Intraoral camera device and method to produce an aligned image of an intraoral object, preferably of a patient tooth

The present invention relates to an intra-oral camera according to the preamble of claim 1 and a The method according to the preamble of claim 12th

The use of intraoral video and / or image recording systems (Hereinafter referred to as "intra-oral camera system" and as a camera device called), has in the field of dentistry over the past few years greatly increased. Such systems be used in a variety of environments, even in Situations where the dentist certain features of wants the patient's mouth to show and illustrate. This intraoral Camera systems are increasingly the key to complex diagnostic and treatment planning. Research has shown that approximately 30% of practicing dentists in the age group 35-54 years intraoral camera systems possess and use. It is anticipated that this Percentage with increasing familiarity with such systems will rise, as, from the Dental Procedures Report Page 22 to 24, in February 1995, is ersichlich.

Intraoral camera systems are often in dental restoration procedures used. Many people now opt for clinical interventions to their smiles and their appearance revalue by restorative procedures. Both Most of these methods is the change in the tooth form, the Tooth position and / or the color of the tooth involved.

A necessary step in changing the color of a The tooth of a patient is to determine the "hue" or "Shade" of this tooth. For this example, the Tooth color of the existing teeth of persons according to one whiter, brighter smile strive rated so a comparison between before and after are carried out can. The color identification is even more important for people, need dentures; it is an object of such restoration process, to attain a natural appearance. For this reason, it is important that the color tone of the existing Knowing the tooth, so that the new restoration exactly can be aligned with him.

Typically, an image of a tooth is taken and in Color analysis systems used to appropriate information get over color and form. Operator of such system often find it difficult to align the intraoral camera correctly. A proper axial alignment and goal setting However, is very important for a software analysis, then is performed for the image to the color or "shade" the existing Chewy capture.

The size of the region of interest, the camera size intraoral location of the region of interest, as well as other Factors make the accurate analysis because it dimensional the affect recording. This can also take pictures arise in which a section of the respective tooth is cut off, or images that are not of interest to the Teeth are matched.

Another disadvantage with systems that in the hand-held use cameras, lies in the fact that even minor Hand movements (eg moving finger while pressing the shutter) significant changes in the targeting the camera can cause.

Frequently, therefore, requires the inclusion of a satisfactory Image-of-interest intraoral article at the Using the known systems, repeated attempts and / or a cumbersome operation of various facilities.

The invention is therefore based on the object, an intraoral Kamer device according to the preamble of claim 1 and a method for generating an axially oriented Image of an intra-oral object according to the preamble creating of claim 12, the rapid uptake allow, a cumbersome operation is avoided to be without the image quality suffers.

This object is achieved according to the claims 1 and 12 dissolved. Advantageous developments emerge from the Subclaims.

According to the invention provides an intraoral camera, a computer-aided Goal setting for capturing images of intraoral ready objects. ensured The target setting that the image of an intraoral object or a region, for example, a patients teeth, in the desired size, in desired angle and added to the desired position becomes. Experience shows that all relevant imaging parameters previously fixed and set so that a mishandling is excluded. The target setting means can use a substantially punctiform light source, which is directed to the object of interest, the is aligned precisely targeted by the camera or to this. In the point-shaped light source may be a laser diode act or other light source, the light spot a produced or limited light area. The punctate Light source can also be integrated in the camera.

Under punctiform Lichquelle was not here in the form of even understood light source, but the nature of the Light source emitted and an illumination area impinging radiation. This is preferably punctiform ie substantially circular so that they as can be designated spot or as a light spot.

From the point light source emitted light of an object of interest is reflected, according to the invention evaluated to determine if a camera just is directed to a location from which the desired image to be recorded. To evaluate an image cutout the camera used. The image can be selected be that he adapted in shape and size of the light spot is ON from the point light source when hitting a related object or area intessierenden is produced. The distance between the camera and its target is preferably be a fixed distance by the Use of a short spacer sleeve or a spacer is determined.

In a modified embodiment, the operator may be supplied with information which determine in which Distance the images to be recorded.

According to the invention it is provided that a geometric pattern like a grid, grid points, an intensity distribution or the like, so a two-dimensional reference system, is laid over the image to the size of the angular deviation to determine the alignment of the camera and at the same time notes to provide for the correction. The correction can be achieved by corresponding signaling "Swivel" in the relevant Direction can be realized. It is also possible to provide an optical dispense or audible signal indicating that the Camera is now target exactly aligned.

In a modified embodiment, it is provided that the only then release the trigger for the camera when the targeting is made. It is also possible for the target orientation as a kind of trigger signal for triggering to use, so that when pressure of the release button, the image pickup is only realized when the targeting given is.

Under light point to be understood here a limited light area. Typically, one of a point-like light source emitted light spot on a circular shape, the center has the highest intensity. Such a light area or light spot is referred to herein as a light spot.

The picture of a camera, for evaluating the Orientation is used, in an advantageous embodiment for use in the evaluation in subdivisions. Of the Content of subdivisions (eg their light properties) can be evaluated to determine whether the camera is substantially is target set. For this purpose, two or more Subsections compared. The subdivisions For example, grating fields of the aforementioned be grating. It is also possible, of intensity gradations the light intensity for the implementation of sub-clips make.

Target setting means, such as a goal setting software can be used to indicate when the camera is targeted essentially set, based on Light information from the point-shaped light source of the generated light. There may an audible or visible sign to be provided. For example, a certain Detail of a display of a camera showing a green light, a proper alignment display. In response, can capture an image of the instantaneous camera view and be stored automatically or manually. If so desired, is, the system may be configured so that the Operator is allowed to make a selection, a automatic image acquisition to enable.

In an advantageous embodiment of the invention, the intraoral Camera automated to a fast, accurate and reliable to provide image recording an intra-oral object. A point light source such as a laser diode, serves to determine when an intraoral camera in a Camera system to the desired position for recording an image has been reached.

The intraoral camera system captures the image automatically, without any involvement of an operator is required if certain criteria are met. To this end, the image is in Image sections divided, which are each rated. The image sections have a shape that for the point-like by the Light source generated light spot on the intraoral Object appears, is suitable. The cut is preferred divided into sub-sections which for comparative analysis can be used, thereby setting the target intraoral camera is detected.

Further details, advantages and features of the invention from the following detailed description of embodiments of the invention with reference to the accompanying Drawings, in which like reference numerals refer to like Components point.

Show it:<dl tsize="14"><dt>Fig. 1</dt><dd>a functional block diagram of an inventive Embodiment of an intra-oral camera, wherein the camera device referred to as Kameraystem referred to as;</dd><dt>FIG. 2</dt><dd>a functional block diagram of the intra-oral camera shown in Figure 1 with a PC.</dd><dt>Fig. 3</dt><dd>is a schematic side view of an embodiment an intraoral camera device according to the invention, showing the image capture and target setting means, on the surface of a tooth are directed, according to the embodiment of FIG. 1 and 2;</dd><dt>Fig. 4</dt><dd>a schematic side view of another Ausfühform an intraoral camera device according to the invention, where image acquisition, and Zieleinstellungs- Focus means that on the surface are directed of a tooth are shown.</dd><dt>Fig. 5</dt><dd>a flowchart of the steps performed in a computerized Goal setting can be made, according to the embodiment according to the invention;</dd><dt>Fig. 6</dt><dd>a flow chart of steps performed in an evaluation the targeting of a camera to be made, according to an embodiment of the invention;</dd><dt>Fig. 7</dt><dd>a flow diagram of the steps involved in an identification To crop an image to be made, according to a further embodiment of the invention;</dd><dt>Fig. 8</dt><dd>a view of a camera image and a detail, used in the target setting of the camera, according to an embodiment of the invention;</dd><dt>Figs. 9 and 10</dt><dd>different perspective views of the camera with laser diodes for the target setting of the camera according to an embodiment of the invention; and</dd><dt>Fig. 11</dt><dd>a view of the shown in Figs. 9 and 10 shown camera, further comprising a camera aperture invention than short distance tube.</dd></dl>

Fig. 1 shows a functional block diagram of a first embodiment an intra-oral camera system. Fig. 1 shows a intraoral camera system 10 for obtaining image information of a patient's tooth is used. The camera system 10 may be used, in particular, values ​​for color or shape properties a tooth to produce. This allows the tooth shade depending viewed determine over the tooth, and it , any other observations to be made. In the Illustrated embodiment, the intraoral camera system 10 an image pickup device 12, a display device 14, a memory 16, a user interface 18, a Processing device 22 and a device for setting 26.

In the image pickup device 12 is a Means for obtaining information on physical and / or color characteristics of a patient's tooth. The Image recording device comprises a digital camera (for example, a intraoral camera) on. Examples of the image pickup means 12, the camera Power 0/00, the company of the Insight is manufactured in San Carlos, California, and the by the company Cygnus Instruments, Inc., Goleta, CA produced model Cygenascope. Another example is the Model VistaCam a. Such cameras are around free hand-held cameras. The cameras typically have a display, a memory, software, and a Interface for communication with a PC. Such Cameras are able to adjust the brightness, the color, hue, detecting the chromaticity or the color saturation and thereby capture an image. The color can be in any desired appropriate coding, for example, disaggregated by RGB, to L *, a *, b *, or in any other suitable manner, are recorded.

In a further embodiment, it is provided more properties the image or capture of the Image, For example, the focus parameters, or the like. Typically, the image pickup device 12 an integrated display such as an LCD display on the back of the digital camera.

With the display device 14, an operator an image of consider patient's tooth. certain software analysis functions also are used, for example, noise analysis. Such sensed parameters can also visit the Display device are recorded. It is according to the invention provided that the display device 14 in any case indicating which is currently targeted by the camera, so by the camera is detected. Instead of the digital LCD display a camera can also be a computer monitor are used, coupled to the camera so that the display information are supplied to the computer monitor.

The inventive memory 16 typically stores the Image and additionally certain image parameters from. For example can color-routing information, for example, specific color characteristics of tooth shades, according to an appropriate color scheme table, be saved. In addition, serves the Memory 16 as a buffer. It may be a semiconductor memory, or a hard drive or any other storage, for example, in a computer be. It is also possible, apart from the image memory, for example, in the image pickup device 12 to use a separate memory, wherein the storage on media such as a CD or is a DVD possible.

When user 18 can per se known elements be used. These include a keyboard, a mouse, a speech recognition system and the like. The user interface 18 allows the operator, on the image pickup means 12 act in a suitable manner, for example, take a picture, select the resolution of images, the define and like male tooth.

The processing device 22 is typically a microprocessor or a micro-computer, whose software analysis and identification of tooth shades is used, and with the provided required function for image acquisition becomes. It is known that the necessary elements for this purpose both by appropriate circuits and take appropriate Software can be provided. For example , a computer such as a PC for processing device 22 may be provided, which is of course also possible is that already in the PC provided elements, such as memory, Display, user interface and communication equipment and Output means, for the inventively provided Elements of the display device 14, the user interface 18, of the memory 16, the communication device 20 and the Receiving means 22 to use at least partially. It can separate processors or combinations of different Processors that partly in the camera and partly in the PC can be provided, can be used.

According to the alignment means or device for setting 26 provided. The target setting means 26 assists the operator in the alignment the image pickup device 22. For this purpose, a plurality of components be provided in the system 10th For example This includes a point light source, for example a Laser diode, or a sharply focused light emitting diode. To this end, but also includes the hardware and the software, the image information Rate of the light spot of the point of the Light source is formed on the tooth.

The intraoral camera device 10 may form part of agencies to be color analysis. Examples of color-analysis devices are disclosed in US Patent 6,305,933 B1 and in WO described 00/25696, wherein these two documents is incorporated by reference. It is preferable that a short tube is used for the sub light shielding, so that the captured images not corrupted by stray light will. Such a pipe is, for example, in the US Patent 6,210,159 shown, full to the here also By reference.

An example of an intra-oral camera device is known from Fig. 2 can be seen where at the same time the connection with illustrated a PC. The intra-oral camera 30 appears that the targeting is right and an image of the patient's tooth can be taken. The intraoral Camera device comprises a PC 32 and an image pickup device 34. In a conventional manner is to the PC 32 is a computer monitor 36 connected as a display device. The image pickup device 34 detects the multicoat color Shape information of the patient's tooth. This computer monitor 36 shows what the image recording device just recorded, so what is targeted by the camera. Depending on Setting can also be a stored image on the View Monitor. At the same time can be over the PC 32, and / or the hardware of the image pickup device 34, the analysis of the Image to be made.

It can be carried out analyzes to determine if the image pickup device 34 really of interest to the Object target set. If desired, other Functions are performed, for example, the identification of shades of a color schema table. According to , the image pickup device 34, the target setting means in support to the operator. This allows the image pickup device 34 in real align manner.

In the figures 3 and 4 are schematically suitable image recording and goal setting bodies represented.

Typically, the correct target setting of the dependent Angle from which has a camera at a subject. According to the present camera angle is analyzed, to determine whether the angle in question is right or not. From the figures 3 and 4 each have a camera 44 can be seen, which is aligned on a tooth surface 46th The Tooth surface 46 is typically convex, with explanation sake the proportions are exaggerated. On Incisor has, for example in a central region plane, but textured, then the Side flanks, ie mesial or distal direction towards is curved. In an alignment would a camera Different shades for consideration areas or "shades" result, so that the restoration result falsified would. In order to prevent this, it is according to the invention provided that Zieleinstelleinrichtung 26 (Fig. 1) to use.

For this purpose, according to FIG. 3 and 4, the point light source 48 is aligned to the tooth surface 46th The punctate Light source 48 is in the illustrated embodiment, mounted on the camera 44, in such a way that it the optical axis 49 is in close proximity, but by this spaced.

To compensate for this divergence, the light source 48 is in a slight angle of, for example, 1 to 10 ° with respect to the optical axis 49 mounted on the camera. The orientation is chosen such that at a predetermined distance between the camera 44 and the tooth surface 46 of the incidence of the optical axis 49 with the light spot coincides with the the light source 48 generates. It is understood that in this way a distance determination is made, at the same time the Focusing of the image pickup device 12 in the camera 44 facilitated.

To such a focus, and thus the distance down visually to the operator, for example, the dentist, to make it clear, it is shown in FIG. 4 provided with two light sources 48 and 50 to work. With proper spacing choice drop the light spots of the two light sources 48 and 50 together, at the same time in which case there the optical axis 49 the generated double-light spot passes, namely preferably centrally.

It is also possible to use a short tube, or other suitable using spacers, the distance from the start specifies. It is also possible to provide a brightness measurement be submitted to the camera 44, the brightness of the generated Light spot measures and displays at maximum brightness, that the targeting is done.

From Fig. 4 it is seen that both light sources 48 and 50 the same, but mirror symmetrical to each other, angle are arranged to the camera. It is understood that, instead which also have any other suitable number of light sources provided for example, distributed in a circle around the camera could be.

From Fig. 5 is a diagram according to the nature of a flow chart apparent that the necessary for the inventive process shows steps. According to the functional block 62 is a camera aimed at a patient's teeth to an image the tooth take. According to step 64 are summary information come about what is covered by the camera becomes. According to step 66 is a point light source, For example, a laser diode, focused on the patients teeth, For example, the integrated light source 48 or 50 according to FIGS. 3 and Fig. 4. It will be understood that instead basically an external light source to the patient tooth could be addressed.

According to step 36 is over the target setting means 26 to find out when the camera is essentially target oriented is.

As can be seen from step 70 is then displayed whether the camera is properly aimed. For example, use an audible or visual indicator provided be indicating to the operator that the camera target oriented is. As shown in step 72, can then the image of the patient's tooth will be taken, for example, automatically when certain previously at step 70 for a indicated period of time that the camera is properly aimed.

Of these steps, the steps 62 and 66 are typically made by the user, while the stone's throw 64, 66, 70 and 72 in the preferred embodiment automatically, so computerized, carried.

The target setting is preferred so that a limited Segment of the captured image is evaluated. This is Detail in Fig . 6. In step 82, it is stated that the image pickup device to a particular interest intraoral object, ie to be detected usually the Tooth is aligned. The image information then - as is noted in step 84 - detected wherein a predetermined or pre-selected segment set is representing a small portion of the entire image. The Surface of that section may, for example, less than 10%, in particular less than 1% of the whole image, include.

The segment size depends on the light spot and its size and shape from that on by the light source 48 and 50 to the Tooth is produced. According to the invention, it is in any case provided, that the cut-captures the entire light spot.

In an advantageous embodiment of the neck now, in Subdivisions divided as shown below based on FIG. 7 is described in more detail.

Instead of the fairly inexpensive laser diode, it is also possible to use a laser of a clear-cut can produce light spot or light point. A laser but is much more expensive and brings invention only a very small additional benefit, so that expensive Light sources, in contrast, preferred.

As is made clear in step 86, the image information of the cut-evaluated to determine whether the camera is correctly aligned on the intraoral object. For example, image information with respect to color, the shape and the brightness of the point-like by the Light source light spot produced are evaluated to accomplish this determine.

From the steps in Fig. 6, steps 84 and 86 typically steps performed by the computer , while step 82 is realized by the operator.

From Fig. 7 shows the manner in which the image information is evaluated. In an advantageous embodiment, a Grid of 3 x 3 grid generated fields as well as in Fig. 8 is shown. In this respect, after selecting a particular Camera image section for analysis (step 92) the cut in Step 94 divided into subdivisions. The Down here can be done automatically, but possibly by an adjustment by the operator. contains preferably each sub-section has an equal number of pixels, for example, 20 pixels, it being understood that any Other divisions may be made.

According to step 96 now, the image information of the subdivisions detected. This includes the light parameters of each Under section which then comparatively evaluated in step 98 will. In step 100 it is then determined whether one of the Subdivisions of the desired portion is the middle the tooth indicates.

Although the inventive method based here on a Image capture of a complete tooth is described, understood that instead of this, a portion of a tooth are detected, and a corresponding review can.

In order to evaluate and identify the subdivisions can For example, brightness characteristics of two sub-outs are compared against each other. The Alignment is then defined as the center, when the brightness these diametrically opposed subdivisions matches. This works if the of Light spot of the light source 48 and 50 produced a symmetrical Brightness distribution, for example, after a Gaussian curve having.

It is also possible, the absolute brightness of the central Unterausschnits located with the brightness of a further outward compare sub-section. In any other way , the symmetry of the brightness to be assessed, which also can be detected, whether the horizontal-lateral and vertical-lateral subdivisions ever the same brightness exhibit.

From Fig. 8 is seen schematically the manner in which a Camera view 102, having an image of a tooth 104 evaluated, can be. Light from a point light source can be directed to the tooth 104 to a light spot 106 to generate on the tooth 104th The grid (section 108) is a cut-out for the evaluation of light properties the light generated by the point-shaped Lichquelle is selected when the light falls on the tooth 104th

Below is shown in Fig. 8 is an enlargement of the detail 108 and the light spot 106 shown. The grid (Neck 108) according to the invention in a plurality of fields (Subdivisions 109) divided. This segment can be a having shape and size that is selected so that they for the typical shape and size of the light spot 106 is suitable. A precise alignment is only achieved when the Light spot of the light source in the central field of the grid (Neck 108). It is understood that typical camera distances are used and the size of the thus produced Light spot can be determined empirically. examples for intraoral camera systems are illustratively described in the publications P 101 20 717.4 and P 101 26 887.4 shown on which is hereby incorporated by reference.

From Figures 9 to 11, a camera according to the invention is in schematic representation seen. Each punctate Light source 206 is in this embodiment, by five arranged next to one another in series laser diode 204 is formed, the formed laterally adjacent to the lens 202 of the camera are. It is understood that instead a single laser diode 204 can be realized. FIG. 11 additionally a short distance pipe with a ring 208 for suitable the system to the patient or the patient's tooth is formed and the distance between camera and tooth specifies. It is understood that such a spacer ring According to the invention, however, is not required.