Digital image processing

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Digital image processing is the use of computer algorithms to perform image processing on digital images. Digital image processing has the same advantages over analog image processing as digital signal processing has over analog signal processing — it allows a much wider range of algorithms to be applied to the input data, and can avoid problems such as the build-up of noise and signal distortion during processing.

The most common kind of digital image processing is digital image editing.

Contents 1 History 2 Digital processing of camera images 3 Uses 4 See also 5 References 6 External links

[edit] History

Many of the techniques of digital image processing, or digital picture processing as it was often called, were developed in the 1960s at the Jet Propulsion Laboratory, MIT, Bell Labs, University of Maryland, and a few other places, with application to satellite imagery, wirephoto standards conversion, medical imaging, videophone, character recognition, and photo enhancement.^[1] But the cost of processing was fairly high with the computing equipment of that era. In the 1970s, digital image processing proliferated, when cheaper computers and dedicated hardware became available. Images could then be processed in real time, for some dedicated problems such as television standards conversion. As general-purpose computers became faster, they started to take over the role of dedicated hardware for all but the most specialized and compute-intensive operations.

With the fast computers and signal processors available in the 2000s, digital image processing has become the most common form of image processing, and is generally used because it is not only the most versatile method, but also the cheapest.

[edit] Digital processing of camera images

Digital cameras generally include dedicated digital image processing chips to convert the raw data from the image sensor into a color-corrected image in a standard image file format. Images from digital cameras often receive further processing to improve their quality, a distinct advantage digital cameras have over film cameras. The digital image processing is typically done by special software programs that can manipulate the images in many ways.

Many digital cameras also enable viewing of histograms of images, to help the photographer understand the intensity range of each shot.

[edit] Uses

Digital Image Processing allows the use of much more complex algorithms for image processing, and hence can offer both more sophisticated performance at simple tasks, and the implementation of methods which would be impossible by analog means.

In particular, digital image processing is the only practical technology for:

• Classification
• Feature extraction
• Pattern recognition
• Projection
• Multi-scale signal analysis

Some techniques which are used in digital image processing include:

• Principal components analysis
• Independent component analysis
• Self-organizing maps
• Hidden Markov models
• Neural networks

[edit] See also

• Digital image editing
• Image processing
• Computer graphics
• Computer vision
• GPGPU
• Imaging
• Satellite imagery
• Machine Vision Glossary
• Matlab image processing

[edit] References

1. Fundamentals of Image Processing by Ian T. Young, Jan J. Gerbrands, Lucas J. Van Vliet, Paperback, ISBN 90-75691-01-7 (1995)
2. Image Analysis and Mathematical Morphology by Jean Serra, ISBN 0-12-637242-3 (1982)
3. Image Analysis and Mathematical Morphology, Volume 2: Theoretical Advances by Jean Serra, ISBN 0-12-637241-1 (1988)
4. Front-End Vision and Multi-Scale Image Analysis by Bart M. ter Haar Romeny, Paperback, ISBN 1-4020-1507-0 (2003)
5. Geometry-Driven Diffusion in Computer Vision by Bart M. ter Haar Romeny (Ed.), ISBN 0-7293-3087-0 (1994)
6. Digital Image Processing by Rafael C. Gonzalez, Richard E. Woods, ISBN 0-201-50803-6 (1992)
7. Digital Image Processing by William K. Pratt, Paperback, ISBN 0-471-01888-0 (1978)

1. ^ Azriel Rosenfeld, Picture Processing by Computer, New York: Academic Press, 1969

[edit] External links

• Wikia has a wiki about: Computer Vision
• VIPBase: A collection of utilities for Video and Image Processing
• Image Processing forum (image coding, compression, digital effects, mpeg, etc)
• GRAIL, the Graphics and Imaging Laboratory of the University of Washington
• Virginia Image and Video Analysis group
• Advanced Imaging Laboratory of the University of Victoria
• The HALCON libraray for digital image processing
• FILTERS : a free open source image processing library
• BSD Licensed C++\C# Image Filters

Digital Signal Processing
Theory — Nyquist–Shannon sampling theorem, estimation theory, detection theory
Sub-fields — audio signal processing | control engineering | digital image processing | speech processing | statistical signal processing
Techniques — Discrete Fourier transform (DFT) | Discrete-time Fourier transform (DTFT) | bilinear transform | Z-transform, advanced Z-transform
Sampling — oversampling | undersampling | downsampling | upsampling | aliasing | anti-aliasing filter | sampling rate | Nyquist rate/frequency
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