Image processing
In the broadest sense, image processing is any form of information processing for which both the input and output are images, such as photographs or frames of video. Most image processing techniques involve treating the image as a two-dimensional signal and applying standard signal processing techniques to it.
Encyclopedia
In the broadest sense,
image processing is any form of information processing for which both the input and output are images, such as photographs or frames of video. Most image processing techniques involve treating the image as a two-dimensional signal and applying standard signal processing techniques to it.
Solution Methods
A few decades ago, image processing was done largely in the analog domain, chiefly by
optical devices. These optical methods are still essential to applications such as
holography because they are inherently parallel; however, due to the significant increase in
computer speed, these techniques are increasingly being replaced by digital image processing methods.
Digital image processing techniques are generally more versatile, reliable, and accurate; they have the additional benefit of being easier to implement than their analog counterparts. Specialized hardware is still used for digital image processing: computer architectures based on pipelining have been the most commercially successful. There are also many massively parallel architectures that have been developed for the purpose. Today, hardware solutions are commonly used in video processing systems. However, commercial image processing tasks are more commonly done by software running on conventional personal computers.
Commonly Used Signal Processing Techniques
Most of the signal processing concepts that apply to one-dimensional signals also extend to the two-dimensional image signal. Some of these one-dimensional signal processing concepts become significantly more complicated in two-dimensional processing. Image processing brings some new concepts, such as connectivity and rotational invariance, that are meaningful only for two-dimensional signals.
The fast fourier transform is often used for image processing operations because it reduces the amount of data and the necessary processing time.
One-Dimensional Techniques
...
- Filtering
- Differential operators
- Edge detection
- Domain modulation
- Noise reduction
Two-Dimensional Techniques
- Connectivity
- Rotational invariance
Typical Problems
- Geometric transformations such as enlargement, reduction, and rotation
- Color corrections such as brightness and contrast adjustments, quantization, or conversion to a different color space
- Registration of two or more images
- Combination of two or more images, e.g. into an average, blend, difference, or image composite
- Interpolation, demosaicing, and recovery of a full image from a RAW image format like a Bayer filter pattern
- Segmentation of the image into regions
- Image editing and digital retouching
- Extending dynamic range by combining differently exposed images
and many more.
Besides static two-dimensional images, the field also covers the processing of time-varying signals such as
video and the output of tomographic equipment. Some techniques, such as morphological image processing, are specific to binary or
grayscale images.
Applications
- Photography and printing
- Satellite image processing
- Medical image processing
- Face detection, feature detection, face identification
- Microscope image processing
- Car barrier detection
Related Concepts
See also
...
References
- Fundamentals of Image Processing by Ian T. Young, Jan J. Gerbrands, Lucas J. Van Vliet, Paperback, ISBN 90 75691 01 7
- Image Analysis and Mathematical Morphology by Jean Serra, ISBN 0 12 637242 3
- Image Analysis and Mathematical Morphology, Volume 2: Theoretical Advances by Jean Serra, ISBN 0 12 637241 1
- Front-End Vision and Multi-Scale Image Analysis by Bart M. ter Haar Romeny, Paperback, ISBN 1 4020 1507 0
- Geometry-Driven Diffusion in Computer Vision by Bart M. ter Haar Romeny , ISBN 0 7293 3087 0
- Digital Image Processing by Rafael C. Gonzalez, Richard E. Woods, ISBN 0 201 50803 6
- Digital Image Processing by William K. Pratt, Paperback, ISBN 0 471 01888 0
External links
