Implementation of PPM Image Processing and Median Filtering

Abstract

Image consists of a rectangular array of discrete picture elements called pixels. The PPM (portable pixmap format (.ppm)) is a particularly simple way used to represent or encode a rectangular image as uncompressed data file. This .ppm file can be viewed with number of tools, including GIMP, gThumb image viewer etc. Reading and Writing PPM images are a difficult task which has been overcome successfully in our experiment. In signal processing, it is often desirable to be able to perform some kind of noise reduction on an image or signal. The median filter is a nonlinear digital filtering technique, often used to remove noise. Such noise reduction is a typical pre-processing step to improve the results of later processing (for example, edge detection on an image). Median filtering is very widely used in digital image processing because under certain conditions, it preserves edges whilst removing noise. The results shows the smoothened image.