The different stages in digital image processing are:

Image Acquisition
  • This is the first stage of digital image processing.
  • The image Acquisition stage involves preprocessing, such as scaling, etc.
Image Enhancement
  • Image enhancement is the simplest and most appealing areas of digital image processing.
  • The idea behind enhancement techniques is to bring out detail that is obscured, or simply to highlight certain features of interest in an image, such as changing brightness and contrast, etc.

 

 

Image Restoration
  • Image Restoration is an area that also deals with improving the appearance of an image.
  • However, unlike enhancement, which is subjective, image restoration is objective, in the sense that restoration techniques tend to be based on mathematical or probabilistic models of image degradation.
Color Image Processing
  • Color image processing is an area that has been gaining its importance because of the significant increase in the use of digital images over the internet.
  • This may include color modeling and processing in a digital domain, etc.
Wavelets and Multi-Resolution Processing
  • Wavelets are the foundation for representing images in various degrees of resolution.
  • The image is subdivided into smaller regions for data compression and pyramidal representation.

 

 

Compression
  • Compression deals with techniques for reducing the storage required to save an image or bandwidth to transmit it.
  • Particularly in the uses of the internet, it is very much necessary to compress data.
Morphological Processing
  • Morphological Processing deals with tools for extracting image components that are useful in the representation and description of shape.
Segmentation
  • Segmentation procedures partition an image into its constituent parts or objects.
  • In general, autonomous segmentation is one of the most difficult tasks in digital image processing.
  • A rough segmentation procedure brings the process a long way towards a successful solution of imaging problems that require objects to be identified individually.

 

 

Representation and Description
  • Representation and Description always follow the output of a segmentation stage, which usually is a raw pixel data, constituting either the boundary of a region or all the points in the region itself.
  • Choosing a representation is only the part of the solution for transforming raw data into a form suitable for subsequent computer processing.
  • Description deals with extracting attributes that result in some quantitative information of interest or are basic for differentiating one class of objects from another.
Object Recognition
  • Object recognition is the process that assigns a label, such as, "vehicle" to an object based on its descriptors.
Knowledge Base
  • Knowledge may be as simple as detailing regions of an image where the information of interest is known to be located, thus limiting the search that has to be conducted in seeking that information.
  • The knowledge base can also be quite complex, such as an interrelated list of all major possible defects in a materials inspection problem or an image database containing high-resolution satellite images of a region in connection with change-detection applications.