WO2019085402A1

WO2019085402A1 - Intraoral 3d scan device and method

Info

Publication number: WO2019085402A1
Application number: PCT/CN2018/083054
Authority: WO
Inventors: 马超; 赵晓波; 陈晓军; 叶子
Original assignee: 先临三维科技股份有限公司
Priority date: 2017-10-30
Filing date: 2018-04-13
Publication date: 2019-05-09
Also published as: CN108261171B; CN108261171A

Abstract

The present invention discloses an intraoral 3D scan device and method. The device comprises: a projection module, configured to project a preset pattern onto an object under measurement to form a projected image thereon, wherein the preset pattern is a color stripe pattern, and the object under measurement is a tooth and/or a gum; an acquisition module, configured to acquire the projected image; and a processing module, configured to use a preset algorithm to extract feature points in the projected image, and obtain, according to the feature points, 3D data of the object under measurement, wherein the preset algorithm comprises a stripe center line extraction algorithm and/or an edge extraction algorithm. The present invention solves the technical problem that a conventional intraoral scanner has to spray a powder to prevent teeth or saliva from affecting image clarity.

Description

Intraoral three-dimensional scanning device and method

Technical field

Embodiments of the present invention relate to the field of three-dimensional scanning, and in particular to an intra-oral three-dimensional scanning apparatus and method.

Background technique

In the process of clinical oral examination and repair, dental impression is an important source of information storage. At present, digital impression technology with easy operation, high precision and convenient storage is more and more valued by the dental profession. Digital impression acquisition According to the scanning position, it can be divided into two types, namely, extraoral scanning and intraoral scanning. The intraoral scanning can directly measure the tooth directly into the patient's mouth, and obtain digital impression in real time, reducing operation time and reducing Material and labor consumption, so it has more obvious advantages. At present, in-oral three-dimensional scanners, which are used in the prior art, need to spray on the surface in order to reduce the reflection and projection of light by the teeth or saliva itself when acquiring the tooth image. A kind of powder that is harmless to the human body, if it is not sprayed, the image of the acquired teeth is unclear, which may result in the inability to perform three-dimensional reconstruction of the teeth. Therefore, only the powder spraying technique can be used to achieve intraoral scanning.

In view of the above-mentioned prior art, the intraoral scanner can only use the method of dusting to reduce the problem that the environmental factors such as teeth or saliva affect the image clarity, and no effective solution has been proposed yet.

Summary of the invention

The embodiment of the invention provides an intra-oral three-dimensional scanning device and method, which can at least solve the technical problem that the intraoral scanner can only use the method of spraying powder to reduce the influence of environmental factors such as teeth or saliva on the image clarity.

According to an aspect of the embodiments of the present invention, an intra-oral three-dimensional scanning apparatus is provided, including: a projection module configured to project a preset pattern onto an object to be measured, and form a projection image on the object to be tested, wherein the preset pattern For the color stripe pattern, the object to be measured is a tooth and/or a gum; the acquisition module is configured to collect a projection image; the processing module is configured to extract a feature point of the projection image using a preset algorithm, and obtain three-dimensional data of the object to be tested according to the feature point. The preset algorithm includes a stripe centerline extraction algorithm and/or an edge extraction algorithm.

Optionally, the projection module comprises a digital micromirror device.

Optionally, the pixel size of the projection module is from 7 microns to 8 microns.

Optionally, the apparatus further comprises: a heating anti-fog module coupled to the processing module and configured to be heated under the control of the processing module.

Optionally, the acquisition module includes at least one camera, and the processing module includes: a first determining module configured to determine between the optical axis of the projection module and the optical axis of the camera before the projection module projects the preset pattern onto the object to be tested. The second determining module is configured to determine whether the included angle is within a preset angle; the adjusting module is set to adjust the included angle to the preset angle when the included angle is not within the preset angle range Within the scope.

Optionally, the preset angle ranges from 5 degrees to 8 degrees.

Optionally, the device further includes: a housing and a heat dissipation module, wherein the heat dissipation module is disposed in the housing.

Optionally, the acquisition module is further configured to acquire a plurality of projection images from different angles; the processing module is further configured to reconstruct the multi-angle three-dimensional data of the measured object according to the plurality of projection images, and supplement one of the three-dimensional data according to the multi-angle. The data of the reflective area of the projected image.

Optionally, the width or gray value peak value of each color stripe in the color stripe pattern is a different value.

According to another aspect of the embodiments of the present invention, an in-oral three-dimensional scanning method is provided, including: a projection module projecting a preset pattern onto an object to be measured, and forming a projection image on the object to be tested, wherein the preset pattern is colored The stripe pattern, the object to be measured is a tooth and/or a gum; the acquisition module collects a projection image; the processing module extracts a feature point of the projected image using a preset algorithm, and obtains three-dimensional data of the object to be measured according to the feature point, wherein the preset algorithm includes the stripe Centerline extraction algorithm and/or edge extraction algorithm.

Optionally, the acquisition module includes at least one camera, and before the projection module projects the preset pattern onto the object to be tested, the method further includes: the processing module determines an angle between the optical axis of the projection module and the optical axis of the camera; and the processing module Determine whether the angle is within the preset angle; if the angle is not within the preset angle, the processing module adjusts the angle to the preset angle.

In the embodiment of the present invention, a predetermined pattern is projected onto the object to be tested by the projection module, and a projected image is formed on the object to be tested, wherein the preset pattern is a color stripe pattern, and the object to be tested is a tooth and/or a gum; The acquisition module collects the projection image; the processing module extracts the feature points of the projection image by using a preset algorithm, and obtains the three-dimensional data of the measured object according to the feature points, wherein the preset algorithm includes a stripe center line extraction algorithm and/or an edge extraction algorithm, and the Without powder spraying, the effect of tooth or saliva on the sharpness of the image can be reduced, thereby realizing the effect of reducing the projection of the tooth enamel or saliva on the light, and improving the sharpness of the image of the tooth, thereby solving the present problem. In the art, the intraoral scanner can only use the method of dusting to reduce the technical problem that the environmental factors such as teeth or saliva affect the image clarity.

DRAWINGS

The drawings are intended to provide a further understanding of the present invention, and are intended to be a part of the present invention, and the description of the present invention is not intended to limit the invention. In the drawing:

1 is a schematic diagram of an intraoral three-dimensional scanning device according to an embodiment of the invention;

2 is a schematic view of homogenizing stripes by adjusting values of width or gradation of each stripe according to an embodiment of the present invention;

3 is a schematic diagram of an optional intraoral three-dimensional scanning device in accordance with an embodiment of the present invention;

4 is a schematic diagram of an optional intraoral three-dimensional scanning device in accordance with an embodiment of the present invention;

FIG. 5 is a schematic diagram of an intra-oral three-dimensional scanning method according to an embodiment of the invention.

Detailed ways

It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. The invention will be described in detail below with reference to the drawings in conjunction with the embodiments.

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is an embodiment of the invention, but not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.

It is to be understood that the terms "first", "second" and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a particular order or order. It is to be understood that the data so used may be interchanged where appropriate, so that the embodiments of the invention described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "comprises" and "comprises" and "the" and "the" are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to Those steps or units may include other steps or units not explicitly listed or inherent to such processes, methods, products or devices.

Example 1

According to an embodiment of the present invention, a product embodiment of an intraoral three-dimensional scanning device is provided. FIG. 1 is an intra-oral three-dimensional scanning device according to an embodiment of the present invention. As shown in FIG. 1, the device includes a projection module, an acquisition module, and a processing module. The projection module is configured to project a preset pattern onto the object to be measured, and form a projected image on the object to be tested, wherein the preset pattern is a color stripe pattern, and the object to be tested is a tooth and/or a gum; the acquisition module The processing module is configured to extract a feature point of the projected image by using a preset algorithm, and obtain three-dimensional data of the measured object according to the feature point, wherein the preset algorithm includes a stripe center line extraction algorithm and/or edge extraction. algorithm.

Specifically, the control module may include a timing control circuit, and the timing control circuit triggers the projection module to project the preset pattern onto the object to be tested. Since the preset pattern is a color stripe pattern, the projected image on the object to be tested is also In the embodiment of the present invention, the color stripe pattern is used for projection, and the stripe center line extraction algorithm and/or the edge extraction algorithm are used to extract the color stripe projection image features, wherein the color stripe is projected onto the teeth to facilitate the extraction of features. A dense point cloud is obtained to achieve dynamic scanning. The high-precision stripe center line extraction algorithm and/or edge extraction algorithm can avoid the irreducible mutual influence between the strips, thus greatly reducing the influence of the tooth enamel on the light scattering of the teeth.

Specifically, for the sake of distinguishing, the color stripe pattern may be composed of a plurality of solid colors, that is, a plurality of solid colors may be used as the basic colors constituting the color stripe pattern. For example, six kinds of solid colors may be used, which are respectively red, green, blue, and blue. Magenta and yellow, it should be noted that the specific color and the number of colors of the solid color are not limited in the embodiment of the present invention, and it is preferable to use two or more color numbers, and the more the number of colors, the more unique the color stripe pattern is. Strong; in order to better distinguish the color stripes in the color stripe pattern, the color of the color stripe in the color stripe pattern and the background color need to have a certain degree of discrimination, for example, when the background color is white, that is, the background color of R, G When the B component is 255, the color of the color stripe cannot be white, that is, at most two of the R, G, and B components of the color stripe are 255; in addition, the color stripe pattern may be composed of a plurality of solid colors. It can also be composed of non-pure colors.

The preset color stripe pattern projected on the tooth surface of the projection module is acquired by the acquisition module after being modulated by teeth, air, etc., and the width value of each color stripe in the color stripe pattern acquired by the acquisition module is relative to the projection module. The width value of each color stripe in the color stripe pattern is changed, and the gray scale distribution of each color stripe in the color stripe pattern acquired by the acquisition module is relative to the gray scale of each color stripe in the preset color stripe pattern in the projection module. The distribution has changed. Due to the difference in the performance of different colors on the surface of the tooth, such as diffusion and light transmission, and when the width of the color stripe changes, the gray scale will change accordingly. When the gray scale of the color stripe changes, the width will change accordingly. As shown in FIG. 2, the gradation maps of the three colors of red (R), green (G), and blue (B) and the corresponding widths, the abscissa is the pixel column coordinates, and the ordinate is the gray value, so In order to obtain better and more uniform color stripes and more uniform contrast, the width or gray value peak value of each color stripe in the preset color stripe pattern in the projection module is set. Optionally, the width of the color stripe or the peak value of the gray scale in the preset color stripe pattern in the projection module is set to a different value. In this embodiment, the width of each color stripe in the color stripe pattern acquired by the acquisition module is different. The value of the gray value of each color stripe is equal or close to the equivalent value, that is, the gray value at the center of each color stripe in the color stripe pattern acquired by the acquisition module is equal or close to the equivalent value, thereby controlling each color stripe. The diffusion property on the teeth allows the stripes to have uniform diffusion performance and average contrast to reduce mutual interference between the stripes and improve the accuracy of stripe extraction.

Since the diffusion performance and contrast of each color stripe are different on the object, the stripe is uniformly adjusted by adjusting the width of each stripe or the peak value of the gray value, so that each color stripe has uniform diffusion performance and an average contrast image. Conducive to the subsequent stripe extraction accuracy.

In an alternative embodiment, the projection module comprises a digital micromirror device.

Specifically, the projection module can use DLP (Digital Light Processing, Digital Light Procession abbreviated) projection technology, and use a digital micromirror device (DMD, Digital Micromirror Device abbreviation) as the main key processing component to implement the digital optical processing process. DMD projection technology captures high-contrast images and keeps the picture colorful.

In an alternative embodiment, the projection module has a cell size of from 7 microns to 8 microns.

Specifically, when the projection module includes the DMD, the DMD can have a built-in 2048X1152 array, and the digital micromirror device can project a pattern onto a single tooth (about 15 mm), and can obtain a single pixel size of about 7.3 um, and the projection module is smaller. The cell size reduces interference between adjacent stripe patterns on the teeth.

Specifically, the projection module can use DLP LightCrafter. As shown in Figure 3, DLP LightCrafter's optical engine can be an RGB LED light source engine developed by Yangming Optical for DLP3000 DMD. DLP3000 DMD is installed at the end of the light source engine, 0.3WVGA. The chipset's DLP3000 DMD consists of 415,872 micromirrors with a micromirror spacing of 7.6μm, which forms a 608x684 micromirror matrix that produces WVGA (854x480) resolution images.

In an optional embodiment, the apparatus further comprises: a heating anti-fog module coupled to the processing module and configured to be heated under control of the processing module.

Specifically, the heating anti-fog module can eliminate the atomization defects caused by the temperature difference between the mouth and the surrounding environment, and reduce the influence of saliva and fogging.

In an optional embodiment, the acquisition module includes at least one camera, and the processing module includes a first determining module, a second determining module, and an adjusting module, wherein the first determining module is configured to project the preset pattern in the projection module Before the object is measured, the angle between the optical axis of the projection module and the optical axis of the camera is determined; the second determining module is set to determine whether the angle is within a preset angle; the adjustment module is set to be in the clip If the angle is not within the preset angle range, adjust the angle to within the preset angle range.

Specifically, the acquisition module may include at least one CCD (Charge Coupled Device Image Sensor, a short for Charge Coupled Device) chip, and the acquisition module may include a single or multiple high-resolution color cameras, which can be simultaneously acquired by using a high-resolution color camera. Projection image on the tooth.

Specifically, the tooth reflection can be reduced by adjusting the angle between the optical axis of the projection module and the optical axis of the camera to a suitable range.

In an alternative embodiment, the preset angle ranges from 5 degrees to 8 degrees.

Specifically, the angle between the optical axis of the projection module and the optical axis of the camera is too small to be excessively reflective, and too large may cause difficulty in matching of the scale of the image and occlusion loss of the projection pattern. 5 degrees -8 degrees can avoid the above problems.

In an optional embodiment, the device further includes: a housing and a heat dissipation module, wherein the heat dissipation module is disposed in the housing.

Specifically, the heat dissipation module may be an electric heat dissipation module or a heat dissipation module without electricity, and specifically may be a heat dissipation plate, a heat dissipation port, etc., and the heat dissipation module may be used to maintain the overall temperature of the three-dimensional scanning device in the mouth, and reduce saliva and fog. The impact of the change.

In an optional embodiment, the acquisition module is further configured to acquire a plurality of projection images from different angles; the processing module is further configured to reconstruct the multi-angle three-dimensional data of the measured object according to the plurality of projection images, and according to the multi-angle The three-dimensional data complements the data of the reflective area of one of the projected images.

Specifically, the image captured by the acquisition module may be missing or unclear due to reflection, so the acquisition module may acquire multiple projection images from multiple angles, and reconstruct multiple projection images from different angles. The three-dimensional data of the angle complements the data of the reflective area to compensate for the lack of reflection, thereby reducing the influence of the tooth on the diffusion and scattering of light.

In an optional embodiment, the processing module acquires feature points of the projected pattern by using a color stripe center line extraction or an edge extraction algorithm, and performs stereo matching by decoding the color stripe to obtain a single piece of sparse three-dimensional point cloud data, and utilizes the sparse point. The depth information of the cloud sub-pixel-level dense matching of the image finally obtains a single piece of dense 3D point cloud data, and obtains a plurality of poses, a single-dimensional three-dimensional point cloud of the measured object, such as a tooth, by an intraoral scanner such as a dynamic moving intraoral scanner. The data is accurately spliced and fused, and finally three-dimensional data of the entire outer surface contour of the measured object such as the tooth can be obtained.

In a specific embodiment, the projection module and the acquisition module may be disposed on the intraoral scanner, and the processing module may be specifically disposed on the computer, and the data transmission between the intraoral scanner and the computer may be performed by wireless and/or wired. Among them, the wireless way can be Bluetooth or WIFI.

It should be noted that the in-oral scanner may include the above-mentioned heating anti-fog module and the heat dissipation module in addition to the above-mentioned projection module and the acquisition module, and may further include a controller, a mirror, and a power module. , display module, button and other conventional components, as shown in Figure 4, Figure 4 shows a specific internal three-dimensional scanning device structure diagram, including the housing 1, the controller 2, the projection module 3, the acquisition module 4, the first A mirror 5, a second mirror 6, and a computer 7.

Example 2

In accordance with an embodiment of the present invention, an embodiment of a method of intra-oral three-dimensional scanning method is provided, it being noted that the steps illustrated in the flowchart of the figures may be performed in a computer system such as a set of computer-executable instructions, and Although the logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in a different order than the ones described herein.

FIG. 5 is an intra-oral three-dimensional scanning method according to an embodiment of the present invention. The method can be applied to the intra-oral three-dimensional scanning system. As shown in FIG. 5, the method includes the following steps:

Step S102, the projection module projects a preset pattern onto the object to be tested, and forms a projection image on the object to be tested, wherein the preset pattern is a color stripe pattern, and the object to be tested is a tooth and/or a gum;

Step S104, the collection module collects a projection image;

Step S106, the processing module extracts feature points of the projected image by using a preset algorithm, and obtains three-dimensional data of the measured object according to the feature points, wherein the preset algorithm includes a stripe center line extraction algorithm and/or an edge extraction algorithm.

In a specific embodiment, the acquisition module includes at least one camera, and before the projection module projects the preset pattern onto the object to be tested, the method further includes:

Step S202, the processing module determines an angle between an optical axis of the projection module and an optical axis of the camera;

Step S204, the processing module determines whether the included angle is within a preset angle range;

Step S206, the processing module adjusts the included angle to a preset angle range if the included angle is not within the preset angle range.

In an optional embodiment, the method further includes:

Step S302, the acquisition module collects multiple projection images from different angles;

Step S304, the processing module reconstructs the multi-angle three-dimensional data of the measured object according to the plurality of projection images, and supplements the data of the reflective area of one of the projected images according to the multi-angle three-dimensional data.

Example 3

According to an embodiment of the present invention, there is provided a product embodiment of a storage medium, the storage medium comprising a stored program, wherein the device in which the storage medium is located is controlled to execute the intra-oral three-dimensional scanning method while the program is running.

Example 4

In accordance with an embodiment of the present invention, a product embodiment of a processor is provided that is configured to execute a program, wherein the intra-oral three-dimensional scanning method is performed while the program is running.

The serial numbers of the embodiments of the present invention are merely for the description, and do not represent the advantages and disadvantages of the embodiments.

In the above-mentioned embodiments of the present invention, the descriptions of the various embodiments are different, and the parts that are not detailed in a certain embodiment can be referred to the related descriptions of other embodiments.

In the several embodiments provided by the present application, it should be understood that the disclosed technical contents may be implemented in other manners. The device embodiments described above are only schematic. For example, the division of the unit may be a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or may be Integrate into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, unit or module, and may be electrical or otherwise.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the embodiments of the present invention may contribute to the prior art or all or part of the technical solution may be embodied in the form of a software product stored in a storage. The medium includes a number of instructions for causing a computer device (which may be a personal computer, server or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: a U disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic disk, or an optical disk, and the like. .

The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Claims

An intraoral three-dimensional scanning device comprising:

a projection module, configured to project a preset pattern onto the object to be measured, and form a projected image on the object to be tested, wherein the predetermined pattern is a color stripe pattern, and the object to be tested is a tooth and/or a gum ;

An acquisition module configured to acquire the projection image;

a processing module, configured to extract feature points of the projected image by using a preset algorithm, and obtain three-dimensional data of the measured object according to the feature points, wherein the preset algorithm includes a stripe center line extraction algorithm and/or an edge Extraction algorithm.
The apparatus of claim 1 wherein said projection module comprises a digital micromirror device.
The apparatus of claim 1 or 2, wherein the projection module has a pixel size of from 7 microns to 8 microns.
The apparatus of claim 1 wherein said apparatus further comprises:

The anti-fog module is heated and coupled to the processing module and configured to be heated under the control of the processing module.
The apparatus of claim 1, wherein the acquisition module comprises at least one camera, the processing module comprising:

a first determining module, configured to determine an angle between an optical axis of the projection module and an optical axis of the camera before the projection module projects the preset pattern onto the object to be tested;

a second determining module, configured to determine whether the included angle is within a preset angle range;

The adjusting module is configured to adjust the angle to the preset angle range if the angle is not within the preset angle range.
The apparatus according to claim 5, wherein said predetermined angle ranges from 5 degrees to 8 degrees.
The apparatus of claim 1, wherein the apparatus further comprises: a housing and a heat dissipation module, the heat dissipation module being disposed within the housing.
The apparatus of claim 1 wherein said acquisition module is further configured to acquire a plurality of said projected images from different angles;

The processing module is further configured to reconstruct three-dimensional data of the multi-angle of the measured object according to the plurality of the projected images, and supplement data of one of the reflective regions of the projected image according to the multi-angle three-dimensional data.
The apparatus according to any one of claims 1, 2, 4 to 8, wherein a width or a gradation value peak value of each color stripe in the color stripe pattern is a different value.
An intraoral three-dimensional scanning method comprising:

The projection module projects a preset pattern onto the object to be tested, and forms a projected image on the object to be tested, wherein the predetermined pattern is a color stripe pattern, and the object to be tested is a tooth and/or a gum;

The acquisition module collects the projection image;

The processing module extracts feature points of the projected image by using a preset algorithm, and obtains three-dimensional data of the measured object according to the feature points, wherein the preset algorithm includes a stripe center line extraction algorithm and/or an edge extraction algorithm.
The method of claim 10, wherein the acquisition module comprises at least one camera, and before the projection module projects the predetermined pattern onto the object to be tested, the method further comprises:

The processing module determines an angle between an optical axis of the projection module and an optical axis of the camera;

The processing module determines whether the included angle is within a preset angle range;

The processing module adjusts the included angle to the preset included angle range if the included angle is not within the preset included angle range.
The method according to claim 10 or 11, wherein the width or gray value peak value of each color stripe in the color stripe pattern is a different value.