{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Image & Video Processing

Image & Video Processing - Image and Video...

Info icon This preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Image and Video Processing Dr. V. K ë puska
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Light and Image Perception
Image of page 2
February 11, 2012 Veton Këpuska 3 Illumination Quantification of human Psycho-visual  sensation: Peak spectral sensitivity of a human observer  at 555 nm wavelength is normalized to unity. Human spectral sensitivity drops to 4/10,000  relative to peak at the two ends of the  spectrum at 400 nm and 735 nm.  
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
February 11, 2012 Veton Këpuska 4 Visible Spectrum We percieve electromagnetic energy having wavelengths in the  range 400-700 nm as  visible light (slide taken from  groups.csail.mit.edu/.../Lecture02/spectrum.gif  ). 
Image of page 4
February 11, 2012 Veton Këpuska 5 Brightness Brightness is proportional to logarithm of the luminous flux as defined by  Fecher’s Law: Consider a point source which emits luminous flux along radial lines: dA r d 2 cos θ = r Ω A Flux Luminus Reference log 0 0 - = F F F k B Ω – measured in steradians
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
February 11, 2012 Veton Këpuska 6 Luminous Intensity Luminous Intensity I at a point source is defined as Thus, luminous flux incident on area  d A from a source of  intensity I is: = d dF I dA r I dF 2 cos θ =
Image of page 6
February 11, 2012 Veton Këpuska 7 Illumination The luminous flux per unit area falling on a surface is called  illumination E and is given by: 2 cos r I dA dF E θ = =
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Digital Image Representation
Image of page 8
February 11, 2012 Veton Këpuska 9 Digital Image Representation (1,1) (2,1) (1,2) (2,2) (1,3) (2,3) (1,4) (2,4) (1,j) (2,j) (1,j+1) (2,j+1) (1,n-1) (2,n-1) (1,n) (2,n) ... ... (3,1) (4,1) (3,2) (4,2) (3,3) (4,3) (3,4) (4,4) (3,j) (4,j) (3,j+1) (4,j+1) (3,n-1) (4,n-1) (3,n) (4,n) ... ... (i,1) (i+1,1) (i,2) (i+1,2) (i,3) (i+1,3) (i,4) (i+1,4) (i,j) (i+1,j) (i,j+1) (i+1,j+1) (i,n-1) (i+1,n-1) (3,n) (i+1,n) ... ... ... ... ... (m-1,1) (m,1) (m-1,2) (m,2) (m-1,3) (4,3) (m-1,4) (4,4) (m-1,j) (4,j) (m-1,j+1) (4,j+1) (m-1,n- 1) (m,n-1) (m-1,n) (m,n) ... ... ... ... ... Digital Image Representation x y Image(y,x) ≡ Matrix(row, colum)
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
February 11, 2012 Veton Këpuska 10 What is an Image  Collection of elements organized in a MATRIX  form. Each Matrix element represent smallest part of a  picture element =  pixel Images are thus characterized by number of  pixels Larger the number of pixels the better the quality of  image. Larger the number of pixels the larger the storage  space required to store the image. More on this latter.
Image of page 10
February 11, 2012 Veton Këpuska 11 Representation of Pixels What information is contained in pixels: If the information is represented as a 4-bit code than  there could be only 2 4  = 16 different representations. Typically 8 bits are used to represent each pixel. This  defines a 2 8  = 256 levels of representation. What does this level represent: Gray Scale Color – there are several ways to represent color that  gives raise to various standards discusses next.
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
February 11, 2012 Veton Këpuska 12 Pixel Information and its Representation Gray Scale Example produced with MATLAB: Two dimensional example from wikipedia with 2 12 =4096  gray scale levels
Image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern