Histogram Specification

picture info	Histogram Specification In image processing, histogram matching or histogram specification is the transformation of an image so that its histogram matches a specified histogram. The well-known histogram equalization method is a special case in which the specified histogram is uniformly distributed. It is possible to use histogram matching to balance detector responses as a relative detector calibration technique. It can be used to normalize two images, when the images were acquired at the same local illumination (such as shadows) over the same location, but by different sensors, atmospheric conditions or global illumination. Implementation Consider a grayscale input image X. It has a probability density function pr(r), where r is a grayscale value, and pr(r) is the probability of that value. This probability can easily be computed from the histogram of the image by p_r (r_j )= Where nj is the frequency of the grayscale value rj, and n is the total number of pixels in the image. Now consider a desi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Image Histogram An image histogram is a type of histogram that acts as a graphical representation of the Lightness (color), tonal distribution in a digital image. It plots the number of pixels for each tonal value. By looking at the histogram for a specific image a viewer will be able to judge the entire tonal distribution at a glance. Image histograms are present on many modern services. Photographers can use them as an aid to show the distribution of tones captured, and whether image detail has been lost to blown-out highlights or blacked-out shadows. This is less useful when using a raw image format, as the Tonal range, dynamic range of the displayed image may only be an approximation to that in the raw file. The horizontal axis of the graphics, graph represents the tonal variations, while the vertical axis represents the total number of pixels in that particular tone. The left side of the horizontal axis represents the dark areas, the middle represents mid-tone values and the right hand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Histogram Equalization Histogram equalization is a method in image processing of contrast adjustment using the image's histogram. Histogram equalization is a specific case of the more general class of histogram remapping methods. These methods seek to adjust the image to make it easier to analyze or improve visual quality (e.g., retinex). Overview This method usually increases the global contrast of many images, especially when the image is represented by a narrow range of intensity values. Through this adjustment, the intensities can be better distributed on the histogram utilizing the full range of intensities evenly. This allows for areas of lower local contrast to gain a higher contrast. Histogram equalization accomplishes this by effectively spreading out the highly populated intensity values, which tend to degrade image contrast. The method is useful in images with backgrounds and foregrounds that are both bright or both dark. In particular, the method can lead to better views of bone s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Cumulative Distribution Function In probability theory and statistics, the cumulative distribution function (CDF) of a real-valued random variable X, or just distribution function of X, evaluated at x, is the probability that X will take a value less than or equal to x. Every probability distribution Support (measure theory), supported on the real numbers, discrete or "mixed" as well as Continuous variable, continuous, is uniquely identified by a right-continuous Monotonic function, monotone increasing function (a càdlàg function) F \colon \mathbb R \rightarrow [0,1] satisfying \lim_F(x)=0 and \lim_F(x)=1. In the case of a scalar continuous distribution, it gives the area under the probability density function from negative infinity to x. Cumulative distribution functions are also used to specify the distribution of multivariate random variables. Definition The cumulative distribution function of a real-valued random variable X is the function given by where the right-hand side represents the probability ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Output Image Output may refer to: * The information produced by a computer, see Input/output * An output state of a system, see state (computer science) * Output (economics), the amount of goods and services produced Gross output in economics, the value of net output or GDP plus intermediate consumption Net output in economics, the gross revenue from production less the value of goods and services * Power (physics) or Work (physics) output of a machine * Dependent variable of a function, in mathematics * ''Output'' (album) See also * Input (other) Input may refer to: Computing * Input (computer science), the act of entering data into a computer or data processing system * Information, any data entered into a computer or data processing system * Input device * Input method * Input port (dis ... {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Input Image Histogram Input may refer to: Computing * Input (computer science), the act of entering data into a computer or data processing system * Information, any data entered into a computer or data processing system * Input device * Input method * Input port (other) * Input/output (I/O), in computing Other * ''Input'' (talk show) * Input (typeface) * International Public Television Screening Conference (INPUT), an international public television organization * ''Input'' (online magazine), an online technology and culture magazine owned by Bustle Digital Group See also * * Independent variable in a mathematical function * In economics, a factor of production, a resource employed to produce goods and services * Advice (opinion) Advice (also called exhortation) is a form of relating personal or institutional opinions, belief systems, values, recommendations or guidance about certain situations relayed in some context to another person, group or party. Advice is often o ... * Impute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Image Processing An image or picture is a visual representation. An image can be two-dimensional, such as a drawing, painting, or photograph, or three-dimensional, such as a carving or sculpture. Images may be displayed through other media, including a projection on a surface, activation of electronic signals, or digital displays; they can also be reproduced through mechanical means, such as photography, printmaking, or photocopying. Images can also be animated through digital or physical processes. In the context of signal processing, an image is a distributed amplitude of color(s). In optics, the term ''image'' (or ''optical image'') refers specifically to the reproduction of an object formed by light waves coming from the object. A ''volatile image'' exists or is perceived only for a short period. This may be a reflection of an object by a mirror, a projection of a camera obscura, or a scene displayed on a cathode-ray tube. A ''fixed image'', also called a hard copy, is one that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Grayscale Image In digital photography, computer-generated imagery, and colorimetry, a greyscale (more common in Commonwealth English) or grayscale (more common in American English) image is one in which the value of each pixel is a single sample (signal), sample representing only an ''amount'' of light; that is, it carries only luminous intensity, intensity information. Grayscale images, are black-and-white or gray monochrome, and composed exclusively of shades of gray. The contrast (vision), contrast ranges from black at the weakest intensity to white at the strongest. Grayscale images are distinct from one-bit bi-tonal black-and-white images, which, in the context of computer imaging, are images with only two colors: black and white (also called ''bilevel'' or ''binary images''). Grayscale images have many shades of gray in between. Grayscale images can be the result of measuring the intensity of light at each pixel according to a particular weighted combination of frequencies (or wavelen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Probability Density Function In probability theory, a probability density function (PDF), density function, or density of an absolutely continuous random variable, is a Function (mathematics), function whose value at any given sample (or point) in the sample space (the set of possible values taken by the random variable) can be interpreted as providing a ''relative likelihood'' that the value of the random variable would be equal to that sample. Probability density is the probability per unit length, in other words, while the ''absolute likelihood'' for a continuous random variable to take on any particular value is 0 (since there is an infinite set of possible values to begin with), the value of the PDF at two different samples can be used to infer, in any particular draw of the random variable, how much more likely it is that the random variable would be close to one sample compared to the other sample. More precisely, the PDF is used to specify the probability of the random variable falling ''within ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]