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Frequency-Place-Transformation

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Presentation for the "Models of Auditory Perception Seminar".
This presentation is about the auditory system and, in particular, the inner ear. After explaining the mechanics of the cochlea in details, I am focusing on the Frequency-Place-Transformation, which takes place along the basilar membrane. This process is then closely connected to the so-called auditory filters and the masking effect. Finally, I am comparing how all these different scales are related to each other.

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Frequency-Place-Transformation

  1. 1. Frequency-Place Transformation AIPA: Models of Auditory Perception Seminar 20 November 2014
  2. 2. The speaker Francesco Bonadiman franzbona@hotmail.it Computer Science Bachelor @UniTN (Trento, IT) 2/29
  3. 3. The speaker Francesco Bonadiman franzbona@hotmail.it Computer Science Bachelor @UniTN (Trento, IT) 2/29
  4. 4. The speaker Francesco Bonadiman franzbona@hotmail.it Computer Science Bachelor @UniTN (Trento, IT) 2/29
  5. 5. The outer ear 3/29
  6. 6. The outer ear 3/29 [Raake2014]
  7. 7. The outer ear 3/29 [Raake2014] catalyzes the sound
  8. 8. The outer ear 3/29 [Raake2014] catalyzes the sound
  9. 9. The middle ear [Raake2014] 4/29
  10. 10. The middle ear [Raake2014] 4/29
  11. 11. The middle ear [Raake2014] 3 smallest bones in the body 4/29
  12. 12. [Blausen2014] 5/29 2 membrane- covered openings
  13. 13. [Blausen2014] 5/29 2 membrane- covered openings
  14. 14. [Blausen2014] 5/29 2 membrane- covered openings
  15. 15. [Blausen2014] 5/29 2 membrane- covered openings
  16. 16. [Blausen2014] 5/29 2 membrane- covered openings opposite directions
  17. 17. How it works [Kidsdiscover2014] 6/29
  18. 18. How it works [Kidsdiscover2014] 6/29 difference of sound pressure
  19. 19. How it works [Kidsdiscover2014] acoustic energy (air) → fluid oscillations 6/29 difference of sound pressure
  20. 20. How it works [Kidsdiscover2014] impedance matching acoustic energy (air) → fluid oscillations 6/29 difference of sound pressure
  21. 21. The inner ear [Amplifon2014] 7/29
  22. 22. The inner ear [Amplifon2014] 7/29
  23. 23. The inner ear [Amplifon2014] 7/29
  24. 24. The cochlea: traditional view 8/29
  25. 25. The cochlea: traditional view [Zwicker,Fastl2007] 8/29
  26. 26. The cochlea: traditional view [Zwicker,Fastl2007] 8/29
  27. 27. The cochlea [Wierstorf2014] 9/29
  28. 28. The cochlea [Wierstorf2014] 9/29 2½ turns for saving space
  29. 29. The cochlea [Wierstorf2014] [RobinsonLibrary2014] 9/29 2½ turns for saving space 32 mm “unwound”
  30. 30. The cochlea [Wierstorf2014] [RobinsonLibrary2014] [Wikipedia2014] 9/29 2½ turns for saving space 32 mm “unwound”
  31. 31. The cochlea [Wierstorf2014] [RobinsonLibrary2014] [Wikipedia2014] 9/29 2½ turns for saving space 32 mm “unwound”
  32. 32. The cochlea [Wierstorf2014] [RobinsonLibrary2014] [Wikipedia2014] helicotrema 9/29 2½ turns for saving space 32 mm “unwound”
  33. 33. Channels and membranes [Flanagan1972] 10/29
  34. 34. Channels and membranes [Flanagan1972] 10/29
  35. 35. Channels and membranes [Flanagan1972] 10/29 hydromechanically → single unit
  36. 36. Channels and membranes [Flanagan1972] 10/29
  37. 37. Channels and membranes [Flanagan1972] 10/29 fluids = oscillations
  38. 38. Overview [WhatWhenHow2014] 11/29
  39. 39. Overview [WhatWhenHow2014] 11/29 O H R
  40. 40. Overview [WhatWhenHow2014] 11/29 O H R
  41. 41. Is this enough? 12/29
  42. 42. Organ of Corti [MixBag2014] 13/29
  43. 43. Organ of Corti [MixBag2014] 13/29
  44. 44. Organ of Corti [MixBag2014] 13/29 membranes excitation → nervous impulses (firings)
  45. 45. Organ of Corti [MixBag2014] [Zwicker,Fastl2007] 13/29 membranes excitation → nervous impulses (firings)
  46. 46. Organ of Corti [MixBag2014] [Zwicker,Fastl2007] 13/29 membranes excitation → nervous impulses (firings)
  47. 47. Organ of Corti [MixBag2014] [Zwicker,Fastl2007] 13/29 IHC → brain OHC → tuning membranes excitation → nervous impulses (firings)
  48. 48. 14/29[GalleryHip2014]
  49. 49. 14/29 membranes shearing → HC-cilia → nerve fibers [GalleryHip2014]
  50. 50. 15/29
  51. 51. Frequency-Place-Transformation [Mandel, Ellis2009] 16/29
  52. 52. Frequency-Place-Transformation [Mandel, Ellis2009] 16/29
  53. 53. Frequency-Place-Transformation [Mandel, Ellis2009] 16/29
  54. 54. Frequency-Place-Transformation [Mandel, Ellis2009] 16/29 BM = kind of Fourier Analysis
  55. 55. Waves and peaks [Moore2013] 17/29
  56. 56. Waves and peaks [Moore2013] 17/29
  57. 57. Waves and peaks [Moore2013] 17/29
  58. 58. Waves and peaks [Moore2013] 17/29 spatial envelope
  59. 59. Waves and peaks [Moore2013] 17/29 place + growth ← frequency spatial envelope
  60. 60. Waves and peaks [Moore2013] 17/29 place + growth ← frequency spatial envelope
  61. 61. Waves and peaks [Moore2013] 17/29 place + growth ← frequency spatial envelope
  62. 62. Waves and peaks [Moore2013] 17/29 place + growth ← frequency spatial envelope
  63. 63. Characteristic Frequencies [Zwicker,Fastl2007] 18/29
  64. 64. Characteristic Frequencies [Zwicker,Fastl2007] 18/29 BM’s maximum displacement
  65. 65. Characteristic Frequencies [Zwicker,Fastl2007] 18/29 BM’s maximum displacement
  66. 66. Mechanical Reasons [Skidmore.edu2014] 19/29
  67. 67. Mechanical Reasons [Skidmore.edu2014] 19/29 stiff thick narrow < 0.1 mm
  68. 68. Mechanical Reasons [Skidmore.edu2014] 19/29 stiff thick narrow < 0.1 mm flexible thinner wider ∼0.5 mm
  69. 69. Mechanical Reasons [Skidmore.edu2014] 19/29 stiff thick narrow < 0.1 mm flexible thinner wider ∼0.5 mm [Wikipedia2014]
  70. 70. Mechanical Reasons [Skidmore.edu2014] [Wikipedia2014] 19/29 stiff thick narrow < 0.1 mm flexible thinner wider ∼0.5 mm Von Békésy (1947) Pioneering work Light microscope Human cadaver ear
  71. 71. 20/29
  72. 72. Masking 21/29[Wikipedia2014]
  73. 73. Masking 21/29 shows the limits of frequency selectivity (FPT) [Wikipedia2014]
  74. 74. Masking 21/29 shows the limits of frequency selectivity (FPT) auditory system → not distinguish between frequencies [Wikipedia2014]
  75. 75. Masking 21/29 shows the limits of frequency selectivity (FPT) depends on both signal and masker auditory system → not distinguish between frequencies [Wikipedia2014]
  76. 76. Masking 21/29 Detailed talk about it shows the limits of frequency selectivity (FPT) depends on both signal and masker auditory system → not distinguish between frequencies [Wikipedia2014]
  77. 77. Fletcher Experiment 22/29[Wikipedia2014]
  78. 78. Fletcher Experiment 22/29[Wikipedia2014] masker = 65 dB masked = 40 dB
  79. 79. Fletcher Experiment 22/29[Wikipedia2014] masker = 65 dB masked = 40 dB NO!
  80. 80. Fletcher Experiment 22/29[Wikipedia2014] masker = 65 dB not masked = 55 dB masked = 40 dB NO!
  81. 81. Fletcher Experiment 22/29[Wikipedia2014] masker = 65 dB not masked = 55 dB masked = 40 dB NO! YES!
  82. 82. Fletcher Experiment 22/29[Wikipedia2014] masker = 65 dB not masked = 55 dB masked = 40 dB NO! YES! detect the shape of the so-called Auditory Filters
  83. 83. Auditory Filters (Critical Bandwidth) [AcousticLab.org2014] [Wikipedia2014] 23/29
  84. 84. Auditory Filters (Critical Bandwidth) [AcousticLab.org2014] [Wikipedia2014] 23/29 USUALLY: sounds located singularly limited range of frequencies different center frequency
  85. 85. Auditory Filters (Critical Bandwidth) [AcousticLab.org2014] [Wikipedia2014] 23/29 USUALLY: sounds located singularly limited range of frequencies different center frequency MASKING: single, broader maximum signal perceived as one same critical bandwidth BM frequency selectivity = fail
  86. 86. Critical-band Rate Scale [Zwicker,Fastl2007] 24/29
  87. 87. Critical-band Rate Scale [Zwicker,Fastl2007] 24/29 new unit leading to critical-band rate scale
  88. 88. Critical-band Rate Scale [Zwicker,Fastl2007] 24/29 boundaries of the critical bands new unit leading to critical-band rate scale
  89. 89. Critical-band Rate Scale [Zwicker,Fastl2007] 24/29 boundaries of the critical bands new unit leading to critical-band rate scale audible frequency range in 24 bands
  90. 90. Critical-band Rate Scale [Zwicker,Fastl2007] 25/29
  91. 91. Critical-band Rate Scale [Zwicker,Fastl2007] 25/29 from 0 to 24 unit = Bark (linear)
  92. 92. Critical-band Rate Scale [Zwicker,Fastl2007] 25/29 higher frequency = bigger amplitude = broader filters from 0 to 24 unit = Bark (linear)
  93. 93. Critical-band Rate Scale [Zwicker,Fastl2007] 25/29 higher frequency = bigger amplitude = broader filters mechanical reasons of the membrane (rigid = high frequencies) from 0 to 24 unit = Bark (linear)
  94. 94. Back to the Cochlea [Zwicker,Fastl2007] 26/29
  95. 95. Back to the Cochlea [Zwicker,Fastl2007] 26/29 GOLDEN RULE: FPT → Inside our ear, frequencies are mapped onto certain locations
  96. 96. Back to the Cochlea [Zwicker,Fastl2007] 26/29 SILVER RULE: Mapping not linear but ∼linear up to 500 Hz ∼logarithmic above GOLDEN RULE: FPT → Inside our ear, frequencies are mapped onto certain locations
  97. 97. 27/29
  98. 98. 28/29
  99. 99. References ● Brian C.J. Moore, 2003 - An introduction to the psychology of hearing, 6th Edition ● Zwicker and Fastl, 2007 - Psychoacoustics: facts and models, 3rd edition ● Mandel, Ellis, 2009 - Speech & Audio Processing & Recognition - Lecture 4 ● Other slides and scripts from professors Raake and Möller ● Huge help given by www.google.com/imghp to find images and references 29/29 AcousticLab.org: 23 Amplifon: 7 Blausen: 5 Flanagan: 10 GalleryHip: 14 Kidsdiscover: 6 Mandel, Ellis: 16 MixBag: 13 Moore: 17 Raake: 3, 4 RobinsonLibrary: 9 Skidmore.edu: 19 WhatWhenHow: 11 Wikipedia: 9, 19, 21, 22, 23 Wierstorf: 9 Zwicker, Fastl: 8 13 18 24 25 26

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