CN211485040U - Intraoral three-dimensional scanner - Google Patents

Abstract

The utility model provides an intraoral three-dimensional scanner, which is an intraoral three-dimensional scanning system based on confocal scanning technology to realize three-dimensional data acquisition, and realizes high-speed image acquisition by matching a plurality of black-and-white image sensors and image splicing technology; the color sensor is matched to acquire full-color information of a uniform view field, so that a colored three-dimensional object structure is realized; compared with the traditional intraoral scanning system, the scanner can improve the image acquisition speed of the high-resolution sensor, and acquire the real color information of an object while realizing the quick acquisition of the surface geometric shape; moreover, the introduction of the liquid lens in the utility model realizes the free adjustment of the focal plane and simultaneously improves the precision and speed of the focal plane change; the volume of the three-dimensional scanning system is also reduced, and the miniaturization of the intraoral three-dimensional scanning system is realized. The intraoral three-dimensional scanning system provided by the system further reduces the volume, accelerates the scanning speed and provides true color three-dimensional information with higher precision.

Description

Intraoral three-dimensional scanner

Technical Field

The utility model relates to a three-dimensional scanning technical field especially relates to an intraoral three-dimensional scanner.

Background

In the clinical oral diagnosis and treatment and repair process, the method for obtaining the three-dimensional digital model of the interior of the oral cavity through three-dimensional scanning mainly comprises two types of extraoral scanning and intraoral scanning. The extraoral scanning mode requires that a doctor firstly takes an impression of an oral cavity to obtain a plaster model of a tooth, and then scans the plaster model of the tooth by using three-dimensional scanning equipment to obtain a three-dimensional digital model of the tooth; the intraoral scanning mode is to extend the detector into the oral cavity to directly scan the teeth so as to obtain the three-dimensional digital model of the teeth, and the intraoral scanning mode has the advantages of simple operation, high efficiency and high measurement speed, thereby saving the time for operating a doctor chair, avoiding errors caused by mold making and mold overturning due to no need of manual impression, having higher measurement precision, more importantly reducing the discomfort of a patient in the impression process and improving the satisfaction degree of the patient.

The main principles of intraoral three-dimensional scanning include: confocal scanning technology, structured light vision measurement technology, binocular stereo vision technology and the like.

Confocal scanning is one of the more important means for acquiring 3D images. The confocal scanning technology is based on the principle of point illumination, point imaging and point detection three-point conjugation, when a detected surface is conjugated with a detection surface, the image point on the point detector is minimum, and the light energy received by the point detector is maximum; when the measured surface deviates from the object point, the image point on the detector becomes large, and the light energy received by the point detector becomes small. During measurement, the control object point is overlapped with the measured surface, the output value of the detector is ensured to be maximum, and the appearance of the measured surface can be described.

The structured light vision measurement technology usually adopts a grating type projection pattern, projects a plurality of sinusoidal structured gratings onto an object to be measured through a grating projection device, synchronously acquires corresponding images through a camera, then decodes the acquired grating images, calculates phase values of pixel points in a visual area, and reconstructs three-dimensional coordinates of each corresponding point according to the phase height corresponding relation, thereby realizing the three-dimensional shape measurement and information digitization of the object. The technology becomes one of effective ways for solving many on-line measurements such as object surface appearance measurement, space position measurement, three-dimensional motion information acquisition and the like, has the characteristics of non-contact, quick dynamic response, good system flexibility and the like, and is widely applied to the fields of product quick design, processing quality control, reverse engineering, automatic control and the like.

Binocular stereo vision is also an important form of machine vision, and is a method for acquiring three-dimensional geometric information of an object from a plurality of images based on the parallax principle. The binocular stereo vision system generally obtains two digital images of a measured object from different angles by two cameras simultaneously, or obtains two digital images of the measured object from different angles at different moments by a single camera, recovers three-dimensional geometric information of an object based on a parallax principle, and reconstructs a three-dimensional contour and a position of the object.

Due to the particularities of intraoral scanning, in addition to requiring a small detector, the scanning speed is also required to be as fast as possible. Therefore, there is a need for an intraoral scanning technique that can directly scan inside the oral cavity of a human body and acquire three-dimensional scanning results in real time.

SUMMERY OF THE UTILITY MODEL

An embodiment of the utility model provides an intraoral three-dimensional scanner for solve the problem that exists among the prior art.

In order to achieve the purpose, the utility model adopts the following technical scheme.

An intraoral three-dimensional scanner comprises a projection lighting device, an imaging device and a control device;

the imaging device comprises a reflecting mirror, a zoom lens, a first beam splitter and a second beam splitter which are arranged in sequence from an object side to an image side, and an image sensor; the zoom lens comprises a liquid lens and a first conventional lens; the image sensor has a high frame rate grayscale image sensor and a color image sensor; the high frame rate gray scale image sensor corresponds to the first beam splitter, and the color image sensor corresponds to the second beam splitter;

the projection lighting device is used for projecting a preset pattern to a measured object to enable the measured object to present the characteristics of a projection image and comprises a lighting source, a digital micro-mirror element and a projection lens; the illumination light source projects an illumination light path to the measured object through the imaging device;

the control device is electrically connected with the imaging device and used for controlling the focal power of the zoom lens and collecting images acquired by the zoom lens.

Preferably, the zoom lens includes a first conventional lens and a liquid lens disposed in this order from the object side to the image side.

Preferably, the first beam splitter and the second beam splitter are polarizing beam splitters; the intraoral three-dimensional scanner also has a phase retardation plate positioned between the mirror and the zoom lens.

Preferably, the high frame rate gray scale image sensor is an array type sensor.

Preferably, the control means is for controlling the optical power of the zoom lens such that the focal plane change step is less than 50 um.

Preferably, the projection lighting fixture has a DLP optical engine and the illumination source is a multi-color illumination source.

Preferably, the high frame rate grayscale image sensor and the color image sensor operate alternately.

Preferably, the device also comprises a processing device which is in communication connection with the control device and is used for processing the images collected by the control device and synthesizing the color three-dimensional images.

Preferably, a second conventional lens is further arranged between the first beam splitter and the high frame rate gray scale image sensor, and a third conventional lens is further arranged between the second beam splitter and the color image sensor.

According to the technical solution provided by the embodiments of the present invention, the intraoral three-dimensional scanning system for acquiring three-dimensional data based on confocal scanning technology provided by the present invention realizes high-speed image acquisition by matching a plurality of gray level image sensors and image splicing technology; the color sensor is matched to acquire full-color information of the same view field and realize a colored three-dimensional object structure, and the method has the greatest advantages of getting rid of the defect of low image acquisition speed of the high-resolution sensor and acquiring real colored information of the object while quickly acquiring the surface geometric shape. The method has great practical significance and application value for rapidly acquiring intraoral real information, providing effective guidance for doctors and reducing discomfort of patients.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural view of an intraoral three-dimensional scanner provided by the present invention.

In the figure:

11. the projection lighting device 21, the first beam splitter 22, the second beam splitter 23, the liquid lens 24, the first conventional lens 25, the phase retardation plate 26, the reflecting mirror 27, the tooth 28, the third conventional lens 29, the second conventional lens 30, the color image sensor 31 and the high frame rate gray scale image sensor.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention, and should not be construed as limiting the present invention.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

For the convenience of understanding the embodiments of the present invention, the following description will be given by way of example only with reference to the accompanying drawings, and the embodiments are not limited thereto.

Referring to fig. 1, the present invention provides an intraoral three-dimensional scanner, which includes a projection lighting device 11, an imaging device and a control device;

the imaging device comprises a reflecting mirror 26, a zoom lens, a first beam splitter 21 and a second beam splitter 22 which are arranged from the object side to the image side in sequence, and the imaging device is also provided with an image sensor; the zoom lens includes a liquid lens 23 and a first conventional lens 24; the zoom lens changes the focal power of the liquid lens 23 to change the focal plane of the lens, has higher precision and smaller step length compared with the traditional mechanical zoom, and reduces the space occupied by the whole optical path compared with the traditional mechanical zoom;

the image sensor is provided with a high frame rate gray scale image sensor 31 and a color image sensor 30, and the color image sensor 30 is used for acquiring a color two-dimensional image of teeth and surrounding soft tissues; the high frame rate gray scale image sensor 31 corresponds to the first beam splitter 21, and the color image sensor 30 corresponds to the second beam splitter 22;

the projection lighting device 11 is used for projecting a preset pattern to a measured object to enable the measured object to present the characteristics of a projection image, and comprises a lighting source, a digital micro-mirror element and a projection lens; the preset pattern can be a stripe pattern, a speckle pattern, a coding pattern and other regular or irregular patterns which can be easily subjected to image recognition, and the measured object is a tooth and surrounding soft tissues; the illumination light source projects an illumination light path to the measured object through the imaging device;

the control device is electrically connected with the imaging device and used for controlling the focal power of the zoom lens and controlling the frequency of focal power change, the smaller the minimum step length of the changeable focal power is, the higher the depth precision is, and the control device is also used for collecting images acquired by the zoom lens.

The utility model provides an intraoral three-dimensional scanner has introduced liquid lens 23, has realized focal plane's freedom adjustment, has improved the precision and the speed that focal plane changed simultaneously. Meanwhile, the volume of the three-dimensional scanning system is reduced, the miniaturization of the intraoral three-dimensional scanning system is realized, and true color three-dimensional information with higher precision can be provided.

Further, in some preferred embodiments, in order to eliminate the influence of reflection of light from teeth, the first beam splitter 21 and the second beam splitter 22 are polarization beam splitters; as shown in fig. 1, the intra-oral three-dimensional scanner further has a phase retardation plate 25, which is located between the mirror 26 and the zoom lens; the polarization beam splitter and the phase retardation plate 25 are matched with each other to eliminate or reduce the flare caused by reflection of the light from the teeth.

In the embodiments provided by the present disclosure, the number and positions of the liquid lens 23 and the first conventional lens 24 may be set as appropriate by those skilled in the art, for example, in some preferred embodiments, the first conventional lens 24 and the liquid lens 23 are arranged in order from the object side to the image side; in these embodiments, the number of the first conventional lenses 24 may be set as appropriate according to imaging needs, and may be, for example, two first conventional lenses 24 as shown in fig. 1.

Further, in some preferred embodiments, the high frame rate gray scale image sensor 31 is an array sensor, and is configured to extract a three-dimensional planar two-dimensional gray scale image, and the images acquired by the high frame rate gray scale image sensor 31 are spliced together; generally speaking, the transmission speed of the image sensors of the same series is related to the resolution, and the lower the resolution, the faster the transmission speed, therefore, the instrument replaces the traditional single high-resolution image sensor with the splicing form of a plurality of high-frame-rate image sensors with low resolution, and the projection images of a plurality of adjacent fields are collected at high speed to splice into a projection image with a large field.

Further, in some preferred embodiments, the high frame rate gray scale image sensor 31 and the color image sensor 30 operate alternately, and the array acquisition frequency of the high frame rate gray scale image sensor 31 is higher than that of the color image sensor 30.

In the embodiment provided by the present invention, for controlling the liquid lens 23 to change the focal power and controlling the frequency of the focal power change, the smaller the minimum step of the changeable focal power, the higher the depth accuracy; and controlling the projection lighting device 11 to alternately light up and alternately collect the high frame rate gray scale image sensor 31 and the color sensor, and controlling the image collection frequency and the like; the focal power change frequency of the liquid lens 23 controlled by the control device is consistent with the acquisition frequency of the image sensor; in some preferred embodiments, the means for controlling the optical power of the zoom lens varies the focal plane by a step size of less than 50 um.

In the preferred embodiment provided by the present invention, the projection lighting device 11 can adopt a DLP optical engine, the digital micromirror device adopts a DMD chip which is TI (texas instruments), the lighting source can be a white LED lighting source composed of three monochromatic LED lamps of red, green and blue, the monochromatic light is used for projecting patterns for three-dimensional detection, the white light is used for lighting for color detection, and the monochromatic light and the white light are alternatively lighted; the illumination light path is positioned at the front end of the illumination light source, light emitted by the illumination light source is uniformly projected to the digital micromirror device, a preset pattern is obtained by controlling the on/off and time ratio of the micromirror, and the obtained preset pattern is projected to teeth and surrounding soft tissues through the projection lens; in a specific embodiment, the image sensor alternate collection and the projection illumination light beam alternate lighting are synchronized, that is, when the DLP projects a stripe pattern, the high frame rate grayscale image sensor array 31 performs image collection; when the DLP emits white illumination light beams, the color image sensor 30 performs image acquisition; for example, as shown in fig. 1, light reflected from the surface of tooth 27 enters the imaging lens via mirror 26, the imaged light is split into two beams by second beam splitter 22, one beam is received by color image sensor 30, and the other beam passes through second beam splitter 22, passes through first beam splitter 21, and is received by the array of high frame rate grayscale image sensors 31.

Further, in some preferred embodiments, a second conventional lens 29 is disposed between the first beam splitter 21 and the high frame rate gray scale image sensor 31, and a third conventional lens 28 is disposed between the second beam splitter 22 and the color image sensor 30.

Furthermore, in some preferred embodiments, the present invention further provides a processing device, which is in communication connection with the control device, and is configured to process the image collected by the control device to synthesize a color three-dimensional image; the method can be specifically used for acquiring three-dimensional information and color information from the acquired two-dimensional image and synthesizing a high-precision color three-dimensional image. Extracting the position and height information of the surface of the body from a two-dimensional gray projection image acquired by a high frame rate gray sensor array to realize the real-time reconstruction of the three-dimensional surface type of teeth and surrounding soft tissues; extracting color information from the color tooth and surrounding soft tissue images collected by the color image sensor 30; and recovering the collected surface position, height information and color information of the object into a high-precision color three-dimensional intraoral image through an image processing technology.

The utility model provides a scanner theory of operation does:

during the three-dimensional scanning, the projection lighting device 11 projects a preset pattern onto a measured object (teeth and surrounding soft tissues), the preset pattern is reflected by the measured object, the image is formed through the imaging lens, the automatic focusing of the lens is realized through the zooming of the liquid lens 23, the focal power is changed for multiple times in a very short time, the preset pattern is imaged on the high-frame-rate gray scale image sensor array, the smaller the focal power step length of the liquid lens 23 changed each time is, the higher the accuracy of the obtained depth information of the teeth and the surrounding soft tissues is, and the change frequency of the focal power of the liquid lens 23 is the same as the acquisition frequency of the high-frame-rate image sensor. During the white light illumination, the projection illumination device 11 also projects a white light illumination beam onto the object to be measured, and the reflected light from the tooth and surrounding soft tissue surfaces is imaged on the color image sensor 30 through the imaging lens. The monochromatic projection pattern and the white illumination beam are alternately illuminated while the high frame rate image sensor and the color image sensor 30 are alternately acquired, the acquisition frequency of the high frame rate image sensor being higher than the acquisition frequency of the color image sensor 30.

The processing device extracts the position and height information of the surface of the object from the two-dimensional gray scale image with preset pattern information acquired by the high frame rate gray scale image sensor 31 to realize the real-time reconstruction of the three-dimensional surface shape of the teeth and the surrounding soft tissues, and extracts the color information from the two-dimensional color image to restore the color of the three-dimensional surface shape of the teeth and the surrounding soft tissues so as to realize a true-color three-dimensional image.

In order to eliminate the influence caused by reflection of light of teeth, a polarization optical device is partially selected in an imaging light path, and the polarization characteristic of light is utilized to weaken or eliminate flare spots formed on the surface of the teeth.

To sum up, the utility model provides an intraoral three-dimensional scanner, based on the intraoral three-dimensional scanning system that confocal scanning technology realized three-dimensional data and obtained, through collocating a plurality of black and white image sensors and image splicing technology, realize high-speed image acquisition; the color sensor is matched to acquire full-color information of a uniform view field, so that a colored three-dimensional object structure is realized; compared with the traditional intraoral scanning system, the scanner can improve the image acquisition speed of the high-resolution sensor, and acquire the real color information of an object while realizing the quick acquisition of the surface geometric shape; furthermore, the utility model discloses well liquid lens's introduction has realized the free adjustment of focal plane, has improved the precision and the speed that the focal plane changed simultaneously. Meanwhile, the volume of the three-dimensional scanning system is reduced, and the miniaturization of the intraoral three-dimensional scanning system is realized. The intraoral three-dimensional scanning system that this system provided will further reduce the volume for scanning speed provides true color three-dimensional information of higher accuracy, and is visible from this, the utility model discloses will have important practical meaning and using value, have very high market potential.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for apparatus or system embodiments, since they are substantially similar to method embodiments, they are described in relative terms, as long as they are described in partial descriptions of method embodiments. The above-described embodiments of the apparatus and system are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (9)

1. An intraoral three-dimensional scanner is characterized by comprising a projection lighting device, an imaging device and a control device;

the imaging device comprises a reflecting mirror, a zoom lens, a first beam splitter and a second beam splitter which are arranged from the object side to the image side in sequence, and an image sensor; the zoom lens comprises a liquid lens and a first conventional lens; the image sensor has a high frame rate grayscale image sensor and a color image sensor; the high frame rate gray scale image sensor corresponds to the first beam splitter, and the color image sensor corresponds to the second beam splitter;

the projection lighting device is used for projecting a preset pattern to a measured object to enable the measured object to show the characteristics of a projected image and comprises a lighting source, a digital micro-mirror element and a projection lens; the illumination light source projects an illumination light path to the measured object through the imaging device;

the control device is electrically connected with the imaging device, and is used for controlling the focal power of the zoom lens and collecting images acquired by the zoom lens.

2. The intraoral three-dimensional scanner according to claim 1, wherein the zoom lens comprises a first conventional lens and a liquid lens arranged in order from the object side to the image side.

3. The intraoral three-dimensional scanner of claim 1, wherein the first and second beam splitters are polarizing beam splitters; the intraoral three-dimensional scanner also has a phase retardation plate positioned between the mirror and the zoom lens.

4. The intraoral three-dimensional scanner of claim 1, wherein the high frame rate grayscale image sensor is an array sensor.

5. The intraoral three-dimensional scanner according to claim 1, wherein the control means is adapted to control the optical power of the zoom lens such that the focal plane changes by a step size of less than 50 um.

6. The intraoral three-dimensional scanner according to claim 1, wherein the projection illumination device has a DLP optical engine, the illumination source being a polychromatic illumination source.

7. The intraoral three-dimensional scanner according to claim 1, wherein the high frame rate grayscale image sensor and the color image sensor operate alternately.

8. The intraoral three-dimensional scanner according to any one of claims 1 to 7, further comprising processing means, communicatively connected to said control means, for processing the images acquired by said control means to synthesize a colored three-dimensional image.

9. The intraoral three-dimensional scanner according to any of claims 1 to 7, wherein a second conventional lens is further provided between the first beam splitter and the high frame rate gray scale image sensor, and a third conventional lens is further provided between the second beam splitter and the color image sensor.

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