KR101859836B1 - Triangulation 3d dental intra-tooth image scanning method and system - Google Patents

Abstract

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and system for obtaining accurate image data in a more simple manner in scanning and imaging a tooth shape for dental treatment.
According to the above object, the present invention provides a method of acquiring a triangular measurement tooth image using a chromatic lens.
That is, according to the present invention, the R, G, and B lights pass through a lens equipped with a pattern through an LED light source, pass through a chromatic lens again to reach teeth, and light reflected from a tooth passes through a chromatic lens By acquiring images on a CCD camera, it is possible to acquire three-dimensional information through a single image collected in one pattern, so that accurate and accurate image data can be obtained quickly and easily.

Description

TECHNICAL FIELD [0001] The present invention relates to a three-dimensional tooth image acquiring method and system,

The present invention relates to a method and system for obtaining a three-dimensional tooth image for dental treatment, and more particularly, to a method and system for obtaining a three-dimensional image of a tooth shape during prosthetic treatment.

In the past, for the purpose of general prosthetic treatment, a casting was made by putting a resin and the like in a cavity to directly cast a plaster model. Such a method is called a so-called roast wax casting method, and there is a problem in that it may not fit well with teeth as well as infection concerns. Accordingly, recently, the tooth shape is scanned into a three-dimensional image to obtain image information, and a prosthesis is manufactured using the CAD / CAM technology accordingly.

Korean Patent No. 10-1628730 was filed and registered by the present applicant and invented by the present inventor. In the imaging by scanning a tooth shape by a confocal system, chromatic aberration So that the shortened distance can be scanned.

According to the above-mentioned publication, although the system is simple and the image acquisition can be made simpler and more accurate than the prior art that does not use chromatic aberration, the image scanning operation is still in vast amount.

Figure 2 is a confocal system tooth image scanning system. According to this confocal method, only one plane of the tooth is focused. Thus, in order to obtain a three-dimensional image of a tooth, it is necessary to perform a considerable interval scanning to move the focal plane. During scanning, a vast amount of image processing must be done on each focal plane. In addition, scanning of the optical system requires driving equipment, and it is difficult to control the scanning drive with high precision and stability.

In the case of FIG. 2, the objective lens shows that an achromatic lens and a chromatic lens can be selected. Even if the scanning distance can be significantly reduced in the depth-of-focus direction by applying a chromatic lens compared to the conventional method using an arcuate lens, the same problem is posed in that a certain section is still scanned in order to obtain a three-dimensional image .

It is therefore an object of the present invention to provide a method and system for obtaining accurate image data in a simpler manner in a method for obtaining a three-dimensional image of a tooth for dental treatment.

According to the above object, the present invention provides a method of acquiring a triangulated tooth image.

That is, according to the present invention, the R, G, and B lights pass through a lens equipped with a pattern through an LED light source, pass through a chromatic lens again to reach teeth, and light reflected from a tooth passes through a chromatic lens By acquiring images on a CCD camera, it is possible to acquire three-dimensional information through a single image collected in one pattern, so that accurate and accurate image data can be obtained quickly and easily.

That is,

A light source including R, G, and B;

A focusing lens for focusing the beam emitted from the light source;

A pattern provided in contact with the focusing lens;

A first chromatic lens for color-separating the beam passing through the focusing lens and the pattern;

A mirror for reflecting R, G and B beams separated from the first chromatic lens with different focal lengths and directing the path of the beam toward the teeth;

A second chromatic lens disposed on a path where the beam incident on the tooth by the mirror is reflected from the teeth and then reflected by the mirror and proceeds;

And a camera disposed on a path of the beam passing through the second chromatic lens to collect and store tooth image data.

In the above, the light source is a two-dimensional surface light source in which R, G, and B are all disposed on a plane, and includes a blocking portion that passes through the focusing lens to leave only the region where all the R, G, Dimensional tooth image acquisition system according to the present invention.

In the above, the pattern may be a plane, and may be a circle, a triangle, a quadrangle, a polygon, or a mesh.

According to the present invention, since three-dimensional shape information of a tooth can be obtained through a single image by using a pattern, it is possible to obtain three-dimensional shape information of a tooth much faster, have.

In addition, since the present invention uses a chromatic lens, the depth of focus is deep compared with the case of using an arctronic lens, so that a tooth image can be sufficiently obtained according to the bending.

FIG. 1 is a schematic diagram illustrating a phenomenon of light according to an achromatic lens, which is a color cast lens, and a chromatic lens, which is a color lens that separates colors before describing the present invention.
FIG. 2 is a view illustrating a tooth shape using an arcuatechromatic objective lens as a confocal type image.
FIG. 3 is a schematic diagram for explaining the difference between the tooth shape scan by the arcuate lens and the chromatic lens.
FIG. 4 is a diagram showing a simple triangulation principle which explains depth of focus according to colors using chromatic lenses and an LED light source including RGB.
5 is an optical system configuration diagram showing the configuration of a triangulation-based tooth image acquisition system according to the present invention.
FIG. 6 is a diagram for explaining a useful field of view (FOV) when the RGB LED chip is used as a light source according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram illustrating a phenomenon of light according to an achromatic lens, which is a color cast lens, and a chromatic lens, which is a color lens that separates colors before describing the present invention. In the case of an arctronic lens, when light is incident, it is focused all at the same focal length regardless of the wavelength (left). However, when light is incident on the chromatic lens, the focal distance differs depending on the wavelength band, and color separation phenomenon occurs (right). R, G, and B are focused in wavelength order, and red with long wavelength has the longest focal length. As described above, when the focal length is changed by the chromatic lens and the focal distance is different, the scan distance can be shortened when a specific section is scanned with light. That is, as shown in FIGS. 2 and 3, it can be seen that such a role emits light in a tooth scan system constituted by a chromatic lens.

Fig. 2 is a configuration diagram for explaining scanning of a tooth shape using a chromatic lens. Fig. It is possible to use this optical system to obtain the image information by scanning the inside of the cavity with light, without making the mold directly into the cavity for the cavity reconstruction, and then making the elaborate prosthesis based on this information. Here, a two-dimensional planar light source having all of RGB as a light source is used. A focusing lens, a half mirror, a chromatic lens, a mirror, another focusing lens, and a CCD camera. Light passes through a focusing lens and then passes through a half mirror, while a straight ray passes through a chromatic lens and RGB is split into different focal lengths, and the path of light is changed toward the tooth through a mirror to scan the tooth cavity. The reflected light is again reflected by the half mirror through the chromatic lens, focused by the focusing lens, and the image is collected on the CCD camera. At this time, image data of a necessary tooth shape can be obtained by scanning light corresponding to the shape of the tooth or the depth of the tooth cavity. Therefore, the required distance for light having a constant focal distance must be scanned. Because it requires precise data, the scan drive must also be done very precisely. In this respect, the scan drive has a heavy burden on the mechanical configuration.

FIG. 3 is a schematic diagram for explaining the difference between the tooth shape scan by the arcuate lens and the chromatic lens. In the case of an arctronic lens, a mechanical drive must be performed to scan the entire travel distance to be scanned in order to have a single focal length to scan the tooth shape. However, when a chromatic lens is used, since each of R, G, and B has a different focal distance, an effect that has already been scanned is obtained by the distance of the focal distance. That is, if the desired tooth image is within the focal length distance of each of RGB, all desired images can be obtained without performing scan driving. The right side of Fig. 3 corresponds to such an example. If the desired tooth image is longer than the spacing between R and B focal lengths, additional scan drive may be required. In this case, however, the scan driving length is much shorter than in the case of an arctronic lens.

In this case, the scan operation may be performed for the optical system, but the target teeth may be scan-driven.

An optical system for scanning using a chromatic lens is shown in Fig. When a light source including RGB is separated by a chromatic lens to obtain an effect of increasing the depth of focus, the light is reflected by a mirror or another object, then focused by a chromatic lens and collected by a CCD camera. Can be obtained.

FIG. 5 shows a triangulation-based tooth image acquisition system using the pattern together with the characteristics of the chromatic lens.

The triangulated tooth image acquisition system includes an LED light source 100 including RGB, a lens 200 having a pattern, a first chromatic lens 300, a mirror 400, a second chromatic lens 500, And a CCD camera 600. Unlike FIG. 2, FIG. 5 includes a pattern and includes two chromatic lenses. The triangulated tooth image acquisition system according to FIG. 5 acquires a tooth image as follows.

Light emitted from the light source 100 passes through a lens 200 having a pattern. The pattern is a plane, and may be various shapes. That is, it may have a plurality of circles, triangles, squares, polygons, or the like, or may be made of a mesh. This pattern is disposed in front of the focusing lens 200 (on the basis of the direction in which light travels). The arrangement of the patterns can be performed by attaching a pattern film or the like. The sizes of the individual graphic shapes constituting the pattern and the sizes of the openings of the mesh may be composed of 100 to 200 mu m in diameter.

By arranging such a pattern, a large amount of image data can be obtained by irradiating a single light on the tooth shape, so that a required tooth image can be obtained without scanning. The light passing through the pattern passes through the first chromatic lens 300, and the focus depth is enlarged by color separation. The chromatic lens has a focus depth of about 15 mm (10 to 20 mm), which enables sufficient image acquisition in the focal direction with respect to the teeth without scan drive. The principle is fully described in Figs. 3 to 4.

The light whose focal depth is enlarged by the color separation is incident on the tooth by changing the path by the mirror 400. Since it is desired to obtain a tooth cavity-shaped image, the mirror 400 is adjusted so that light enters into the cavity. At this time, as described above, since light beams that are two-dimensionally dispersed by the pattern are incident on the tooth cavity in a state in which each of the R, G, and B lights are separated in the focus depth direction, a large amount of image data is acquired at one time without scanning the optical system .

That is, according to the triangulation method of the present invention, by applying a pattern and applying a chromatic lens, all the desired image data can be acquired by one shot of irradiating light only without scan driving of the optical system, And an accurate image can be obtained. Therefore, it is not necessary to configure the scan driving device of the optical system unlike the case of the confocal scanning method.

Light reflected back from the tooth is directed to the mirror 400, reflected by the mirror 400, and passes through the second chromatic lens 500. As described in FIG. 5, beams separated by color through the second chromatic lens 500 are stored in the CCD camera 600 by providing image data. That is, according to the present invention, it is possible to acquire a large amount of image data for a wide range of necessary tooth parts without scan driving of the optical system or target chain through placement of the chromatic lens together with the pattern use.

In addition, the camera may be replaced with a high performance CMOS image sensor.

In the present invention, an LED light source in which RGB is all arranged in one plane in a plane is used.

FIG. 6 is a diagram for explaining a useful field of view (FOV) when the RGB LED chip is used as a light source according to the present invention. The FOV is the part where the three colors are mixed by the LED light source in which the RGB is all arranged in the two-dimensional plane. That is, after passing through the first focusing lens and the second focusing lens, a two-dimensional flat LED light source in which all of the RGB are arrayed is passed through a blocking portion which leaves only a region where all three colors are mixed and blocks the rest, Position to constitute a light source. 6, the positions of the light sources of R, G, and B are shown in the lower left corner.

In the above, the light source is composed of LED, but it may be replaced with another.

In addition, the system can be used to photograph not only the tooth cavity but also the shape of the tooth outer surface.

Thus, a triangulated optical system capable of obtaining accurate image data on a tooth shape can be realized.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: Light source
200: lens
300: first chromatic lens
400: mirror
500: second chromatic lens
600: camera

Claims (3)

A light source including R, G, and B;
A condensing lens for condensing a beam emitted from the light source;
A pattern provided in contact with the focusing lens;
A first chromatic lens for color-separating the beam passing through the focusing lens and the pattern;
A mirror for reflecting R, G and B beams separated from the first chromatic lens with different focal lengths and directing the path of the beam toward the teeth;
A second chromatic lens disposed on a path where the beam incident on the tooth by the mirror is reflected from the teeth and then reflected by the mirror and proceeds;
And a camera disposed on a path of the beam passing through the second chromatic lens to collect and store tooth image data,
Wherein the pattern comprises a plurality of discrete shapes and is a pattern comprising a plurality of circular, triangular, square, polygonal or mesh surfaces. The light source according to claim 1, wherein the light source is a two-dimensional surface light source in which R, G, and B are all disposed on a plane, and passes through a focusing lens to leave only an area in which all of R, G, Wherein the three-dimensional tooth image acquisition system comprises: 2. The method according to claim 1, wherein the size of the individual figure or the size of the opening of the mesh constituting the pattern is 100 to 200 mu m in diameter, and the focal depth formed by the first chromatic lens is 10 to 20 mm, Wherein the three-dimensional tooth image is acquired without scan driving of the three-dimensional tooth image acquisition system.

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