- Digital image processing
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This article is about mathematical processing of digital images. For artistic processing of images, see Image editing.
Paranal Observatory' landscape after application of the city globe image technique.
The Digital image processing is the use of computer algorithms to perform image processing on digital images. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image 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. Since images are defined over two dimensions (perhaps more) digital image processing may be modeled in the form of multidimensional systems.
Contents
History
Many of the techniques of digital image processing, or digital picture processing as it often was called, were developed in the 1960s at the Jet Propulsion Laboratory, Massachusetts Institute of Technology, Bell Laboratories, University of Maryland, and a few other research facilities, with application to satellite imagery, wire-photo standards conversion, medical imaging, videophone, character recognition, and photograph enhancement.[1] The cost of processing was fairly high, however, with the computing equipment of that era. That changed in the 1970s, when digital image processing proliferated as cheaper computers and dedicated hardware became available. Images then could 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 computer-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 generally, is used because it is not only the most versatile method, but also the cheapest.
Digital image processing technology for medical applications was inducted into the Space Foundation Space Technology Hall of Fame in 1994.[2]
Tasks
A 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:
- Pixelization
- Linear filtering
- Principal components analysis
- Independent component analysis
- Hidden Markov models
- Anisotropic diffusion
- Partial differential equations
- Self-organizing maps
- Neural networks
- Wavelets
Applications
Further information: Digital imagingDigital 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 that digital cameras have over film cameras. The digital image processing typically is executed by special software programs that can manipulate the images in many ways.
Many digital cameras also enable viewing of histograms of images, as an aid for the photographer to understand the rendered brightness range of each shot more readily.
Film
Westworld (1973) was the first feature film to use digital image processing to pixellate photography to simulate an android's point of view.[3]
Intelligent transportation systems
Digital image processing has a wide applications in intelligent transportation systems, such as automatic number plate recognition and traffic sign recognition.
See also
- Computer graphics
- Computer vision
- Digitizing
- Comparison of image processing software
- GPGPU
- Homomorphic filtering
- Standard test image
- Super-resolution
- Multidimensional systems
- IEEE Intelligent Transportation Systems Society
References
- ^ Azriel Rosenfeld, Picture Processing by Computer, New York: Academic Press, 1969
- ^ "Space Technology Hall of Fame:Inducted Technologies/1994". Space Foundation. 1994. http://www.spacetechhalloffame.org/inductees_1994_Digital_Image_Processing.html. Retrieved 7 January 2010.
- ^ A Brief, Early History of Computer Graphics in Film, Larry Yaeger, 16 August 2002 (last update), retrieved 24 March 2010
Further reading
- Wilhelm Burger and Mark J. Burge (2007). Digital Image Processing: An Algorithmic Approach Using Java. Springer. ISBN 1846283795 and ISBN 3540309403. http://www.imagingbook.com/.
- R. Fisher, K Dawson-Howe, A. Fitzgibbon, C. Robertson, E. Trucco (2005). Dictionary of Computer Vision and Image Processing. John Wiley. ISBN 0-470-01526-8.
- Bernd Jähne (2002). Digital Image Processing. Springer. ISBN 3-540-67754-2.
- Tim Morris (2004). Computer Vision and Image Processing. Palgrave Macmillan. ISBN 0-333-99451-5.
- Milan Sonka, Vaclav Hlavac and Roger Boyle (1999). Image Processing, Analysis, and Machine Vision. PWS Publishing. ISBN 0-534-95393-X.
- Rafael C. Gonzalez, Richard E. Woods and Steven L. Eddins (2004). Digital Image Processing using MATLAB. Pearson Education. ISBN 978-81-7758-898-9.
External links
- Tutorial for image processing (contains a Java applet)
- Image processing algorithms, implementations and demonstrations
- Image processing Research Group
- open-source digital image processing library in C++
Digital signal processing Theory Sub-fields audio signal processing · digital image processing · speech processing · statistical signal processingTechniques Discrete Fourier transform (DFT) · Discrete-time Fourier transform (DTFT) · Impulse invariance · bilinear transform · pole–zero mapping · Z-transform · advanced Z-transformSampling oversampling · undersampling · downsampling · upsampling · aliasing · anti-aliasing filter · sampling rate · Nyquist rate/frequencyCategories:
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