What is an Digital image?
  • Digital Image is composed of a finite number of elements, each of which elements have a particular value at a particular location.
  • These elements are referred to as picture elements,image elements,and pixels.
Image result for digital images contains pixels
Digital image processing:
  • Image processing is a method to perform some operations on an image, in order to get an enhanced image or to extract some useful information from it. 
  • The input of that system is a digital image and the system process that image using efficient algorithms, and gives an image as an output.
  • The most common example is Adobe Photoshop. It is one of the widely used application for processing digital images.
  • Image processing basically includes the following three steps:
      - Importing the image via image acquisition tools;
      - Analysing and manipulating the image;
      - Output in which result can be altered image or report that is based on image analysis.
  • There are two types of methods used for image processing namely, analog and digital image processing. 
  • Analog image processing can be used for the hard copies like printouts and photographs.
  • Digital image processing techniques help in manipulation of the digital images by using computers.
Phases of image processing:
  • Image Acquisition: It could be as simple as being given an image which is in digital form. The main work involves:
       a) Scaling
       b) Color conversion(RGB to Gray or vice-versa)
  • Image Enhancement: It is amongst the simplest and most appealing in areas of Image Processing. It is also used to extract some hidden details from an image and is subjective. It sharpens image features such as edges, boundaries, or contrast to make a graphic display more helpful for display and analysis.
  • Image Restoration: It also deals with appealing of an image. It is the process of recovering an image from a degraded version usually a blurred and noisy image.
  • Morphological Processing: It deals with tools for extracting image components that are useful in the representation and description of shape.
  • Segmentation: It includes partitioning an image into its constituent parts or objects. Autonomous segmentation is the most difficult task in image processing. 
  • Object Recognition: It is a process that assigns a label to an object based on its descriptor.
  • Representation and Description: It follows output of segmentation stage, choosing a representation is only the part of solution for  transforming raw data into processed data.
  • Image Compression: It involves in developing some functions to perform this operation. It mainly deals with image size or resolution.
  • Colour Image Processing: It deals with pseudocolor and full color image processing color models are applicable to digital image processing.  
Advantages:
  • It improves the visual quality of an image and the distribution of intensity.
  • It can process an image in such a way that the result is more suitable than the original image.
  • An image can be easily modified using a number of techniques.
Disadvantages:
  • Digital cameras which are used for digital image processing have some drawbacks like memory card problems, higher cost, battery consumption. 
Applications:

Used in fingerprint recognition     
Used to improve quality and remove noise

Used for number plate recognition for speed cameras