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Oversampled Binary Image Sensor
An oversampled binary image sensor is an image sensor with non-linear response capabilities reminiscent of traditional photographic film. Each pixel in the sensor has a binary response, giving only a one-bit quantized measurement of the local light intensity. The response function of the image sensor is non-linear and similar to a logarithmic function, which makes the sensor suitable for high dynamic range imaging. Working principle Before the advent of digital image sensors, photography, for the most part of its history, used film to record light information. At the heart of every photographic film are a large number of light-sensitive grains of silver-halide crystals.T. H. James, The Theory of The Photographic Process, 4th ed., New York: Macmillan Publishing Co., Inc., 1977. During exposure, each micron-sized grain has a binary fate: Either it is struck by some incident photons and becomes "exposed", or it is missed by the photon bombardment and remains "unexposed". In the subse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Image Sensor
An image sensor or imager is a sensor that detects and conveys information used to make an image. It does so by converting the variable attenuation of light waves (as they pass through or reflect off objects) into signals, small bursts of current that convey the information. The waves can be light or other electromagnetic radiation. Image sensors are used in electronic imaging devices of both analog and digital types, which include digital cameras, camera modules, camera phones, optical mouse devices, medical imaging equipment, night vision equipment such as thermal imaging devices, radar, sonar, and others. As technology changes, electronic and digital imaging tends to replace chemical and analog imaging. The two main types of electronic image sensors are the charge-coupled device (CCD) and the active-pixel sensor (CMOS sensor). Both CCD and CMOS sensors are based on metal–oxide–semiconductor (MOS) technology, with CCDs based on MOS capacitors and CMOS senso ... [...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] |
Image Processing
An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensional picture, that resembles a subject. In the context of signal processing, an image is a distributed amplitude of color(s). In optics, the term “image” may refer specifically to a 2D image. An image does not have to use the entire visual system to be a visual representation. A popular example of this is of a greyscale image, which uses the visual system's sensitivity to brightness across all wavelengths, without taking into account different colors. A black and white visual representation of something is still an image, even though it does not make full use of the visual system's capabilities. Images are typically still, but in some cases can be moving or animated. Characteristics Images may be two or three-dimensional, such as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Image Sensors
An image sensor or imager is a sensor that detects and conveys information used to make an image. It does so by converting the variable attenuation of light waves (as they pass through or reflect off objects) into signals, small bursts of current that convey the information. The waves can be light or other electromagnetic radiation. Image sensors are used in electronic imaging devices of both analog and digital types, which include digital cameras, camera modules, camera phones, optical mouse devices, medical imaging equipment, night vision equipment such as thermal imaging devices, radar, sonar, and others. As technology changes, electronic and digital imaging tends to replace chemical and analog imaging. The two main types of electronic image sensors are the charge-coupled device (CCD) and the active-pixel sensor (CMOS sensor). Both CCD and CMOS sensors are based on metal–oxide–semiconductor (MOS) technology, with CCDs based on MOS capacitors and CMOS sensors b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Photography
Digital photography uses cameras containing arrays of electronic photodetectors interfaced to an analog-to-digital converter (ADC) to produce images focused by a lens, as opposed to an exposure on photographic film. The digitized image is stored as a computer file ready for further digital processing, viewing, electronic publishing, or digital printing. Digital photography spans a wide range of applications with a long history. In the space industry, where much of the technology originated, it pertains to highly customized, embedded systems combined with sophisticated remote telemetry. Any electronic image sensor can be digitized; this was achieved in 1951. The modern era in digital photography is dominated by the semiconductor industry, which evolved later. An early semiconductor milestone was the advent of the charge-coupled device (CCD) image sensor, first demonstrated in April 1970; the field has advanced rapidly and continuously ever since, paced by concurr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single Photon Avalanche Diode
A single-photon avalanche diode (SPAD) is a solid-state photodetector within the same family as photodiodes and avalanche photodiodes (APDs), while also being fundamentally linked with basic diode behaviours. As with photodiodes and APDs, a SPAD is based around a semi-conductor p-n junction that can be illuminated with ionizing radiation such as gamma, x-rays, beta and alpha particles along with a wide portion of the electromagnetic spectrum from ultraviolet (UV) through the visible wavelengths and into the infrared (IR). In a photodiode, with a low reverse bias voltage, the leakage current changes linearly with absorption of photons, i.e. the liberation of current carriers (electrons and/or holes) due to the internal photoelectric effect. However, in a SPAD, the reverse bias is so high that a phenomenon called impact ionisation occurs which is able to cause an avalanche current to develop. Simply, a photo-generated carrier is accelerated by the electric field in the device ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maximum Likelihood
In statistics, maximum likelihood estimation (MLE) is a method of estimating the parameters of an assumed probability distribution, given some observed data. This is achieved by maximizing a likelihood function so that, under the assumed statistical model, the observed data is most probable. The point in the parameter space that maximizes the likelihood function is called the maximum likelihood estimate. The logic of maximum likelihood is both intuitive and flexible, and as such the method has become a dominant means of statistical inference. If the likelihood function is differentiable, the derivative test for finding maxima can be applied. In some cases, the first-order conditions of the likelihood function can be solved analytically; for instance, the ordinary least squares estimator for a linear regression model maximizes the likelihood when all observed outcomes are assumed to have Normal distributions with the same variance. From the perspective of Bayesian infere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SPAD EPFL BINARY IMAGES
SPAD may refer to: In aircraft manufacture * Société Pour L'Aviation et ses Dérivés, also Société Provisoire des Aéroplanes Deperdussin and Blériot-SPAD, French aircraft manufacturer (1912–1921) * SPAD VII, SPAD S.XII and SPAD S.XIII, French fighter planes of World War I produced by Société Pour L'Aviation et ses Dérivés * A-1 Skyraider, nicknamed ''Spad'', an attack aircraft (1950s and 1960s) * Simple Plastic Airplane Design, a type of radio-controlled model airplane In science * Single Pass Albumin Dialysis, liver dialysis * Single-photon avalanche diode, a photodetector Other uses * Special adviser (UK), a government post * Self-propelled air defence, weapons * Signal passed at danger A signal passed at danger (SPAD), known in the United States as a stop signal overrun and in Canada as passing a stop signal, is an event on a railway where a train passes a stop signal without authority. In the United States and Canada, this ... by a train * ''Suruhanj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog-to-digital Converter
In electronics, an analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a digital signal. An ADC may also provide an isolated measurement such as an electronic device that converts an analog input voltage or current to a digital number representing the magnitude of the voltage or current. Typically the digital output is a two's complement binary number that is proportional to the input, but there are other possibilities. There are several ADC architectures. Due to the complexity and the need for precisely matched components, all but the most specialized ADCs are implemented as integrated circuits (ICs). These typically take the form of metal–oxide–semiconductor (MOS) mixed-signal integrated circuit chips that integrate both analog and digital circuits. A digital-to-analog converter (DAC) performs the reverse function; it converts a digital s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosensitive
Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicity. The photosensitive ganglion cells in the mammalian eye are a separate class of light-detecting cells from the photoreceptor cells that function in vision. Skin reactions Human medicine Sensitivity of the skin to a light source can take various forms. People with particular skin types are more sensitive to sunburn. Particular medications make the skin more sensitive to sunlight; these include most of the tetracycline antibiotics, heart drugs amiodarone, and sulfonamides. Some dietary supplements, such as St. John's Wort, include photosensitivity as a possible side effect. Particular conditions lead to increased light sensitivity. Patients with systemic lupus erythematosus experience skin symptoms after sunlight exposure; some ty ... [...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] |
Binary Sensor Model
Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two digits (0 and 1) * Binary function, a function that takes two arguments * Binary operation, a mathematical operation that takes two arguments * Binary relation, a relation involving two elements * Binary-coded decimal, a method for encoding for decimal digits in binary sequences * Finger binary, a system for counting in binary numbers on the fingers of human hands Computing * Binary code, the digital representation of text and data * Bit, or binary digit, the basic unit of information in computers * Binary file, composed of something other than human-readable text ** Executable, a type of binary file that contains machine code for the computer to execute * Binary tree, a computer tree data structure in which each node has at most two children Astronomy * Binary star, a star system with two stars in it * Binary planet, two planetary bodies of comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
