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					                              Digital Image Processing                                                                           Digital Image Processing
Gianni Ramponi                                                    Images © 2002 Gonzalez & Woods   Gianni Ramponi                                                      Images © 2002 Gonzalez & Woods
University of Trieste                                                                              University of Trieste
http://www.units.it/ramponi                                                                        http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                            Chapter 1: Introduction
                              What is digital image processing?                                                                  What is digital image processing?

          Image: a two-dimensional function f(x,y), where x and y are                                        Digital Image Processing concerns the transformation of an
          spatial coordinates and the amplitude f at any pair of coordinates                                 image to a digital format and its processing by a computer or by
          (x,y) is called the intensity or gray level.                                                       dedicated hardware
          When x, y, and f are discrete quantities the image is digital.                                     - both input and output are digital images
          f can be a vector and represent a colour image, e.g. using the RGB
          model, or in general a multispectral image.
                                                                                                             Digital Image Analysis concerns the description and recognition
          A video signal is similarly expressed as a sequence of frames                                      of the image contents.
          f(x,y,t).
                                                                                                             - the input is a digital image, the output is a symbolic description
          As far as we are concerned, the gray-level image will be
          represented by a matrix with 8-bit integer values, in the range
          [0=black, 255=white].                                                                              Computer Vision uses digital electronics to emulate human vision,
                                                                                                             including learning, making inferences, and taking actions




                              Digital Image Processing                                                                           Digital Image Processing
Gianni Ramponi                                                    Images © 2002 Gonzalez & Woods   Gianni Ramponi                                                      Images © 2002 Gonzalez & Woods
University of Trieste                                                                              University of Trieste
http://www.units.it/ramponi                                                                        http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                            Chapter 1: Introduction
                              History of digital images                                                                          History of digital images




                                                                  “Halftone”
                                                                  pattern printing
                                                                                                               Photographic
                                                                                                               process: light
                                                                                                               modulated by
                                                                                                               digital data
                                 Digital Image Processing                                                                                  Digital Image Processing
Gianni Ramponi                                                            Images © 2002 Gonzalez & Woods   Gianni Ramponi                                                     Images © 2002 Gonzalez & Woods
University of Trieste                                                                                      University of Trieste
http://www.units.it/ramponi                                                                                http://www.units.it/ramponi




                                  Chapter 1: Introduction                                                                                  Chapter 1: Introduction
                                  History of digital images                                                                                History of digital images

                                                                                                           Khao Lak, Thailand            Dec.29,2004
                                                                                                           Jan.13,2003




                                                                 Markers are used
                                                                 for geometric
                                                                 correction
                                                                                                                                                             several IKONOS one-meter
                                                                                                                                                             images fused together to create a
                                                                                                           Space Imaging/CRISP-Singapore                     larger-area, low-resolution image




                                 Digital Image Processing                                                                                  Digital Image Processing
Gianni Ramponi                                                            Images © 2002 Gonzalez & Woods   Gianni Ramponi                                                     Images © 2002 Gonzalez & Woods
University of Trieste                                                                                      University of Trieste
http://www.units.it/ramponi                                                                                http://www.units.it/ramponi




                                  Chapter 1: Introduction                                                                                  Chapter 1: Introduction
                                  The whole EM spectrum sources images                                                                     The whole EM spectrum sources images


                                                                                                                     Gamma-ray imaging
                                                                                                   nm                A radioactive isotope is injected,
                                                                                                                     which emits positrons as it decays;
                                                                                                                     when a positron meets an electron,
                      E = hv = hc/λ                                                                                  they annihilate and two gamma rays
                                                                                                                     are generated.
                      h = 4.135 ×10^ −15 eV ⋅ s = 6.626 × 10^-34 J·s ( Planck )
                      c = 3 ⋅108 m/sec
                              Digital Image Processing                                                                     Digital Image Processing
Gianni Ramponi                                           Images © 2002 Gonzalez & Woods   Gianni Ramponi                                              Images © 2002 Gonzalez & Woods
University of Trieste                                                                     University of Trieste
http://www.units.it/ramponi                                                               http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                       Chapter 1: Introduction
                              The whole EM spectrum sources images                                                          The whole EM spectrum sources images


          Positron-Emission Tomography                                                              Natural gamma ray source
          The collected gamma rays are used                                                         Superheated stationary gas
          to construct a CT                                                                         cloud in the constellation of
                                                                                                    Cygnus (“Cygnus Loop”,
                                                                                                    15,000 light-years from
                                                                                                    earth)




                              Digital Image Processing                                                                     Digital Image Processing
Gianni Ramponi                                           Images © 2002 Gonzalez & Woods   Gianni Ramponi                                              Images © 2002 Gonzalez & Woods
University of Trieste                                                                     University of Trieste
http://www.units.it/ramponi                                                               http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                       Chapter 1: Introduction
                              The whole EM spectrum sources images                                                          The whole EM spectrum sources images
                                                                                                                    X-ray imaging
    X-ray imaging
                                                                                                                    Head CT; Cygnus Loop.
    Chest; aortic angiogram;
    circuit boards.


    Electrons are emitted from a
    heated cathode with an
    energy such that their
    impact on a nucleus
    generates X-rays. A film or a
    digital sensor collects the
    transmitted rays.
    In angiography, a contrast
    medium is injected.
                              Digital Image Processing                                                                  Digital Image Processing
Gianni Ramponi                                           Images © 2002 Gonzalez & Woods   Gianni Ramponi                                           Images © 2002 Gonzalez & Woods
University of Trieste                                                                     University of Trieste
http://www.units.it/ramponi                                                               http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                   Chapter 1: Introduction
                              The whole EM spectrum sources images                                                      The whole EM spectrum sources images

    Ultraviolet imaging                                                                       Ultraviolet imaging
    Microphotography;                                                                         Cygnus Loop in the
    normal corn and corn                                                                      high-UV band
    infected by parasites


    Visible radiation is
    excited by UV light
    (fluorescence)




                              Digital Image Processing                                                                  Digital Image Processing
Gianni Ramponi                                           Images © 2002 Gonzalez & Woods   Gianni Ramponi                                           Images © 2002 Gonzalez & Woods
University of Trieste                                                                     University of Trieste
http://www.units.it/ramponi                                                               http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                   Chapter 1: Introduction
                              The whole EM spectrum sources images                                                      The whole EM spectrum sources images
                              Digital Image Processing                                                                        Digital Image Processing
Gianni Ramponi                                                 Images © 2002 Gonzalez & Woods   Gianni Ramponi                                           Images © 2002 Gonzalez & Woods
University of Trieste                                                                           University of Trieste
http://www.units.it/ramponi                                                                     http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                         Chapter 1: Introduction
                              The whole EM spectrum sources images                                                            The whole EM spectrum sources images




  Bands in LANDSAT-7 imagery. Resolution 30 m. One more band
  exists,, with 10m res., 0.50-0.90 µm




                              Digital Image Processing                                                                        Digital Image Processing
Gianni Ramponi                                                 Images © 2002 Gonzalez & Woods   Gianni Ramponi                                           Images © 2002 Gonzalez & Woods
University of Trieste                                                                           University of Trieste
http://www.units.it/ramponi                                                                     http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                         Chapter 1: Introduction
                              The whole EM spectrum sources images                                                            The whole EM spectrum sources images
                                                                                                    Infrared imaging: US map




                                                    (National
                                                    Oceanographics and
                                                    Atmospheric Admin.)
                              Digital Image Processing                                                                          Digital Image Processing
Gianni Ramponi                                                   Images © 2002 Gonzalez & Woods   Gianni Ramponi                                                   Images © 2002 Gonzalez & Woods
University of Trieste                                                                             University of Trieste
http://www.units.it/ramponi                                                                       http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                           Chapter 1: Introduction
                              The whole EM spectrum sources images                                                              The whole EM spectrum sources images




                              Digital Image Processing                                                                          Digital Image Processing
Gianni Ramponi                                                   Images © 2002 Gonzalez & Woods   Gianni Ramponi                                                   Images © 2002 Gonzalez & Woods
University of Trieste                                                                             University of Trieste
http://www.units.it/ramponi                                                                       http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                           Chapter 1: Introduction
                              The whole EM spectrum sources images                                                              The whole EM spectrum sources images
                                                Microwave band imaging:                                                                           RF imaging: a human knee
                                                Mt. Vesuvius                                                                                      Magnetic Resonance Imaging
                                                                                                                                                  (MRI-NMR): nuclei with
                                                                                                                                                  nonzero magnetic moment will
                                                Image acquired on April 15,                                                                       align with a strong magnetic
                                                1994 by the Spaceborne                                                                            field, and resonate with a time-
                                                Imaging Radar-C/X-Band                                                                            varying component of the field.
                                                Synthetic Aperture Radar (SIR-                                                                    After the time-varying
                                                C/X-SAR) aboard the Space                                                                         component is removed, the
                                                Shuttle Endeavour.                                                                                exponential decay time of the
                                                                                                                                                  re-alignment is measured and
                                                SIR-C/X-SAR, a joint mission
                                                                                                                                                  used to develop image contrast
                                                of the German, Italian and the
                                                                                                                                                  between different tissues.
                                                United States space agencies,
                                                is part of NASA's “Mission to                                                                     E.g.: Hydrogen nuclei in a 1.5
                                                Planet Earth”.                                                                                    Tesla magnetic field resonate
                                                                                                                                                  at 64 MHz
                              Digital Image Processing                                                                  Digital Image Processing
Gianni Ramponi                                           Images © 2002 Gonzalez & Woods   Gianni Ramponi                                                    Images © 2002 Gonzalez & Woods
University of Trieste                                                                     University of Trieste
http://www.units.it/ramponi                                                               http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                   Chapter 1: Introduction
                              The whole EM spectrum sources images                                                      Non-EM image sources

                                                                                                                                                   … and high frequencies
                                                                                                         Acoustic imaging: at low
                                                                                                         frequencies (<100 Hz)




                              Digital Image Processing                                                                  Digital Image Processing
Gianni Ramponi                                           Images © 2002 Gonzalez & Woods   Gianni Ramponi                                                    Images © 2002 Gonzalez & Woods
University of Trieste                                                                     University of Trieste
http://www.units.it/ramponi                                                               http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                   Chapter 1: Introduction
                              Non-EM image sources                                                                      Non-EM image sources
                                                                                               Scanning Electron Microscopy: direct excitation of phosphors by
                                                                                               an electronic beam
                              Digital Image Processing                                                                  Digital Image Processing
Gianni Ramponi                                           Images © 2002 Gonzalez & Woods   Gianni Ramponi                                           Images © 2002 Gonzalez & Woods
University of Trieste                                                                     University of Trieste
http://www.units.it/ramponi                                                               http://www.units.it/ramponi




                              Chapter 1: Introduction                                                                   Chapter 1: Introduction

				
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