Introduction to Digital Image Processing
                                                                                                   Overview (1):
                                                                                                         What is Digital Image Processing (DIP) ?
                                                                                                            What is an image ?
                                                                                                            Relationship to Computer Vision
                                               Fall 2005                                                 Origins of Digital Image Processing
                                                                                                            Brief historical overview
                                          Introduction                                                   Fields that Use Digital Image Processing
                                                                                                            Image categorization and the electromagnetic 
                                              Bill Kapralos                                                 spectrum (EM)
                                                                                                               Gamma ray, x-ray, ultraviolet, visible, infrared, 
                                                                                                               microwave, radio wave
                   ELIC 629, Fall 2005, Bill Kapralos
                    Overview (2):
                          Fundamental Steps 
                             Methodologies
                             Overview of what this course will cover                                    What is Digital Image
                          Components of a Digital Image Processing 
                          System                                                                                     Processing ?
                             Hardware
                             Software
                          Conclusions
                             Summary
                     ELIC 629, Fall 2005
                     Bill Kapralos
                    Introduction to Digital Image Processing
                         What is a Digital Image ? (1):                                                                      What is a Digital Image ? (2):
                               A Discrete Two-Dimensional Function f(x,y)                                                          Intensity
                                   x,y denote the spatial coordinates                                                                  The value (or amplitude) of the function f at spatial 
                                       Consider a table (or matrix or grid)  where x                                                   coordinates (x,y)
                                       indicates the row and y the column                                                                  Finite and discrete when considering digital images
                                       Example: matrix with 5 rows and 6 columns (5 x 6)                                                   Non-discrete and non-finite → not a digital image!
                                                     012345                                                                                                         NOTE:
                                                0   0,0    0,1   0,2   0,3   0,4    0,5
                                             )  1   1,0    1,1   1,2   1,3    1,4   1,5                                                )                                 The digital image is obtained 
                                             x                                                                                         x
                                              (                                                                                         (                                by sampling an analog 2D 
                                             w  2   2,0    2,1   2,2   2,3   2,4    2,5                                                w                                 image but for now, lets not 
                                             Ro 3   3,0    3,1   3,2   3,3   3,4    3,5                                                Ro                                be concerned with this.  
                                                4   4,0    4,1   4,2   4,3   4,4    4,5                                                                                  Sampling will be discussed 
                                                                                                                                                Column (y)               next week!
                                                               Column (y)
                         What is a Digital Image ? (3):                                                                      What is a Digital Image ? (4):
                               Intensity (continued…)                                                                              Pixel
                                   The intensity of a digital image can vary from a wide                                               Each element of a digital image e.g., each entry in the 
                                   range of values                                                                                     grid (matrix) with its distinct spatial location
                                       Typical examples: 0 – 255, 0 – 32,767 etc…                                                      Also known as
                                   Can also have more than one intensity value                                                             Picture element or pel
                                   associated with each spatial location                                                                   Image element 
                                       Color images → one intensity value for each color 
                                       (e.g., red, green, blue color channels – more of this                                                                    Pixel
                                       in the future)…
                                       Single color → intensity also known as gray level
                          ELIC 629, Fall 2005
                          Bill Kapralos
               Introduction to Digital Image Processing
                  Digital Image Processing (1):                                           Digital Image Processing (2):
                      Definition                                                              Covers a Large and Varied Field of 
                         Processing digital images with a digital computer                    Applications
                      Two Principle Applications of Digital Image                                Although the human visual system can only respond to 
                                                                                                 the visual band of the electromagnetic spectrum, 
                      Processing                                                                 machines can be used to image (sample) the (almost) 
                                                                                                 entire electromagnetic spectrum
                         Improvement of images for human interpretation                             More about this later
                         Processing of image data for storage, transmission 
                         and representation for autonomous machine 
                         perception
                  Digital Image Processing (3):                                           Digital Image Processing (4):
                      Relationship to Other Fields                                            Relationship to Other Fields (cont…) 
                         Computer vision                                                         Too restrictive! e.g., then the common operation of 
                            Create real-world model from one or more images                      computing the average intensity of an image is not 
                            Recovers useful information about a scene from a                     part of image processing!
                            2D projection of the 3D world                                        A useful paradigm is to consider three types of 
                            Ultimately emulate human visual system!                              computerized processes
                         Where does image processing stop and image                                 Low level → primitive operations such as noise 
                         analysis/computer vision start ?                                           reduction, contrast enhancement, image sharpening
                            No clear cut boundaries!                                                Mid Level → segmentation, classification, 
                            How about defining image processing such that                           High level → making sense of recognized objects, 
                            both input and output are images ?                                      even performing cognitive functions
                   ELIC 629, Fall 2005
                   Bill Kapralos
                       Introduction to Digital Image Processing
                             Digital Image Processing (5):                                                                                     Origins of Digital Image Processing (1):
                                   Definition Used in this Course                                                                                     One of the First Applications was in the 
                                        Processes whose inputs and outputs are images but                                                             Newspaper Industry 
                                        we also include processes which extract attributes 
                                        from images including the recognition of individual                                                               Pictures sent by submarine cable between Europe and 
                                        objects                                                                                                           North America
                                   As an “Aside” – Computer Graphics                                                                                           Bartlane transmission system → transfer picture 
                                                                                                                                                               in a couple of hours instead of more than one week
                                        Computer used to recreate a “picture” given some                                                                       Code picture at the transmitting end, send coded 
                                        description of a scene/environment                                                                                     data over cable, receive and decode at the 
                                             “Almost” like the opposite problem to image                                                                       receiving end
                                             processing although there is some overlap!                                                                        Five discrete levels of gray and later up to 15
                             Origins of Digital Image processing (2):                                                                          Origins of Digital Image Processing (3):
                                   Bartlane Transmitter                                                                                                 Early Examples did not Include Computer!
                                                                                                                                                            Technically, do not fall into our definition of image 
                                                                                                                                                            processing since we require the use of a computer!
                                                                                                                                                                  Although the notion of a computer can be traced 
                                                                                                                                                                  back more than 5000 years, the modern digital 
                                                                                                                                                                  computer dates back to the 1940s and the two 
                                                                                                                                                                  key concepts introduced by John von Neumann
                                                                                                                                                                  1.  Memory to hold stored programs and data
                                           Sample Image                                                                                                           2. Conditional branching
                              ELIC 629, Fall 2005
                              Bill Kapralos