Oral cavity scanning device and control method thereof

Abstract

The invention discloses an oral cavity scanning device, which relates to the field of three-dimensional scanning and comprises an optical catheter, a projection system, an imaging system and a control system. The optical conduit has a first opening and a second opening; the projection system is used for emitting a preset original stripe image towards the first opening, emitting the preset original stripe image from the second opening and projecting the preset original stripe image to a to-be-detected part in the oral cavity; the imaging system is used for acquiring a reflected deformed stripe image at the first opening; the control system is used for controlling the projection system to project an original stripe image and controlling the imaging system to synchronously acquire a deformed stripe image, and the control system processes the acquired deformed stripe image to reconstruct an intraoral three-dimensional model. Through the optical conduit and the micro mirror surface structure, multiple times of light path turn-back can be realized in a narrow oral cavity environment, and high-precision and miniaturized design is taken into account. The method can be widely applied to orthodontics, implantation, repair and other oral diagnosis and treatment scenes, and has the advantages of high measurement precision, convenient operation, good stability and the like.

Description

Technical Field

[0001] The present application relates to the field of three-dimensional scanning, and in particular to an oral scanning device and a control method thereof. Background Art

[0002] With the continuous acceleration of the digitalization process in the field of oral medicine, dental diagnosis and treatment are gradually changing from traditional manual mold taking to the use of 3D scanning and computer-aided design / manufacturing. In the traditional way, medical staff usually use silicone rubber or plaster materials to take molds of patients' teeth, and then make molds of the obtained models and perform subsequent restorations. However, this process has many shortcomings such as long time consumption, inconvenient operation, and poor patient experience. In addition, the mold making and mold making links will bring certain errors, which will affect the fit and accuracy of the restoration.

[0003] However, traditional 3D scanners are generally large in size and contain complex optical systems and electronic control systems, making them difficult to miniaturize. If the equipment is forcibly reduced in size, imaging accuracy will usually be sacrificed or system costs will increase, which is not conducive to its application in a small oral environment. At the same time, functions such as high-speed acquisition and real-time processing place stringent requirements on the control system of oral 3D scanning devices, and existing products also have bottlenecks in data bandwidth, imaging synchronization, and timing control. Therefore, how to minimize the size of the equipment, ensure scanning accuracy and speed, and control the overall cost of the system has become a key issue in the development of intraoral 3D scanning technology. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes an oral three-dimensional scanning device that can complete the acquisition of oral images and three-dimensional image reconstruction in a compact space.

[0005] The present application also proposes a control method applied to the above-mentioned oral scanning device.

[0006] In a first aspect, the present application proposes an oral three-dimensional scanning device, comprising:

[0007] An optical conduit, wherein a first opening is provided at one end of the optical conduit and a second opening is provided at the side wall of the other end; a projection system, which is used to emit a preset original fringe image toward the first opening, form a projection light path in the optical conduit and emit from the second opening, so as to project the original fringe image onto a part to be measured in the oral cavity; an imaging system, which is used to collect a deformed fringe image at the first opening; wherein the deformed fringe image is an image emitted from the second opening at the part to be measured in the oral cavity, and forms an imaging light path in the optical conduit, and the imaging light path and the projection light path are independent of each other; a control system, which is connected to the projection system and the imaging system respectively, and is used to control the projection system to project the original fringe image and control the imaging system to synchronously collect the deformed fringe image, and the control system processes the collected deformed fringe image to reconstruct a three-dimensional model of the oral cavity.

[0008] According to the oral scanning device of the embodiment of the present application, at least the following beneficial effects are achieved: by arranging the projection light path and the imaging light path in the optical conduit respectively and separating the two light paths, the mutual interference between the projection light and the imaging light can be minimized, the scattering or reflection noise can be reduced, and the accuracy and stability of the stripe image shooting can be significantly improved. At the same time, the unique structure of the optical conduit is conducive to the flexible adjustment of the angle in the narrow oral space, ensuring that the scanning device can effectively cover the part to be measured. The control system realizes synchronous triggering and real-time data processing in projection and imaging, which improves the scanning efficiency and data accuracy while reducing the operation steps, making the reconstructed three-dimensional model more refined. The overall structure of the oral scanning device of the present application is compact and easy to be integrated into the scanning head or handheld device, which reduces the size of the device, improves the convenience of the physician's operation and the comfort of the patient when using it, and the system design has a good suppression effect on noise and interference, and is easier to adapt to complex oral imaging environments.

[0009] According to some embodiments of the present application, the projection system includes a projection light source, a projection grating and a projection lens arranged in sequence along the projection light path, the light source is used to emit illumination light, the projection grating is used to generate the original fringe image for the illumination light, and the projection lens is used to project the original fringe image onto the first opening.

[0010] According to some embodiments of the present application, the imaging system includes an imaging lens and an image sensor arranged in sequence along the imaging optical path, the imaging lens is used to image the deformed stripe image entering the optical conduit, and the image sensor is used to collect image information output by the imaging lens and output it to the control system.

[0011] According to some embodiments of the present application, relatively parallel first reflecting mirror surfaces are provided inside the upper and lower surfaces of the optical conduit, and the first reflecting mirror surfaces are used to reflect the deformed fringe image multiple times and form the imaging light path.

[0012] According to some embodiments of the present application, the second opening is provided with a second reflecting mirror surface for changing the direction of the projection light path, the second reflecting mirror surface forms a certain angle with the first reflecting mirror surface, and the second reflecting mirror surface makes the projection light path and the imaging light path distributed at a preset angle in the oral cavity.

[0013] According to some embodiments of the present application, a scanning head housing is further included, wherein the scanning head housing is provided with a mounting cavity, a scanning head lens and a reflection port connected to the mounting cavity, the optical conduit is arranged in the mounting cavity, and the scanning head lens is arranged on the reflection port.

[0014] According to some embodiments of the present application, the control system includes:

[0015] A main control module, the main control module includes a fringe generation submodule, a timing control submodule and a data processing submodule, the fringe generation submodule is used to generate and send coded fringe information to the projection system, the timing control submodule is used to control the synchronous operation of the projection system and the imaging system, and the data processing submodule is used to collect the deformed fringe image and perform three-dimensional reconstruction; a power supply and clock module provides a stable voltage and system clock reference for the main control module, the imaging system and the projection system.

[0016] According to some embodiments of the present application, the oral scanning device also includes a slave control module and an LED driving module, a temperature control module, an environmental monitoring module, a status display module and a button module connected to the slave controller, and the slave control module is connected to the main control module. The slave control module is used to configure and manage the main control module and control the peripheral functions of the oral scanning device.

[0017] In a second aspect, the present application further proposes a control method applied to the oral scanning device of the first aspect, comprising:

[0018] Load multiple groups of pre-stored fringe patterns and power on and initialize the projection system; control the projection system to sequentially project the original fringe images of different phases onto the oral surface to be tested; when the projection system outputs the specified original fringe pattern, send a trigger signal to the imaging system to enable the imaging system to capture the deformed fringe image corresponding to that time; perform phase solution, three-dimensional reconstruction and stitching processing on the fringe deformed image to obtain a three-dimensional model of the oral target surface.

[0019] According to the control method of the oral scanning device of the embodiment of the present application, at least the following beneficial effects are achieved: by projecting multi-phase stripes on the tooth surface in a narrow space and triggering imaging through time-series synchronization, the deformed stripe image can be accurately captured. After superimposing multiple phase stripes, high-precision, high-detail three-dimensional contour data is obtained to achieve partial or overall splicing of the entire oral cavity. Combined with the oral scanning device of the embodiment of the first aspect, the system volume is greatly reduced while having high accuracy, which is convenient for handheld operation and rapid scanning in clinical scenarios.

[0020] According to some embodiments of the present application, the number of original fringe images is at least 3. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present application is further described below with reference to the accompanying drawings and embodiments, wherein:

[0022] Figure 1 This is a schematic structural diagram of an oral scanning device according to an embodiment;

[0023] Figure 2 It is a schematic diagram of the structure of the projection system and the imaging system of the embodiment;

[0024] Figure 3 A schematic diagram of the connection relationship between the various components of the oral scanning device of the embodiment;

[0025] Figure 4 A schematic diagram of the connection relationship between the control system of the embodiment, the projection system and the imaging system;

[0026] Figure 5 Flow chart of a control method of an oral scanning device according to an embodiment.

[0027] Reference numerals:

[0028] Optical conduit 100; first opening 110; second opening 120; first reflective mirror 130; second reflective mirror 140; projection system 200; projection light source 210; projection grating 220; projection lens 230; imaging system 300; image sensor 310; imaging lens 320; control system 400; projection light path 520; imaging light path 510. DETAILED DESCRIPTION

[0029] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0030] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0031] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0032] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0033] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0034] like Figure 1 and Figure 2As shown, the oral scanning device of the embodiment includes an optical conduit 100, a projection system 200, an imaging system 300, and a control system 400 connected to the projection system 200 and the imaging system 300, wherein a first opening 110 is provided at one end of the optical conduit 100, and the first opening 110 is usually perpendicular to the axis of the optical conduit 100, and a second opening 120 is provided at the side wall of the other end for light projection and image acquisition of the target area in the oral cavity. The projection system 200 and the imaging system 300 are both installed at a position of the optical conduit 100 close to the first opening 110, and are arranged in a certain height difference or up and down layout. For example, the projection system 200 is directly opposite to the first opening 110, and the imaging system 300 is located below the projection system 200, so as to ensure that the projection 520 optical path and the imaging optical path 510 are at a certain angle in the optical conduit 100, and are independent of each other and do not interfere with each other. For example, the projection system 200 includes components such as a projection light source 210, a projection grating 220, and a projection lens 230. When in use, the projection light source 210 emits illumination light toward the projection grating 220, and the projection grating 220 modulates the illumination light and generates an original fringe image, which is then vertically projected into the first opening 110 of the optical conduit 100 by the projection lens 230. In the embodiment, in order to minimize the overall size of the device and meet the requirements of projection in the narrow space inside the oral cavity, a compact projection optical design can be used, such as a combination of an LED micro light source and a small-sized projection lens 230, and a high-efficiency grating, etc., to achieve high resolution and high brightness of the projected image.

[0035] The optical conduit 100 is used to guide the projection light path 520 and the imaging light path 510 inside the device. Figure 1 As shown, the upper and lower surfaces of the optical conduit 100 are respectively provided with first reflective mirrors 130 parallel to each other, which are used to repeatedly reflect and transmit the deformed stripe image reflected from the oral cavity. A second reflective mirror 140 for changing the direction of the projection light path 520 is provided at one end of the optical conduit 100 close to the second opening 120; the second reflective mirror 140 can be at an angle of 45 degrees with the axis of the optical conduit 100, so as to change the direction of the light path of the original stripe image vertically entering the optical conduit 100, and vertically project it to the target surface in the oral cavity through the second opening 120. Correspondingly, the deformed stripe image returns from the oral cavity and enters the second opening 120 along a path opposite to the projection light path 520, and then is reflected multiple times by the first reflective mirror 130 in the optical conduit 100 and arrives at the position of the first opening 110.

[0036] Exemplarily, the imaging system 300 includes components such as an imaging lens 320 and an image sensor 310 (such as a CCD or CMOS image sensor 310), which are arranged near the first opening 110 and are arranged at a certain separation angle with the projection lens 230. After the deformed fringe image enters the optical conduit 100 from the second opening 120, it is reflected multiple times in the upper and lower first reflection mirrors 130, arrives at the first opening 110 along the imaging optical path 510, is imaged by the imaging lens 320, and finally converges on the image sensor 310. After receiving the fringe image with specific phase or frequency information, the image sensor 310 will output a digital image signal to the control system 400 for subsequent three-dimensional reconstruction processing.

[0037] During the operation of the oral 3D scanning device of this embodiment, when the control system 400 starts the projection system 200, the projection light source 210 emits projection light, and the projection light forms a preset original fringe image through the projection grating 220, and then is vertically projected to the first opening 110 of the optical conduit 100 by the projection lens 230. After the original fringe image enters the optical conduit 100, it is deflected by the second reflective mirror 140 and vertically projected from the second opening 120 to the surface of the teeth or oral soft tissue of the part to be measured. Due to the three-dimensional undulations on the oral surface, the fringe pattern is deformed on the oral surface and reflected back to the optical conduit 100; after the deformed fringe image is projected from the second opening 120, it is reflected multiple times by the two first reflective mirrors 130 to reach the first opening 110, collected by the imaging lens 320 and finally imaged on the image sensor 310. The control system 400 can perform phase resolution and three-dimensional reconstruction processing on the image data output by the sensor to obtain the three-dimensional structure information inside the oral cavity.

[0038] In some embodiments, the control system 400 includes a main control module and a power supply and clock module. Figure 5Schematic diagram of the connection relationship between the exemplary control system 400 and the various components of the projection system 200 and the imaging system 300. The main control module further includes a stripe generation submodule, a timing control submodule and a data processing submodule. The stripe generation submodule is usually composed of a programmable logic device (such as FPGA) or a high-performance microprocessor, and is used to generate and send pre-designed coded stripe information to the projection system 200, wherein the stripe information may include a single or multiple sinusoidal stripes, grid stripes or other structured light stripes with different phases. In order to improve the quality and accuracy of the stripes, the corresponding mathematical model can be loaded in the submodule and the stripes can be generated in real time or offline in combination with high-speed digital computing capabilities. The timing control submodule is responsible for coordinating the synchronization of the projection system 200 and the imaging system 300 to ensure that the projected fringe images of different phases are closely coordinated with the acquisition process of the deformed fringe image. Specifically, the timing control module can start or enable the imaging system 300 to collect data in a timely manner after the projection system 200 outputs the fringe image of the specified phase through trigger signals and other means. Through precise clock distribution and interrupt management mechanisms, it is ensured that the image data acquired by the imaging system 300 corresponds to the projection fringe phase information one by one. The data processing submodule mainly completes the reading, storage and three-dimensional reconstruction of image data. For high-performance requirements, the phase solution and three-dimensional reconstruction algorithm of the deformed fringe image can be implemented in an FPGA or a dedicated DSP processor; the data can also be transmitted to the GPU or CPU in the host computer for subsequent calculations. The data processing submodule usually has a high-speed cache function to facilitate the storage of multiple frames of high-resolution images in a short time. The three-dimensional reconstruction process usually includes steps such as fringe demodulation, phase unfolding, calibration parameter correction and point cloud generation, and finally obtains a high-precision three-dimensional model of the oral cavity. The power supply and clock module mainly provides electrical power supply and clock reference functions for the oral scanning device of the entire embodiment. In addition to providing a stable voltage for the main control module, the electrical power supply is also responsible for the power supply of the projection system 200, the imaging system 300 (such as CCD / CMOS photosensitive chip) and other peripheral functional modules (such as LED lighting, temperature detection, display module, etc.). A low-noise voltage-stabilized power supply can usually be selected to ensure that fringe generation and image acquisition are not interfered by the power supply. The clock reference provides a unified high-precision clock signal for the FPGA or microprocessor. Through a phase-locked loop (PLL) or a dedicated crystal oscillator, the timing accuracy of fringe projection and imaging acquisition can be guaranteed, and the synchronization and stability of the high-speed data processing process can be ensured. In some implementations, the module can also perform multiple clock configurations according to different sampling rates or projection frequency requirements to support flexible control under different resolutions or working modes.

[0039] Furthermore, in some embodiments, the control system 400 further includes a slave control module and an LED driving module, a temperature control module, an environment monitoring module, a status display module and a key module connected to the slave control module. Figure 3 The following is a schematic diagram of the connection relationship of various components. The slave control module is connected to the master control module. Its main responsibilities include managing and issuing the configuration information of the master control module, assisting the master control module in system initialization, parameter adjustment, and hardware status detection. The slave control module can also take over many peripheral functions, such as LED driving, temperature control, environmental monitoring, status display, and key input, etc. Through unified firmware and communication protocols, the peripheral functions of the whole machine can be centrally managed, which can not only reduce the real-time burden of the master control module, but also improve the flexibility of system maintenance and upgrades. For example, the slave control module controls the operation of the LED driver module. Unlike ordinary monochrome LED lighting solutions, the projection part of this device needs to quickly switch between red, green and blue to achieve time color mixing. Therefore, the slave control module needs to receive the timing trigger information in the master control module in real time to drive the red, green and blue LEDs respectively and keep the brightness controllable; for example, if the entire device is over-temperature protected, core components such as the LCoS micro display panel, LED light source and FPGA will generate significant heat when working at high frequency. By combining temperature sensors (thermistors or digital thermometers) with heating / air cooling / TEC cooling components, the slave control module can automatically maintain the temperature of key components in a safe range. If the temperature is too high, the slave control module will automatically maintain the temperature of key components in a safe range. The slave control module can issue an alarm to the outside, or notify the main control module to reduce the projection frame rate and adjust the LED power to slow down heat accumulation; for example, to detect whether the scanning environment is normal. When it is detected that the scanning head has left the oral cavity or there are other unfavorable factors, the slave control module will issue a prompt to the main control module or the operator; such as status display and key input, the slave control module drives a simple LED digital indicator light, LCD or OLED screen to display the working status, error warning, temperature and other information of the scanning device in real time. Several function buttons are reserved on the scanning handle or the scanning head shell for the operator to quickly start / stop scanning, switch stripe mode or perform calibration operations. All key signals are collected by the slave control module and can be transmitted to the main control module for further processing.

[0040] It is understandable that the embodiment of the oral three-dimensional scanning is also provided with a scanning head housing. The scanning head housing is a miniaturized, portable structure as a whole, which is used to accommodate and fix the optical catheter 100, the lens and other components. The scanning head housing can reduce the risk of leakage of electrical components that may occur when encountering saliva or water vapor during medical operations, thereby ensuring the safety of doctors and patients. The scanning head housing is provided with an installation cavity and a reflection port connected to the installation cavity, and a scanning head lens is provided on the reflection port to help realize the stripe light projection and deformed stripe image acquisition inside the oral cavity. The scanning head housing is slender or streamlined as a whole, which not only meets the stringent requirements of the space for intraoral operation, but also takes into account the ergonomics during handheld operation. It is preferred that the length of the housing is controlled to be about 100 mm or shorter, so as to penetrate into the narrow oral area and flexibly scan different parts. An installation cavity is provided inside the scanning head housing, and a bracket for carrying the optical catheter 100 and related optical components is built in. According to the application requirements, various fixing structures such as buckles, screw holes and limit steps can be reasonably arranged in the installation cavity to ensure that the optical conduit 100 is firmly positioned inside the scanning head. The optical conduit 100 is fixed in the installation cavity by a positioning member, and the second opening 120 of the optical conduit 100 corresponds to the position of the reflection port. The reflection port is connected to the installation cavity and is used to collect or project images into the oral cavity. The scanning head lens is arranged on the reflection port. The scanning head lens can be used as dustproof, anti-fog or sealing to prevent saliva and water vapor in the oral cavity from contaminating the optical system and electronic components. The overall design of the scanning head strives to be small in size and light in weight, and the length is usually not more than 100 mm, so as to meet the operator's needs for flexible operation in the patient's mouth. For children, adults and other different oral sizes or different scanning parts, a variety of specifications of scanning head housing and lens combinations can also be provided to adapt to complex clinical environments. Furthermore, an electrical cable channel or interface can be reserved inside the scanning head housing to facilitate the lead-out of the driving harness, sensor interface, etc. of the imaging system 300 and the projection system 200 to the handle of the scanning gun or the external host. At the same time, the host box can be selected as a suitcase type or a trolley type structure according to needs, and connected to the electrical cable channel or interface in the scanning head housing through cables to match the operating mode of different working environments.

[0041] In a second aspect, the present application proposes a control method for an oral scanning device applied to an embodiment of the first aspect, such as Figure 5 As shown, the following steps are included:

[0042] s100 , loading a plurality of groups of pre-stored stripe patterns, and powering on and initializing the projection system 200 .

[0043] For example, multiple stripe patterns with different phases and colors (such as red, green, and blue multi-channels) are pre-stored in the internal or external memory of the main control module of the oral scanning device. After powering on, the main control module will load these original stripe patterns into the cache or register in sequence, and prepare for subsequent output to the projection system 200. At the same time, the projection system 200 (such as an LCoS or DLP micro-projector) and the LED driver module that cooperates with it are powered on and initialized, including setting the display resolution, refresh rate, color mode or time mixing strategy, etc. In this process, it may be necessary to enable the temperature control module for real-time detection and fan / TEC adjustment according to the power and thermal management requirements of the projection light source (R / G / B three-color LED, etc.) to ensure that the projection system 200 enters standby in the best state.

[0044] s200, controlling the projection system 200 to sequentially project original fringe images of different phases onto the oral cavity surface to be tested.

[0045] For example, the main control module sends the loaded multiple stripe patterns (such as three-step phase shift, four-step phase shift, six-step phase shift and other self-set coded stripes) to the projection system 200 in a set order, and combines the LCoS micro-display technology and the driving mechanism of time mixing color (R / G / B sequential lighting) to achieve multi-color and multi-phase stripe projection. The projection light is guided to the surface of the tooth to be measured through the optical guide 100 to achieve clear and stable stripe projection in a narrow space. If the measurement is performed at different scanning angles, the scanning head position can be rotated or moved in the mechanical structure or handheld operation to perform multi-segment splicing scanning of adjacent tooth areas.

[0046] It can be understood that, taking the three-step phase shift as an example, the first fringe phase is 0°, the second fringe phase is 120°, and the third fringe phase is 240°. At this time, each fringe has sufficient grayscale gradient distribution to support phase measurement profilometry. The projection system 200 projects the three fringe in sequence, and the tooth surface in the oral cavity receives the fringe light of different phases in sequence. If the device adopts time color mixing technology (such as RGB three channels), the red light, green light or blue light LED is turned on in sequence in the same period, combined with the three-step phase shift stripes output by the FPGA, to achieve rapid switching and projection of the three fringe images at the subframe level. In this way, not only color information can be obtained, but also richer phase data can be obtained to support more complex three-dimensional reconstruction algorithms. By measuring the phase shift of at least three fringe images, the limitation of the traditional single or double fringe affecting the reconstruction accuracy is overcome. Of course, if the accuracy or detail requirements are higher, the three-step phase shift can be expanded to four-step, six-step and other multi-step phase shift fringe projections, and even the same viewing angle can be collected multiple times, so as to obtain higher-precision phase data at the algorithm level.

[0047] s300, when the projection system 200 outputs the designated original fringe pattern, a trigger signal is sent to the imaging system 300, so that the imaging system 300 acquires the corresponding deformed fringe image at that time.

[0048] For example, while projecting a certain phase fringe, the main control module sends a trigger signal (such as GPIO level, high-speed serial or interrupt flag) to the imaging system 300; the imaging system 300 thus opens the shutter in the correct time window and acquires the corresponding deformed fringe image. This ensures that when the projection system 200 switches to the red or blue subframe, the camera accurately captures the deformed fringe image of the corresponding color to avoid image aliasing or timing disorder. The acquired deformed fringe image can be first stored in the local cache of the imaging system 300 or the memory of the main control module, and then the multiple phase-shifted fringe images are marked according to the serial number or timestamp, so that the subsequent three-dimensional solution algorithm can perform pairing operations; if the hardware resources permit, it can also be uploaded to the host computer (PC or host) for real-time processing while being acquired.

[0049] s400, performing phase solution, three-dimensional reconstruction and splicing processing on the stripe deformation image to obtain a three-dimensional model of the oral target surface.

[0050] In the example, after collecting enough phase-shifted fringes, the grayscale in the image is phase-unwrapped and demodulated according to the principle of phase measurement profilometry to obtain the phase value corresponding to each pixel on the tooth surface. If the system integration is high, this step can be completed directly in the FPGA or high-performance DSP processor, or the data can be transmitted to the PC through a high-speed interface such as USB 3.0 or GigE for offline / quasi-real-time calculation. Then, based on the phase value and the calibrated system parameters (such as the focal length of the projection lens 230 and the imaging lens 320, the compensation of the geometric distortion caused by the optical catheter 100, the correction of the spatial angle between projection and imaging, etc.), the three-dimensional coordinate values ​​of the corresponding points on the surface of the object are calculated using triangulation to form an initial three-dimensional point cloud or mesh model. For measurement scenarios with a large oral area, it is usually necessary to align and stitch the local three-dimensional results obtained under multiple scanning angles. A global stitching algorithm based on feature points or feature surfaces can be used to achieve reconstruction of a large-scale three-dimensional model of the oral target surface. The three-dimensional model obtained after the splicing is completed can be displayed in real time on the status display module (such as a small LCD screen) through the main control module, and can also be uploaded to the host computer software for further rendering, measurement and analysis, which is convenient for doctors to make professional decisions such as orthodontics and restoration.

[0051] By projecting multi-phase stripes on the tooth surface in a narrow space and triggering imaging through time-series synchronization, the deformed stripe image can be accurately captured. Multiple phase stripes are superimposed to obtain high-precision, high-detail three-dimensional contour data, and partial or overall splicing of the entire oral cavity can be achieved. Combined with the oral scanning device of the first embodiment, the system volume is greatly reduced while having high accuracy, which is convenient for handheld operation and rapid scanning in clinical scenarios.

[0052] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. An oral scanning device, characterized in that: include: An optical conduit, wherein one end of the optical conduit is provided with a first opening, and a side wall of the other end of the optical conduit is provided with a second opening; A projection system, configured to emit a preset original fringe image toward the first opening, form a projection light path in the optical conduit and emit from the second opening, so as to project the original fringe image onto a part to be measured in the oral cavity; An imaging system, used for collecting a deformed fringe image at the first opening; wherein the deformed fringe image is an image incident from the second opening at the part to be measured in the oral cavity, and forms an imaging light path in the optical conduit, and the imaging light path and the projection light path are independent of each other; A control system, wherein the control system is connected to the projection system and the imaging system respectively, and is used to control the projection system to project the original fringe image, and simultaneously control the imaging system to synchronously acquire the deformed fringe image, and the control system processes the acquired deformed fringe image to reconstruct the intraoral three-dimensional model.

2. The oral scanning device according to claim 1, characterized in that: The projection system includes a projection light source, a projection grating and a projection lens which are sequentially arranged along the projection light path. The projection light source is used to emit illumination light, the projection grating is used to generate the original fringe image for the illumination light, and the projection lens is used to project the original fringe image onto the first opening.

3. The oral scanning device according to claim 1, characterized in that: The imaging system comprises an imaging lens and an image sensor sequentially arranged along the imaging optical path. The imaging lens is used to image the deformed fringe image entering the optical conduit. The image sensor is used to collect image information output by the imaging lens and output it to the control system.

4. The oral scanning device according to claim 1, characterized in that: Relatively parallel first reflecting mirrors are arranged inside the upper and lower surfaces of the optical conduit. The first reflecting mirrors are used to reflect the deformed fringe images multiple times and form the imaging light path.

5. The oral scanning device according to claim 4, characterized in that: A second reflecting mirror is provided at one end of the optical conduit close to the second opening for changing the direction of the projection light path. The second reflecting mirror forms a certain angle with the first reflecting mirror. The second reflecting mirror makes the projection light path and the imaging light path distributed at a preset angle in the oral cavity.

6. The oral scanning device according to any one of claims 1 to 5, characterized in that: It also includes a scanning head shell, which is provided with a mounting cavity, a scanning head lens and a reflection port communicated with the mounting cavity, the optical conduit is arranged in the mounting cavity, and the scanning head lens is arranged on the reflection port.

7. The oral cavity scanning device according to any one of claims 1 to 5, characterized in that: The control system comprises: A main control module, the main control module includes a fringe generation submodule, a timing control submodule and a data processing submodule, the fringe generation submodule is used to generate and send coded fringe information to the projection system, the timing control submodule is used to control the synchronous operation of the projection system and the imaging system, and the data processing submodule is used to collect the deformed fringe image and perform three-dimensional reconstruction; The power supply and clock module provides a stable voltage and system clock reference for the main control module, the imaging system and the projection system.

8. The oral scanning device according to claim 7, characterized in that: It also includes a slave control module and an LED driving module, a temperature control module, an environment monitoring module, a status display module and a button module connected to the slave control module. The slave control module is connected to the main control module. The slave control module is used to configure and manage the main control module and control the peripheral functions of the oral scanning device.

9. A method for controlling an oral scanning device, characterized in that: The control method is applied to the oral scanning device according to any one of claims 1 to 8, and the control method comprises the following steps: Loading a plurality of pre-stored groups of stripe patterns and powering on and initializing the projection system; Controlling the projection system to sequentially project the original fringe images of different phases onto the oral cavity surface to be tested; When the projection system outputs the designated original fringe image, a trigger signal is sent to the imaging system to enable the imaging system to acquire the deformed fringe image corresponding to that time; Phase solution, three-dimensional reconstruction and splicing processing are performed on the fringe deformation image to obtain a three-dimensional model of the part to be measured in the oral cavity.

10. The control method according to claim 9, characterized in that: The number of the original fringe images is at least 3.

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