1. Digital image processing: means processing of images which are digital in nature by a digital computer.

2. Digital image processing is the use of a digital computer to process digital images through an algorithm. 

Analog Image Processing

The analog image processing is applied on analog signals and it processes only two-dimensional signals. The images are manipulated by electrical signals. In analog image processing, analog signals can be periodic or non-periodic

Examples of analog images are television images, photographs, paintings, and medical images etc

Why Do we need Image Processing? 

digital image processing techniques is motivated by three major applications.

1. improvement of pictorial information for human perception

   this means that whatever image you get, we want to enhance the quality of
   image, so that the image will have a better look and it will be much better when you look at
   the image.

2. autonomous machine applications:

   This has various applications in industries particularly for quality control, in assembly automation and many such applications. We will look at them one after another.

3. Third application which is for efficient storage and transmission: 

   if we want to store an image on a computer, then this image will need certain amount of disk space. Now we will look at whether it is possible to process the image using
   certain image properties so that the disk space required for storing the image will be less; not
   only that, we can also have applications where we want, where we want to transmit the image
   or the video signal over a transmission medium.

So let us first look at the first major application which is meant for human perception.

Human Perception: 

• Noise filtering

• Content enhancement 
  • contrast enhancement 
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  • deblurring 
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• Remote Sensing 

Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring information about the Earth and other planets