电子信息专业英语-11.ppt

Technical English For Information Science and Electronic Engineering Unit 11 Digital Image Processing Part I Two-Dimensional Digital Images New Words New Words 1 Images are two-dimensional signals representing spatial distribution of some physical parameters, typically light intensity, and more generally any form of energy. Motion pictures and multi-spectral remote sensing images, for example, are three or higher dimensional signals. 1 Modern digital technology has made it possible to manipulate multi-dimensional signals with systems that range from simple digital circuits to advanced parallel computers.1 1 The goal of this manipulation can be divided into three categories: Image processing: image in ? image out Image analysis: image in ? measurements out Image understanding: image in ? high-level description out 2 We will focus on the fundamental concepts of image processing. Space does not permit us to make more than a few introductory remarks about image analysis and image understanding. Further, we will restrict ourselves to two-dimensional (2D) image processing although most of the concepts and techniques that are to be described can be extended easily to three or more dimensions.2 3 We begin with certain basic definitions. An image defined in the “real world” is considered to be a function of two real variables, for example, a(x, y) with a as the amplitude (e.g. brightness) of the image at the real coordinate position (x, y). An image may be considered to contain sub-images sometimes referred to as regions-of-interest, ROIs, or simply regions. This concept reflects the fact that images frequently contain collections of objects each of which can be the basis for a region. 3 In a sophisticated image processing system it should be possible to apply specific image processing operations to selected regions. Thus one part of an image might be processed to suppress motion blur while another part might be processed to improve color rendition.3 4 The amplitud