Note: Descriptions are shown in the official language in which they were submitted.
1;~5t~:31'7
Technical Field.
The invention relates to spoken-word recogni-
tion systems.
~O
Background Art
Suzuki, et al. (U.S. patents 4,060,694,
4,078,154 and 4,100,370) teach a voice recognition system
in which the phonemes as spoken by different speakers and
the voice of the person speaking can be recognized. A
key phrase is spoken. Parallel filters derive a spectral
characteristic parameter which contains weighting factors
extracted and compared with the selected phoneme in
memory. Improved specificity over other speakers can be
obtained by varying the weighting factors through a num-
ber of different values, and storing in memory the set of
parameters for each sound as spoken by a specific
speaker. The system can be used thus for voice verifica-
tion.
Felix et al. (U.S. patent 4,449,189) disclose amethod for identifying an individual using a combination
Dl: ~
1258~17
of speech and face recognition. The voice signature of a
person uttering a key word into a microphone is compared
in a pattern matched with the previously stored voice
signature of a known person uttering the same key word.
At the same time, a momentary image of that person's
mouth region is recorded and compared with that of the
same known person. The results of the comparison are
analyzed to verify that the identity of the speaker is
that of the known person.
Katayama (U.S. patent 4,461,023) discloses a
method of storing spoken words for use in a speech recog-
nition system. Spoken words are input, then analyzed.
The resulting patterns are stored in memory. A-second
memory stores the digitized speech that was input. The
addresses of both memory units are specified to be the
same for a particular word.
Systems that recognize voice commands require
memory for storing speech characteristics for later com-
parison. The system must first be "taught" the speech
characteristics before it can rècognize specific voice
commands. A problem with this is that each speaker has
his own speech characteristics that the system must
learn. Computer memory space is limited, so the speech
characteristics of an individual must be relearned each
time the speaker changes.
An object of the invention is to devise a
spoken word recognition system which is of reduced com-
plexity and which can be quickly and easily programmed to
understand any individual's voice commands more readily.
Another object of the invention is to devise a
system in which a voice command unit can be initialized
easily by each individual user without needing a
knowledge of programming or of the unit's operation.
Disclosure of Invention
The above objects have been met by a system
which stores a person's voice characteristics on a
wallet-size card containing a laser recordable strip.
1;~583~7
These cards may be inserted into and removed from a word
recognition processor. Every user has a card with
his own pre-recorded speech characteristics thereon.
Upon insertion into a word recognition processor, the
processor unit would be initialized with respect to the
particular voice charcteristics of the owner of the card.
To encode the card, a set of words is spoken by
a user into a microphone. The spoken words are analyzed
and speech characteristics are extracted. Such charac-
teristics include pitch, intonation, speed of speaking,accent parameters, and other parameters. A sufficient
number of these characteristics is recorded on the card
so that the words spoken later by the speaker may be
understood by the word recognition unit.
A spoken-word recognition unit receives a
user's voice message and identifies the words with the
; help of the speaker's voice characteristics in its mem-
ory, which was initialized by the spoken-word identifica-
tion data on a card. In this manner, the spoken words
can be recognized. For each new speaker, the unit must
first be "taught" a particular speaker's characteristics
so that the unit can more easily recognize the spoken `
words. The card provides the information to teach the-
unit. A record of an individual's speech characteristics
is laser recorded on a card which is later read into the
unit by placing it in a card reader and the character-
istics entered into the short-term memory of the spoken-
word recognition unit.
The card has a strip of laser recording
material, such as the reflective direct-read-after-write
material described in U.S. patent 4,284,716 to Drexler et
al. A modulated laser beam records data on the strip, in
situ, by ablation, melting, physical or cnemical change
or deformation, thereby forming spots having a detectable
3~ change in an optical characteristic relative to the
strip. The recording process on the above mentioned
direct-read-after-write material produces differences in
reflectivity detectable by a light detector. No pro-
1;~5~17
cessing after laser recording is required when the re-
cording strip is a direct-read-after-write material.
Laser recording materials also may be used that require
heat processing after laser recording.
Each person has his own speech characteris-
tics, in much the same way that each person has his own
set of fingerprints. The card with the recorded speech
characteristics is read by shining a laser beam or light
emitting diode onto the strip. The beam, typically, has
an intensity of ten percent of the recording intensity.
The beam is reflected from the strip to a photodetector.
The detector detects the contrast in optical character-
istics between the strip and the recorded spots, and
transmits corresponding signals to the speech recognition
unit's short-term memory. The system is now ready to
listen to words spoken by the user and to identify the
words with the help of the speaker's voice characteris-
tics stored in the memory. By this procedure the
speaker's words are more clearly identified.
The uniform surface reflectivity of this reflec-
tive strip before recording typically would range be-
tween 8% and 65~. For a highly reflective strip the
average reflectivity over a laser recorded spot might be
in the range of 5% to 25%. Thus, the reflective contrast
ratio of the recorded spots would range between 2:l and
7:l. Laser recording materials are known in the art that
create either low reflectivity spots in a reflective
field or high reflec~ive spots in a low reflectivity
field. An example of the latter type is described in
U.S. patent 4,343,879. When the reflectivity of the
field is in the range of 8~ to 20% the reflective spots
have a reflectivity of about 40~. The reflective con-
trast ratio would range from 2:l to 5:l. Photographic
pre-formatting would create spots having a 10% reflectivi-
ty in a reflective field or 40~ in a low reflectivity
field.
The voice information on the card would typi-
cally be in digital form. It would inform the word
1~58:~17
--5--
recognition unit of macro aspects of speech such as
accent parameters, speed of speaking, dropping of "th"
beginnings or "g" endings, variations in intensity as
well as the micro aspects such as tone, pitch,
intonation, etc. With this advance knowledge about the
speech characteristics of the words about to be spoken
the words can more easily be recognized.
The card can store tens, hundreds or even
thousands of deviation parameters from a ~normal" voice.
When a word is not understood the word interpreter unit
would add in corrections to the unidentified word based
upon the individual's speech deviation information. At-
tempts to recognize the word are then repeated.
Brief Description of the Drawings
Fig. l is a schematic diagram of the spoken-
word recognition system of the present invention.
Fig. 2 is a schematic diagram of the data card
encoding of the present invention.
Fig. 3 is a plan view of one side of a data
card in accord with the present invention.
Fig. 4 is a partial side sectional view taken
along lines 4-4 in Fig. 3.
Fig. S is a detail of laser writing on a
portion of the laser recording strip illustrated by
dashed lines in Fig. 3.
Fig. 6 is a plan view of an apparatus for
reading and writing on the optical recording media strip
illustrated in Fig. 3.
Best Mode for Carrying Out the Invention
With reference to Fig. l, a spoken-word recog-
nition system lO reads a person's voice characteristics
from a wallet-size card 31 containing a strip of laser
recordable material. Each person would have a card 3l
with his own speech characteristics prerecorded thereon.
The system lO is initialized with respect to the particular
voice characteristics of the card owner by inserting the
(
1;~58;~7
card 31 into system lO. A sufficient number of character-
istics is recorded so that words spoken by a particular
speaker may be identified.
With reference to Fig. 2 a data card encoding
system llO is used to form a card 131. A set of words
116 is spoken by a person`into a microphone 117. The
resulting signal is analyzed by a speech analyzer 121 and
speech characteristics 122 are extracted. such charac-
teristics 122 include pitch, formats, ratio of voiced to
unvoiced amplitudes, and other parameters used to help
identify words and parts of words. The exact set of
parameters will vary from one system to another, de-
pending on the type of speech analysis which is used.
Macro aspects of speech such as accent parameters, speed
of speaking, dropping of particular sounds at the begin-
ning or ending of words, and variations in tone may also
be included to make word recognition even easier. In any
case, speech analyzer 121 sends a digital signal 122 repre-
senting a person's speech characteristics to a data card
writer/reader 129 which writes the data with a laser onto
card 131 by shining a modulated laser beam 130 onto the
card 131. The card 131 has a strip of optical contrast
laser recording material disposed thereon. The beam 130
records data onto the card 131, in situ, by ablation,
melting physical or chemical change or deformation,
thereby forming spots with contrasting reflectivity rela-
tive to the unreccrded strip. Reflected beam 132 is read
by the card reader/w~iter 129 to confirm laser writing.
In Fig. 1 the spoken-word recognition system lO
is initialized by placing a prerecorded card 31 in data
card reader 29. The card reader 29 shines a light beam
30 from a laser or a LED onto the prerecorded strip.
This read beam, typically, has an intensity of five to ten
percent of the typical semiconductor laser recording
intensity. The light beam 32 is reflected from the strip
to a photodetector, which detects this contrast in re-
flectivity between the strip and recorded spots. Card
reader 29 transmits a signal 24 corresponding to the
1;~5~3~317
--7--
recorded data to the short-term memory of the spoken-word
recognition unit 23.
The system 10 is now ready to listen to words
16 spoken by the user. The words 16 spoken into micro-
phone 17 are analyzed and interpreted by the speechrecognition unit 23 with respect to the voice character-
istics 24, now stored in its short-term memory. The words
16 are recognized and the result is sent to an output
device 27, such as a CRT terminal.
With reference to Figs. 3 and 4, a data card 11
is illustrated having a size common to most credit cards.
The width dimension of such a card is approximately 54 mm
and the length dimension is approximately 85 mm. These
dimensions are not critical, but preferred because such a
size easily fits into a wallet and has historically been
adopted as a convenient size for automatic teller ma-
chines and the like. The card's base 13 is a dielectric,
usually a plastic material such as polyvinyl chloride or
similar material. Polycarbonate plastic is preferred.
The surface finish of the base should have low specular
reflectivity, preferably less than 10%.
Base 13 carries strip 15. The strip is about
16 or 35 millimeters wide and extends the length of the
card. Alternatively, the strip may have other sizes and
orientations. The strip is relatively thin, approximate-
ly 60-200 microns, although this is not critical. The
strip may be applied to the card by any convenient method
which achieves flatness.
The strip is adhered to th~ card with an adhe-
sive and covered by a transparent laminating sheet 19which serves to keep strip 15 flat, as well as protecting
the strip from dust and scratches. Sheet 19 is a thin,
transparent plastic sheet laminating material or a coat-
ing, such as a transparent lacquer. The material is
preferably made of polycarbonate plastic.
The opposite side of base 13 may have user
identification indicia embossed on the surface of the
1;~5~:~1 7
--8--
card. Other indicia such as card number and the like may
be optionally provided.
The high resolution laser recording material
which forms strip 15 may ~e any of the reflective record-
ing material which have been developed for use as directread-after-write (DRAW) optical disks, so long as the
materials can be formed on thin substrates. An advantage
of reflective materials over transmissive materials is
that the read/write equipment is all on one side af the
card, the data storage capacity is doubled, and the
automatic focus is easier. For example, the high resolu-
tion material described in U.S. patent 4,230,939 issued
to de 8Ont, et al. teaches a thin metallic recording
layer of reflecti~e metals such as Bi, Te, Ind, Sn, Cu ,
Al, Pt, Au, Rh, As, Sb, Ge, Se, Ga.
Materials which are preferred are those having
high reflectivity and low melting point, particularly Cd,
Sn, Tl, Ind, Bi and amalgams. Suspensions of reflective
metal particles in organic colloids also form low melting
temperature laser recording media. Silver is one such
metal. Typical recording media are described in U.S.
patents Nos. 4,314,260, 4,298,684, 4,278,758, 4,278,758,
4,278,756 and 4,269,917, all assigned to the assignee of
the present invention.
The laser recording material which is selected
should be compatible with the laser which is used for
writing on it. Some materials are more sensitive than
others at certain wavelengths. Good sensitivity to in-
frared light is preferred because infrared is affected
least by scratches and dirt on the transparent laminating
sheet. The selected recording material should have a
favorable signal-to-noise ratio and form chigh contrast
data bits with the read/write system with which it is
used.
The material should not lose data when
subjected to temperatures of about 17SF(79C) for long
periods. The material should also be capable of re-
cording at speeds of at least several thousand bits/sec.
1;~58;~.7
This generally precludes the use of materials that re-
quire long heating times or that rely on slow chemical
reactions in the presence of heat, which may permit
recording of only a few bits/sec. A large number of
highly reflective laser recording materials have been
used for optical data disk applications.
Data is recorded by forming spots in the sur-
rounding field of the reflective layer itself, thereby
altering the reflectivity in the data spot. Data is read
by detecting the optical reflective contrast between the
surrounding reflective field of unrecorded areas and the
recorded spots. Spot reflectivity of less than half the
reflectivity of the surrounding field produces a contrast
ratio of at least two to one, which is sufficient con-
trast for reading. Greater contrast is preferred. Re-
flectivity of the strip field of about 50% is preferred
with reflectivity of a spot in the reflective field being
less than 10%, thus creating a contrast ratio of greater
than five to one. Alternatively, data may also be re-
corded by increasing the reflectivity of the strip. Forexample, the recording laser can melt a field of dull
microscopic spikes on the strip to create flat shiny
spots. This method is described in SPIE, Vol. 329,
Optical Disk Technology (1982), p. 202. A spot re-
flectivity of more than twice the surrounding spikedfield reflectivity produces a contrast ratio of at least
two to one, which is sufficient contrast for reading.
With reference to Fig. 5, a magnified view of
laser writing on the laser recording-material strip 15
may be seen. The dashed line 33, corresponds to the
dashed line 33 in Fig. 3. The oblong spots 35 are
aligned in a path and have generally similar dimensions.
The spots are generally circ~lar or oval in shape with
the axis of the oval perpendicular to the lengthwise
dimension of the strip. A second group of spots 37 is
shown aligned in a second path. The spots 37 have
similar dimensions to the spots 35. The spacing between
paths is not critical, except that the optics of the
1~5~
-10-
readback system should be able to easily distinguish
between paths. Presently, in optical data storage
technoloqy, tracks which are separated by only a few
microns may be resolved. The spacing and pattern of the
spots along each path is selected for easy decoding.
The spots illustrated in Fig. 5 have a recom-
mended size of approximately 5 microns by 20 microns, or
circular spots 5 microns or 10 microns in diameter.
Generally, the smallest dimension of a spot should be
less than 50 microns. In the preferred embodiment the
largest dimension would also be less than 50 microns. Of
course, to offset lower densities from larger spots, the
size of the strip 15 could be expanded to the point where
it covers a large extent of the card. In Fig. 3, the
laser recording strip 15 could completely cover a single
side of the card. A minimum information capacity of
250,000 bits is indicated and a storage capacity of over
one million bits is preferable.
In Fig. 6, a side view of the lengthwise dimen-
sion of a card 41 is shown inserted into cardreader/writer 29. The card is usually received in a
movable holder 42 which brings the card into the beam `
trajectory. A laser light source 43, preferably a pulsed
semiconductor laser of near infrared wavelength emits a
beam 45 which passes through collimating and focussing
optics 47. The beam is sampled by a beam splitter 49
which transmits a portion of the beam through a focusing
lens 51 to a photodetector 53. The detector 53 confirms
laser writing and is not essential. The beam is then
directed to a first servo controlled mirror 55 which is
mounted for rotation along the axis 57 in the direction
indicated by the arrows A. The purpose of the mirror 55
is to find the lateral edges of the laser recording
material in a coarse mode of operation and then in a fine
3~ mode of operation identify data paths which exist prede-
termined distances from the edges.
From mirror 55, the beam is directed toward
mirror 61. This mirror is mounted for rotation at pivot
1'~58;317
63. The purpose of mirror 55 is for fine control of
motion of the beam along the length of the card. Coarse
control of the lengthwise position of the card relative
to the beam is achieved by motion of movable holder 42.
The position of the holder may be established by a linear
motor adjusted by a closed loop position servo system of
the type used in magnetic disk drives.
During itsmanufacturethe card may be pre-
recorded with database information or a preinscribed
pattern containing servo tracks, timing marks, program
instructions, and related functions. These positioning
marks can be used as a reference for the laser recording
system to record or read data at particular locations.
Each of the various spoken word recognition systems may
have formats specific to its particular needs. U.s.
patent No. 4,304,848 describes how formatting may be done
photolithographically. Formatting may also be done using
laser recording or surface molding of the servo tracks,
having marks, programming and related functions. Dil, in
U.S. patent 4,209,804 teaches a type of surface molding.
Reference position information may be prerecorded on the
card so that position error signals may be generated and
used as feedback in motor control. Upon reading one data
path, the mirror 55 is slightly rotated. The motor moves
holder 4l lengthwise so that the path can be read, and so
on.
Light scattered and reflected from the spots con-
trasts with the surrounding field where no spots exist.
The beam should deliver sufficient laser pulse energy to
the surface of the recording material to create spots.
Typically, 5-20 milliwatts is required, depending on the
recording material. A 20 milliwatt semiconductor laser,
focussed to a five micron beam size, records at tempera-
tures of about 200 C and is capable of creating
spots in less than 25 microseconds. The wavelength of
the laser should be compatible with the recording mate-
rial. In the read mode, power is lowered to about 5% to
10% of the record power.
-`` 1;~5~3~7
-12-
Optical contrast between a spot and surrounding
field are detected by light detector 65 which may be a
photodiode. Light is focussed onto detector 65 by beam
splitter 67 and focusing lens 69. Servo motors, not
shown, control the positions of the mirrors and drive the
mirrors in accord with instructions received from control
circuits, as well as from feedback devices. The detector
65 produces electrical signals corresponding to spots.
These signals are processed by the spoken-word recognition
unit and used for identifying words spoken by a
particular speaker.
