What is digital image processing?
As evident from the question, digital image processing is the processing of images that are digitally stored using a computer. In other words, we can say that “Digital Image Processing refers to the processing of digital images by means of a digital computer.“
Now that we have understood that what is digital image processing, let us understand that what do we mean by the digital image. Before understanding about a digital image, let us see first that what is an image.
An image can be defined as a function f(x,y). Here
- x and y are spatial (plane) coordinates.
- the amplitude of function f at any point (x,y) is called intensity or gray level of an image at that point.
Now an image is said to be a digital image when x,y and amplitude values of function f(x,y) are finite and discrete in nature.
A digital image is composed of finite number of elements (known as pixels), each of which has
- a particular value
- a particular location
Three levels of processing in digital image processing:
In general, there are three levels of processing or three types of processes in digital image processing namely: low, mid and high-level processes.
- Low-level processing involves primitive operation such as image preprocessing to reduce noise, contrast enhancement, image sharpening, etc. In the low-level process, both input and output are images.
- Mid-level processing involves tasks such as image segmentation, description of images, object recognition, etc. In the mid-level process, inputs are generally images but its outputs are generally image attributes.
- High-level processing involves “making sense” from a group of recognized objects. This process is normally associated with computer vision.
Applications of digital image processing:
- Automatic character recognition.
- Military recognition.
- Automatic processing of fingerprints.
- Screening of X-ray and blood samples.
- It is used in the study of pollution particles.
- It is used to restore blurred pictures of rare artifacts (application in archaeology).
- Industrial machine vision for products assembly and inspection.
- Machine processing of aerial and satellite imagery for weather prediction.
- In astronomy, biology, nuclear medicine, law enforcement, defence and industry, etc.