, scene light and displayed light. Definition The opto-electronic transfer function (OETF) is the transfer function having the scene light as input and converting into the picture or video signal as output. This is typically done within a camera. The electro-optical transfer function (EOTF) is the transfer function having the picture or video signal as input and converting it into the linear light output of the display. This is done within the display device. The opto-optical transfer function (OOTF) is the transfer function having the scene light as input and the displayed light as output. The OOTF is the result of the OETF and the EOTF and is usually non-Linear function (calculus), linear. List of transfer functions Linear function (calculus), Linear * RAW format, Raw formats *Some OETF and EOTF have an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tone Mapping
Tone mapping is a technique used in image processing and computer graphics to map one set of colors to another to approximate the appearance of high-dynamic-range images in a medium that has a more limited dynamic range. Print-outs, CRT or LCD monitors, and projectors all have a limited dynamic range that is inadequate to reproduce the full range of light intensities present in natural scenes. Tone mapping addresses the problem of strong contrast reduction from the scene radiance to the displayable range while preserving the image details and color appearance important to appreciate the original scene content. Inverse tone mapping is the inverse technique that allows to expand the luminance range, mapping a low dynamic range image into a higher dynamic range image. It is notably used to upscale SDR videos to HDR videos. Background The introduction of film-based photography created issues since capturing the enormous dynamic range of lighting from the real world on a chemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-dynamic-range Video
High-dynamic-range television (HDR or HDR-TV) is a technology that improves the quality of display signals. It is contrasted with the retroactively-named standard dynamic range (SDR). HDR changes the way the luminance and colors of videos and images are represented in the signal, and allows brighter and more detailed highlight representation, darker and more-detailed shadows, and a wider array of more intense colors. HDR allows compatible displays to receive a higher quality image source. It does not improve a display's intrinsic properties (brightness, contrast, and color capabilities). Not all HDR displays have the same capabilities, and HDR content will look different depending on the display used. HDR-TV was first used in 2014 to enhance videos, and it is now also available for still pictures. HDR-TV is a part of HDR imaging, an end-to-end process of increasing the dynamic range of images and videos from their capture and creation, to their storage, distribution and displa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raw Image Format
A camera raw image file contains unprocessed or minimally processed data from the image sensor of either a digital camera, a motion picture film scanner, or other image scanner. Raw files are named so because they are not yet processed and therefore are not ready to be Photographic printing, printed, viewed or edited with a bitmap graphics editor. Normally, the image is processed by a raw converter in a wide-gamut internal color space where precise adjustments can be made before file format conversion, conversion to a viewable file format such as JPEG or PNG for storage, printing, or further manipulation. There are dozens of raw formats in use by different manufacturers of digital image capture equipment. Rationale Raw image files are sometimes incorrectly described as "digital Negative (photography), negatives", but neither are they negatives nor do the unprocessed files constitute visible images. Rather, the Raw datasets are more like Exposure (photography), exposed but Lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exposure (photography)
In photography, exposure is the amount of light per unit area (the image plane's illuminance times the exposure time) reaching a frame of photographic film or the surface of an electronic image sensor, as determined by shutter speed, lens F-number, and scene luminance. Exposure is measured in lux seconds, and can be computed from exposure value (EV) and scene luminance in a specified region. An "exposure" is a single shutter cycle. For example, a long exposure refers to a single, long shutter cycle to gather enough dim light, whereas a multiple exposure involves a series of shutter cycles, effectively layering a series of photographs in one image. The accumulated ''photometric exposure'' (''H''v) is the same so long as the total exposure time is the same. Definitions Radiant exposure Radiant exposure of a ''surface'', denoted ''H''e ("e" for "energetic", to avoid confusion with photometric quantities) and measured in , is given by :H_\mathrm = E_\mathrmt, where *''E'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HDR10+
HDR10+ is a high dynamic range (HDR) video technology that adds dynamic metadata to HDR10 source files. The dynamic metadata are used to adjust and optimize each frame of the HDR video to the consumer display's capabilities in a way based on the content creator's intents. HDR10+ is a competitor to Dolby Vision, which also uses dynamic metadata. HDR10+ is the default variant of dynamic metadata as part of the HDMI 2.1 standard. HDR10+ Adaptive is an update designed to optimize HDR10+ content according to the ambient light. Description HDR10+, also known as HDR10 Plus, was announced on 20 April 2017, by Samsung and Amazon Video. HDR10+ updates HDR10 by adding dynamic metadata that can be used to more accurately adjust brightness levels up to 10,000 nits maximum brightness on a scene-by-scene or frame-by-frame basis and supports up to 10-bit colour depth and 8K resolution. This function is based on Samsung variant of metadata format defined in SMPTE ST 2094-40. HDR10+ is an open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HDR10
HDR10 Media Profile, more commonly known as HDR10, is an open high-dynamic-range video (HDR) standard announced on 27 August 2015 by the Consumer Technology Association. It is the most widespread of the HDR formats. HDR10 is not backward compatible with SDR. It includes HDR static metadata but not dynamic metadata. It doesn't offer the ability to optimize content to the consumer display's capabilities in a way based on the content creator's intent. PQ10 refers to an HDR format that is same as HDR10 without any metadata. Technical details HDR10 is defined as: * EOTF: SMPTE ST 2084 ( PQ) * Bit depth: 10 bit * Color primaries: ITU-R BT.2020 (identical to BT.2100 primaries) * Static metadata: SMPTE ST 2086 (mastering display color volume), MaxFALL (maximum frame-average light level), and MaxCLL (maximum content light level) * Color sub-sampling: 4:2:0 (for compressed video sources) PQ10 refers to an HDR format that uses PQ, 10-bit and Rec. 2100 color primaries without having ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-dynamic-range Rendering
High-dynamic-range rendering (HDRR or HDR rendering), also known as high-dynamic-range lighting, is the Rendering (computer graphics), rendering of computer graphics scenes by using computer graphics lighting, lighting calculations done in high dynamic range (HDR). This allows preservation of details that may be lost due to limiting contrast ratios. Video games and Computer animation, computer-generated movies and special effects benefit from this as it creates more realistic scenes than with more simplistic lighting models. Graphics processor company Nvidia summarizes the motivation for HDR in three points: bright things can be really bright, dark things can be really dark, and details can be seen in both. History The use of high-dynamic-range imaging (HDRI) in computer graphics was introduced by Greg Ward in 1985 with his open-source Radiance (software), Radiance rendering and ''lighting simulation'' software which created the first file format to retain a high-dynamic-range im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photography
Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed in many fields of science, manufacturing (e.g., photolithography), and business, as well as its more direct uses for art, film and video production, recreational purposes, hobby, and mass communication. Typically, a lens is used to focus the light reflected or emitted from objects into a real image on the light-sensitive surface inside a camera during a timed exposure. With an electronic image sensor, this produces an electrical charge at each pixel, which is electronically processed and stored in a digital image file for subsequent display or processing. The result with photographic emulsion is an invisible latent image, which is later chemically "developed" into a visible image, either negative or positive, depending on the purp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenEXR
OpenEXR is a high-dynamic range, multi-channel raster file format, released as an open standard along with a set of software tools created by Industrial Light & Magic (ILM), under a free software license similar to the BSD license. It is notable for supporting multiple channels of potentially different pixel sizes, including 32-bit unsigned integer, 32-bit and 16-bit floating point values, as well as various compression techniques which include lossless and lossy compression algorithms. It also has arbitrary channels and encodes multiple points of view such as left- and right-camera images. Overview A full technical introduction of the format is available on the OpenEXR website. OpenEXR, or EXR for short, is a deep raster format developed by ILM and broadly used in the computer-graphics industry, both visual effects and animation. OpenEXR's multi-resolution and arbitrary channel format makes it appealing for compositing, as it alleviates several painful elements of the process ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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