An image is an array of pixels (picture elements) arranged in columns and rows. So image is a collection of discrete (and usually small) cells, which is known as pixel in image processing. In a 8-bit greyscale image each picture element has an assigned intensity that ranges from 0 to [...]
Image Rescaling or resampling is the technique used to create a new version of an image with a different size. Increasing the size of the image is called upsampling, and reducing the size of an image is called downsampling. Image scaling operations is not lossless. For example, if you downsample [...]
Image filtering refers to processing of an input image to produce either a better-looking output image by contrast/sharpness and/or signal-to-noise ratio enhancement. It also includes computing some low-level image features such as edges, corners, or spatial-gradient values that may be used in subsequent image processing. Usually a RGB image is [...]
A color model in Image Processing is an abstract mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values or color components. When this model is associated with a precise description of how the components are to be interpreted (viewing conditions, [...]
CIE RGB Color Space CIE RGB color space is one of many RGB color spaces. It is based on the series of experiments conducted on human eye, to determine the colors in human vision. Eye reacts to the three primaries i.e. Red, Green and Blue separately. Colors we see are [...]
Introduction BT.709 is also known by the abbreviations Rec. 709. It standardizes the format of high-definition television, having 16:9 (widescreen) aspect ratio. YPbPr color model used in analog component video and its digital version YCbCr used in digital video.Y′ stands for the luma component (the brightness) and U and V [...]
Introduction YUV is a color encoding system used as part of a color image pipeline. It encodes a color image or video taking human perception into account, allowing reduced bandwidth for chrominance components. Y'UV model defines a color space in terms of one luma (Y') and two chrominance (UV) components. [...]
Wavelength Wavelength of light determines the nature of the light. We can describe light as electromagnetic waves with color identified by its wavelength. A single photon of one color differs from a photon of another color only by its energy. Visible light is the range of wavelengths within the electromagnetic [...]
Introduction For 8 bit color, [0, 255] range is referred as Full Range, and [16, 235] range is referred as Narrow Range (aka Limited Range, Low RGB, Broadcast). For YUV signals the Narrow Range is [16, 235 ] for Y, and [16, 240] for UV. In broadcast environment levels from [...]
XYZ Color Space This color model is based on three hypothetical primaries, XYZ. All visible colors can be represented by using only positive values of X, Y, and Z. The Y primary match closely to luminance, while X and Z primaries give color information. An RGB matrix color space is [...]