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Pg. 1 Introduction In the last thirty years digital image processing has grown from a scientific research field to a technical area that has many scientific and commercial applications. Many of these applications are due to the enormous improvements in computer technologies. Electronic image processing is now readily available on most typical desktop computers as opposed to the past when only a limited few had these capabilities. Digital image processing has been used to determine the brightness of the stars in a picture from a telescope, to determine the structure of a virus in a microscope image, and to produce highly accurate maps of the earth from satellite-gathered pictures. It has been used to control a sausage slicing machine to get equal weight slices from the irregularly shaped sausage, and to help restore classic paintings. It has applications in medicine, cartography, industry, manufacturing, printing, and publishing, cosmetics and personal grooming, and a variety of scientific and research fields. In all the cases, digital image processing is concerned with the computer processing of pictures or, more generally, images that have been converted into numeric form. These images can come from many sources. Digital cameras that are broadly available produce digital images instead of the classic piece of exposed film, although any photograph can be digitized by using devices such as scanners and microdensitometers. In fields such as medicine, materials testing, and astronomy, instruments are available that produce digital images from X-rays, gamma rays, and ultrasound waves. Satellite sensors directly produce digital images from Pg.2 measurements of reflected or emitted visible, infrared, or microwave radiation. There are many useful applications for digital image processing and the list could continue indefinitely. The main focus of this report is to provide the fundamentals of digital image processing. Also to enable the reader to know what digital image processing is and how it works, and also to provide useful examples of digital image processing. Digital Image Processing A natural image captured with a camera, telescope, microscope, or other type of optical instrument displays a continuously varying array of shades and color tones. Photographs made with film, or video images produced by a television camera tube, are a division of all possible images and contain a wide spectrum of intensities. They range from dark to light, and a spectrum of colors that can include just about any imaginable hue and saturation level. Images of this type are referred to as continuous-tone because the various tonal shades and hues blend together without disruption to generate a faithful reproduction of the original scene. Continuous-tone images are produced by analog optical and electronic devices, which accurately record image data by several methods, such as a sequence of electrical signal fluctuations or changes in the chemical nature of a film emulsion that vary continuously over all dimensions of the image. In order for a continuous-tone or analog image to be processed or displayed by a computer, it must first be converted into a computer-readable form or digital format. This process applies to all Pg. 3 images, regardless the origin and complexity, and whether they exist as black and white (grayscale) or full color.
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