06-07-2012, 02:08 PM
Digital image processing Methods
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Introduction
Digital image processing is a broad field with extensive literature. This introduction could only summarize some of the more important methods in common use and may suffer from a bias towards industrial applications. One of the first applications of digital images was in the newspaper industry, when pictures were first sent by submarine cable between London and New York. Introduction of the Bartlane cable picture transmission system in the early 1920s reduced the time required to transport a picture across the Atlantic from more than a week to less than three hours. Specialized printing equipment coded pictures for cable transmission and then reconstructed them at the receiving end. Some of the initial problems in improving the visual quality of these early digital pictures were related to the selection of printing procedures and the distribution of intensity levels.
What is digital image processing?
An image may be defined as a two-dimensional function, f(x, y), where x and y are spatial (Plane) coordinates, and the amplitude of f at any pair of coordinates (x, y) is called the intensity or Gray level of the image at that point. When (x, y) and amplitude values of f are all finite, discrete Quantities, we call the image a digital image. The field of digital image processing refers to processing digital images by means of a digital computer. Note that a digital image is com- posed of a finite number of elements, each of which has a particular location and value. These elements are referred to as picture elements, image elements, pixels, and pixels. Pixel is the term most widely used to denote the elements of a digital image.Vision is the most advanced of our senses, so it is not surprising that images play the single most important role in human perception. However, unlike humans, where limited to the visual band of the electromagnetic (EM) spectrum, imaging machines cover almost the entire EM spectrum, ranging from gamma to radio waves. They can operate on images generated by sources that humans are not accustomed to associating with images.
Explaining digital image processing
The term digital image processing generally refers to processing of a two-dimensional picture by a digital computer. In a broader context, it implies digital processing of any two-dimensional data. A digital image is an array of real or complex numbers .Digital image processing has a broad spectrum of applications, such as remote sensing via satellites and other spacecrafts, image transmission and storage for business Applications medical processing, radar, sonar, and acoustic image processing, robotics, and automated industrial parts.
Fundamental steps in digital image processing
Image acquisition is the first process.
Image enhancement is among the simplest and most appealing areas of digital processing. Basically the Idea behind enhancement techniques is to bring out detail that is obscured ,or simply to highlight Certain Features of interest in an image. A familiar example of enhancement is when we increase the contrast of an image because “it looks better”. It is important to keep in mind that enhancement is a very subjective area of Image processing.
Image restoration is an area that also deals with improving the appearance of an image.
Color image processing is an area that has been gaining in importance because of the significant increase in the use if digital images over the internet.