Color mapping

Color mapping

Color mapping example

Source image
Reference image
Source image color mapped using histogram matching

Color mapping is a function that maps (transforms) the colors of one (source) image to the colors of another (target) image. A color mapping may be referred to as the algorithm that results in the mapping function or the algorithm that transforms the image colors. Color mapping is also sometimes called color transfer or, when grayscale images are involved, brightness transfer function (BTF).

Algorithms

There are two types of color mapping algorithms: those that employ the statistics of the colors of two images, and those that rely on a given pixel correspondence between the images.

An example of an algorithm that employs the statistical properties of the images is histogram matching. This is a classic algorithm for color mapping, suffering from the problem of sensitivity to image content differences. Newer statistic-based algorithms deal with this problem. An example of such algorithm is adjusting the mean and the standard deviation of Lab channels of the two images.[1]

A common algorithm for computing the color mapping when the pixel correspondence is given is building the joint-histogram (see also co-occurrence matrix) of the two images and finding the mapping by using dynamic programming based on the joint-histogram values.[2]

When the pixel correspondence is not given and the image contents are different (due to different point of view), the statistics of the image corresponding regions can be used as an input to statistics-based algorithms, such as histogram matching. The corresponding regions can be found by detecting the corresponding features.[3]

Applications

Color mapping can serve two different purposes: one is calibrating the colors of two cameras for further processing using two or more sample images, the second is adjusting the colors of two images for perceptual visual compatibility.

Color calibration is an important pre-processing task in computer vision applications. Many applications simultaneously process two or more images and, therefore, need their colors to be calibrated. Examples of such applications are: Image differencing, registration, object recognition, multi-camera tracking, co-segmentation and stereo reconstruction.

References


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Color — This article is about the perceptual property. For other uses, see Color (disambiguation). For usage of color on Wikipedia, see Wikipedia:Colors. Colored pencils Color or colour (see spelling differences) is the visual perceptual property… …   Wikipedia

  • Color calibration — The aim of color calibration is to measure and/or adjust the color response of a device (input or output) to a known state. In ICC terms this is the basis for a additional color characterization of the device and later profiling[1]. In non ICC… …   Wikipedia

  • Color correction — This article is about color correction using lighting and camera filters. For video color correction in post production, see Color grading. For color correction of still images in post production, see Color balance. For mutual color correction of …   Wikipedia

  • Color alphabet — is a one to one mapping of a subset of discrete colors to a standardized set of signs (alphabet or graphemes) that allows one to construct meaning out of color directly and unambiguously using an existing system of writing.The choice of colors… …   Wikipedia

  • Color depth — 1 bit monochrome 8 bit grayscale 8 bit color 15/16 bit color (High color) 24 bit color (True color) 30/36/48 bit color (Deep color) Related Indexed color Palette RGB color model Web safe color This box …   Wikipedia

  • Color printing — Color separation redirects here. For other uses, see Chroma key. Color printing or Colour printing is the reproduction of an image or text in color (as opposed to simpler black and white or monochrome printing). Any natural scene or color… …   Wikipedia

  • Color constancy — Color constancy: The colors of a hot air balloon are recognized as being the same in sun and shade …   Wikipedia

  • Color superconductivity — is a phenomenon predicted to occur in quark matter if the baryon density is sufficiently high (well above nuclear density) and the temperature is not too high (well below 1012 kelvin). Color superconducting phases are to be contrasted with the… …   Wikipedia

  • Color progression — Color progressions are ranges of color whose values transition smoothly through a hue, saturation, luminance, or any combination of the three. There may be multiple steps in the progression as well for example, it may start by transitioning from… …   Wikipedia

  • Color management — In digital imaging systems, color management is the controlled conversion between the color representations of various devices, such as image scanners, digital cameras, monitors, TV screens, film printers, computer printers, offset presses, and… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”