1. UNIT VI DSP in Speech Processing & Image Processing
Audio Processing:
Human Hearing, Timbre, Sound Quality Versus Data rate, High Fidelity Audio, Companding, Speech Synthesis and Recognition, Non Linear Audio Processing
Image Foundation and Display:
Digital Image Structure, Cameras and Eyes, Television Video Signals, Other Image Acquisition and display, Brightness and Contrast Adjustments, Gray Scale Transforms

2. Audio Processing

3. Structure of the human ear
Human hearing
Structure of the human ear
Phys1061, S.Boyd

4. Click to add title
Click to add text

5. Important parts of the ear
Human hearing
Important parts of the ear
Outer Ear:
Auditory canal
Ear drum
Middle ear:
Ossicles: hammer (malleus),
anvil (incus),
stirrup (stapes)
Inner Ear
Cochlea
Auditory nerve
Phys1061, S.Boyd

6. Frequency response localized in Cochlea
Neuronal Decoding of Sound (Schematic)
Low Frequency
High Frequency
Frequency response localized in Cochlea

7. Mechanism of signal transport
Human hearing
Mechanism of signal transport
Hall, Musical Acoustics, 3rd Ed.
Phys1061, S.Boyd

8. Copy out these notes
Pinna = outer portion of ear used to collect sound waves
Auditory Canal = tube that sound travels down
Ear Drum = membrane that sends sound waves to hammer
Hammer = first of 3 bones. It vibrates, striking the anvil to carry on the sound
Anvil = gets hit by the hammer, striking the Stirrup
Stirrup = vibrates against OVAL WINDOW, carrying on sound
Cochlea = a spiral full of sensory “hairs,” which when bent, send an electrical signal to the AUDITORY NERVE
Auditory Nerve = carries all signals for sound to brain
SemiCircular Canals = full of gel-like material. Indicates if you are right side up or upside down. (Balance)

9. Structure of the Ear

10. designed to gather and collect sound into the ear canal
Outer Ear = Pinna
designed to gather and collect sound into the ear canal

11. Middle Ear – the Auditory Canal
Channels the sound toward the EAR DRUM

12. Middle Ear – the Ear Drum is actually called the “TYMPANIC MEMBRANE”
Sound waves = vibrations
HAMMER hits ANVIL moving the STIRRUP!

13. What Happens Next? Sound waves travel into the SPIRALLED COCHLEA
Tiny hairs in the COCHLEA move to the beat, and send impulses along nerve fibers
All nerve fibres link to the AUDITORY NERVE, to the brain.

14. Inside the COCHLEA!
Eustacian Tube

15. Detectable Sound Levels – What can the Machinery Pick UP?

16. What Frequencies can we Hear?Hz
– Hz

17. Detectable Sound Levels – What can be Heard?

18. Sound Wave Production
Levels of Intensity
Soft (Low)
Harsh(High)

19. Defeating Deafness – Cochlear Implants
The implant generates electric signals as the sound bounces off detector
Vibrations = electricity
Electricity stimulates the AUDITORY NERVE directly

20. Protect your Hearing!
Ear plugs
Ear – muffs
Keep the volume down

21. Spidey knows the Value of Protecting Your Hearing!

22. Copy out these notes
Pinna = outer portion of ear used to collect sound waves
Auditory Canal = tube that sound travels down
Ear Drum = membrane that sends sound waves to hammer
Hammer = first of 3 bones. It vibrates, striking the anvil to carry on the sound
Anvil = gets hit by the hammer, striking the Stirrup
Stirrup = vibrates against OVAL WINDOW, carrying on sound
Cochlea = a spiral full of sensory “hairs,” which when bent, send an electrical signal to the AUDITORY NERVE
Auditory Nerve = carries all signals for sound to brain
SemiCircular Canals = full of gel-like material. Indicates if you are right side up or upside down. (Balance)

23. Inverse Square Law, Sound

24. Units of sound intensity
Units of sound intensity. Sound intensity is expressed as power per unit area (such as watts/cm2), or more commonly on a logarithmic scale called decibels SPL(Sound Pressure Level). As this table shows, human hearing is the most sensitive between 1 kHz and 4 kHz.

25. Decibel levels of some common sounds
Sound Source
Sound Pressure Level (dB)
threshold of excellent youthful hearing
normal breathing, threshold of good hearing 10
soft whisper 30
mosquito buzzing 40
average townhouse, rainfall 50
ordinary conversation 60
busy street 70
power mower, car horn, ff orchestra
100
air hammer at 1m, threshold of pain
120
rock concert
130
jet engine at 30m
150
rocket engine at 30m
180
More decibel levels here:

26. Audio data rate vs. sound quality

27. Laser Wavelength

28. The Piano keyboard
The keyboard of the piano is a logarithmic frequency scale, with the fundamental frequency doubling after every seven white keys. These white keys are the notes: A, B, C, D, E, F and G.

29. Pregroove on (Re)Writable Disks
empty
track
land
mark
(data)
laser
beam
written
wobbled
pregroove
(Re)Writable Disk
CD stores about 1 bit per (μm)2, corresponding to 1 million bits per (mm)2, and 15 billion bits per disk.

30. Timbre Loudness: sound wave intensity
Pitch: fundamental component in the sound
Timbre : harmonic content of the signal

31. High Fidelity Audio Compact disc surface

32. Playback-CD
During playback, an optical sensor detects if the surface is reflective or nonreflective, generating the corresponding binary information.
Binary one must be part of a group of 3 to 13 ones
Two-level Reed- Solomon coding: combining the left and right stereo channels along with data for error detection and correction

33. -Cont Compact disc playback block diagram
EFM: Eight-to-Fourteen Modulation

34. Speech Synthesis and Recognition Human speech model

35. Nonlinear Audio Processing
Homomorphic separation of multiplied signals

36. Homomorphic separation of convolved signals