Abstract:
An intra-oral camera for producing an axially aligned picture of an intra-oral item of interest permits a rapid taking of pictures, whereby burdensome usage requirements are avoided without, however, suffering any diminishment in the quality of the picture that is taken. A computer-controlled picture taking positioning of the intra-oral camera properly positions the camera for taking pictures of objects of interest. The proper picture taking position of the camera ensures that the picture of an intra-oral object or an area of interest such as, for example, a tooth of a patient, is taken in the desired size, at the desired angle, and at the desired location.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims foreign priority benefits under 35 U.S.C. §119 from German patent application Ser. No. 103 52 394.4 filed Nov. 10, 2003.  
       TECHNICAL FIELD  
       [0002]     The present invention relates to an intra-oral camera as well as a method for using such an intra-oral camera.  
       BACKGROUND OF THE INVENTION  
       [0003]     The use of intra-oral video and/or picture taking-systems (hereinafter designated as an “intra-oral camera system” and as a camera device), has strongly increased over the recent years in the area of use of dental medicine. Such systems are deployed in a variety of settings as well as in situations in which a dentist desires to point out and display certain features of a patient&#39;s mouth. These intra-oral camera systems are more and more frequently the passport to complex diagnostic and treatment planning. With respect to such systems, it has been shown that approximately 30% of the practicing dentists between ages 35 and 54 own intra-oral camera systems and use such. It is expected that this percentage will increase as confidence is gained in the use of such systems, according to Dental Procedures Report, pages 22 to 24, February 1995.  
         [0004]     Intra-oral camera systems are often deployed in connection with dental restoration efforts. Many people opt nowadays for clinical intervention to improve, via restorative processes, their smiles and appearance. In most such processes, modification of the form or shape of the tooth, the position of the tooth, and/or the color of the tooth are involved.  
         [0005]     A necessary step in connection with the modification of the color of a tooth of a patient is the determination of the color shade of the respective tooth. In this connection, for example, the color of the teeth of those patients who are interested in a whiter, beaming smile are evaluated so that a comparison between the appearance of the teeth prior to the restorative treatment and the appearance of the teeth after the restorative treatment can be undertaken. The determination of the color shade is even more important for those persons who require replacement teeth; it is the goal of such restoration processes to achieve a natural appearance of the replacement teeth. For this reason, it is important to properly identify the color shade of the respective tooth so that the new restoration piece can be approximated to the original tooth or teeth.  
         [0006]     Typically, a picture of a tooth is taken and a color shade analysis system is used in order to receive suitable information concerning the color shade and the tooth form. The users of such systems often find it difficult to properly orient the intra-oral camera. A correct axial orientation and proper picture taking alignment is, however, of significant importance for enabling the use of analysis software which then processes the picture of the tooth to determine the color shade of the respective tooth.  
         [0007]     The size of the region of interest, the size of the camera, the intra-oral location of the area of interest, and, as well, other factors, render difficult the relevant analysis, as such factors influence the two-dimensional picture that is taken. In this connection, it may occur that less than desirable pictures are taken, such as pictures in which a to-be highlighted area of the respective tooth has been cut out or pictures of teeth that are not of interest.  
         [0008]     A further disadvantage of such systems, which involve picture taking via a hand-held camera, is that even relatively small hand movements (such as, for example, the movement of a finger to press the shutter actuator) can cause a considerable deviation of the camera from its proper picture taking orientation.  
         [0009]     Frequently, the taking of a satisfactory picture of an intra-oral item of interest requires, in connection with such known conventional systems, repeated attempts and/or the burdensome deployment of various devices.  
       OBJECTS AND SUMMARY OF THE INVENTION  
       [0010]     The present invention offers a solution to the challenge of providing an intra-oral camera as well as a method of using such an intra-oral camera for producing an axially aligned picture of an intra-oral item of interest which permits a rapid taking of pictures, whereby burdensome usage requirements are avoided without, however, suffering any diminishment in the quality of the picture that is taken.  
         [0011]     In accordance with the present invention, a computer controlled picture taking positioning of the intra-oral camera properly positions the camera for taking pictures of objects of interest. The proper picture taking position of the camera ensures that the picture of an intra-oral object or an area of interest such as, for example, a tooth of a patient, is taken in the desired size, at the desired angle, and at the desired location. Drawing upon experience, one can set or adjust beforehand all relevant picture taking parameters so that an error-causing hand movement is foreclosed. The devices for setting the proper picture taking position can use a light source emitting a substantially pinpoint light which is oriented toward the respective object of interest that just then, at that instance, is viewable via the viewfinder of the camera or that is oriented toward the camera. In connection with pinpoint light sources, a laser diode or another light source can be deployed which produces a point of light or a limited light beam region. The pinpoint light source can also be integrated into the camera.  
         [0012]     In connection with pinpoint-type light sources, it is to be understood that this concept does not relate to the form of the light source itself but, rather, to the type of light emitted by the light source and directed as a light beam onto an area to be illuminated. This light beam is preferably a pinpoint light beam—that is, the light beam is substantially annular—whereupon a light beam of this type can also be characterized as a point of light or as a light patch.  
         [0013]     The light emitted from a pinpoint light source, which is, in turn, reflected by an object of interest, is evaluated, in accordance with the present invention, so as to verify whether a camera is directly oriented toward a respective location a picture of which is desired. A selectively cropped camera frame portion is used to evaluate the orientation of the camera. The selectively cropped camera frame portion can be selected such that it is suitable in shape and size relative to the respective point of light that is produced by the irradiation of the relevant object or area of interest by the pinpoint light source. The distance between the camera and its target is preferably a predetermined distance or spacing which can be set or adjusted via the use of a short standoff tube or a standoff retainer.  
         [0014]     In accordance with one embodiment of the present invention, the user can be provided with information which specifies the distances at which the pictures should be taken.  
         [0015]     In accordance with the present invention, it is provided that a geometric pattern such as a grating, raster points, an intensity distribution or the like—that is, a two-dimensional reference system—is imposed or overlaid on the picture in order to determine the size of the angle deviation in connection with the orientation of the camera and, at the same time, to provide information for undertaking a correction of the angle deviation. The correction can be effected via a corresponding signal to effect “trimming” in the relevant direction. It is also possible to emit an optical or acoustic signal that indicates that the camera is now exactly aligned or on target.  
         [0016]     In an embodiment of the present invention, it is provided that actuation of the shutter actuator for the camera can only be undertaken if a picture target alignment has been performed. It is also possible to use the picture target alignment as a type of trigger signal for actuation of the camera so that the taking of the picture upon pressing of the camera shutter actuator can only be effected if the picture target alignment has been performed.  
         [0017]     With regard to the concept of a point of light, it is to be understood that this concept has reference to a limited lighted or illuminated region. Typically, a light patch created by light emitted from a pinpoint light source has an annular shape or configuration, wherein the highest intensity thereof is in the central portion of the light patch. A light region or light patch of this type is herein designated as a point of light.  
         [0018]     The selectively cropped camera frame portion, which is used for evaluating the camera orientation, is, in an advantageous embodiment of the present invention, used in connection with evaluating sub-areas into which the selectively cropped frame portion has been subdivided or partitioned, such sub-areas being herein designated as “subdivisions.” The content of the subdivisions (for example, their light properties) can be evaluated in order to verify whether the camera is substantially in proper picture taking alignment with respect to the respective area to be photographed. In this connection, two or more subdivisions are compared with one another. The subdivisions can, for example, be grating fields comprised of the previously noted gratings. It is also possible to establish a gradation of the intensity values of the light intensities among the subdivisions.  
         [0019]     The devices for setting the proper picture taking position can, for example, have targeting software associated therewith to generate an indication that the camera is substantially in proper picture taking alignment with the respective area to be photographed, wherein the confirmation of such alignment is based upon information concerning the light produced by the pinpoint light source. The indication can be an audible or visible indication. For example, a green light can illuminate in a designated area of a display of a camera to indicate a proper picture taking alignment. Correspondingly, a picture of the instantaneous camera view can be taken and automatically or manually stored. In the event that such is desired, a system of this type can be so configured to permit the user to chose an automatic picture taking mode in which the camera will take a picture automatically.  
         [0020]     In an advantageous embodiment of the present invention, the intra-oral camera is automated in order to deliver a fast, precise, and reliable picture of an intra-oral object of interest. A pinpoint light source such as, for example, a laser diode, serves to verify when a camera in an intra-oral camera system has assumed the desired position for the taking of a picture.  
         [0021]     The intra-oral camera system automatically takes the picture without requiring user intervention, provided that certain criteria are fulfilled. In this connection, the picture is subdivided into selectively cropped camera frame portions each of which is evaluated. The selectively cropped camera frame portions are of a form which is suitable for the point of light, produced by the pinpoint light source, that irradiates the object to be photographed. The selectively cropped camera frame portion is preferably subdivided into subdivisions which can be used for a comparison analysis, whereby the properly aligned orientation of the intra-oral camera can be verified.  
         [0022]     Further details, advantages, and features of the present invention are described in the hereinafter-following description of an embodiment of the present invention taken with reference to the figures of the drawings. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0023]      FIG. 1  is a functional block diagram of one embodiment of the intra-oral camera device of the present invention, whereby the camera device is hereinafter also referred to as a camera system;  
         [0024]      FIG. 2  is a functional block diagram of the intra-oral camera shown in  FIG. 1  associated with a personal computer (PC);  
         [0025]      FIG. 3  is a schematic side elevational view of the one embodiment of the intra-oral camera of the present invention shown in  FIGS. 1 and 2  and showing, in its position relative to a surface of a tooth, the picture taking alignment device for properly orienting the intra-oral camera in its operating position for orienting the intra-oral camera for taking a picture of the surface of the tooth;  
         [0026]      FIG. 4  is a schematic side elevational view of another embodiment of the intra-oral camera of the present invention, and showing, in their respective positions relative to a surface of a tooth, the picture taking alignment device for properly orienting the intra-oral camera in its operating position for orienting the intra-oral camera for taking a picture of the surface of the tooth and a picture sharpening adjustment device, both such devices being oriented toward the surface of the tooth;  
         [0027]      FIG. 5  is a flow diagram of the steps which a computer controlled picture taking alignment device for properly orienting the intra-oral camera performs to properly orient the intra-oral camera in accordance with the present invention;  
         [0028]      FIG. 6  is a flow diagram of the steps by which an evaluation of the proposed orientation of the intra-oral camera is performed by a respective embodiment of the present invention;  
         [0029]      FIG. 7  is a flow diagram of the steps by which an identification of a suitable selectively cropped camera frame portion is performed by a further embodiment of the present invention;  
         [0030]      FIG. 8  is an enlarged front plan view of a camera picture and showing a selectively cropped camera frame portion of such camera picture which is used in connection with evaluating a proposed orientation of the intra-oral camera in accordance with the present invention;  
         [0031]      FIG. 9  is a front elevational view of an embodiment of the camera system of the present invention having laser diodes for assisting in orienting the intra-oral camera;  
         [0032]      FIG. 10  is a top plan view of the embodiment of the camera system of the present invention shown in  FIG. 9 ; and  
         [0033]      FIG. 11  is a perspective view of the embodiment of the camera system of the present invention shown in  FIGS. 9 and 10  which further shows an inventive camera lens aperture configured with a short standoff tube. 
     
    
     DETAILED DESCRIPTION  
       [0034]      FIG. 1  shows a functional block diagram of an embodiment of the intra-oral camera system of the present invention.  FIG. 1  shows an intra-oral camera system  10  which is used for obtaining picture information of a tooth of a patient. The intra-oral camera system  10  can be deployed, in particular, to produce metrics concerning the color or shape properties of a tooth. In this connection, the respective color shade of a tooth to be observed can be characterized and other desired capturable information can also be obtained. In the illustrated embodiment, the intra-oral camera system  10  comprises a picture taking device  12 , a display device  14 , a memory  16 , a user interface  18 , a communications device  20 , a processing device  22 , and a device for setting the camera into a proper picture taking position  26 .  
         [0035]     The picture taking device  12  is a device for obtaining information concerning physical and/or color-related properties of a tooth of a patient. The picture taking device comprises a digital camera (for example, an intra-oral camera). Examples of suitable picture taking devices include the camera Power 0/00, which is manufactured by the Insight Company in San Carlos, Calif., and the Cygenascope brand camera manufactured by Cygnus Instruments, Inc. in Goleta, Calif. A further example of such a camera is the model VistaCam. Such cameras are the type of cameras which can be freely supported in the hand of a user. The cameras typically comprise a display, a storage component, software, and a port for communication with a personal computer. Such cameras are in the position to capture the light characteristics, the color, the color shade, the type of color, or, as well, the color saturation of the object of interest and to take a picture while taking into consideration such factors. The color can be classified in any suitable desired classification code such as, for example, classified in accordance with RGB, in accordance with L*, a*, b*, or in another suitable desired classified manner.  
         [0036]     In another embodiment of the present invention, it is provided that additional properties of the picture or, as well, of the selectively cropped camera frame portions, are captured such as, for example, the focus parameter or the like. Typically, the picture taking device  12  comprises an integrated display such as, for example, an LCD display on the backside of the digital camera.  
         [0037]     A user of the intra-oral camera can see a picture of a tooth of a patient via the display device  14 . Also, certain software analysis functions can be deployed to provide, for example, color shade analysis. Such captured parameters can, as well, be displayed on the display device. It is provided, in accordance with the present invention, that what is shown in the display device  14  is that which can be seen at that instance in the viewfinder of the camera—that is, that which would be captured in a picture taken by the camera at that instant. In lieu of the digital LCD display of a camera, a computer monitor can also be used which is coupled with a camera such that display information can be transmitted to the computer monitor.  
         [0038]     The storage component  16  of the present invention stores, typically, the picture and, additionally, certain picture parameters. For example, color shade information such as, for example, certain color properties of tooth color shades, in accordance with a suitable color shade scheme table, are stored. Additionally, the storage element  16  serves as a buffer. The storage element  16  can be a semiconductor storage or a fixed plate or another suitable storage element such as, for example, a storage element in a computer. It is also possible, apart from the storage of a picture, to use a separate storage element, whereby it is possible to accomplish such storage via media such as a CD or a DVD.  
         [0039]     Conventional elements can be deployed to serve as the user interface  18 . In this connection, a keyboard, a mouse, a voice recognition system, and the like can be deployed. The user interface  18  permits a user to manipulate the picture taking device  12  in a suitable manner to thereby, for example, take a picture, to select a picture to be deleted, to determine the respective tooth a picture of which is to be taken, or the like.  
         [0040]     The processing device  22  is typically a microprocessor or a microcomputer whose software operates for analyzing and identifying teeth color shades and which is available to provide the necessary functions for the taking of a picture. The required elements capable of performing such functions are conventionally available as circuits or, as well, as software. For example, a computer such as a personal computer (PC) can be provided to operate as the processing device  12 , whereby it is to be understood that it is also possible to use elements which are conventionally comprised in a personal computer such as storage elements, displays, user interfaces, and communication devices as well as transmission devices to at least partially fulfill the operations of the display device  14 , the user interface  18 , the storage element  16 , the communication device  20 , and the output device  24 . Separate processors or, as well, combinations of various processors, which are, in part, integrated into the camera and, in part, integrated into the personal computer, can be deployed.  
         [0041]     In accordance with the present invention, a device for setting the camera into a proper picture taking position  26  is provided. The device for setting the camera into a proper picture taking position  26  supports the user with respect to the orientation of the picture taking device  22 . Several components in the system  10  can be provided in this connection. Such components may comprise a pinpoint light source such as, for example, a laser diode, or a sharp focused light diode. Additionally, the hardware and the software which evaluate the picture information of the light patch produced by the irradiation of the area of interest by the pinpoint light source can also be considered.  
         [0042]     The intra-oral camera  10  can be a component of a device for performing a color shade analysis. Such color shade analysis devices are described, for example, in U.S. Pat. No. 6,305,933 B1 and in WO 00/25696, whereby both of these references are fully incorporated by reference herein. It is preferred that a short tube for protection against false light is provided so that the picture that is taken is not contaminated by such false light. A tube of this type is shown, for example, in U.S. Pat. No. 6,210,159 which is hereby fully incorporated by reference herein.  
         [0043]     An example of an intra-oral camera can be seen in  FIG. 2 , whereby, at the same time, the connection with a PC is illustrated. In connection with the intra-oral camera  30 , it can be seen that the target alignment is completed and a picture of the tooth of a patient can be taken. An intra-oral camera comprises a PC  32  and a combination alignment setting and picture taking device  34 . In a conventional manner, the PC  32  is communicated with a computer monitor  36  which operates as a display device. The combination alignment setting and picture taking device  34  captures the color and shape information relating to the tooth of a patient. The computer monitor  36  displays the picture which the picture taking device has just captured—that is, the picture of the object of interest which can be seen at that instant through the viewfinder of the camera. Depending upon the respective adjustment setting, a stored picture can be displayed as well on the monitor. At the same time, an analysis of the picture can be undertaken via the PC  32  and/or via the hardware of the combination alignment setting and picture taking device  34 .  
         [0044]     Analyses can be performed in order to determine whether the combination alignment setting and picture taking device  34  is properly aimed toward the object of interest. As desired, other functions can be performed as well such as, for example, an identification of the color shade with reference to a color shade reference table. In accordance with the present invention, the combination alignment setting and picture taking device  34  includes, for supporting the user&#39;s picture taking task, a picture taking alignment device for properly orienting the intra-oral camera in its operating position. In this regard, the picture taking alignment device for properly orienting the intra-oral camera in its operating position assures that the combination alignment setting and picture taking device  34  is properly aimed.  
         [0045]      FIGS. 3 and 4  schematically illustrate suitable picture taking and aiming devices. Typically, the correct aiming alignment is dependent upon the angle at which the camera is aimed toward the object a picture of which is to taken. In accordance with the present invention, the actual camera angle is analyzed in order to determine whether the relevant angle is correct or not. In  FIGS. 3 and 4 , cameras  44  are each aimed at a respective surface  46 . The tooth surface  46  is typically convex, whereby, solely for the purposes of facilitating the description thereof herein, the proportions thereof are shown in an exaggerated manner. An incisor tooth comprises, for example, in its middle region, a planar but, nonetheless, structural surface that curves toward the side flanks—that is, the surface curves in the mesial or distal directions. In the event of an aiming error, a camera would record various color shades of the object of interest so that the restoration result based upon such color shades would not faithfully duplicate the respective dental structure comprising the object of interest. In order to prevent this occurrence, it is provided, in connection with the present invention, that the device for setting the camera into a proper picture taking position  26  ( FIG. 1 ) is deployed.  
         [0046]     In this connection, as seen in  FIGS. 3 and 4 , the pinpoint light source  48  is aimed toward the tooth surface  46 . The pinpoint light source  48  is mounted, in the illustrated embodiment, on the camera  44  and, in fact, is so mounted that it is closely adjacent the optical axis  49  but is, however, spaced therefrom.  
         [0047]     The light source  48  is mounted on the camera at a slight angle of, for example, 1 through 10° relative to the optical axis  49 . To compensate for this divergence, the orientation is selected such that, at a given or predetermined spacing between the camera  44  and the tooth surface  46 , the optical axis  49  and the light point produced via the light source  48  coincide at an intersection point. It is to be understood that, in this connection, a spacing determination is effected as well which, at the same time, facilitates the focusing of the picture taking device  12  in the camera  44 .  
         [0048]     In order to, as well, make visually clear for a user, such as, for example, a dentist, the focus operation of this type and, therefore, the establishment of the spacing, it is provided, as can be seen in  FIG. 4 , that two light sources  48  and  50  are operated together. The light points of both light sources  48  and  50  coincide upon achieving the proper spacing selection, in connection with which the optical axis  49  contemporaneously intersects the double light points and, preferably, intersects the double light points centrally thereof.  
         [0049]     It is also possible to use a short tube or another suitable distance retainer which thereafter maintains the spacing following the initial setting thereof. Also, it is possible to undertake a measurement of the lightness via the camera  44 , whereupon such a measurement measures the lightness of the produced light point and indicates, upon measuring a maximum lightness value, that the aiming orientation is being performed.  
         [0050]      FIG. 4  illustrates that both light sources  48  and  50  are arranged at the same angle relative to the camera, with the respective angles being mirror-symmetrical to one another. It is to be understood that, in lieu of this, any other suitable desired number of suitable light sources can be arranged in a distribution pattern around the camera such as, for example, an annular distribution.  
         [0051]      FIG. 5  shows a schematic view in the form of a flow diagram which displays the inventive steps of the method of the present invention. In accordance with the function block  62 , a camera is aimed toward the tooth of a patient in order to take a picture of the tooth. In accordance with step  64 , the sight information is transmitted which pertains to the view that could at that instance be captured by the camera. According to step  66 , a pinpoint light source such as, for example, a laser diode, is aimed toward the tooth of the patient and the light source is, for example, the integrated light source  48  or  50  illustrated in  FIGS. 3 and 4 . It is to be understood that, in lieu of such an arrangement, the basic principle can also be implemented by an external light source directed toward the tooth of the patient.  
         [0052]     In accordance with step  68 , a picture taking alignment device for properly orienting the intra-oral camera in its operating position  26  is provided if the camera is to be substantially properly aimed.  
         [0053]     As can be seen in step  70  illustrated in  FIG. 5 , a display is provided indicating whether the camera has been properly aimed or not. In this regard, an audible or visual display device can be provided, for example, which indicates to the user that the camera is properly aimed. As is illustrated in step  72  of the flow diagram, a picture of the tooth of the patient is taken, for example, automatically, if the step illustrated in step  70  has shown that a predetermined interval has passed during which the indicator indicating the camera has been properly aimed has been actuated.  
         [0054]     Of these steps, the steps  62  and  66  are typically performed by the user, while the steps  64 ,  68 ,  70 , and  72  are, in the preferred embodiment of the invention, automatically performed—that is, are computer-controlled steps.  
         [0055]     The aiming is preferably performed such that a limited selectively cropped camera frame portion of the captured picture is evaluated. This is shown in individual detail in  FIG. 6 . In step  82 , it is determined that the picture taking device is aimed at a predetermined object of interest—that is, typically, aimed at the tooth a picture of which is to be taken. The picture information is then captured—and retained in step  84 , whereby a predetermined or preselected selectively cropped camera frame portion is established which illustrates a small portion of the entire picture. The surface of the respective selectively cropped camera frame portion can comprise, for example, less than 10% and, in particular, less than 1%, of the entire picture.  
         [0056]     The size of the selectively cropped camera frame portion is dependent upon the light patch and its size and configuration, that is, the light patch being produced by the light sources  48  and  50  on the tooth. In accordance with the present invention, it is, in any event, provided that the selectively cropped camera frame portion captures the entire light patch.  
         [0057]     In an advantageous embodiment of the present invention, the selectively cropped camera frame portion is now partitioned into subdivisions which are explained in more detail with reference to  FIG. 7 .  
         [0058]     In lieu of the decidedly cost favorable laser diode, it is also possible to deploy a laser which can produce a sharply limited light patch or light point. A laser is, however, substantially more expensive and brings with it only a certain limited value so that the cost favorable light sources are, in contrast, preferable.  
         [0059]     As is clearly indicated in step  86 , the picture information of the selectively cropped camera frame portion is evaluated in order to determine whether the camera is properly aimed at the object of interest. For example, picture information relating to the color, the shape, and the lightness of the light point produced by the pinpoint light source can be evaluated in order to determine if proper aiming has been accomplished.  
         [0060]     In the steps illustrated in  FIG. 6 , the steps  84  and  86  are typically steps which are performed by the computer, while step  82  is performed by the user.  
         [0061]      FIG. 7  illustrates the manner in which the picture information is evaluated. In an advantageous embodiment, a grating of 3×3 grating fields is produced, as is also illustrated in  FIG. 8 . In that there is a selection [step  92 ] of a predetermined selectively cropped camera frame portion for the analysis, the selectively cropped camera frame portion is then, in step  94 , partitioned into subdivisions. The partitioning can be automatically performed at this step but, however, as the occasion arises, can also be performed by the user via a justification operation. Preferably, each subdivision contains the same number of pixels such as, for example, 20 pixels, whereby it is to be understood that any suitable desired subdivision arrangement can be set up.  
         [0062]     In accordance with step  96 , the picture information of the subdivisions is now captured. In this connection, the light parameter of each subdivision is captured, this information then being compared, in step  98 , to that of the other subdivisions. According to step  100 , it is then determined whether one of these subdivisions is the desired selectively cropped camera frame portion which displays the middle of the tooth.  
         [0063]     Also, if the inventive method is deployed with respect to capturing a picture of a complete tooth, it is to be understood, that, in lieu of this, a portion of a tooth can be captured as well and a corresponding evaluation of such can be undertaken.  
         [0064]     To evaluate and identify the subdivisions, a comparison can be performed on, for example, the lightness properties of two subdivisions disposed opposite one another. The orientation is then determined as the middle orientation if the lightness values of these opposed two subdivisions agree with one another. This serves to provide the orientation evaluation function, then, so long as the light patch produced by the light sources  48  and  50  exhibits a symmetrical lightness distribution such as, for example, a distribution in accordance with a Gaussian curve.  
         [0065]     It is also possible to compare the absolute lightness value of the central subdivision with the lightness value of a relatively more remote subdivision. In a suitable different manner, the symmetry of the lightness can be evaluated, whereby, as well, information can also be captured to determine whether the horizontal-lateral and the vertical lateral subdivisions are each comprised of the same lightness.  
         [0066]      FIG. 8  schematically illustrates the manner in which a camera view  102 , which comprises a picture of a tooth  104 , can be evaluated. Light from a pinpoint light source can be directed onto the tooth  104  in order to produce a light point  106  on the tooth  104 . The raster [portion  108 ], is a selectively cropped camera frame portion which is selected to evaluate the light properties of the light produced on the tooth  104  by the irradiation thereof by the pinpoint light source.  
         [0067]     As can be seen in the lower portion of  FIG. 8 , an enlargement of the selectively cropped camera frame portion  108  and of the light point  106  is illustrated. The raster [selectively cropped camera frame portion  108 ] is, in accordance with the present invention, subdivided into a plurality of fields [subdivisions  109 ]. This selectively cropped camera frame portion can be comprised of a configuration and size which is selected such that they are suitable for the typical form and size of the light point  106 . An exact aiming is then achieved if the light point of the light source is located in the central field of the raster [selectively cropped camera frame portion  108 ]. It is to be understood, that typical camera spacings can be deployed and the size of the thus produced light point can be empirically transmitted. Examples of intra-oral camera systems are described in German Patent Publications P 101 20 717.4 and P 101 26 887.4, both of these references being fully incorporated by reference herein.  
         [0068]      FIGS. 9-11  illustrate a camera  200  in accordance with the present invention. Each pinpoint light source  206  is, in this embodiment, configured via five laser diodes  204  arranged serially adjacent one another in a row, these laser diodes being laterally to the side of the objective or lens  202  of the camera. It is to be understood, that in lieu of this arrangement, an individual laser diode  204  can be deployed.  FIG. 11  shows, additionally, a short standoff tube with a ring  208  that is configured for disposition on the patient or the tooth of the patient and which sets the spacing between the camera and the tooth. It is to be understood that a standoff ring of this type is not strictly required.  
         [0069]     The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.  
         [0070]     While a preferred form of this invention has been described above and shown in the accompanying drawings, it should be understood that applicant does not intend to be limited to the particular details described above and illustrated in the accompanying drawings, but intends to be limited only to the scope of the invention as defined by the following claims. In this regard, the term “means for” as used in the claims is intended to include not only the designs illustrated in the drawings of this application and the equivalent designs discussed in the text, but it is also intended to cover other equivalents now known to those skilled in the art, or those equivalents which may become known to those skilled in the art in the future.