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May, 28, 2004 Topics in Preservation ScienceLecture Series
1 Carl HaberLBNL.
The Reconstruction of Mechanically Recorded Sound by Image Processing
Update on Collaboration with the Library of Congress
Carl Haber
Lawrence Berkeley National Lab
rotational stage + encoder
cylinder
optical probe
fiber
controller
host PC
linear stage + encoder
motion control and driver
May, 28, 2004 Topics in Preservation ScienceLecture Series
2 Carl HaberLBNL.
CollaboratorsVitaliy Fadeyev, Carl Haber,Zach Radding, and Jim TriplettLawrence Berkeley National Lab
Christian MaulTaicaan Technology, U.K.
John W. McBrideUniversity of Southampton, U.K.
Mitch Golden
Peter AlyeaLarry ApplebaumMark RoosaSam BrylawskiThe Library of Congress
Bill KlingerARSC
George HornFantasy Records, Berkeley
May, 28, 2004 Topics in Preservation ScienceLecture Series
3 Carl HaberLBNL.
Lawrence Berkeley National Labwww.lbl.gov
• Founded in 1931 by E.O.Lawrence• Oldest of US National Labs• Operated by the University of California
for the US DoE• 4000 Staff, 800 Students, 2000 Guests• 14 Research Divisions including
– Physics, Nuclear Science– Materials, Chemical Science– Life Sciences, Physical Bioscience– Energy and Environment, Earth– Computing
• Major user facilities- – Advanced Light Source– Nat. Center for Electron Microscopy– Nat. Energy Research Super Computer Center
May, 28, 2004 Topics in Preservation ScienceLecture Series
4 Carl HaberLBNL.
Outline• Introduction
• Summary of method (mostly a repeat)*
• Towards a real 2D machine (I.R.E.N.E.)**
• 3D reconstruction of an Edison cylinder***
• Plans for the 3D research program
• Conclusions* V.Fadeyev & C. Haber, J. Audio Eng. Soc., vol. 51, no.12, pp.1172-1185 (2003 Dec.).
** IRENE Proposal 12-Feb-2004
*** V. Fadeyev et al, LBNL Report-54927
May, 28, 2004 Topics in Preservation ScienceLecture Series
5 Carl HaberLBNL.
Introduction• We have investigated the problem of optically recovering
mechanical sound recordings without contact to the medium• Address concerns of the preservation, archival, and research
communities:– The reconstruction of delicate or damaged media– Mass digitization of diverse media
• The approach evolved naturally out of methods of optical metrology, pattern recognition, and image processing.
• First shown at the LC in July 2003.• Research is now supported by an LC/DOE agreement.• Message to take away from today’s presentation:
– The techniques yield good reproductions and some improvements.– Measurement, data storage, and computing technologies may be
approaching performance levels required for this application.– Strong development program for the near future in both the mass
digitization and analytic aspects.
May, 28, 2004 Topics in Preservation ScienceLecture Series
6 Carl HaberLBNL.
Traditional Contact Playback
Bulky stylus riding in a narrow groove => Issues with• tracking• condition of the groove
•debris and contamination• wear
Presence of trained manpower or supervision is de-facto required.
Modulation is lateral for most discmedia, and vertical for Edisoncylinders
Transduction may be electrical oracoustic
Groove width = 160 mLateral modulation
radius at bottom
width
depthcontact depth
groove angle
parameter 78 rpm coarse 33 1/3 ultrafine width 0.006 - 0.008 0.001 depth ~0.0029 ~0.0006 contact depth 0.0008 0.0004 radius 0.0015-0.0023 0.00015 angle 82 - 98 87 - 92 units are inches or degrees
stylus
May, 28, 2004 Topics in Preservation ScienceLecture Series
7 Carl HaberLBNL.
A Non-contact Method• Using digital optical techniques, the pattern of
undulations in a surface can be imaged.• Cover surface with sequential views or grid of points.• Views can be stitched together: surface map• The images can be processed to remove defects and
analyzed to model the stylus motion.• The stylus motion model can be sampled at a
standard frequency and converted to digital sound format.
• Real time playback is not required de-facto, method is aimed at reconstruction and digitization.
May, 28, 2004 Topics in Preservation ScienceLecture Series
8 Carl HaberLBNL.
Parameter 78 rpm, 10 inch Cylinder
Cut Lateral Vertical
Revolutions per minute 78.26 80-160
Max/Min radii inches (mm) 4.75/1.875 (120.65/47.63)
2– 5 fixed (50.8-127)
Area containing audio data (mm2 ) 38600 16200 (2”)
Total length of groove 152 meters 64-128 meters
Groove width at top inches (m) 0.006 (160) variable
Lines/inch (mm) Gd 96-136 (5.35-3.78) 100-200 (3.94-7.87)
Line spacing microns 175 – 250 125 – 250
Ref level peak velocity@1KHz 7 cm/sec (11 m) NA
Max groove amplitude (microns) 100 - 125 ~10
Groove depth 80 m “~20 m”
Noise level below reference, S/N 17-37 dB ?
Dynamic range 30-50 dB ?
Groove max ampl@noise level 1.6 - 0.16 m ?
May, 28, 2004 Topics in Preservation ScienceLecture Series
9 Carl HaberLBNL.
c
de
a
b
May, 28, 2004 Topics in Preservation ScienceLecture Series
10 Carl HaberLBNL.
Imaging Methods: Electronic Camera
• 2D method, CCD or CMOS image sensor: frame or line format• Cameras contains 1 x 4000, or 768 x 494 pixels, or up to few Mega-Pixels• 1 pixel = ~ 1 micron on the disc surface• Magnification and pixel size yield sufficient resolution for audio data
measurement due to pixel interpolation• Frames acquired at 30-100 fps, lines at 10-20K lps
surface
scratch
dust
groovebottom
160 m
Coaxially illuminated grooveon a shellac 78 rpm disc
May, 28, 2004 Topics in Preservation ScienceLecture Series
11 Carl HaberLBNL.
Imaging Methods: Confocal Scanning Probe3D methodAcquire measurementsover a grid of points atup to 4 KHzGrid spacing may be optimized in design of the scan.
Surface of an Edison cylinder
May, 28, 2004 Topics in Preservation ScienceLecture Series
12 Carl HaberLBNL.
Imaging Methods: White Light Interferometry
•3D method, requires depth scan.•Acquire frames at 1-20 seconds/frame, depending upon depth and slope•Frame size ~0.5 – 2.5 mm2
•Stitch together adjacent frames
Scratch in a 78 rpm shellac discWax cylinder surface
May, 28, 2004 Topics in Preservation ScienceLecture Series
13 Carl HaberLBNL.
Issue of Aliasing• Sampling theorem1. Sample at 2*f where f is highest frequency of interest
2. Apply low pass filter above f to prevent aliased components appearing in data unless noise above f can be neglected.
• In optical approach sampling is done by pixelization of image.1. High sampling frequency
2. Use of pixel size to achieve effective low pass filtering
May, 28, 2004 Topics in Preservation ScienceLecture Series
14 Carl HaberLBNL.
Comparison of SpecificationsParameter 2D Digital Camera W.L.I. Confocal
Acquisition n (x m) pixels n x m pixels point
Transverse resolution 0.5 - 1 m Pixel projection 1-10 m
1.5 - 10 m
Vertical resolution NA 10 nanometers 10 nanometers
Points/measurement 4000 480x540 = 259200 1
Max Time/measurement 50 s 1-10 seconds 250 s
Effective time/point 12.5 ns 4-40 s 250 s
Low pass filtering? Image field twice w. offset
Image field twice w. offset
2 passes w. offset
Depth of field ~ 0 – 75 m Depth is scanned 20 m – mm
Cost of probe only ~$7K >$100K ~$30K
May, 28, 2004 Topics in Preservation ScienceLecture Series
15 Carl HaberLBNL.
Speed and Data• 2D scans for lateral discs
– Line scan camera: ~5-15 min/scan for 10” 78 rpm disc
– 190 Mbytes / 1 s of raw audio images
• 3D scans for vertical media– Confocal methods depends upon grid.
~12 - 24 hours, 450 M points.– Interferometric frame methods 1 - 5 hours
• 3D for deep groove lateral discs– Confocal with optimized grid ~15 - 60 hours for 10” 78 rpm disc– Interferometric frame method ~10 - 100 hours (groove depth)
Lateral groove
Vertical groove
Key 3D issues are slope and depth
May, 28, 2004 Topics in Preservation ScienceLecture Series
16 Carl HaberLBNL.
Image Processing• Intensity profile and edge
finding: measure features• Shape recognition• Dilation operation can
remove dust particles• Example is 2D but
generalizes to 3D• Knowledge of groove
geometry provides a powerful constraint for rejecting debris and damage
dilation
Edge finding
May, 28, 2004 Topics in Preservation ScienceLecture Series
17 Carl HaberLBNL.
Signal Analysis• For recording and playback, signal is proportional to stylus velocity
“electrical”: magnetic induction
“acoustic”: plane wave approximation, air pressure and velocity are proportional and in-phase
• Electrical recordings are (deliberately) mediated by equalization scheme to attenuate low frequencies and boost high frequencies
• Acoustic recordings are (naturally) mediated by the frequency response of horns and diaphragms.
• Potential to improve fidelity with modeling of acoustic component response
• Groove data is in digital form, numerical analysis
• Determine velocity by numerical differentiation Max. Slope
Wavelength
Amplitude
f
vA pp 2
May, 28, 2004 Topics in Preservation ScienceLecture Series
18 Carl HaberLBNL.
RM
+x direction
hstylus
mechanical linkage
diaphragm of radius R
listener
source
D
media surface
time
xo
exponential horn
conical horn
0
0.2
0.4
0.6
0.8
1
1.2
1 10 100 1000 10000
Frequency
Tra
nsm
issi
on
Co
effi
cien
t
Exponential
Conical
Response of horn and diaphragm atlow frequency can modify response anddeviations from “constant velocity” characteristic.
May, 28, 2004 Topics in Preservation ScienceLecture Series
19 Carl HaberLBNL.
Response of one real horn
From Maxfield, J.P. and Harrison, H.C., The Bell System Technical Journal, Volume V, No.3, July 1926, pp. 493-524
May, 28, 2004 Topics in Preservation ScienceLecture Series
20 Carl HaberLBNL.
(Dis)Advantages of Imaging Method
♪ Delicate samples can be played without further damage.♪ Independent of record material and format – wax, metal, shellac, acetates…♪ Effects of damage and debris (noise sources) reduced by image processing.
Scratched regions can be interpolated, re-assemble broken media♪ Discrete noise sources are resolved in the “spatial domain” where they
originate rather than as a random effect in the audio playback.♪ Dynamic effects of damage (skips, ringing) are reduced.♪ Classic distortions (wow, flutter, tracing and tracking errors, pinch effects
etc) are absent or resolved as geometrical corrections♪ Operator intervention during transcription is reduced, mass digitization.
Data intensive, storage and manipulation of large data-setsScanning speed, 3D methods may be quite slow, use for special cases only?Is ultimate resolution sufficient to provide required fidelity?
May, 28, 2004 Topics in Preservation ScienceLecture Series
21 Carl HaberLBNL.
Relationship to Other Work
• Laser turntables (www.ELPJ.com): reflected laser spot, susceptible to damage, debris, and surface reflectivity.
• Stanke and Paul, (“3D Measurement and modelling in cultural applications”, Inform. Serv. & Use 15 (1995) 289-301): depth sensed from greyscale in 2D image of “galvano”, states the basic approach in general
• S.Cavaglieri et al, Proc of AES 20th International Conference, Budapest, Oct 5-7, 2001: photographic contact prints and scanner to archive groove pattern in 2D – no 3D analog.
• O.Springer (http://www.cs.huji.ac.il/~springer/): use of desk top scanner on vinyl record – lacks resolution
• W.Penn: (First Monday, volume 8, number 5 (May 2003)) real time interferometric cylinder playback system in development.
May, 28, 2004 Topics in Preservation ScienceLecture Series
22 Carl HaberLBNL.
Test of Concept using 2D Imaging • Precision optical metrology
system “SmartScope” manufactured by Optical Gauging Products.
• Video zoom microscope with electronic camera and precision stage motion in x-y-z.
• Image acquisition with pattern recognition and analysis & reporting software
• Wrote program to scan groove, report, and process data (offline).
• Study of 78 rpm shellac disc ~1950
May, 28, 2004 Topics in Preservation ScienceLecture Series
23 Carl HaberLBNL.
Offline Data Processing
Reformatting data in one global coordinate system
Removal of big outliers
Filtering by selecting on the distance between interval pair;merging two sides into one.
Matching the adjacent frames
Fit the groove shape R’=R0+C*’+A*sin2(’ + 0)
Numerical Differentiation and resampling
Multiple runs addition; conversion to WAV format
1
2
3
4
5
6
7
May, 28, 2004 Topics in Preservation ScienceLecture Series
24 Carl HaberLBNL.
Raw measurementof groove bottom edges
Averaged and filteredfor known width R<cut
Frames aligned
Stylus velocity by numerical differentiation4th order polynomial fit of15 points about each sample
Width across groove bottom
Measurement spacing alongtime axis ~ 66 KHz
R
R distribution
May, 28, 2004 Topics in Preservation ScienceLecture Series
25 Carl HaberLBNL.
Waveform comparison
• Clear reduction in “clicks and pops”• Similarity of fine waveform structure
optical
stylus
CD
19.1 seconds 40 ms
May, 28, 2004 Topics in Preservation ScienceLecture Series
26 Carl HaberLBNL.
Sound Comparison
Sound from the optical readout.
Sound from the mechanical (stylus) readout.
Sound from the CD of re-mastered tape.
“Goodnight Irene” by H. Ledbetter (Leadbelly) and J.Lomax, performedby The Weavers with Gordon Jenkins and His Orchestra ~1950
optical + commercial noise reduction
May, 28, 2004 Topics in Preservation ScienceLecture Series
27 Carl HaberLBNL.
Frequency Spectra
•FFT spectra of optical (top), stylus (middle), and CD/tape (bottom)•Audio content in range 100 - 4000 Hz very similar•More high frequency content in stylus and CD versions.•Effects of equalization and differentiation?•Low frequency structure in optical sample (audible).
2 4 14 34 134 1234 5234 20K
May, 28, 2004 Topics in Preservation ScienceLecture Series
28 Carl HaberLBNL.
Waveform Comparison: 2nd Sample
optical
stylus
CD
May, 28, 2004 Topics in Preservation ScienceLecture Series
29 Carl HaberLBNL.
Sound Comparison
Sound from the optical readout.
Sound from the mechanical (stylus) readout.
Sound from the CD of re-mastered tape.
“Nobody Knows the Trouble I See ” , traditional, performedby Marion Anderson, Matrix D7-RB-0814-2A, 1947
optical + commercial noise reduction
May, 28, 2004 Topics in Preservation ScienceLecture Series
30 Carl HaberLBNL.
Directions
In July 2003, at the LC, some possible future directions were discussed:
1. The 2D test was promising, what would it take to make a machine to run near real-time on discs? Could this address mass digitization needs?
2. 3D may be the ultimate goal, could you do a small feasibility study similar to the 2D test?
3. Can you propose a research program to further the 3D technology?
May, 28, 2004 Topics in Preservation ScienceLecture Series
31 Carl HaberLBNL.
Design of a 2D Machine
• In Fall of 2003 LBNL supported design study for a 2D machine based upon methods shown in the test.
• Specifications vetted with LC staff.• Media sample collection provided by LC.• Basic design developed by LBNL mechanical and
software engineering staff.• Design, cost, and schedule passed internal reviews at
LBNL.• Documents submitted to LC in 2/2004
May, 28, 2004 Topics in Preservation ScienceLecture Series
32 Carl HaberLBNL.
Basic Features and Goals
• I.R.E.N.E. (Image, Reconstruct, Erase Noise, Etc.)• Follow 2D approach used in test, image groove bottom and/or
top since that is known to work at some level. Quality consistent with test or better(?).
• Emphasize throughput.• Encompass as much variation in media as possible.• Handle broken or partial discs.• Facility to (temporarily) flatten flexible media (Memovox)• User friendly interface.• Commercial off-the-shelf components• Provide a test bed for the mass digitization application.
May, 28, 2004 Topics in Preservation ScienceLecture Series
33 Carl HaberLBNL.
Media Condition Survey
• Approx 40 discs provided by LC
• 65% GOOD: should reconstruct well
• 25% FAIR: may require additional software developments to reconstruct well
• 10% POOR: reconstruct with excess noise or distortions, or not at all.
• Similar breakdown on a random set of 78 rpm shellac discs.
May, 28, 2004 Topics in Preservation ScienceLecture Series
34 Carl HaberLBNL.
Media Condition: Shellacgood
fair
fair
poor
Rough groovebottomedge
Multipleedges
May, 28, 2004 Topics in Preservation ScienceLecture Series
35 Carl HaberLBNL.
Media Condition: Acetate
good
Exudateddeep cleaned
Exudatedsurface cleaned
May, 28, 2004 Topics in Preservation ScienceLecture Series
36 Carl HaberLBNL.
System Layout
May, 28, 2004 Topics in Preservation ScienceLecture Series
37 Carl HaberLBNL.
Components
May, 28, 2004 Topics in Preservation ScienceLecture Series
38 Carl HaberLBNL.
• 4000 pixel, 18 KHz line scan sensor
• Magnify to 1 pixel = 1 m
• 7.6 x 105 lines/outer ring– 390 KHz sampling
• Time/ring = 40 seconds
• 73 mm / 4 mm = 19 rings
• 19 x 40 sec = 13 minutes
• Reduce with variable speed on inner rings: 9 minutes
• Scan time increased if warping is large.
direction of radial scan
direction of azimuthal scan
indicates radial width of 1 sweep
73 mm
sensor field of view projected onto surface 1 x 4000 microns
4.000
bluebird
Based upon 10 inch, 78 rpm geometry
May, 28, 2004 Topics in Preservation ScienceLecture Series
39 Carl HaberLBNL.
PerformanceFeature Targets Best Effort Upgrade
Coarse grooves, track and measure groove bottom or top X Measure additional features on groove wall X X Use of coaxial lighting X Use of alternative lighting approach X X Reconstruct GOOD based on LOC sample set (Figure 7) X Reconstruct FAIR based on LOC sample set (Figure 8) X X Reconstruct POOR based on LOC sample set (Figure 9) ? Scan time of 6-15 minutes on flat samples X X Processing time of 3-5 minutes X X Scan time on warped samples – as fast as practical X Reconstruct Memovox or other highly warped items X Reconstruct broken records, good quality debris X Reconstruct broken records, lower quality debris X X Exudated lacquers – well cleaned (Figure 11a left) X Exudated lacquers–moderate cleaning (Figure 11a right,b) X Available sampling rates < 200 KHz X Available sampling rates > 200 KHz X Reconstruct stampers X Data and statistical results on quality of scan and sample X
May, 28, 2004 Topics in Preservation ScienceLecture Series
40 Carl HaberLBNL.
Software Interface
May, 28, 2004 Topics in Preservation ScienceLecture Series
41 Carl HaberLBNL.
Software Features
• Control framework• Data acquisition functions• Image processing, data reduction• Analysis package (filter, noise reduction), data
quality monitor• Calibration tools• Directory structure• Configuration management• Display tools and diagnostics• Commented source code
May, 28, 2004 Topics in Preservation ScienceLecture Series
42 Carl HaberLBNL.
Issue of Alternative Lighting• Addition of diffuse ring light adds
new features to image.• Diameter of light source is important• Depends strongly on location of
features which reflect back into optics• Inclusion of these features requires
additional algorithms• Usefulness still needs to be tested
1 ring
2 rings
May, 28, 2004 Topics in Preservation ScienceLecture Series
43 Carl HaberLBNL.
IRENE Summary
• Design study completed and documented.
• Projected scan time reasonable for a production-like machine.
• Includes a suite of attractive features (GUI, broken, warped discs, data quality plots etc.)
• Would also provide a powerful test-bed for further development.
• Provides a new statistical view of disc media
May, 28, 2004 Topics in Preservation ScienceLecture Series
44 Carl HaberLBNL.
Test of 3D Scanning
• 2 methods were identified: confocal scanning and white light interferometry
• Collaboration with Taicaan Technology and Dept of Engineering Sciences, U of Southampton, UK: confocal tools in hand
• LBNL, MG designed the experiment, performed analysis and interpretation.
• UK Group configured the hardware and performed the scan.
• Scan speed was not emphasized, wanted to perform a proof-of-concept.
May, 28, 2004 Topics in Preservation ScienceLecture Series
45 Carl HaberLBNL.
3D Study of an Edison Cylinder
rotational stage + encoder
cylinder
optical probe
fiber
controller
host PC
linear stage + encoder
motion control and driver
Utilize confocal scanning probe at 300 Hz,Along axis at 3 mm/sec (10 m points)Angular increment = 0.01o = 96 KHz
~59 hours for 30 seconds
May, 28, 2004 Topics in Preservation ScienceLecture Series
46 Carl HaberLBNL.
Frequency – Distance Map
diameter (inches) 2.1875
RPM 80 90 120 144 160
surface velocity (mm/s) 232.740 261.832 349.109 418.931 465.479
frequency wavelength m)
10 23274.0 26183.2 34910.9 41893.1 46547.9
100 2327.4 2618.3 3491.1 4189.3 4654.8
500 465.5 523.7 698.2 837.9 931.0
1000 232.7 261.8 349.1 418.9 465.5
5000 46.5 52.4 69.8 83.8 93.1
10000 23.3 26.2 34.9 41.9 46.5
15000 15.5 17.5 23.3 27.9 31.0
20000 11.6 13.1 17.5 20.9 23.3
44100 5.3 5.9 7.9 9.5 10.6
88200 2.6 3.0 4.0 4.7 5.3
100000 2.3 2.6 3.5 4.2 4.7
May, 28, 2004 Topics in Preservation ScienceLecture Series
47 Carl HaberLBNL.
Confocal Probe Specifications
Parameter Value
Probe Model STIL CHR150
Depth of field 350 microns
Spot size 7.5 microns
Sampling Frequency 300 Hz
Vertical Resolution 10 nanometers
Vertical Accuracy 100 nanometers
Step size across grooves 10 microns
Step size along grooves (circumferential) 0.01o (= 5 microns on circumference)
Linear scan speed (parallel to cylinder axis) 3 mm/second
May, 28, 2004 Topics in Preservation ScienceLecture Series
48 Carl HaberLBNL.
Methodology
• Parabolic fits to each groove bottom with fixed curvature to determine depth. Damage and debris are filtered with shape constraint.
• No explicit low pass filter applied but high sampling avoids most of the noise.
• Overall shape is distorted but can constrain with an averaged measurement of ridge heights
• Signal is (approximately) stylus velocity, perform numerical differentiation using Discrete Fourier Transform
May, 28, 2004 Topics in Preservation ScienceLecture Series
49 Carl HaberLBNL.
Overall Shape of Cylinder
• Perfect cylinder would be flat in this view
• Off center rotation• Out of round – elliptical• Local deformity• Heard as “rumble” and
other low frequency effects
May, 28, 2004 Topics in Preservation ScienceLecture Series
50 Carl HaberLBNL.
May, 28, 2004 Topics in Preservation ScienceLecture Series
51 Carl HaberLBNL.
1
0
1
0
1
)()()(1
)()()(
1)](
)()(
)(N
k
nTik
N
k
nTikDF
ekCkMikN
ekCkMnTd
d
NkCF
nTd
dnTA
nTd
d
The filtering factor M is defined as follows.
)23(
2.50
2.5,8.44.0
8.40.1
8.4,201
200
KHzffor
KHzKHzfforf
KHzHzffor
Hzffor
M
1.The cut below 20 Hz removes the low frequency structure in the bottom-only data due to the cylinder shape irregularity. 2.The 400 Hz wide transition to zero at 5.0 KHz was used to avoid the interference-like pattern triggered by jumps in the data. 3.The cut above 5.2 KHz satisfies the Nyquist criteria before re-sampling to a lower digital audio standard.
Numerical Differentiation and Filtering
May, 28, 2004 Topics in Preservation ScienceLecture Series
52 Carl HaberLBNL.
Waveforms
bottoms
tops
top - bottom
May, 28, 2004 Topics in Preservation ScienceLecture Series
53 Carl HaberLBNL.
Comparison of Waveforms
optical(t – b)
stylus
May, 28, 2004 Topics in Preservation ScienceLecture Series
54 Carl HaberLBNL.
Sound Comparison• “Just Before the Battle, Mother”, composed by George F.
Root, performed by Will Oakland and Chorus 1909, 1516 (..76; 4M-297-2) originally as Amberol #297 1909
• with stylus, flat equalization
• Optical version, flat equalization
• + commercial noise reduction + low frequency boost *
*thanks to George Horn, Fantasy Records, Berkeley
May, 28, 2004 Topics in Preservation ScienceLecture Series
55 Carl HaberLBNL.
Frequency Spectra
3D optical versionwith top-bottom shape correction
Version playedon modern cylindersystem with electricalstylus
May, 28, 2004 Topics in Preservation ScienceLecture Series
56 Carl HaberLBNL.
Groove bottoms only
Ridge tops only (T)
(B)
T – B (version played already)
Frequency Spectra
May, 28, 2004 Topics in Preservation ScienceLecture Series
57 Carl HaberLBNL.
3D Research Plan
• Setting up similar scanning system at LBNL.• Acquired 4000 Hz confocal probe with high intensity
xenon light source.• Configure stages for raster and helical scans.• Study data quality versus probe speed and grid
spacing to optimize overall scan time.• Study media with mould growth and other damage.• Development of scratch correction code.• Some 3D studies of disc media may be possible.• Possibility of WLI study (?)
May, 28, 2004 Topics in Preservation ScienceLecture Series
58 Carl HaberLBNL.
May, 28, 2004 Topics in Preservation ScienceLecture Series
59 Carl HaberLBNL.
May, 28, 2004 Topics in Preservation ScienceLecture Series
60 Carl HaberLBNL.
Conclusions• Image based methods have sufficient resolution to reconstruct
audio data from mechanical media and reduce impulse noise.• Basic process is data intensive compared to simple stylus
playback.– 2D approach may be suitable for mass digitization. How general is the
2D image quality? IRENE design can address these and other key issues.
– At present 3D methods may be suitable for reconstruction of particular samples since they require ~hours per scan.
• Upcoming 3D research program should clarify some issues of ultimate scan time, address damaged media
• Reports available – 2D: LBNL-51983, JAES Dec 2003 – 3D: LBNL-54927, to be submitted to JAES
• Info at URL www-cdf.lbl.gov/~av
May, 28, 2004 Topics in Preservation ScienceLecture Series
61 Carl HaberLBNL.
Extra Slides
May, 28, 2004 Topics in Preservation ScienceLecture Series
62 Carl HaberLBNL.
Measurement of Noise at Rmin & Rmax
Optical readingsUpper sample is at outer radiusLower sample is at inner radiusFrom “Goodnight Irene” discIf noise is dominated by surface structuresof constant size distribution, the outer radiusamplitude and frequency should be greater due to greater linear speed there
May, 28, 2004 Topics in Preservation ScienceLecture Series
63 Carl HaberLBNL.
Physical Origin of Noise in Optical Reconstruction
• View of raw groove shape data from region of pause, before differentiation into velocities.
• Upper plot is 0.6 second portion.
• Lower plot shows deviations about 10 Hz waveform.
• Each point is an independent edge detection across the groove bottom.
• Clear structures, spanning multiple points are resolved of typical scale:
100 microns (0.2 ms) x 0.2 microns !!!
0.1 seconds
May, 28, 2004 Topics in Preservation ScienceLecture Series
64 Carl HaberLBNL.
Parameter 78 r.p.m., 10 inch 33 1/3 r.p.m., 12 inch
Groove width at top 150-200 m 25-75 m
Grooves/inch (mm) Gd 96-136 (3.78-5.35) 200-300 (7.87-11.81)
Groove spacing 175-250 m 84-125 m
Reference level peak velocity@1KHz 7 cm/sec 7 cm/sec (0.0011 cm)
Maximum groove amplitude 100-125 m 38-50 m
Noise level below reference, S/N 17-37 dB 50 dB
Dynamic range 30-50 dB 56 dB
Groove max amplitude at noise level 1.6 - 0.16 m 0.035 m
Maximum/Minimum radii 120.65/47.63 mm 146.05/60.33 mm
Area containing audio data 38600 mm2 55650 mm2
Total length of groove 152 meters 437 meters
May, 28, 2004 Topics in Preservation ScienceLecture Series
65 Carl HaberLBNL.
Cylinder Sample
Parameter Value
Cylinder issue Edison Blue Amberol
Diameter 2 inch (2.1875 inches)
Artist Will Oakland and Chorus
Title “Just Before the Battle, Mother”
Serial number 1516 (..76; 4M-297-2) originally as Amberol #297 1909
Date of original recording 1909
Date of manufacture ~1920’s
Tracks per inch (t.p.i.) 200
Groove spacing 127 m