United States Patent [191
`Murljacic
`
`I 1111111111111111 11111 111111111111111 IIIII IIIII 1111111111 111111111111111111
`US005766006A
`[lll Patent Number:
`[45] Date of Patent:
`
`5,766,006
`Jun. 16, 1998
`
`[54) TOOffl SHADE ANALYZER SYSTEM AND
`METHODS
`
`[76)
`
`Inventor: Maryann Lehmann Murljacic. 21
`Heather La.. Darien. Conn. 06820
`
`[21] Appl. No.: 494,979
`Jun. 26, 1995
`[22] Filed:
`fut. CL 6
`••••••••••••••••••••••••••••••••••••••••••••••••••••• A61C 19/10
`[51]
`[52) U.S. Cl . ............................................... 433/26; 356/408
`[58) Field of Search ............................ 433/26. 29. 203.L
`433/215; 364/413.28; 356/402. 405, 406,
`408
`
`[56]
`
`Refettnces Cited
`
`U.S. PATENT DOCUMENTS
`
`3,986,777
`4,247,202
`4.414,635
`4,518,258
`4,547,074
`4,623,973
`4,654,794
`4,692,481
`4,836,674
`4,881,811
`5,012,431
`5,124,797
`5,231,472
`5,240,414
`
`10/1976 Roll ......................................... 356/176
`1/1981 Failes ...................................... 356/310
`11/1983 Gast et al.
`.............................. 364/526
`5/1985 Broersma ................................ 356/405
`10/1985 Hinoda et al ........................... 356/405
`11/1986 Hoffricbter et al. ......•....•.•..•... 364/526
`3/1987 O'Brien .................................. 364/413
`9/1987 Kelly ....................................... 523/210
`6/1989 Lequime et al ......................... 356/319
`ll/1989 O'Brien .................................. 356/323
`4/1991 Stanziola ................................. 364/526
`6/1992 Williams et al .......................... 433/29
`7/1993 Marcus et al ........................... 356/402
`8/1993 Thompson ................................ 433/26
`
`5/1994 MacFarlene et al .................... 356/405
`5,313,267
`5,373,364 12/1994 Knyminski ............................. 356/405
`5,383,020
`1/1995 Vieillefosse ............................. 356/405
`
`FOREIGN PATENT DOCUMENfS
`
`0360657
`4301530
`4338465
`WO 86/03292
`9102955
`
`3/1990
`10/1992
`11/1992
`6/1986
`3/1991
`
`European Pat. Off ..
`Japan ..................................... 356/402
`Japan .................................. 433/203. l
`WIPO.
`WIPO ................................. 433/203. l
`
`Primary Examiner-Cary E. O'Connor
`Attome}; Agent, or Firm-Curtis A. Vock
`
`[57]
`
`ABSTRACT
`
`An intraoral camera connects to a shade analyzer subsystem.
`e.g .• a digital video processor. and a color display monitor.
`The camera captures a digital color image of the patient's
`tooth and the subsystem compares that image to a stored
`plurality of tooth shades. Each tooth shade is represented in
`a block of data. including color image data. a tooth shade
`digital word, and a manufacturer type. The patient's tooth
`image includes an RGB chromaticity representation that is
`scanned and compared with the several tooth shades stored
`in memory. and a match is determined and communicated to
`a user of the system. The methodology includes the speci(cid:173)
`fication of fractional tooth shades, if needed. corresponding
`to a plurality of porcelain films for manufacturing a recon(cid:173)
`structed tooth.
`
`4 Claims, 8 Drawing Sheets
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`32a
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`32b
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`30
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`44
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`29/
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`US. Patent
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`Jun. 16, 1998
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`Sheet 1 of 8
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`5,766,006
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`FIG. 1 (PRIOR ART)
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`US. Patent
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`Jun. 16, 1998
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`Sheet 2 of 8
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`5,766,006
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`FIG. 3 (PRIOR ART)
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`40
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`A2
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`40a
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`FIG. 3A (PRIOR ART)
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`US. Patent
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`Jun. 16, 1998
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`Sheet 3 of 8
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`5,766,006
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`DIGITAL COLOR IMAGE
`DATA
`42a
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`h2e
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`TOOTH SHADE DATA
`42b
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`MANUFACTURER DATA
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`FIG. 4
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`U.S. Patent
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`Jun. 16, 1998
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`Sheet 4 of 8
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`5,766,006
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`3SHAPE 1025
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`U.S. Patent
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`Jun. 16, 1998
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`Sheet 5 of 8
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`5,766,006
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`U.S. Patent
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`Jun. 16, 1998
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`Sheet 6 of 8
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`5,766,006
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`FIG.7
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`Sheet 7 of 8
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`5,766,006
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`U.S. Patent
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`Jun. 16, 1998
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`FIG.8
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`3SHAPE 1025
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`U.S. Patent
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`Jun. 16, 1998
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`Sheet 8 of 8
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`5,766,006
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`1
`TOOTH SHADE ANALYZER SYSTEM AND
`METHODS
`
`In dentistry. there has been a shift in recent years from a
`philosophy of drilling and filling to one of prevention and
`cosmetics. By way of example. many people today are
`choosing to have clinical procedures done to enhance their
`smile and appearance. Most of these procedures involve the
`modification of tooth shape. alignment. and/or color.
`A necessary step in altering a patient's tooth color is to 10
`determine the "shade" of the existing tooth. For example,
`those persons seeking a whiter, brighter smile are still
`assessed to establish their existing tooth color so that an
`appropriate before and after comparison can be made. Shade
`determination is even more important for those persons 15
`seeking reconstructive work, since one goal of the recon(cid:173)
`structive process is to achieve a natural appearance.
`Therefore. it is important to know the existing tooth shade
`so that it can be accurately matched with the new restoration.
`The dental profession utilizes standardized shade guides 20
`created by those companies which manufacture the recon(cid:173)
`structive materials. One well-known shade guide is the
`Vita™ shade guide, which includes sixteen different shades.
`Other. less popular shade guides include those guides pro(cid:173)
`vided by Bioform™ and SR-Vivaden™.
`These shade guides are utilized in a rudimentary fashion.
`The guide itself is a plastic plate with a plurality of remov(cid:173)
`able color tabs that are shaped like a tooth. e.g., the front
`tooth. Typical1y, to assess a patient's tooth shade, a dentist
`removes one of the colored tabs and holds it up to the 30
`patient's tooth so that she can "eyeball" the closest match
`possible. Understandably, there are many variables to this
`method, some of which stem from the subjectivity of the
`dentist making the eyeball assessment.
`Once the tooth shade is determined, the information is 35
`used relative to the particular procedure needed. In bonding
`or filling a tooth, for example. the composite materials
`required for the restoration are specified within the range of
`the shade guide, e.g .. one of sixteen shades for the Vita™
`range. More particularly, if a crown. bridge or denture is 40
`needed. the patient's shade must be determined and com(cid:173)
`municated correctly to the lab that make the crown, bridge
`or denture.
`The communication of shade information between the
`dentist and the lab is extremely important. Often. there is a
`break-down or failure in this communication. resulting in a
`poor shade match for the patient. In some cases. a particular
`dentist utilizes an uncommon shade guide, thereby leaving
`the lab technician to eyeball and convert the shade infor(cid:173)
`mation to a Vita standard shade ( since porcelain is often
`made from the Vita™ shade guide). This too can result in
`improper shade matching.
`The process for selecting the porcelain for a particular
`tooth shade illustrates the difficulty in assessing and manu(cid:173)
`facturing the correct color match. If. for example. a crown
`of Vita™ shade A3 is desired. porcelain is built by hand with
`a paint brush onto a model of the tooth to be restored. The
`porcelain is built in layers on the model to achieve translu(cid:173)
`cency and natural appearance. Each layer has a particular
`color and intensity associated with it. To generate shade A3.
`the technician follows a "recipe" that is given by the
`manufacturer Vident™. requiring a different shade for each
`layer of porcelain applied If a doctor asks for a shade that
`is not a Vita™ standard shade, the technician typically seeks
`to achieve that shade by combining different porcelain shade
`combinations together, to increase or decrease the chroma.
`hue and value of the shade.
`
`2
`To further complicate the color-matching process, same
`dentists are simply not skilled in taking and determining
`shade information. Therefore. these dentists sometimes send
`their patients directly to the lab where the technician can
`5 determine the shade information. Alternatively, these den(cid:173)
`tists sometimes have a technician come to the office. In
`either event. there is, at times, one more level of subjective
`uncertainty injected into the correct match and determina-
`tion of a patient's tooth shade.
`It is. accordingly. an object of the invention to provide a
`shade analyzer system which reduces the afore-mentioned
`difficulties.
`Still another object of the invention is to provide meth(cid:173)
`odology for assessing and communicating a patient's tooth
`color in an objective manner.
`These and other objects of the invention will become
`apparent in the description which follows.
`SUMMARY OF THE INVENI1ON
`In one aspect. the invention provides a system for deter-
`mining the tooth shade of a patient's tooth. An intraoral
`camera captures the image of the patient's tooth. including
`color information representative of the tooth's color. A shade
`analyzer sub-system connects in electrical communication
`25 with the intraoral camera, and has (i) a color processing
`section for determining the color of the patient's tooth from
`the color information of the image; (ii) storage memory for
`storing shade information representative of a plurality of
`tooth shades (i.e., each of the tooth shades corresponds to a
`different tooth color). (ill) a color correlation section for
`comparing the color of the patient's tooth to the plurality of
`tooth shades and for identifying a tooth shade with a color
`corresponding to the color of the patient's tooth. and (iv)
`means such as a display terminal for communicating the
`identified tooth shade to a user of the system.
`In another aspect, the system includes a monitor used to
`display the color image to a user of the system. The shade
`analyzer sub-system thus communicates a tooth color rep(cid:173)
`resentative of the identified tooth shade to the monitor,
`thereby providing a user of the system with a visual com(cid:173)
`parison of the patient's tooth color with the color of the
`identified tooth shade.
`In a further aspect. the color processing section deter(cid:173)
`mines RGB chromatidties of the color image, and each of
`45 the plurality of tooth shades has a corresponding RGB
`representation of the tooth color stored in memory. In such
`an aspect. the color correlation section quantitatively com(cid:173)
`pares the RGB chromaticities with the RGB representation
`of each of the tooth shades. and compares and identifies a
`50 tooth shade based upon an comparison of the chromatidties
`and the RGB representations.
`In still another aspect of the invention. the system asso(cid:173)
`ciates one or more of the plurality of tooth shades with at
`least one standardized shade corresponding to a particular
`55 manufacturer's porcelain product. Accordingly. the system
`communicates the standardized shade to a user of the system
`so that the desired tooth may be constructed.
`The color correlation section of the invention can also
`identify a combination of tooth shades having a combined
`60 color corresponding to the color of the patient's tooth. As
`such, the system can (i) associate each of the tooth shades in
`the combination with at least one standardized shade corre(cid:173)
`sponding to an particular manufacturer's porcelain product.
`(ii) specify fractions of each of the standardized shades
`65 needed to form the combined color. and (iii) communicate
`information identifying the fractions of each of the tooth
`shades in the combination to a user of the system.
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`the CCD camera. and has (i) a color processing section for
`determining the color of the patient's tooth from the color
`information of the image, (ii) a storage section for storing
`shade information representative of a plurality of tooth
`5 shades, each of the tooth shades corresponding to a different
`tooth color, (iii) a color correlation section for comparing the
`color of the patient's tooth to the plurality of tooth shades
`and for identifying a tooth shade with a color corresponding
`to the color of the patient's tooth, and (iv) a section for
`10 communicating the identified tooth shade to a user of the
`system.
`In accord with the invention. the CCD camera can include
`three CCD arrays, each of the arrays collecting image data
`corresponding to a color selected from the group of red,
`15 green and blue. Alternatively, the CCD camera can include
`a single CCD array, including a plurality of proximately
`located pixels corresponding to a color selected from the
`group of red, green and blue. each of any group of three
`pixels having a different color associated therewith.
`The invention is next described further in connection with
`preferred embodiments. and it will become apparent that
`various additions, subtractions. and modifications can be
`made by those skilled in the art without departing from the
`scope of the invention.
`
`20
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`3
`The invention also provides a tooth shade analyzer system
`for determining the tooth shade of a patient's tooth. One
`section of the analyzer communicates with an intraoral
`camera of the type which captures the image of the patient's
`tooth. including color information representative of a color
`of the tooth. Other sections of the analyzer (i) determines the
`color of the patient's tooth from the color information of the
`image. and (ii) stores shade information representative of a
`plurality of tooth shades. A color correlation section com(cid:173)
`pares the color of the patient's tooth to the plurality of tooth
`shades and identifies one or more tooth shades with a
`combined color corresponding to the color of the patient's
`tooth. Finally, the system includes means for communicating
`with devices such as display monitors to communicate the
`one or more identified tooth shades to a user of the system.
`In this manner, the analyzer matches the patient's tooth with
`one or more corresponding tooth shades and assists in
`reconstructing the patient's tooth.
`The invention also includes a method for determining the
`tooth shade of a patient's tooth. including the steps of:
`capturing the image of the patient's tooth with an intraoral
`camera. the image including color information representa(cid:173)
`tive of a color of the tooth; determining the color of the
`patient's tooth from the color information of the image;
`comparing the color of the patient's tooth to a plurality of 25
`tooth shades, the tooth shades being stored in an electronic
`medium; identifying one or more tooth shades with a
`combined color corresponding to the color of the patient's
`tooth; and communicating the one or more identified tooth
`shades to a user of the system.
`A further method of the invention compares the tooth
`shade of a patient's tooth after the patient's teeth are
`cosmetically whitened. including the steps of: capturing a
`first image of the patient's tooth with an intraoral camera
`before the tooth is cosmetically whitened. the first image 35
`including first color information representative of a color of
`the tooth; processing the color information of the image to
`determine the color of the patient's tooth; comparing the
`color of the patient's tooth to a plurality of tooth shades, the
`tooth shades being stored in an electronic medium; identi- 40
`fying one or more tooth shades with a combined color
`corresponding to the color of the patient's tooth; whitening
`the teeth; communicating the one or more identified tooth
`shades to a user of the system; and viewing the patient's
`tooth on a monitor after the whitening step while simulta- 45
`neously displaying an image of the patient's pre-whitened
`tooth. to provide before and after imagery.
`In another aspect of the invention, a process is provided
`for manufacturing a reconstructive tooth for a patient,
`including the steps of: capturing the image of the patient's 50
`tooth with an intraoral camera. the image including color
`information representative of a color of the tooth; processing
`the color information of the image to determine the color of
`the patient's tooth; comparing the color of the patient's tooth
`to a plurality of tooth shades. the tooth shades being stored 55
`in an electronic medium; specifying one or more tooth
`shades. and any fractions thereof. having a combined color
`corresponding to the color of the patient's tooth; and paint(cid:173)
`ing one or more layers of porcelain onto a model of the
`patient's tooth, each of the layers of porcelain corresponding 60
`to the specified tooth shades and the fractions thereof.
`The invention also includes a system for determining the
`tooth shade of a patient's tooth by utilzing color CCD
`cameras. In one aspect, a color CCD camera captures the
`image of the patient's tooth, including color information 65
`representative of a color of the tooth. A shade analyzer
`sub-system is connected for electrical communication with
`
`30
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`A more complete understanding of the invention may be
`obtained by reference to the drawings. in which:
`FlG. 1 shows a prior art intraoral camera system;
`FlG. 2 illustrates a tooth shade analyzer system con(cid:173)
`structed according to the invention;
`FlG. 3 illustrates a typical prior art tooth shade guide;
`FlG. 3A illustrates one tooth shade tab of the shade guide
`of FlG. 3;
`FlG. 4 illustrates a digital data block constructed accord(cid:173)
`ing to the invention for specifying a tooth shade color. color
`image information. and an associated manufacturer;
`FIG. 5 shows an operational use of the system of FIG. 2;
`FIG. 6 illustrates image averaging and specification
`techniques. according to the invention;
`FIG. 7 illustrates an image comparison on the system of
`FIG. 2;
`FIG. 8 illustrates a common aperature color CCD camera
`and handpiece constructed according to the invention, and
`which form another embodiment of a shade analyzer system;
`and
`FIG. 9 shows an alternative CCD array technology.
`according to the invention, and which is suitable for use
`within the camera of FIG. 8.
`
`DETAILED DESCRIPTION OF THE DRAWINGS
`The use of intraoral video and/or imaging systems
`(hereinafter "intraoral camera system") has grown rapidly in
`dentistry over the past few years. Such systems are widely
`utilized in "show and tell" settings. i.e., where the dentist can
`show and illustrate particular features of a patient's mouth.
`However. these intraoral camera systems are rapidly becom(cid:173)
`ing key to complex diagnostic and treatment planning.
`Presently. approximately 30% of the practicing dentists in
`the age group between about 35-54 own and utilize intraoral
`camera systems. It is expected that that percentage will only
`increase with increased familiarity. See Dental Products
`Report pgs. 22-24. February 1995.
`FIG. 1 illustrates a typical prior art intraoral camera
`system 10. The system 10 includes a wall-mounted intraoral
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`camera 12, which includes twin halogen lamp light source
`(not shown) for uniform illumioance, one or more hand(cid:173)
`pieces 14a, 14b, a digital video processor 16 (typically an
`IBM-compatible PC). which includes a hard drive 18 and
`floppy drive 20. and a color video monitor 22.
`In operation, a dentist points a selected handpiece 14a,
`14b at the target location within the patient's mouth to
`illuminate and view the resulting, full color image on the
`monitor 22. The endoscope handpieces 14a, 14b come in
`varying styles, including a wide angle configuration, e.g .. a
`100 degree field of view (FOV) for posterior and anterior
`views. and a near O degree FOV for full-arch and full-face
`images. The processor 16 provides storage for any selected
`image. and can further display selected close-ups on the
`monitor 22 through zoom capabilities.
`There are several manufacturers of intraoral camera
`systems. offering an array of features. For example,
`Insight™, of San Carlos. Calif .. offers a Power 0/100 similar
`to the one shown in FIG. 1. Other manufacturers include
`Cygnus Instruments, Inc. (CygnaScope™), of Goleta. Calif.
`VistaCam™ is yet another prior art intraoral camera system
`that incorporates a 90-degree FOV fiberoptic handpiece that
`delivers full color images from about 6 mm, i.e., the size of
`one typical tooth. to an image of the patient's whole smile.
`Therefore. the prior art intraoral camera systems
`described above offer full color imagery of a patient's tooth.
`The image may be stored on disk 18, 20 and/or displayed on
`the screen 22.
`The invention makes use of an intraoral camera system of 30
`the type described above. Specifically, FIG. 2 illustrates one
`embodiment of the invention and which shows a tooth shade
`analyzer 29 including an intraoral camera 30. associated
`handpieces 32a, 32b, and a shade-analyzer subsystem 34.
`Preferably. the subsystem 34 is a digital video processor that 35
`is similar to the processor 16 of FIG. 1. and thus preferably
`includes the video processing capabilities of the processor
`16, such as known to those skilled in the art. A storage
`medium 36, such as a hard disk 18 or floppy 20, stores digital
`color images of a plurality of tooth shades. such as each of 40
`the sixteen shades of the Vita™ shade guide. The storage
`medium 36 further stores any images collected by a user of
`the system 29.
`The storage of the digital color images of one or more
`shade guides is relatively straight-forward. In particular. 45
`FlG. 3 illustrates one shade guide 38 having sixteen separate
`tabs 40. Each of the tabs 40 is removable from the guide 38
`so that it can be ported and viewed next to the patient's teeth.
`FlG. 3A illustrates one tab 40 that is removed from the guide
`38. The tab holder 40a typically includes color information 50
`about the selected tab 40. here shown as shade "A2."
`In accord with the invention. each of the tabs 40 are
`illuminated by one or the handpieces 32a or 32b so that a
`color image is captured and stored in the medium 36. The
`image is accompanied by associated information about that
`shade. such as the manufacturer type. e.g .• the Vita shade
`guide, and the particular shade. e.g .. "A2." For example.
`FIG. 4 illustrates one storage block 42 of data for storage as
`digital memory and which is representative of one tooth
`shade. In particular. block 42a includes digital color image
`information. block 42b denotes the particular tooth shade.
`e.g. "A2." and block 42c denotes the manufacturer name, so
`that the associated tooth shade porcelain can be purchased
`from the correct manufacturer. Generally. the blocks 42b,
`42c of data are represented by digital words that specify the
`information, while block 42a includes image data corre(cid:173)
`sponding to both color and spatial information.
`
`6
`Preferably. the color image data within the block 42a is in
`a RGB format (i.e., Red. Green. Blue digital format. such as
`known to those skilled in the art) which specifies a color
`pixel within the image to an accuracy exceeding the number
`5 and color spread of the selected shade guides. For example,
`if sixteen shades are stored within the memory 36, then the
`bit-specificity required of the color-coded data within the
`image block 42a should span and discriminate at least those
`sixteen shades of white. For example. if each color of the
`10 RGB is specified at 3-bits each. then 256 standard colors are
`discernible by the system 29 to cover sixteen tooth shades.
`Greater color determination accuracy is achieved with
`increased color-coding. In addition. if all the manufacturers
`of tooth shades are loaded into the memory 36. then even
`15 more color-coded accuracy is required. e.g .. 8-bit per RGB
`color.
`The display of the color imagery within the digital data
`block 42a is known to those skilled in the art. Specifically,
`the RGB information within the data block 42a specifies the
`20 color for each pixel on the monitor 44. FIG. 2, which is
`similar in capability to the monitor 22 of FIG. 1. The
`particular video driver (not shown) used to drive the monitor
`44 specifies and controls the color and image display as
`appropriate. The RGB format specifies a color correspond-
`25 ing to signals which produce a suitable color picture on the
`monitor having the reference colors defined by the RGB
`chromaticities.
`Once the plurality of shades are loaded into memory 36.
`the system 29 is ready for use. FIG. 5 illustrates this process
`in more detail. A user illuminates the desired tooth 50,
`(illustratively shown outside of the patient's mouth) with the
`handpiece 32a such that an image 52 of the tooth 50 is
`displayed on the monitor 44. Although this step of forming
`an image on the screen 44 is not required. it helps to assess
`the accuracy to which the camera 30 captured the image 52.
`As above, this image data 52 is stored into a block such
`as block 42, FIG. 4. The shade analyzer subsystem then
`compares the digital information within the block of data
`representing the image 52 with the blocks of data represen(cid:173)
`tative of the several tooth shades. In one embodiment. a
`comparison of the RGB values is made between the tooth
`image data 52 and the several shades to find a best fit or
`match.
`It is important to note that this process has several
`advantages over the prior art. In particular, as long as the
`same camera 30 captures the data of the tooth shades and the
`patient's tooth shade data. it does not matter that the stored
`image color within the processor 34 match the perceived
`color or hue observed by a typical human. That is. as long
`as the data captured by the system 29 correlates to the same
`reference, e.g .• the same camera 30. the match between the
`image 52 and the plurality of tooth shades will be calibrated
`automatically. This is in contrast to many of the prior art
`55 references. e.g., U.S. Pat. No. 5.383.020. which requires a
`sensitivity maxima of the human eye. The invention has no
`corresponding limitation because the camera of the system
`29 objectively gathers the data from the same internal
`source. Nevertheless. it is preferable that the color display
`60 and coding of the camera 30 correspond to natural and
`perceived colors so that the image appears normal to a
`viewer.
`Those skilled in the art should appreciate that the data
`from the plurality of tooth shades can also be loaded from a
`65 floppy disk into the subsystem 34. More particularly. the
`tooth shade data from the one or more manufacturers can be
`installed directly into the system 29 without physically
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`7
`capturing the image of each tooth shade. provided that the
`data is captured by a camera that is similar to the camera 30,
`or by a camera that is calibrated to within an acceptable
`margin to the camera 30. In this manner, a user of the system
`29. e.g .• a dentist, need never have actual tooth shade tabs at
`the office. Rather, the system 29 is used to capture color data
`on the patient's tooth; and the stored tooth shade information
`within the system 29 is automatically extracted. including a
`manufacturer identifier.
`It is worth noting that not all tooth shade information is
`readily derived from the patient. In particular. unlike the
`tooth shades from the shade guides, which are very uniform
`in color. a patient's tooth can include a myriad of different
`shades. Tooth stains and the like alter the tooth's color
`spatially. so that a selection or integration of color is
`preferred. FIG. 6 illustrates one embodiment of the inven(cid:173)
`tion for dealing with this non-uniformity.
`Specifically. FIG. 6 shows a tooth image 60 of a patient's
`tooth on the monitor 44. Each pixel 62. which is grossly
`over-sized for illustrative purposes. corresponds to a differ- 20
`ent spatial location and color of the tooth's image 60.
`Accordingly. a user of the system 29 can select one of the
`pixels at the desired color by pointing and clicking a mouse
`pointer 64. via the mouse 66, at any selected location (the
`details of the mouse and mouse pointer are widely known to 25
`those skilled in the art without further reference hereto. and
`are shown for illustrative purposes only). This selected
`information is then stored with the block of data. e.g .. block
`42b of FIG. 4.
`Alternatively. the image of the tooth 60 can be averaged
`over a selected area by selecting a particular region for
`which the color imagery is averaged. For example. if the
`tooth 60 is to be averaged over the two pixels identified by
`the outline 68. then the subsystem 29 averages the two RGB
`values and specifies the tooth shade match in block 42b as
`an average of the two.
`FIG. 7 illustrates another monitor 44' and subsystem 34'
`constructed according to the invention, each of which is
`similar to the monitor 44 and subsystem 34 of FIG. 2.
`respectively. In the illustrated embodiment. an image 70 of
`a patient's tooth is matched to the appropriate shade. as
`above. and then an image 72 of the matched shade is also
`displayed on the monitor 44'. The subsystem 34' further
`generates and displays the tooth shade identifying match.
`e.g .. "A2," on the screen 44' so that the ordering information
`about the tooth reconstruction is easily ascertained. In the
`illustrated embodiment, a visual comparison between the
`tooth and the selected shade is made available to both the
`dentist and the patient. The display 44' can also display the 50
`particular porcelain product information.
`It should be apparent to those skilled in the art that the
`data and information displayed on the monitor 44' can also
`be downloaded to a printer 76, so that a permanent record of
`the exam is obtained in hard-copy fonn.
`In the event that the system 29 of FIG. 2 does not find a
`close match to one existing tooth shade. the subsystem 34
`specifies a combination of tooth shades that correspond to
`the color of the patient's tooth image data. e.g .• the image 52
`of FIG. 5. Preferably. this information is determined in 60
`fractions of the appropriate shade. e.g.. ½ "A2" and ½
`"C4."Such fractions are determinable. according to one
`embodiment of the invention. by comparing the RGB data
`within the plurality of tooth shade blocks 42b with the actual
`patient's tooth shade image information. If the RGB data of 65
`the patient's tooth is equal to the chromaticity sum of ½
`"A2" and ½ "C4." then such a fraction is entered into the
`
`8
`match data block 41.b for the selected tooth shade, and
`displayed on the screen 44 for the user. The chromaticity
`mathematics used to combine and subtract colors is known
`to those skilled in the art. Further detail may be found with
`5 reference to ''Television Engineering Handbook," edited by
`K. Blair Benson, McGraw-Hill (1986), which is incorpo(cid:173)
`rated herein by reference.
`The patient's tooth shade information is typically com(cid:173)
`municated to a laboratory which manufactures the recon-
`10 structed tooth via a plurality of porcelain coatings. This
`process of constructing porcelain layers onto a tooth model
`is known in the art; although the specification of the differing
`porcelain layers by data generated by an intraoral camera is
`specific to the invention. In the event that certain fractions
`15 of different porcelain layers are needed, such as described
`above. the system of the invention again provides and
`generates the appropriate shade fractions corresponding to
`the multiple layers.
`Other color theory details. including the adding and
`subtracting of multiple colors. may be found with reference
`to the following patents, each of which is expressly incor(cid:173)
`porated herein by reference: U.S. Pat. No. 5.383.020.
`entitled "Method and apparatus for determining the color of
`a translucent object such as a tooth;" WO 86/0