Definition of Contrast
 
 
 
 
 
 
 
Fourier Analysis <ul><li>Square wave = Sum of sine waves </li></ul><ul><li>Square wave = Fundamental sine wave + harmonics...
 
 
Modulation Transfer Function <ul><li>Object Contrast->  Lens ->  Image contrast </li></ul><ul><li>MTF =  Image Contrast/ O...
Modulation Transfer Function (MTF) Frequency Object Contrast Image Contrast MTF 2 10 8 0.80 5 9 7.5 0.83 8 8.7 6.3 0.72 10...
 
Contrast Sensitivity Function(CSF)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Ganglion cell Receptive Field
Ganglion cell receptive field
Ganglion cell receptive field
Ganglion cell response to diffuse illumination
Ganglion cell response to spatial grating
Mach bands Dark band Bright band
Mach bands
Recognition Acuity <ul><li>Snellen </li></ul><ul><li>HOTV </li></ul><ul><li>LEA </li></ul><ul><li>Patti Pics </li></ul>
LEA Symbols
Patti Pics
HOTV Test
Resolution Acuity <ul><li>Tumbling E </li></ul><ul><li>Landolt C </li></ul><ul><li>Broken Wheel </li></ul>
Broken Wheel test
Tumbling E
Landolt C
Minimum detectable acuity
 
Hyperacuity <ul><li>Vernier </li></ul><ul><li>Alignment test </li></ul><ul><li>Tilt test </li></ul>
 
 
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Spatial vision i revised jan 25 2011

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Spatial vision i revised jan 25 2011

  1. 1. Definition of Contrast
  2. 9. Fourier Analysis <ul><li>Square wave = Sum of sine waves </li></ul><ul><li>Square wave = Fundamental sine wave + harmonics </li></ul><ul><li>Fundamental sine wave is a wave with the same frequency as the square wave </li></ul><ul><li>Third harmonic is a sine wave with 3 times the square wave </li></ul><ul><li>Fifth harmonic is a sine wave with 5 times the frequency of the square wave </li></ul>
  3. 12. Modulation Transfer Function <ul><li>Object Contrast-> Lens -> Image contrast </li></ul><ul><li>MTF = Image Contrast/ Object Contrast </li></ul><ul><li>MTF = 1.0 for an ideal lens (or system) </li></ul><ul><li>MTF is determined by frequency to obtain a graph. </li></ul>
  4. 13. Modulation Transfer Function (MTF) Frequency Object Contrast Image Contrast MTF 2 10 8 0.80 5 9 7.5 0.83 8 8.7 6.3 0.72 10 7.5 5.2 0.69 15 6.3 3.8 0.60 18 5.2 2.1 0.40 25 4.2 1.5 0.36 30 4 0.9 0.23 40 4 0.7 0.18 50 3.8 0.4 0.11 60 3.6 0.33 0.09
  5. 15. Contrast Sensitivity Function(CSF)
  6. 39. Ganglion cell Receptive Field
  7. 40. Ganglion cell receptive field
  8. 41. Ganglion cell receptive field
  9. 42. Ganglion cell response to diffuse illumination
  10. 43. Ganglion cell response to spatial grating
  11. 44. Mach bands Dark band Bright band
  12. 45. Mach bands
  13. 46. Recognition Acuity <ul><li>Snellen </li></ul><ul><li>HOTV </li></ul><ul><li>LEA </li></ul><ul><li>Patti Pics </li></ul>
  14. 47. LEA Symbols
  15. 48. Patti Pics
  16. 49. HOTV Test
  17. 50. Resolution Acuity <ul><li>Tumbling E </li></ul><ul><li>Landolt C </li></ul><ul><li>Broken Wheel </li></ul>
  18. 51. Broken Wheel test
  19. 52. Tumbling E
  20. 53. Landolt C
  21. 54. Minimum detectable acuity
  22. 56. Hyperacuity <ul><li>Vernier </li></ul><ul><li>Alignment test </li></ul><ul><li>Tilt test </li></ul>

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