HISTOGRAM EQUALIZATION TECHNIQUE IN IMAGE PROCESSING

Abstract

Two principle areas viz, improvement in pictorial informa-tion and processing of scene data for machine interpretation requires image processing methods to be developed.Introduction of Bartlane cable picture transmission system in early 1920s was the first application of this kind. This methodical system reduced traLismission time from weeks to hours. This system was able to code images in 5 distinct brightness levels. It was then further enhanced to 15 levels in 1929. By this time reproduction methods were also developed further. Hence the system could produce better results. The similar methods were then further improved for about 35 years and some better results could be obtained. But the potential and the real need for image processing was brought out by the advent of digital computers promising fast and faith-ful processing and the space programs, where there could be no other alternative available. Such an application was developed in Jet Propulsion Laboratory in 1964 when pictures from moon were transmitted by Ranger 7. Since then this field of image process-ing has been progressing vigorously and as on today better tech-niques for processing the pictures for good results and compati-bility with printing machines and techniques are existing. In addition to space programs some more applications of utmost importance were developed and every day new applications are being added to this branch, Popular areas are Medicine for clear and better interpretation of X-ray images, Geographical image processing, Pollution pattern analysis, etc.