Intraoral scanning system with improved scan sequence planning

Abstract

The present disclosure relates to an intraoral scanning system configured to determine three-dimensional data of a dental object. The intraoral scanning system comprises a projection unit configured to emit a first visible light, a second visible light and an infrared light during a scanning sequence, wherein the emitted first visible light comprises an illumination pattern; an image sensor unit configured to acquire a two-dimensional visible image based on the first visible light and the second visible light, and / or to acquire a two-dimensional infrared image based on the infrared light from the dental object; and one or more processors configured to control the projection unit and / or the image sensor unit according to a plurality of scanning sequence plans, wherein each scanning sequence plan of the plurality of scanning sequence plans comprises a timing of the projection unit and / or the image sensor. The one or more processors are configured to determine a three-dimensional model of the dental object based on the two-dimensional visible images comprising the first visible light, and the one or more processors are configured to switch between each scanning sequence plan of the plurality of scanning sequence plans.

Description

Technical Field

[0001] This disclosure relates to an intraoral scanning system. More specifically, this disclosure relates to one or more processors of the system configured to control a plurality of scan sequence plans, wherein each of the plurality of scan sequence plans includes timing of a projection unit and / or an image sensor. Background Technology

[0002] Many dental and orthodontic procedures can benefit from a precise three-dimensional (3D) description of the patient's dentition and oral cavity. Specifically, providing a three-dimensional description of the tooth surface and internal structures, including the enamel and dentin, as well as the overall internal composition of caries and tooth volume, would be extremely useful. While pure surface representations of the three-dimensional tooth surfaces have proven extremely useful in the design and fabrication of dental restorations such as crowns or bridges, the ability to image internal structures, including the development of caries and tooth cracks in the enamel and underlying dentin, would be of great use, especially when combined with surface topography mapping.

[0003] In the prior art, ionizing radiation (e.g., X-rays) has been used to image teeth for diagnostic purposes. For example, X-ray bite wings are often used to provide non-quantitative images of the internal structure of teeth. However, in addition to the risks of ionizing radiation, such images are generally limited in their ability to show early changes in tooth mineralization (e.g., early caries), leading to an underestimation of demineralization depth; they cannot assess the presence of microcavities; and they can cause frequent overlap of adjacent tooth surfaces, requiring repeated X-ray image acquisitions, which can therefore involve a lengthy and costly process.

[0004] Because soft tissues and certain oral cavity features, such as dental plaque, have low density, they are usually not visible to X-rays. Other techniques, such as cone-beam computed tomography (CBCT), can provide tomographic images and are used to gather more information about tissues and internal structures, but still require ionizing radiation.

[0005] Furthermore, near-infrared (NIR) light is known to be used to assess the internal structure and surface of teeth, in the form of transillumination or light reflection and backscattering from the teeth. The near-infrared range provides a non-ionizing and safe method for assessing dental caries, restorations, cracks, enamel, and dentin defects.

[0006] Subsurface diagnostics provided by infrared / near-infrared imaging can be supplemented by using blue / ultraviolet light to excite bacteria in dental plaque and perform fluorescence visualization of teeth, while simultaneously capturing fluorescence signals. These fluorescence signals can be converted into images and combined with three-dimensional information of the jawbone to aid in the diagnosis of the risk of early caries formation and facilitate communication of proper oral hygiene practices.

[0007] A fundamental requirement for intraoral scanners is that additional diagnostic capabilities should not compromise the quality of 3D scans.

[0008] In known intraoral scanning devices, the scan sequences are pre-programmed to make customization difficult without significant changes to the scanner's firmware. Therefore, a user may be satisfied with a pre-programmed scan sequence that may not be suitable for the scan they need to perform on the patient. Summary of the Invention

[0009] One aspect of this disclosure is to provide a scanning sequence, meaning a sequence that captures structural and diagnostic information during routine scanning of the jawbone, thereby providing a solution that meets the basic requirements of intraoral scanners.

[0010] Another aspect of this disclosure is providing users with the ability to change the scanning sequence without involving the manufacturer of the intraoral scanning system or with only minimal involvement of the manufacturer.

[0011] According to various aspects, an intraoral scanning system is disclosed. The intraoral scanning system can be configured to determine a three-dimensional (3D) model of a dental object. The intraoral scanning system may include a projection unit configured to emit first visible light, second visible light, and infrared light during a scanning sequence, wherein the emitted first visible light includes an illumination pattern. The second visible light may include the illumination pattern. The system may include an image sensor unit configured to acquire a two-dimensional visible image based on the first and second visible light, and / or acquire a two-dimensional infrared image based on the infrared light from the dental object. The captured first visible light may include the illumination pattern, which can be used to determine the three-dimensional model of the dental object. The second visible image, which may include the second visible light, may include an illumination pattern not used to determine the 3D model, but rather the second visible image is used to combine with the first visible light and the captured infrared image to generate combined scan information.

[0012] The projection unit may include multiple light sources configured to emit different wavelengths, such as first visible light with a wavelength range between 450 nm and 750 nm, second visible light with a wavelength range between 350 nm and 450 nm, and infrared light with a wavelength range between 800 nm and 1150 nm.

[0013] The projection unit can be configured to emit light of different wavelengths onto at least a dental object during multiple time periods, wherein the different wavelengths include at least near-infrared wavelengths and at least visible wavelengths. The wavelength can be different for each time period.

[0014] The projection unit may include multiple light sources configured to emit light suitable for determining the surface information, fluorescence information, and internal structural information of the teeth in the dental arch.

[0015] The projection unit may include one or more first light sources and at least one or more second light sources, wherein the one or more first light sources are configured to emit light in the near-infrared wavelength spectrum during a first set of time periods, and the one or more second light sources are configured to emit light in the visible wavelength spectrum during a second set of time periods. The system may be configured to switch between the one or more first light sources and the at least one or more second light sources. The switching may mean turning the light sources on and off, and / or adjusting the power applied to the light sources.

[0016] The light source can be a combination of one or more of the following:

[0017] Light-emitting diode (LED)

[0018] Broadband light-emitting diodes, and

[0019] Continuous broadband light-emitting diode.

[0020] The projection unit may include at least one or more third light sources, wherein the one or more second light sources may be configured to emit light at a first visible wavelength during a second set of time periods, and the one or more third light sources may be configured to emit light at a second visible wavelength during a third set of time periods. The first visible wavelength may be different from the second visible wavelength, and the visible light information may include information corresponding to reflections caused by the first visible wavelength and captured by the image sensor, and the visible light information may include information corresponding to fluorescence information caused by the second visible wavelength and captured by the image sensor unit.

[0021] The near-infrared wavelength can be between 800 nm and 1150 nm, the first visible wavelength can be between 380 nm and 700 nm, the second visible wavelength can be between 100 nm and 500 nm, and the visible wavelength can be between 100 nm and 700 nm.

[0022] The image sensor unit may include one or more cameras, wherein each of the one or more cameras includes a pixel array. The image sensor unit may be disposed within an end housing.

[0023] The image sensor unit and the projection unit can be arranged within the scanning unit. In some embodiments, the scanning unit may include at least two camera units having at least partially overlapping fields of view along different camera optical axes. Preferably, each scanning unit includes at least four camera units having at least partially overlapping fields of view along different camera optical axes. One advantage of overlapping the fields of view of the camera units is that it improves accuracy by reducing the amount of image stitching error.

[0024] The one or more processors may be configured to control the projection unit and / or the image sensor unit according to a plurality of scan sequence plans, wherein each of the plurality of scan sequence plans includes the timing of the projection unit and / or the image sensor. Each of the plurality of scan sequence plans may include a time slot for emitting the first visible light, the second visible light, and / or the infrared light by the projection unit. The scan sequence plans may be user-programmed to include combinations of time slots, the combination of which includes one or more of the first visible light, the second visible light, and the infrared light; alternatively, the scan sequence plan may include a time slot for emitting only one of the first visible light, the second visible light, and the infrared light. Each of the plurality of scan sequence plans may include a time slot for acquiring the two-dimensional visible image and / or the two-dimensional infrared image via the image sensor unit. A time slot for emitting a specific wavelength may be synchronized with a time slot for acquiring the specific wavelength. The specific wavelength may be included in the first visible light, the second visible light, or the infrared light. Each of the plurality of scanning sequence plans may include a time slice for processing the acquired two-dimensional visible image and / or the two-dimensional infrared image. The timing of the processing may be aligned with the timing of the emitted light and / or the timing of the acquired two-dimensional visible image and / or the two-dimensional infrared image. The scanning sequence plan may include time slices, wherein each time slice includes a timing sequence of emitted light, image acquisition, and image processing.

[0025] The timing of the projection unit and / or the image sensor unit may include the timing of emitting the first visible light and the infrared light, and / or the timing of acquiring the two-dimensional visible image and / or the two-dimensional infrared image.

[0026] The one or more processors may be configured to process the acquired two-dimensional visible image and the two-dimensional infrared image according to each of the plurality of scan sequence plans.

[0027] The timing of the time slices in each of the plurality of scan sequence plans can be based on a cyclical rotation principle, which includes a specific number of time slices repeated in a cyclical order.

[0028] Processing performed by the one or more processors may include downsampling the acquired image for wireless transmission.

[0029] The one or more processors may be configured to process the acquired 2D visible image and / or the 2D infrared image by downsampling the acquired image and / or by performing color space conversion on the acquired image, wherein the color space conversion includes converting the image from a first color space model to a second color space model and vice versa. The first color space model may include a red-green-blue (RGB) color space model, and the second color space model includes a Y (luminance) and UV (grayscale deviation) (YUV) color space model. Conversion to the YUV color space is performed to apply the H.265 compression protocol to the YUV-converted 2D visible image and / or the 2D infrared image. The compressed 2D visible image and / or the 2D infrared image is then wirelessly transmitted to an external processor of the system.

[0030] The system may include a user interface configured to receive user input regarding an operating mode of the intraoral scanning system, wherein the operating mode selects one or more scanning sequence plans from a plurality of scanning sequence plans. For example, the operating mode may be one of the following modes:

[0031] A diagnostic mode in which a combination of infrared and ultraviolet (visible) light is emitted at different time slices in a scan sequence plan, and wherein the one or more processors are configured to determine fluorescence and infrared images;

[0032] An infrared diagnostic mode, wherein infrared light is emitted in different time slices of a scan sequence plan, and wherein the one or more processors are configured to determine an infrared image;

[0033] A fluorescence diagnostic mode in which ultraviolet light (visible light) is emitted at different time slices in a scan sequence plan, and wherein the one or more processors are configured to determine a fluorescence image;

[0034] A combined diagnostic mode, wherein a combination of infrared light, ultraviolet light (visible light), and white light (light) is emitted at different time slices in a scan sequence plan, and wherein; the one or more processors are configured to determine a combined scan image, the combined scan image including differences between a fluorescence image, a white light image, and an infrared image; and

[0035] A three-dimensional scanning mode in which white light with an illumination pattern is emitted, and wherein the one or more processors are configured to determine a three-dimensional model based on the illumination pattern.

[0036] In another example, the three-dimensional scanning mode can be combined with any of the following modes: diagnostic mode, infrared diagnostic mode, fluorescence diagnostic mode, and combined diagnostic mode.

[0037] The plurality of scan sequence plans may include two or more of the following plans:

[0038] A 3D scanning sequence plan, which includes time slices for emitting first visible light with wavelengths between 400 nm and 750 nm to determine a 3D model of a dental object.

[0039] The ultraviolet scanning sequence plan includes time slices for emitting first visible light with wavelengths between 400 nm and 750 nm and second visible light with wavelengths between 350 nm and 450 nm emitted by a projection unit.

[0040] The hyperspectral scanning sequence program includes time slices for emitting first visible light with wavelengths between 400 nm and 750 nm, second visible light with wavelengths between 350 nm and 450 nm, and infrared light with wavelengths between 850 nm and 1100 nm.

[0041] The plurality of scan sequence plans may include two or more of the following plans:

[0042] A 3D scanning sequence plan, which includes time slices for acquiring the two-dimensional visible images with wavelengths between 400 nm and 750 nm to determine a 3D model of the dental object;

[0043] An ultraviolet scanning sequence plan includes acquiring a two-dimensional visible image of the dental object with a fluorescence wavelength provided by the second visible light, and acquiring the two-dimensional visible image with a wavelength between 400 nm and 750 nm in a time slice to determine a 3D model of the dental object;

[0044] The hyperspectral scanning sequence plan includes time slices for acquiring the two-dimensional visible image with wavelengths between 400 nm and 750 nm to determine a 3D model of the dental object, acquiring the two-dimensional visible image from the dental object with fluorescence wavelengths, and acquiring the two-dimensional infrared image with wavelengths between 850 nm and 1100 nm.

[0045] The plurality of scan sequence plans may include two or more of the following plans:

[0046] A 3D scanning sequence plan, comprising timing for the one or more processors to process a 3D model determined based on the two-dimensional visible image with wavelengths between 400 nm and 750 nm;

[0047] An ultraviolet scanning sequence plan includes processing the acquired two-dimensional visible image, including fluorescence wavelengths from the dental object provided by the second visible light, by the one or more processors, and processing the acquired two-dimensional visible image with wavelengths between 400 nm and 750 nm to determine the timing of a 3D model of the dental object;

[0048] A hyperspectral scanning sequence plan comprising the timing of processing by the one or more processors of the acquired two-dimensional visible image with wavelengths between 400 nm and 750 nm, the acquired two-dimensional visible image including fluorescence wavelengths from the dental object, and the acquired two-dimensional infrared image with wavelengths between 850 nm and 1100 nm.

[0049] The multiple scanning sequence plans can be combined such that the 3D scanning sequence plan, the ultraviolet scanning sequence plan, and the hyperspectral scanning sequence plan will include light emission, light acquisition, and processing of the acquired light. For example, the hyperspectral sequence plan may include, for each time slice:

[0050] The device emits first visible light with a wavelength between 400 nm and 750 nm, second visible light with a wavelength between 350 nm and 450 nm, and infrared light with a wavelength between 850 nm and 1100 nm.

[0051] Acquire the two-dimensional visible image with wavelengths between 400 nm and 750 nm to determine a 3D model of the dental object; the two-dimensional visible image of the dental object with fluorescence wavelengths; and the two-dimensional infrared image with wavelengths between 850 nm and 1100 nm; and

[0052] The process involves processing the acquired two-dimensional visible image with wavelengths between 400 nm and 750 nm, the acquired two-dimensional visible image including fluorescence wavelengths from the dental object, and the acquired two-dimensional infrared image with wavelengths between 850 nm and 1100 nm.

[0053] For example, the 3D scan sequence plan may include, for each time slice:

[0054] The first visible light with a wavelength between 400 nm and 750 nm is emitted to determine the 3D model of the dental object.

[0055] Two-dimensional visible images with wavelengths between 400 nm and 750 nm were acquired to determine a 3D model of the dental object, and

[0056] The 3D model is determined based on the two-dimensional visible image with wavelengths between 400 nm and 750 nm.

[0057] For example, the ultraviolet scanning sequence plan may include, for each time slice:

[0058] The projection unit emits first visible light with wavelengths between 400 nm and 750 nm and second visible light with wavelengths between 350 nm and 450 nm.

[0059] Acquire the two-dimensional visible image of the dental object with a fluorescence wavelength provided by the second visible light, and acquire the two-dimensional visible image with a wavelength between 400 nm and 750 nm to determine a 3D model of the dental object.

[0060] The acquired two-dimensional visible image, including the fluorescence wavelength from the dental object provided by the second visible light, is processed to determine a 3D model of the dental object.

[0061] In a hyperspectral scanning sequence plan, light acquired by the image sensor unit can be combined into a composite scan image. Furthermore, acquired light, including wavelengths of the first visible light, is used to determine a 3D model of the dental object and is combined into the composite scan image. Additionally, acquired fluorescence excited by wavelengths of the second visible light is used to determine a fluorescence image of the dental object and is combined into the composite scan image. Furthermore, acquired infrared light is used to determine an infrared image or is combined into the composite scan image.

[0062] The combined scan image may include differences between the following: the wavelength of the acquired light, the acquired fluorescence, and / or the acquired infrared light.

[0063] The operation mode can be one or more of the following modes:

[0064] The first diagnostic mode includes the hyperspectral scanning sequence plan;

[0065] The second diagnostic mode includes the aforementioned ultraviolet scanning sequence plan;

[0066] A three-dimensional model, comprising the 3D scan sequence plan; and

[0067] The fourth mode includes two or more of the first diagnostic mode, the second diagnostic mode, and the three-dimensional mode.

[0068] The one or more processors may be configured to determine a 3D model of the dental object based on the two-dimensional visible image including the first visible light, and wherein the one or more processors are configured to switch between each of the plurality of scan sequence plans. The switching between each of the plurality of scan sequence plans may be programmed by a user for a specific scan scenario.

[0069] The intraoral scanning system may include a focusing lens unit configured to change the focus of the image sensor unit during a scanning sequence. The focus is changed by moving a focusing lens of the focusing lens unit. The focusing lens may be configured to move along a first direction, and the image sensor unit may be configured to acquire two-dimensional visible images and / or two-dimensional infrared images through the focusing lens and while the focusing lens moves at least along the first direction. The focusing lens may move from an initial position along the first direction to an end position, and a complete scan of the focusing lens occurs when the focusing lens has reached the end position. Multiple 2D visible images and multiple infrared images may be acquired at different positions from the initial position to the end position, and at each different position, a portion of the pixels in the acquired 2D visible images and the acquired infrared images are in focus. After a complete scan, the pixels in focus of the multiple 2D visible images can be combined into a three-dimensional model of a dental object. Furthermore, after a complete scan, the pixels in focus of the multiple infrared images can be combined into an infrared image in which all pixels are in focus.

[0070] After a complete scan, the focusing lens returns to the initial position so that another scan can be performed. No image acquisition occurs during the movement of the focusing lens back to the initial position. In another example, the focusing lens may be configured to move along a second direction, wherein the first direction is opposite to the second direction. The image sensor unit may be configured to acquire the two-dimensional visible image and the two-dimensional infrared image simultaneously, according to the plurality of scan sequences, as the focusing lens moves along the first direction and then along the second direction. In this example, the acquisition rate of the two-dimensional visible image and the two-dimensional infrared image is significantly improved. This results in a faster scanning experience. The frame rate of the image sensor unit is different when the focusing lens moves in the first and second directions. For example, the intraoral scanner may include an accelerometer configured to determine the movement speed of the intraoral scanner, or one or more processors may be configured to determine the movement speed of the intraoral scanner by tracking the positions of at least two or more known elements appearing in the captured two-dimensional image and the frame rate of the image sensor. Based on the movement speed, the frame rates in the two directions may be different. For example, if the user moves the intraoral scanner too quickly, the frame rate of the image sensor unit will be higher when the focusing lens moves in the second direction than when the focusing lens moves in the first direction. In another example, if the user moves the intraoral scanner in an ideal manner, the frame rate of the image sensor will be lower when the focusing lens moves in the second direction than when the focusing lens moves in the first direction.

[0071] Each time slice of each of the plurality of scan sequence plans can determine whether a two-dimensional image should be acquired during the movement of the focusing lens in both directions, or whether a two-dimensional image should be acquired only during the movement in one of the two directions.

[0072] The timing of acquiring an image set including a 2D visible image, a 2D visible fluorescence image, and a 2D infrared image can be determined by the focusing position of the focusing lens. For example, the plurality of scanning sequence plans include a focusing scanning sequence plan, wherein the focusing scanning sequence plan includes time slices timed by the focusing lens at least in the focusing position of the focusing lens in the first direction and / or the second direction. The time slices of the focusing scanning sequence plan are used to acquire an image set comprising: the 2D visible image with wavelengths between 400 nm and 750 nm to determine a 3D model of the dental object; the 2D visible image from the fluorescence wavelength of the dental object; and the 2D infrared image with wavelengths between 850 nm and 1100 nm. The image set can be combined into a composite scan image. Each image in the image set can include multiple color channels, and the combination of two or more images in the image set can involve one or more color fusions of the multiple color channels. Each color channel can be assigned a weighting coefficient, which is adjusted by the one or more processors to improve the contrast of the composite scan image. Furthermore, the contrast of the composite scan image can be further improved by a contrast enhancement algorithm. The contrast enhancement algorithm can be applied once or multiple times to one or more color channels of one or more images in the image group. The contrast enhancement algorithm can also be applied to one or more color channels of the combined scanned image.

[0073] The contrast enhancement algorithm may be one or more of the following linear contrast stretching algorithms, or a combination of two or more of the following linear contrast stretching algorithms:

[0074] Minimum-Maximum Linear Contrast Stretch (MMLC);

[0075] Percentage Linear Contrast Stretch (PLC) and segmentation;

[0076] Linear Contrast Stretch (PWLC).

[0077] The contrast enhancement algorithm may be one or more of the following nonlinear contrast enhancement algorithms, or a combination of two or more of the following nonlinear contrast enhancement algorithms:

[0078] This includes histogram equalization (HE) of histogram distribution.

[0079] Adaptive Histogram Equalization (AHE) and

[0080] Homomorphic filters (HF) include combinations of low-pass and high-pass filters.

[0081] The contrast enhancement algorithm may be a combination of one or more nonlinear contrast enhancement algorithms and one or more linear contrast enhancement algorithms.

[0082] The focusing scan sequence plan may include a set of time slices for emitting a light sequence, the set of time slices being timed by the focusing position such that the set of time slices is activated when the focusing lens reaches the focusing position. Activating the set of time slices involves emitting light for each grouped time slice. For example, a first time slice in the set of time slices may be configured to emit infrared light, a second time slice in the set of time slices may be configured to emit first visible light, and a third time slice in the set of time slices may be configured to emit second visible light. Each time slice in the grouped time slices may involve acquiring the emitted light and processing the acquired light.

[0083] The focusing scan sequence plan may include another set of time slices, which, when not enabled, may be configured to emit the first visible light. The first visible light may be used to determine a three-dimensional model of the dental object.

[0084] The focus position can be determined by the one or more processors during the first scan stroke of the focusing lens, and during subsequent scan strokes following the first scan stroke, grouped time slices of the focus scan sequence plan are enabled at the focus position.

[0085] The focus position can be determined by the one or more processors during the first full scan stroke of the focusing lens, and during subsequent full scan strokes following the first scan stroke, grouped time slices of the focus scan sequence plan are enabled at the focus position.

[0086] The first scan stroke precedes the scan stroke of the focusing lens when the grouped time slices are activated.

[0087] When all time slices of the set of time slices have been executed by the one or more processors, the set of time slices of the focus scan sequence plan can be disabled.

[0088] The focusing position of the focusing lens can be determined by the one or more processors, and at the focusing position, a specific group of pixels in one of the acquired two-dimensional visible images is in focus, wherein the focus is determined by the intensity of the specific group of pixels. The specific group of pixels includes pixels of the acquired two-dimensional visible image arranged at the center of the acquired two-dimensional visible image.

[0089] The one or more processors are configured to switch from a 3D scanning sequence plan to a hyperspectral scanning sequence plan based on a trigger signal. The trigger signal can be determined by the one or more processors when the focusing lens of the focusing unit is located in focus on a specific portion of the acquired two-dimensional visible image. Upon completion of the hyperspectral scanning sequence plan, the one or more processors can be configured to switch back to the 3D scanning sequence plan.

[0090] The plurality of scan sequence plans are arranged in a master sequence plan, wherein the one or more processors can be configured to switch between each of the plurality of scan sequence plans based on the master sequence plan.

[0091] The multiple scan sequence plans can be arranged in the main sequence plan based on a round-robin principle.

[0092] The system may include a user interface configured to arrange or rearrange two or more scan sequence plans among the plurality of scan sequence plans in the master sequence plan. Thus, the user can customize the master sequence plan for a specific scan scenario.

[0093] Each of the plurality of scan sequence plans may include at least three time slices.

[0094] According to various aspects, an intraoral scanning system is disclosed. The intraoral scanning system can be configured to determine 3D data of a dental object in an oral cavity. The intraoral scanning system may include a handheld intraoral scanner including a projection unit configured to emit visible light and infrared light during a scanning sequence. The system may include an image sensor unit configured to acquire visible light signals and infrared signals, respectively, caused by the emitted visible light and infrared light, from at least the dental object. The image sensor unit may be a high-speed camera with a frame rate higher than 60 frames per second. The image sensor unit may be an ultra-high-speed camera with a frame rate higher than 500 frames per second. The system may include one or more processors configured to control the projection unit and / or the image sensor unit according to a plurality of scanning sequence plans, wherein each of the plurality of scanning sequence plans includes a timing sequence of the projection unit and / or the image sensor. The one or more processors may be configured to determine a 3D model of the dental object based on a two-dimensional visible image including a first visible light, and wherein the one or more processors are configured to switch between each of the plurality of scanning sequence plans.

[0095] The one or more processors may be configured to control the power level of the emitted infrared light to a first power level during a first time period of the scanning sequence, and to switch the power level of the emitted infrared light between the first power level and a second power level during a second time period, wherein the first power level is lower than the second power level. The one or more processors may also be configured to determine 3D data based on visible light signals acquired during the first time period and to determine internal regions of the dental object based on infrared signals acquired during the second time period.

[0096] One or more of the plurality of monochrome channels may be configured to transmit infrared light and block visible light.

[0097] The power of the projection unit controlled by the one or more processors may be the power supplied to the projection unit.

[0098] The image sensor unit may include multiple cameras, such as high-speed cameras. In one example, the multiple cameras may be arranged around or adjacent to the projection unit.

[0099] The internal region of the dental object can be determined by the one or more processors based on the infrared signal. The internal region may include information about dental features disposed within the dental object. The dental features may be one or more of anatomical features, disease features, and mechanical features. The anatomical features may be enamel, dentin, or pulp. The disease features may be plaque, cracks, or caries. The mechanical features may be fillings and / or composite restorations.

[0100] The projection unit may include multiple light sources configured to emit light of one or more colors and infrared light. The multiple light sources may be arranged within a single module, which includes multiple light-emitting diodes (LEDs) configured to emit different wavelengths in the visible and invisible wavelength ranges. Alternatively, the light source configured to emit infrared light (i.e., one or more LEDs) may be arranged separately from the light source configured to emit visible light.

[0101] During the first time period, the one or more processors may be configured to determine sub-internal region information based on the infrared signal and enhance 3D data by combining the visible light signal with the sub-internal region information. In this example, the sub-internal region information is subtracted from the visible light signal to obtain the enhanced 3D data, wherein noise that may have been generated in the 3D data due to the emission of infrared light during the first time period is removed.

[0102] During the second time period, the one or more processors may be configured to determine internal region information based on the infrared signal and to determine a combined scan image based on the infrared signal and the visible light signal, wherein the combined scan image includes enhanced internal region information. In this example, the combined scan image may include the visible light signal subtracted from the infrared signal.

[0103] During the first time period, the first power level of the emitted infrared light can be lower than the noise floor level of the image sensor unit. By not turning off the infrared light, but instead reducing the power of the emitted infrared light to the first power level just below the noise floor level, the quality of the 3D data is not affected by the emitted infrared light during the first time period. Furthermore, since the infrared light is not turned off, no undesirable transients occur on the emitted light pulses.

[0104] The one or more processors may be configured to control the projection unit during a scan sequence, wherein during the first time period, the emitted visible light includes first visible light, which is turned on at a constant power level, and the infrared light is also turned on at the first power level. During the second time period, the emitted visible light includes second visible light, which is turned on and off at a second pulse repetition frequency, while the first visible light is turned on and off at a first pulse repetition frequency. The on / off switching of the first visible light is asynchronous with that of the second visible light. When both the first and second visible light are off, the power level of the infrared light is increased, and when either the first or second visible light is on, the power level of the infrared light is decreased. The power level of the infrared light is adjusted between the first and second power levels.

[0105] The internal region can be determined by a combined scan image, which includes the difference between the infrared signal and the visible light signal.

[0106] The fluorescence information may include green fluorescence information and / or red fluorescence information, wherein the one or more processors may be configured to determine a first difference between the infrared signal and the green fluorescence information and a second difference between the infrared signal and the red fluorescence information, and wherein the combined scan image includes the sum of the first difference and the second difference. In this example, the contrast between the dental features within the internal region of the dental object is significantly improved.

[0107] The combined scan image may include the sum of the infrared signal, the green fluorescence information, and the red fluorescence information. In another example, the combined scan image may include the infrared signal minus the visible light signal, the visible light signal including white or green wavelengths.

[0108] The one or more processors may be configured to determine the 3D data based on one or more colors of the visible light signal, such as white, red, and / or green wavelengths. Attached Figure Description

[0109] A better understanding of the various aspects of this disclosure can be achieved by reading the following detailed description in conjunction with the accompanying drawings. The drawings are schematic and simplified for clarity; they illustrate only the details that aid in understanding the claims, while other details are omitted. Throughout, the same or corresponding reference numerals are used for the same parts. Features of each aspect may be combined with any or all features of other aspects. These and other aspects, features, and / or technical effects will become apparent and elucidated in conjunction with the drawings described below, in which:

[0110] Figure 1A , 1B 1C and 1C showcase different examples of intraoral scanning systems;

[0111] Figure 2A , 2B 2C demonstrates different examples of multiple scan sequence plans;

[0112] Figure 3A , 3B 3C showcased different examples of various scan sequence plans;

[0113] Figure 4A , 4B The 4C demonstrates different examples of multiple scan sequence plans;

[0114] Figure 5A and 5B Different examples of master sequence plans are shown;

[0115] Figure 6A , 6B Examples of intraoral scanning systems with focusing lenses are shown in 6C and 6D; and

[0116] Figure 7 Another example of an intraoral scanning system is shown. Detailed Implementation

[0117] The following detailed description, given in conjunction with the accompanying drawings, is intended to describe various configurations. This detailed description includes specific details to provide a full understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be implemented without these specific details. Various aspects of devices, systems, media, programs, and methods are described by various blocks, functional units, modules, components, circuits, steps, processes, algorithms, etc. (collectively, “elements”). Depending on the specific application, design constraints, or other reasons, these elements may be implemented using electronic hardware, computer programs, or any combination thereof.

[0118] Electronic hardware may include microprocessors, microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. The term "computer program" should be understood broadly as instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, application programs, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description languages, or other names.

[0119] Scanning to provide intraoral scanning data can be performed by a dental scanning system, which may include intraoral scanning devices, such as the TRIOS series scanners from 3Shape A / S. The dental scanning system may include wireless capabilities provided by a wireless networking unit. The scanning device may employ scanning principles such as triangulation-based scanning, confocal scanning, focused scanning, ultrasonic scanning, X-ray scanning, stereo vision, motion reconstruction, optical coherence tomography (OCT), or any other scanning principle. In one embodiment, the scanning device acquires surface information by projecting a pattern and translating a focal plane along the optical axis of the scanning device, and capturing multiple 2D images at different focal plane locations, such that each series of captured 2D images corresponding to each focal plane constitutes a 2D image stack. The acquired 2D images are also referred to herein as raw 2D images, where, in this context, "raw" means that these images have not yet undergone image processing. The focal plane position is preferably moved along the optical axis of the scanning system, such that 2D images captured at multiple focal plane positions along the optical axis form a stack of 2D images (also referred to herein as subscans) for a given viewpoint of the object (i.e., for a given arrangement of the scanning system relative to the object). A new stack of 2D images for that view can be captured after moving the scanning device relative to the object or imaging the object from a different view. The focal plane position can be changed by at least one focusing element (e.g., a movable focusing lens). During a scanning session, the scanning device is typically moved and angled relative to the dentition such that at least a portion of the subscan set overlaps at least partially, enabling the reconstruction of a digital dental 3D model by stitching the overlapping subscans in real time and displaying the progress of the virtual 3D model construction on a monitor as feedback to the user. The result of stitching is a digital 3D representation of a surface larger than that captured by a single subscan (i.e., larger than the field of view of the 3D scanning device). Stitching (also known as registration and fusion) generates a digital 3D model by identifying overlapping areas of the 3D surfaces in the individual subscans and transforming the subscans to a common coordinate system such that the overlapping areas match. For this purpose, the Iterative Closest Point (ICP) algorithm can be used. Another example of a scanning device is a triangulation scanner, in which a time-varying pattern is projected onto the dental arch, and image sequences of different pattern configurations are acquired by one or more cameras positioned at an angle relative to the projection unit.

[0120] The color texture of a dental arch can be obtained by illuminating the object with different monochromatic lights (e.g., individual red, green, and blue lights) or by illuminating the object with polychromatic lights (e.g., white light). A 2D image can be acquired during a flash of white light.

[0121] Typically, the process of acquiring surface information of a dental arch in real time requires a scanning device to illuminate the surface and acquire a large number of 2D images. Typically, depending on the technology and the resolution of the 2D images, a high-speed camera with a frame rate of 300 to 2000 2D frames per second is used. The large amount of image data that the scanning device needs to process either directly forwards the raw image data stream to an external processing device or performs some image processing before transmitting the data to an external device or display. This process requires multiple electronic components inside the scanner to operate under high load, thus demanding high current.

[0122] The scanning device includes one or more light projectors configured to generate an illumination pattern to be projected onto a three-dimensional dental arch during a scanning session. The light projector preferably includes a light source, a mask with a spatial pattern, and one or more lenses, such as collimating lenses or projection lenses. The light source may be configured to generate light of a single wavelength or a combination of multiple wavelengths (monochromatic or polychromatic). Wavelength combinations can be generated using a light source configured to produce light containing different wavelengths (e.g., white light). Alternatively, the light projector may include multiple light sources, such as LEDs that produce light of different wavelengths (e.g., red, green, and blue light), which can be combined to form light containing different wavelengths. Thus, the light generated by the light source can be defined by wavelengths that define a specific color, or by a series of different wavelengths that define color combinations (e.g., white light). In one embodiment, the scanning device includes a light source configured to excite fluorescent material in the teeth to obtain fluorescence data from the dental arch. This light source may be configured to produce a narrow range of wavelengths. In another embodiment, the light from the light source is infrared (IR) light, which is capable of penetrating tooth tissue. The light projector can be a digital light processing (DLP) projector that uses a micromirror array to generate time-varying patterns, a diffractive optical element (DOE), or a backlit mask projector, wherein the light source is placed behind a mask having a spatial pattern, thereby patterning the light projected onto the dental arch surface. A backlit mask projector may include a collimating lens for collimating the light from the light source, positioned between the light source and the mask. The mask may have a checkerboard pattern, such that the generated illumination pattern is a checkerboard pattern. Alternatively, the mask may have other patterns, such as lines or dots.

[0123] The scanning apparatus preferably also includes optical components for guiding light from the light source onto the surface of the dental arch. The specific arrangement of the optical components depends on whether the scanning apparatus is a focusing scanning apparatus, a scanning apparatus using triangulation, or any other type of scanning apparatus. Focusing scanning apparatuses are further described in the same applicant's EP 2 442 720 B1, the entire contents of which are incorporated herein by reference.

[0124] The optical components of the scanning device guide light reflected from the dental arch in response to illumination of the dental arch toward an image sensor. The image sensor is configured to generate multiple images based on the incident light received from the illuminated dental arch. The image sensor unit can be a high-speed image sensor, for example, an image sensor configured to acquire images with an exposure time of less than 1 / 1000 of a second or a frame rate of more than 250 frames per second (fps). For example, the image sensor can be a rolling shutter (CCD) or a global shutter sensor (CMOS). The image sensor can be a monochrome sensor including a color filter array (e.g., a Bayer filter) and / or additional filters, which can be configured to substantially remove one or more color components from the reflected light before it is converted into an electrical signal and retain only the remaining unremoved components. For example, such an additional filter can be used to remove a specific portion of the white light spectrum, such as the blue component, and retain only the red and green components in the signal generated in response to the excitation of fluorescent materials on the teeth.

[0125] The network unit can be configured to connect a dental scanning system to a network comprising multiple network elements, including at least one network element configured to receive processed data. The network unit can include a wireless network unit or a wired network unit. A wireless network unit is configured to wirelessly connect the dental scanning system to a network comprising multiple network elements, including at least one network element configured to receive processed data. A wired network unit is configured to establish a wired connection between the dental scanning system and a network comprising multiple network elements, including at least one network element configured to receive processed data.

[0126] The dental scanning system preferably further includes a processor configured to generate scan data (e.g., extraoral scan data and / or intraoral scan data) by processing two-dimensional (2D) images acquired by the scanning device. The processor may be part of the scanning device. For example, the processor may include a field-programmable gate array (FPGA) and / or an Advanced Reduced Instruction Set Machine (ARM) processor located on the scanning device. The scan data includes information related to a three-dimensional dental arch. The scan data may include any of the following: 2D images, 3D point clouds, depth data, texture data, intensity data, color data, and / or combinations thereof. As an example, the scan data may include one or more point clouds, where each point cloud includes a set of 3D points describing the three-dimensional dental arch. As another example, the scan data may include images, each image including image data described, for example, by image coordinates and timestamps (x, y, t), where depth information can be inferred from the timestamps. The image sensors of the scanning device may acquire multiple raw 2D images of the dental arch in response to illumination of the object using one or more light projectors. Multiple raw 2D images may also be referred to herein as a 2D image stack. The 2D images can then be provided as input to a processor, which processes them to generate scan data. Processing the 2D images may include determining which parts of each 2D image are in focus to derive / generate depth information from the images. The internal depth information can be used to generate a 3D point cloud comprising a set of 3D points in space, for example, described by Cartesian coordinates (x, y, z). The 3D point cloud can be generated by the processor or another processing unit. Each 2D / 3D point may also include a timestamp indicating when the 2D / 3D point was recorded, i.e., which image in the stack of 2D images the point originated from. The timestamp is associated with the z-coordinate of the 3D point, meaning the z-coordinate can be inferred from the timestamp. Therefore, the processor's output is scan data, which may include image data and / or depth data, for example, described by image coordinates and timestamps (x, y, t), or alternatively (x, y, z). The scanning device may be configured to transmit other types of data besides the scan data. Data examples include 3D information, texture information (e.g., infrared (IR) images, fluorescence images, reflective color images, X-ray images) and / or combinations thereof.

[0127] The example shown in the figure below can be executed by one or more processors.

[0128] Figures 1A to 1CDifferent examples of an intraoral scanning system 1 are shown, comprising three different handheld intraoral scanners 1. System 1 is configured to determine a three-dimensional (3D) model of a dental object. System 1 includes a projection unit 7, an image sensor unit 5, and one or more processors 11. The projection unit 7 is configured to emit first visible light, second visible light, and infrared light during a scanning sequence, wherein the emitted first visible light includes an illumination pattern. The image sensor unit 5 is configured to acquire a two-dimensional visible image based on the first and second visible light, and / or acquire a two-dimensional infrared image based on infrared light from the dental object. The one or more processors 11 are configured to control the projection unit 7 and / or the image sensor unit 5 according to a plurality of scanning sequence plans, wherein each of the plurality of scanning sequence plans includes a timing sequence of the projection unit and / or the image sensor. The one or more processors are configured to determine a 3D model of the dental object based on the two-dimensional visible image including the first visible light, and wherein the one or more processors are configured to switch between each of the plurality of scanning sequence plans. Figure 1A The handheld intraoral scanner 1 is based on a focusing scanning principle and includes a movable focusing lens 60 along the optical axis of the scanner 1. The focusing lens 60 can move in two directions along the optical axis. Figure 1B In this design, the handheld intraoral scanner 1 is based on the triangulation scanning principle, wherein the image sensor unit 5 and the projection unit 7 are arranged according to this scanning principle. Figure 1A and Figure 1B Of the two, the image sensor unit 5 and the projection unit 7 are arranged in the main housing 3. Figure 1C In this embodiment, the image sensor unit 5 and the projection unit 7 are arranged in the end housing 2. In this example, the projection unit includes multiple light sources 7, and the image sensor unit 5 includes multiple cameras 5. Figure 1C The scanning principle in it is based on triangulation.

[0129] Figures 2A to 2C Different examples of several scan sequence plans (25A, 25B, 25C) are shown. Figure 2A An example of a 3D scanning sequence plan 25A is shown, wherein all time slices 20 are configured to emit and acquire first visible light with an illumination pattern to determine a three-dimensional model. In each time slice, a projection unit 7 emits first visible light with a wavelength between 400 nm and 750 nm to determine a 3D model of the dental object. Furthermore, in each time slice, an image sensor unit 5 acquires a two-dimensional visible image. In each time slice, one or more processors 11 are configured to process the 3D model determined based on the two-dimensional visible image. Figure 2BAn example of an ultraviolet scanning sequence plan 25B is shown. In this example, time slice 20 is configured to emit a first visible light 21A to determine a 3D model of a dental object, and then emit a second visible light 21B to acquire a two-dimensional fluorescence image. In this example, projection unit 7 is configured to switch between emitting the first visible light 21A in the first time slice and emitting the second visible light 21B in the second time slice. In the corresponding time slice 20, a two-dimensional visible image 21B with a fluorescence wavelength is acquired, and a two-dimensional visible image 21A with a wavelength between 400 nm and 750 nm for determining the 3D model of the dental object is acquired. In the corresponding time slice 20, one or more processors are configured to process the acquired two-dimensional visible image 21B including the fluorescence wavelength, and to process the acquired two-dimensional visible image 21A with a wavelength between 400 nm and 750 nm to determine the 3D model of the dental object.

[0130] Figure 2C An example of a hyperspectral scanning sequence plan 25C is shown. In this example, time slice 20 is configured to emit a first visible light 21A, a second visible light 21B, and infrared light 21C; in another example, the time slice arrangement may include the following sequence: 3D, UV, 3D, IR, and 3D, which is then repeated. For example, the sequence may be repeated in a roundrobin manner. In this example, projection unit 7 is configured to switch between emitting the first visible light 21A in the first time slice, emitting the second visible light 21B in the second time slice, and emitting infrared light 21C in the third time slice. In the corresponding time slice 20, a two-dimensional visible image 21B with a fluorescence wavelength is acquired, a two-dimensional visible image 21A with a wavelength between 400 nm and 750 nm for determining a 3D model of a dental object is acquired, and an infrared image 21C is acquired. Furthermore, the visible image with a fluorescence wavelength and the two-dimensional visible image with a wavelength between 400 nm and 750 nm are combined with the acquired infrared image to determine a combined scan image. The order of the time slices can be changed, such that the first time slice 21A may include emitting and acquiring infrared light, the second time slice 21B may include emitting and acquiring first visible light, and the third time slice 21C may include emitting second visible light and acquiring fluorescence excited by the second visible light. Figure 2C In the corresponding time slice 20, one or more processors are configured to process the acquired two-dimensional visible image 21B, including a fluorescence wavelength, the acquired two-dimensional visible image 21A, with wavelengths between 400 nm and 750 nm, used to determine a 3D model of a dental object, and an infrared image.

[0131] Figures 3A to 3CDifferent examples of multiple scan sequence plans (25A, 25B, 25C) are shown, wherein processing 22 in each time slice 20 includes downsampling the acquired image 21. Figure 3C In each time slice 20, processing 22 includes color space conversion (YUV) of the image 21 of the corresponding time slice 20, and specifically, for time slices 20 that include UV light emission, processing 22 includes a combination of downsampling and color conversion (YUV+Down). One or more processors are configured to process the acquired two-dimensional visible image 21 and / or two-dimensional infrared image by downsampling 22 of the acquired image and / or by color space conversion 22 of the acquired image, wherein color space conversion includes converting the image from a first color space model to a second color space model and vice versa. The first color space model includes a red-green-blue (RGB) color space model, and the second color space model includes a Y (luminance) and UV (grayscale deviation) (YUV) color space model. The conversion to YUV color space is for the use of the H.265 compression protocol for 3D, IR, and UV time slices in the hyperspectral scanning sequence plan 25C.

[0132] In one example, the intraoral scanning system 1 includes a focusing lens 60, which is configured to move in a first direction and a second direction, wherein the first direction is opposite to the second direction. Each time slice is configured to emit and acquire light 21 and process light / image 22 as the focusing lens moves along the first direction 40A. Each time slice is further configured to emit and acquire light 23 and process light / image 24 as the focusing lens 60 moves along the opposite direction 40B, see [link to relevant documentation]. Figures 4A to 4C .exist Figures 4A to 4C In the example shown, the image sensor unit 5 is configured to acquire two-dimensional visible images (21, 23) as the focusing lens moves along a first direction and then along a second direction, according to a multiple scanning sequence plan. Specifically, for Figure 4C The image sensor unit 5 is configured to acquire (21, 23) two-dimensional visible images and two-dimensional infrared images as the focusing lens moves along a first direction and then along a second direction according to a multiple scanning sequence plan. Figure 4B The sequence of time slice 23 in the second direction is UV, 3D, UV, 3D, UV, and... Figure 4C The sequence of time slice 23 in the second direction is UV, 3D, IR, 3D and UV.

[0133] Figure 5A and Figure 5BDifferent examples of a master sequence plan 50 are shown, which includes multiple scan sequence plans (25, 25A, 25B, 25C). In both examples, the multiple scan sequence plans (25, 25A, 25B, 25C) are arranged in the master sequence plan 50, wherein one or more processors 11 are configured to switch between each of the multiple scan sequence plans (25, 25A, 25B, 25C) based on the master sequence plan 50. The multiple scan sequence plans are arranged in the master sequence plan based on a round-robin principle. Figure 5A In a specific example, first time slice 20A includes a 3D scanning sequence plan (25A, 3D-SS), and second time slice 20B includes another 3D scanning sequence plan (25A, 3D-SS). Third time slice 20C includes an ultraviolet scanning sequence plan 25B, and sixth time slice 20D includes a hyperspectral scanning sequence plan 25C. The system may include a user interface configured to arrange or rearrange two or more of the multiple scanning sequence plans (25, 25A, 25B, 25C) within the master sequence plan 50. Figure 5B The main sequence plan 50 includes a master sequence plan 50, in which the arrangement of multiple scan sequence plans (25, 25A, 25B) includes a 3D scan sequence plan 25A and an ultraviolet scan sequence plan 25B. Another example of the master sequence plan 50 would include four 3D-SS scan sequence plans, followed by one IR-SS scan sequence plan and three 3D-SS scan sequence plans. The master sequence plan may be repeated multiple times, for example, in a round-robin manner.

[0134] Figure 6A and Figure 6B An intraoral scanning system 1 is shown, which includes a focusing lens 60. Figure 6B In this embodiment, multiple scanning sequence plans 25 include a focusing scanning sequence plan 25D, wherein the focusing scanning sequence plan 25D includes time slices 21, which are timed by the focusing lens 60 at a focusing position (P1, P2) in at least a first direction 40A and / or a second direction 40B. In this specific example, one or more processors 11 are configured to control the projection unit 7, the image sensor unit 5, and the one or more processors 11 based on the focusing scanning sequence plan 25D, wherein the projection unit emits first visible light 21A to determine a 3D model of a dental object until the focusing lens reaches the focusing position P2. According to the focusing scanning sequence plan 25D, the one or more processors 11 are triggered 20' by the focusing position P2 to emit and acquire infrared light / images 21B before emitting the first visible light 21B' and the second visible light 21B'' in the respective time slices 20.

[0135] The time slices 20' of the focusing scan sequence plan 25D are configured to acquire a set of images (21B, 21B', 21B''), which include a two-dimensional visible image 21B' with wavelengths between 400 nm and 750 nm, a two-dimensional visible image 21B'' from a dental object with fluorescence wavelengths, and a two-dimensional infrared image 21 with wavelengths between 850 nm and 1100 nm. The focusing scan sequence plan 25D includes a set of time slices 20' activated by the focusing position P2, wherein the set of time slices 20' includes a first time slice configured to emit infrared light 21B, a second time slice configured to emit first visible light 21B', and a third time slice configured to emit second visible light 21B''. A time slice for emitting the first visible light 21A is allocated to another set of time slices 20 of the focusing scan sequence plan 25D. Figure 6C An example of the main sequence plan is shown, in which the hyperspectral scanning sequence plan 25C is activated (20') when the focusing lens 60 reaches the focusing position P2.

[0136] The focusing lens 60 can move from an initial position (Pinit) to an end position (Pend) along a first direction 40A, and a complete scan stroke of the focusing lens 60 means that the focusing lens has moved from the initial position (Pinit) to the end position (Pend), or vice versa when moving along a second direction. The focusing position P2 is determined by one or more processors 11 during the first scan stroke of the focusing lens, wherein, during subsequent scan strokes following the first scan stroke, the first scan stroke of the focusing scan sequence plan 25D and the grouped time slices 20' are enabled at the focusing position P2.

[0137] The focus position P2 is determined by one or more processors 11 during the first full scan stroke of the focusing lens 60, and during subsequent full scan strokes following the first scan stroke, grouped time slices 20' of the focus scan sequence plan 25D are enabled at the focus position.

[0138] exist Figure 6D In this process, when the focusing lens 60 of the focusing unit is positioned at position P2, one or more processors 11 determine a trigger signal 20' at position P2, where a specific portion of the acquired two-dimensional visible image (71A, 71B) is in focus. The image information is divided into a pixel array, and in this specific example, the focus position P2 is determined when the central portion of the pixel array is in focus. At focus position P1, the central portion of the pixel array is not in focus.

[0139] Figure 7An example of an intraoral scanning system 1 is shown, wherein one or more processors 11 are arranged in a handheld intraoral scanner 100, an external computer 202, and a server 204. In this specific example, the handheld intraoral scanner 100 is configured to communicate with the server 204 and the external computer 202 via a wireless link 95. In another example, communication 95 may be conducted via a wired link.

[0140] Although some embodiments have been described in detail and illustrated, this disclosure is not limited to these details, but may also be implemented in other ways within the scope of the subject matter defined in the following claims. In particular, it should be understood that other embodiments may be utilized, and structural and functional modifications may be made without departing from the scope of the invention.

[0141] This document has described beneficial effects, other advantages, and solutions to technical problems in conjunction with specific embodiments. However, the beneficial effects, advantages, solutions to technical problems, and any one or more components / units that may lead to or make more significant any beneficial effect, advantage, or technical problem should not be construed as any or all of the claims or as key, essential, or necessary features or components / elements of the invention. Therefore, the scope of the invention should be defined only by the appended claims, wherein references to the singular form of a component / unit / element, unless specifically stated otherwise, do not mean "only one," but rather "one or more." A claim may refer to any one of the preceding claims, wherein "any one" should be understood as "any one or more" of the preceding claims.

[0142] The aim is to enable the structural features of the apparatus described above in the specification and / or claims to be combined with the steps of the method when they correspond appropriately to the corresponding method steps.

[0143] Unless otherwise expressly stated, the singular forms “a” and “described” as used herein are intended to include the plural forms (i.e., having the meaning of “at least one”). Furthermore, it should be understood that the terms “comprising” and / or “including” as used herein are used to indicate the presence of the stated feature, integer, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. It should also be understood that when an element is described as “connected” or “coupled” to another element, it may be directly connected or coupled to the other element, but intermediate elements may also be present, unless otherwise expressly stated. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. As used herein, the term “and / or” includes any and all combinations of one or more of the listed related items. Unless otherwise expressly stated, the steps of any disclosed method are not limited to the exact order described herein.

[0144] It should be understood that references to "an embodiment," "a implementation," "an aspect," or features included in the form of "may" in this specification mean that a particular feature, structure, or characteristic associated with that embodiment is included in at least one embodiment of this disclosure. Furthermore, these particular features, structures, or characteristics may be suitably combined in one or more embodiments of this disclosure. The foregoing description is intended to enable those skilled in the art to implement the various aspects described herein. Those skilled in the art will readily understand various modifications to these aspects, and the general principles defined herein may be applied to other aspects.

[0145] The claims should not be construed as limited to the aspects shown herein, but should be given the full scope consistent with the wording of the claims, wherein references to singular elements, unless otherwise specified, do not mean "only one," but rather "one or more." Unless otherwise specifically stated, the term "some" means one or more.

[0146] project

[0147] 1. An intraoral scanning system configured to determine a three-dimensional (3D) model of a dental object, said intraoral scanning system comprising:

[0148] A projection unit configured to emit a first visible light, a second visible light, and infrared light during a scanning sequence, wherein the emitted first visible light includes an illumination pattern;

[0149] An image sensor unit configured to acquire a two-dimensional visible image based on the first visible light and the second visible light, and / or acquire a two-dimensional infrared image based on the infrared light from the dental object; and

[0150] One or more processors configured to control the projection unit and / or the image sensor unit according to a plurality of scan sequence plans, wherein each of the plurality of scan sequence plans includes the timing of the projection unit and / or the image sensor;

[0151] The one or more processors are configured to determine a 3D model of the dental object based on the two-dimensional visible image including the first visible light, and the one or more processors are configured to switch between each of the plurality of scan sequence plans.

[0152] 2. The intraoral scanning system according to Item 1 includes a focusing lens unit configured to change the focal point during the scanning sequence by moving a focusing lens of the focusing lens unit, wherein the focusing lens is configured to move in a first direction, and wherein the image sensor unit is configured to acquire a two-dimensional visible image and / or a two-dimensional infrared image via the focusing lens while the focusing lens moves at least along the first direction.

[0153] 2B. The intraoral scanning system according to Item 1, wherein the timing of the projection unit and / or the image sensor unit includes timing for emitting the first visible light and the infrared light, and / or timing for acquiring the two-dimensional visible image and / or the two-dimensional infrared image.

[0154] 2C. An intraoral scanning system according to any one of the preceding items, wherein the one or more processors are configured to process the acquired two-dimensional visible image and the two-dimensional infrared image according to the plurality of scanning sequence plans.

[0155] 3. The intraoral scanning system according to any one of the preceding items, wherein the focusing lens is configured to move in a second direction, and wherein the first direction is opposite to the second direction.

[0156] 4. The intraoral scanning system according to any one of the preceding items, wherein the image sensor unit is configured to acquire the two-dimensional visible image and the two-dimensional infrared image while the focusing lens moves along the first direction and then along the second direction, according to the plurality of scanning sequence plans.

[0157] 5. The intraoral scanning system according to any one of the preceding items, wherein each of the plurality of scanning sequence plans includes a time slice for emitting the first visible light, the second visible light, and / or the infrared light by the projection unit.

[0158] 6. The intraoral scanning system according to any one of the preceding items, wherein each of the plurality of scanning sequence plans includes a time slice for acquiring the two-dimensional visible image and / or the two-dimensional infrared image through the image sensor unit.

[0159] 7. The intraoral scanning system according to any one of the preceding items, wherein each of the plurality of scanning sequence plans includes a time slice for processing the acquired two-dimensional visible image and / or the two-dimensional infrared image.

[0160] 8. The intraoral scanning system according to any one of the preceding items, wherein the timing of the time slices is based on a round-robin principle.

[0161] 9. The intraoral scanning system according to any one of the preceding items, wherein the plurality of scanning sequence plans comprises two or more of the following plans:

[0162] A 3D scanning sequence plan, comprising time slices for emitting first visible light with wavelengths between 400 nm and 750 nm to determine the 3D model of the dental object;

[0163] An ultraviolet scanning sequence plan includes time slices for emitting first visible light with wavelengths between 400 nm and 750 nm and second visible light with wavelengths between 350 nm and 450 nm emitted by the projection unit; and

[0164] The hyperspectral scanning sequence plan includes time slices for emitting first visible light with wavelengths between 400 nm and 750 nm, second visible light with wavelengths between 350 nm and 450 nm, and infrared light with wavelengths between 850 nm and 1100 nm.

[0165] 10. The intraoral scanning system according to any one of the preceding items, wherein the plurality of scanning sequence plans comprises two or more of the following plans:

[0166] A 3D scanning sequence plan, comprising time slices for acquiring the two-dimensional visible images at wavelengths between 400 nm and 750 nm to determine the 3D model of the dental object;

[0167] An ultraviolet scanning sequence plan includes acquiring a two-dimensional visible image of the dental object with a fluorescence wavelength provided by a second visible light source, and acquiring time slices of the two-dimensional visible image with wavelengths between 400 nm and 750 nm to determine the 3D model of the dental object; and

[0168] A hyperspectral scanning sequence plan includes time slices for acquiring the two-dimensional visible image with wavelengths between 400 nm and 750 nm to determine the 3D model of the dental object, acquiring the two-dimensional visible image from the dental object with fluorescence wavelengths, and acquiring the two-dimensional infrared image with wavelengths between 850 nm and 1100 nm.

[0169] 11. The intraoral scanning system according to any one of the preceding items, wherein the plurality of scanning sequence plans comprises two or more of the following plans:

[0170] A 3D scanning sequence plan, comprising timing for processing by the one or more processors based on the 3D model determined from the two-dimensional visible image including wavelengths between 400 nm and 750 nm;

[0171] An ultraviolet scanning sequence plan includes processing, by the one or more processors, the acquired two-dimensional visible image comprising fluorescence wavelengths provided by a second visible light from the dental object, and processing the acquired two-dimensional visible image at wavelengths between 400 nm and 750 nm to determine the timing of the 3D model of the dental object; and

[0172] A hyperspectral scanning sequence plan comprising a timing sequence for processing by the one or more processors of the acquired two-dimensional visible image with wavelengths between 400 nm and 750 nm, the acquired two-dimensional visible image including fluorescence wavelengths from the dental object, and the acquired two-dimensional infrared image with wavelengths between 850 nm and 1100 nm.

[0173] 12. The intraoral scanning system according to any one of the preceding items, wherein the one or more processors are configured to process the acquired two-dimensional visible image and / or the two-dimensional infrared image by downsampling the acquired image and / or by performing a color space conversion on the acquired image, wherein the color space conversion includes converting the image from a first color space model to a second color space model, or vice versa.

[0174] 13. The intraoral scanning system according to any one of the preceding items, wherein the first color space model comprises a red-green-blue (RGB) color space model, and the second color space model comprises a Y (luminance) and UV (grayscale deviation) (YUV) color space model.

[0175] 14. An intraoral scanning system according to any one of the preceding items, comprising a user interface configured to receive user input regarding an operating mode of the intraoral scanning system, wherein the operating mode selects one or more of the plurality of scanning sequence plans.

[0176] 15. The intraoral scanning system according to Item 14, wherein the operating mode is one or more of the following modes:

[0177] The first diagnostic mode includes the hyperspectral scanning sequence plan;

[0178] The second diagnostic mode includes the aforementioned ultraviolet scanning sequence plan;

[0179] A three-dimensional model, comprising the 3D scan sequence plan; and

[0180] The fourth mode includes two or more of the first diagnostic mode, the second diagnostic mode, and the three-dimensional mode.

[0181] Super Focus Project:

[0182] 16. The intraoral scanning system according to any one of the preceding items, wherein the plurality of scanning sequence plans include a focusing scanning sequence plan, wherein the focusing scanning sequence plan includes time slices timed by the focusing lens at least in the focusing position in the first direction and / or the second direction.

[0183] 17. The intraoral scanning system according to any one of the preceding items, wherein the time slice is used to acquire the two-dimensional visible image with a wavelength between 400 nm and 750 nm to determine the 3D model of the dental object, acquire the two-dimensional visible image from the dental object having a fluorescence wavelength, and acquire the two-dimensional infrared image with a wavelength between 850 nm and 1100 nm.

[0184] 18. An intraoral scanning system according to any one of the preceding items, wherein the one or more processors are configured to control the projection unit to emit a light sequence, the light sequence comprising a set of time slices planned for a focusing scanning sequence at the focusing position of the focusing lens, wherein the set of time slices includes a first time slice for emitting the infrared light, a second time slice for emitting the first visible light, and a third time slice for emitting the second visible light.

[0185] 19. The intraoral scanning system according to any one of the preceding items, wherein the focusing scanning sequence is configured to emit the first visible light before the light sequence, including the set of time slices, is initiated by the position of the focusing lens.

[0186] 20. An intraoral scanning system according to any one of the preceding items, wherein the focusing position of the focusing lens is determined by the one or more processors, and at the focusing position, a specific group of pixels of one of the acquired two-dimensional visible images is in focus, wherein the focusing is determined by the intensity of the specific group of pixels.

[0187] 21. The intraoral scanning system according to any one of the preceding items, wherein the specific pixel group comprises pixels arranged at the center of the two-dimensional visible image acquired by one of the items.

[0188] 22. The intraoral scanning system according to any one of the preceding items, wherein the one or more processors are configured to switch from a 3D scanning sequence plan among the plurality of scanning sequence plans to a hyperspectral scanning sequence plan among the plurality of scanning sequence plans based on a trigger signal.

[0189] 23. The intraoral scanning system according to any one of the preceding items, wherein the one or more processors determine the trigger signal when the focusing lens of the focusing unit is positioned to bring a specific portion of the acquired two-dimensional visible image into focus.

[0190] 24. The intraoral scanning system according to any one of the preceding items, wherein the one or more processors are configured to switch from the hyperspectral scanning sequence plan to the 3D scanning sequence plan upon completion of the hyperspectral scanning sequence plan.

[0191] 25. The intraoral scanning system according to any one of the preceding items, wherein the plurality of scanning sequence plans are arranged in a master sequence plan, wherein the one or more processors are configured to switch between each of the plurality of scanning sequence plans based on the master sequence plan.

[0192] 26. The intraoral scanning system according to any one of the preceding items, wherein the plurality of scanning sequence plans are arranged in the main sequence plan based on a round-robin principle.

[0193] 27. An intraoral scanning system according to any one of the preceding items, comprising a user interface configured to arrange or rearrange two or more of the plurality of scan sequence plans in the master sequence plan.

[0194] 28. The intraoral scanning system according to any one of the preceding items, wherein each of the plurality of scanning sequence plans includes at least three time slices.

Claims

1. An intraoral scanning system configured to determine a three-dimensional (3D) model of a dental object, said intraoral scanning system comprising: A projection unit configured to emit a first visible light, a second visible light, and infrared light during a scanning sequence, wherein the emitted first visible light includes an illumination pattern; An image sensor unit configured to acquire a two-dimensional visible image based on the first visible light and the second visible light, and / or acquire a two-dimensional infrared image based on the infrared light from the dental object; A focusing lens unit configured to change focus during the scanning sequence by moving a focusing lens of the focusing lens unit, wherein the focusing lens is configured to move in a first direction and a second direction, and wherein the image sensor unit is configured to acquire a two-dimensional visible image and / or a two-dimensional infrared image via the focusing lens while the focusing lens moves along the first direction and the second direction; and One or more processors configured to control the projection unit and / or the image sensor unit according to a plurality of scan sequence plans, wherein each of the plurality of scan sequence plans includes the timing of the projection unit and / or the image sensor, and wherein the one or more processors are configured to determine a 3D model of the dental object based on the two-dimensional visible image including the first visible light, and wherein the one or more processors are configured to switch between each of the plurality of scan sequence plans.

2. The intraoral scanning system according to claim 1, wherein, The frame rate of the image sensor unit is different when the focusing lens moves in the first direction and the second direction.

3. The intraoral scanning system according to claim 2, wherein, The first direction is opposite to the second direction.

4. The intraoral scanning system according to any one of the preceding claims, wherein, The image sensor unit is configured to acquire the two-dimensional visible image and the two-dimensional infrared image while the focusing lens moves along the first direction and then along the second direction, according to the plurality of scanning sequence plans.

5. The intraoral scanning system according to any one of the preceding claims, wherein, Each of the plurality of scan sequence plans includes a time slice for emitting the first visible light, the second visible light, and / or the infrared light by the projection unit.

6. The intraoral scanning system according to any one of the preceding claims, wherein, Each of the plurality of scan sequence plans includes a time slice for acquiring the two-dimensional visible image and / or the two-dimensional infrared image through the image sensor unit.

7. The intraoral scanning system according to any one of the preceding claims, wherein, Each of the plurality of scan sequence plans includes a time slice for processing the acquired two-dimensional visible image and / or the two-dimensional infrared image.

8. The intraoral scanning system according to any one of claims 5 to 7, wherein, The timing of the time slices is based on a round-robin principle.

9. The intraoral scanning system according to any one of the preceding claims, wherein, The plurality of scan sequence plans includes two or more of the following plans: A 3D scanning sequence plan, comprising time slices for emitting first visible light with wavelengths between 400 nm and 750 nm to determine the 3D model of the dental object; An ultraviolet scanning sequence plan comprising time slices for emitting first visible light with wavelengths between 400 nm and 750 nm and second visible light with wavelengths between 350 nm and 450 nm emitted by the projection unit; and The hyperspectral scanning sequence plan includes time slices for emitting first visible light with wavelengths between 400 nm and 750 nm, second visible light with wavelengths between 350 nm and 450 nm, and infrared light with wavelengths between 850 nm and 1100 nm.

10. The intraoral scanning system according to any one of the preceding claims, wherein, The plurality of scan sequence plans includes two or more of the following plans: A 3D scanning sequence plan, comprising time slices for acquiring the two-dimensional visible images at wavelengths between 400 nm and 750 nm to determine the 3D model of the dental object; An ultraviolet scanning sequence plan includes acquiring a two-dimensional visible image of the dental object with a fluorescence wavelength provided by a second visible light source, and acquiring time slices of the two-dimensional visible image with wavelengths between 400 nm and 750 nm to determine the 3D model of the dental object; and A hyperspectral scanning sequence plan includes time slices for acquiring the two-dimensional visible image with wavelengths between 400 nm and 750 nm to determine the 3D model of the dental object, the two-dimensional visible image of the dental object with fluorescence wavelengths, and the two-dimensional infrared image with wavelengths between 850 nm and 1100 nm.

11. The intraoral scanning system according to any one of the preceding claims, wherein, The plurality of scan sequence plans includes two or more of the following plans: A 3D scanning sequence plan, comprising timing for processing by the one or more processors based on the 3D model determined by the two-dimensional visible image including wavelengths between 400 nm and 750 nm; An ultraviolet scanning sequence plan includes processing, by the one or more processors, the acquired two-dimensional visible image comprising fluorescence wavelengths provided by a second visible light from the dental object, and processing the acquired two-dimensional visible image at wavelengths between 400 nm and 750 nm to determine the timing of the 3D model of the dental object; and A hyperspectral scanning sequence plan comprising a timing sequence for processing by the one or more processors of the acquired two-dimensional visible image with wavelengths between 400 nm and 750 nm, the acquired two-dimensional visible image including fluorescence wavelengths from the dental object, and the acquired two-dimensional infrared image with wavelengths between 850 nm and 1100 nm.

12. The intraoral scanning system according to any one of the preceding claims, wherein, The plurality of scanning sequence plans include a focusing scanning sequence plan, wherein the focusing scanning sequence plan includes time slices timed by the focusing lens at least in the focusing position in the first direction and / or the second direction.

13. The intraoral scanning system according to claim 12, wherein, The time slice of the focusing scan sequence is configured to acquire a set of images, the set of images including a two-dimensional visible image with wavelengths between 400 nm and 750 nm, a two-dimensional visible image from the dental object with fluorescence wavelengths, and a two-dimensional infrared image with wavelengths between 850 nm and 1100 nm.

14. The intraoral scanning system according to any one of claims 12 and 13, wherein, The focus scanning sequence plan includes a set of time slices enabled by the focus position, wherein the set of time slices includes a first time slice configured to emit the infrared light, a second time slice configured to emit the first visible light, and a third time slice configured to emit the second visible light.

15. The intraoral scanning system according to claim 14, wherein, The focusing scan sequence plan includes another set of time slices, which are configured to emit the first visible light when the first set of time slices is not enabled.

Images