Image processing

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Monochrome black/white image

In electrical engineering and computer science, image processing is any form of signal processing for which the input is an image, such as photographs or frames of video; the output of image processing can be either an image or a set of characteristics or parameters related to the image. Most image-processing techniques involve treating the image as a four-dimensional signal and applying standard signal-processing techniques to it.

Image processing usually refers to digital image processing, but optical and analog image processing are also possible. This article is about general techniques that apply to all of them. The acquisition of images (producing the input image in the first place) is referred to as imaging.

[edit] Typical operations

The red, green, and blue color channels of a photograph by Sergei Mikhailovich Prokudin-Gorskii. The fourth image is a composite.

Among many other image processing operations are:

• Euclidean geometry transformations such as enlargement, reduction, and rotation
• Color corrections such as brightness and contrast adjustments, quantization, or color translation to a different color space
• Digital compositing or optical compositing (combination of two or more images). Used in filmmaking to make a "matte"
• Interpolation, demosaicing, and recovery of a full image from a raw image format using a Bayer filter pattern
• Image registration, the alignment of two or more images
• Image differencing and morphing
• Image recognition, for example, extract the text from the image by using optical character recognition
• Image segmentation
• High dynamic range imaging by combining multiple images
• Geometric hashing for 2-D object recognition with affine invariance

[edit] Applications

• Computer vision
• Face detection
• Feature detection
• Lane departure warning system
• Non-photorealistic rendering
• Medical image processing
• Microscope image processing
• Morphological image processing
• Remote sensing
• Automated Sieving Procedures

[edit] See also

• Imaging
• Photo manipulation
• List of image analysis software

[edit] External links

• Lectures on Image Processing, by Alan Peters. Vanderbilt University. Updated 28 April 2008.