CN-122023639-A - Computer-implemented method and intraoral scanning system for eliminating glare defects in image scan data

CN122023639ACN 122023639 ACN122023639 ACN 122023639ACN-122023639-A

Abstract

The invention relates to a computer-implemented method and an intraoral scanning system. A computer-implemented method of eliminating glare defects in processed image scan data includes receiving a plurality of image scan data of a dental object produced by an intraoral scanner, processing one or more of the plurality of image scan data into processed image scan data, wherein the processed image scan data includes a plurality of pixels, determining a plurality of defective pixels in the processed image scan data by a glare detection algorithm, wherein the glare detection algorithm may be configured to determine a plurality of defective pixels when a pixel value of each of the plurality of defective pixels meets one or more pixel value criteria and when a plurality of defective pixel arrangement geometry meets one or more geometry criteria, analyzing pixels in the plurality of pixels in the vicinity of the plurality of defective pixels by a glare elimination algorithm to determine non-glare image scan data, and replacing the processed image scan data in the plurality of defective pixels with the non-glare image scan data.

Inventors

F. Mikhov
A. Hoseni
S. Bazaau

Assignees

3形状股份有限公司

Dates

Publication Date: 20260512
Application Date: 20251107
Priority Date: 20241108

Claims (15)

1. A computer-implemented method for eliminating glare defects from diagnostic image scan data of a dental object obtained by an intraoral scanner, the method comprising: Receiving a plurality of image scan data of a dental object generated by an intraoral scanner, wherein the plurality of image scan data includes image scan data having three-dimensional image scan data and diagnostic image scan data; processing the diagnostic image scan data into processed image scan data, wherein the processed image scan data includes a plurality of pixels; determining a plurality of defective pixels in the processed image scan data by a glare detection algorithm, wherein the glare detection algorithm is configured to determine the plurality of defective pixels when a pixel value of each of the defective pixels meets one or more pixel value criteria, and when a geometry of an arrangement of the plurality of defective pixels meets one or more geometry criteria; determining non-glare image scanning data by analyzing pixels of the plurality of pixels in the vicinity of the plurality of defective pixels by a glare elimination algorithm; replacing processed image scan data in the plurality of defective pixels with the non-glare image scan data; Reconstructing and displaying a three-dimensional model of the dental object based on the image scan data having three-dimensional image scan data, and Displaying diagnostic image scan data having the non-glare image scan data.
2. The computer-implemented method of claim 1, wherein the one or more pixel value criteria comprises a pixel value variation between the plurality of defective pixels and pixel values of pixels in the plurality of pixels in the vicinity of the plurality of defective pixels, wherein the pixel value variation is above a contrast threshold.
3. The computer-implemented method of any of the preceding claims, wherein the one or more pixel value criteria include a pixel value threshold above which the pixel values of the plurality of defective pixels are above.
4. The computer-implemented method of any of the preceding claims, wherein the plurality of image scan data comprises first image scan data comprising visible wavelengths and at least second image scan data comprising non-visible wavelengths, wherein the processed image scan data comprises a composite of the first image scan data and the at least second image scan data.
5. The computer-implemented method of claim 4, comprising determining a composite of the first image scan data and the processed image scan data, wherein the processed image scan data includes the at least second image scan data and the processed image scan data of the plurality of defective pixels is replaced with the non-glare image scan data.
6. The computer-implemented method of any of the preceding claims, wherein the arrangement of the plurality of defective pixels comprises consecutive pixels.
7. The computer-implemented method of any of the preceding claims, wherein the one or more geometric criteria comprise: a size criterion that evaluates whether the geometric shape has an area within an area range; a width criterion that evaluates whether the geometric shape has a width in a width range along a dimension of the plurality of defective pixels, and Shape criteria that evaluates whether the geometric shape has a shape that matches a plurality of glare shape templates.
8. The computer-implemented method of any preceding claim, wherein the glare detection algorithm comprises a top hat transform, wherein the top hat transform comprises one or more of the following transforms: white top hat transform (WTH) including an open operation, and Black top hat transform (BTH), which includes a closed operation.
9. The computer-implemented method of claim 8, wherein the white top hat transform comprises the following equation: wherein f is the processed image scan data, b is a structured glare defect element comprising the size or width of a glare defect to be detected by the white top hat transformation, and Is an open operation.
10. The computer-implemented method of claim 8, wherein the black top hat transform comprises the following equation: wherein f is the processed image scan data, b is a structured glare defect element comprising the size or width of a glare defect to be detected by the black top hat transformation, and Is a closed operation.
11. The computer-implemented method of any preceding claim, wherein the glare detection algorithm comprises the steps of: processing the diagnostic image scan data into second processed image scan data; Determining a first set of defective pixels based on pixel values of a plurality of pixels of the processed image scan data; Determining a second set of defective pixels based on pixel values of a plurality of pixels of the second processed image scan data; By comparing the first processed image scan data and the second processed image scan data, a defective pixel of a plurality of defective pixels of the first processed image scan data is determined when the positions of defective pixels of the first set of defective pixels and the second set of defective pixels relative to a dental object match.
12. The computer-implemented method of claim 11, wherein the first processed image scan data comprises diagnostic image scan data captured after diagnostic image scan data of the second processed image scan data.
13. An intraoral scanning system configured to eliminate glare defects from diagnostic image scan data of a dental object obtained by an intraoral scanner, wherein the intraoral scanning system comprises: an intraoral scanner configured to generate a plurality of image scan data of a dental object, wherein the plurality of image scan data includes image scan data having three-dimensional image scan data and diagnostic image scan data; one or more of the processors of the present invention, the one or more processors are configured to: processing the diagnostic image scan data into processed image scan data, wherein the processed image scan data includes a plurality of pixels; Determining a plurality of defective pixels in the processed image scan data by a glare detection algorithm, wherein the glare detection algorithm is configured to determine the plurality of defective pixels when a geometry of an arrangement of a plurality of pixels having pixel values above a pixel value threshold meets one or more geometry criteria; Determining non-glare image scan data by analyzing pixels in the vicinity of the plurality of defective pixels by a glare elimination algorithm, and Replacing a plurality of defective pixels in the processed image scan data with the non-glare image scan data; Reconstructing and displaying a three-dimensional model of the dental object based on the image scan data having three-dimensional image scan data, and Displaying diagnostic image scan data having the non-glare image scan data.
14. The intraoral scanning system of claim 13 wherein the intraoral scanner comprises a first light source configured to emit visible wavelengths and a second light source configured to emit invisible wavelengths, and wherein the plurality of image scan data comprises first image scan data comprising the visible wavelengths and at least second image scan data comprising the invisible wavelengths, and wherein the processed image scan data comprises a composite of the first image scan data and the at least second image scan data.
15. The intraoral scanning system of claim 14 wherein the intraoral scanner comprises a third light source configured to emit another invisible wavelength, and wherein the plurality of image scan data comprises third image scan data comprising the another invisible wavelength, and wherein the processed image scan data comprises a composite of the first image scan data, the at least second image scan data, and the third image scan data.

Description

Computer-implemented method and intraoral scanning system for eliminating glare defects in image scan data Technical Field The present invention relates to a computer-implemented method and an intraoral scanning system configured to eliminate glare defects in image scan data. More specifically, the glare defect is eliminated based on image processing. Background Scanning a patient's mouth may involve many artifacts, caused for example by loss of fringes due to scene geometry, shadows in the scene, tooth defects and/or other factors affecting fringe shape, continuity and/or alignment, failure of fringe reconstruction and/or false detection of fringes may be caused for example by specular reflection of different materials in the scene (e.g. teeth and gums), liquids in the scene (e.g. blood, saliva) and natural shadows and/or projected shadows in the scene. In particular, specular reflection is not an artifact that is easily overcome. One way to overcome specular reflection is by cross-polarizing the illumination and light sources, but it is difficult to achieve effective cross-polarization over a broad wavelength spectrum in the sense of eliminating glare. For example, in intraoral scanning systems that emit wavelengths from Ultraviolet (UV) wavelengths to infrared (NIR/IR) wavelengths, there is a risk of glare defects in the UV and/or NIR/IR wavelength images. It is well known that NIR/IR light can be used to evaluate internal structures, internal features (e.g., cracks, caries) and tooth surfaces of teeth in the form of transillumination of teeth or light reflection and back scattering of teeth. Unfortunately, it may be difficult for some dentists to distinguish between glare defects and caries, etc., which may lead to false positives, i.e., false caries. Accordingly, there is a need for a solution to the problem of eliminating glare defects when emitting light comprising wavelengths between UV and NIR/IR. Disclosure of Invention An aspect of the present invention aims to solve the above-mentioned problem, namely how to eliminate glare defects in image scan data when the emitted light contains wavelengths between UV and NIR/IR. According to this aspect, a computer-implemented method for eliminating glare defects in processed image scan data is disclosed. The method includes receiving a plurality of image scan data of a dental object generated by an intraoral scanner. The dental object may be a tooth, a series of teeth and/or gums. The dental object may be a single jaw, or a combination of upper and lower jaws that are separated or in a closed state. The plurality of image scan data may include image scan data having three-dimensional image scan data and/or two-dimensional image scan data (e.g., diagnostic image scan data). The three-dimensional image scan data may be stitched together to produce a three-dimensional model of the dental object, wherein the two-dimensional image scan data may be used for diagnosis of the dental object manually by a user (via a display unit configured to display the two-dimensional image scan data and the three-dimensional model) or automatically by artificial intelligence. Intraoral scanners may employ scanning principles such as triangulation-based scanning, confocal scanning, or focused scanning. The method may also include processing one or more of the plurality of image scan data or the two-dimensional image scan data into processed image scan data, wherein the processed image scan data includes a plurality of pixels. The one or more image scan data may be similar to two-dimensional image scan data and diagnostic image scan data. The processed image scan data may include captured image scan data that has been processed to improve the quality of the captured image scan data. For example, improvements may include enhancement of detail and contrast, and reduction of noise and distortion. The processed image scan data may include a composition of a plurality of image scan data including wavelengths in an Ultraviolet (UV) wavelength range, a visible light (VIS) wavelength range, and an infrared (NIR/IR) wavelength range. The composite of the plurality of image scan data may include a weighted combination of image scan data having different wavelengths. The advantage of the compounding of multiple image scan data is that the contrast and detail of the tooth interior features and structures is improved more significantly than the processed image scan data containing only wavelengths in the NIR/IR range. The method may further include determining, by the glare detection algorithm, a plurality of defective pixels in the processed image scan data by analyzing pixel values for each of the plurality of pixels. The processed image scan data includes a plurality of pixels, which may correspond to pixels of the intraoral scanner image sensor, and some of these pixels in the processed image scan data may include glare defects that exhibit high intensity specular reflection. The plurality