Polychromatic light structured light three-dimensional imaging system

Abstract

The invention discloses a polychromatic light structured light three-dimensional imaging system, which relates to the technical field of three-dimensional imaging, and comprises a shell, a light path for light beams to pass through is arranged in the shell, one end of the shell is a handheld end, an object surface is mounted on the bottom wall of the other end of the shell, the object surface is used for stretching into the oral cavity of a patient, and the object surface is positioned at the front end of the shell; the refraction prism is located at the front end of the light path, is arranged at the object plane end and is used for refracting light beams emitted from the light path; the compensation prism is located at the rear end of the light path and between the object plane and the light path, and the compensation prism can counteract chromatic aberration introduced by the refraction prism to form a polychromatic light system. According to the invention, the measurement performance of the three-dimensional structured light measurement equipment can be maintained while the volume increase caused by included angle arrangement is avoided, so that the system volume is effectively controlled on the premise of ensuring high precision, and the system is suitable for application scenes with high precision and small volume.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional imaging technology, specifically to a polychromatic structured light three-dimensional imaging system. Background Technology

[0002] The key to structured light binocular 3D imaging lies in the need for the two optical systems to generate a certain parallax at corresponding points. In traditional binocular 3D imaging systems, the two optical systems are typically arranged at a certain angle. For example... Figure 4 As shown, optical path 1 and optical path 2 are the two core optical paths of the 3D structured light measurement system. The larger the angle between the two optical paths, the more significant the parallax, which is more beneficial for improving the accuracy of 3D measurement. Figure 4 As shown, whether using a dual-path passive imaging optical structure or a "one-projection-one-receiver" 3D imaging system where "one optical path projects a specific pattern (such as a grating fringe pattern) + another optical path receives the fringe deformation image," the imaging essence is the same, and both can be used... Figure 4 describe.

[0003] Traditional binocular 3D imaging systems are widely used in various applications and can meet the needs of most scenarios. However, their application is limited in certain special situations, especially when there are strict limitations on system size. For example, in scenarios such as intraoral 3D scanners and polychromatic structured light 3D imaging systems, both high precision and a highly compact device with a slender design are required for easy handling and placement inside the oral cavity for 3D scanning. However, to achieve high-precision measurements, it is usually necessary to increase the angle between the two optical systems. This increased angle, in turn, leads to a larger baseline in the optical path at the tail end, making it difficult to achieve overall miniaturization. Summary of the Invention

[0004] The purpose of this invention is to provide a polychromatic structured light three-dimensional imaging system to solve the problems mentioned in the background art.

[0005] To solve the above technical problems, the present invention provides the following technical solution: a polychromatic structured light three-dimensional imaging system, including a housing, wherein an optical path for the passage of a light beam is provided inside the housing, one end of the housing is a handheld end, and an object surface is installed on the bottom wall of the other end, the object surface is used to probe into the patient's oral cavity, and the object surface is located at the front end of the housing; A refracting prism is located at the front end of the optical path and is disposed at the object surface end. The refracting prism is used to refract the light beam emitted from the optical path. A compensating prism is located at the rear end of the optical path and between the object plane and the optical path. The compensating prism can cancel the chromatic aberration introduced by the refracting prism to form a polychromatic light system.

[0006] In a further embodiment, the optical path includes two optical paths, namely optical path three and optical path four, which are distributed in parallel; the light beams in optical path three and optical path four respectively enter and exit into the refracting prisms at corresponding positions; Both optical path three and optical path four use a central field of view for imaging or projection. The wedge angle of the refracting prism is adjustable.

[0007] In a further embodiment, there are two compensation prisms, namely a trichromatic optical path compensation prism and a tetrachromatic optical path compensation prism. The wedge angles of the optical path trichromatic dispersion compensation prism and the optical path tetrachromatic dispersion compensation prism are adjustable, and their thicknesses can be adjusted according to the imaging optical path.

[0008] In a further embodiment, the optical path includes a three-image surface and a four-image surface, wherein the three-image surface is located at the rear end of the three-dispersion-compensating prism and the four-image surface is located at the rear end of the four-dispersion-compensating prism.

[0009] In a further embodiment, the polychromatic light system is used for polychromatic binocular three-dimensional imaging.

[0010] In a further embodiment, the polychromatic light system further includes a transmit-receive binocular structured light system for use as a monochromatic light system.

[0011] Compared with the prior art, the beneficial effects of the present invention are: This invention is a polychromatic structured light three-dimensional imaging system that can maintain the measurement performance of the three-dimensional structured light measurement device while avoiding the increase in volume caused by the angled arrangement. Therefore, it can effectively control the system volume while ensuring high precision, thus adapting to application scenarios that emphasize both high precision and small size. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the main structure of an embodiment of the present invention; Figure 2 and Figure 3 These are all schematic diagrams of a polychromatic light binocular three-dimensional imaging system with a refractive prism and a compensation prism, according to embodiments of the present invention. Figure 4 This is a schematic diagram of the structure of a conventional cross-type binocular three-dimensional imaging system according to an embodiment of the present invention.

[0013] In the diagram: 1: Optical path one; 2: Optical path two; 3: Optical path three; 4: Optical path four; 5: Refractive prism; 6: Object plane; 7: Optical path three dispersion compensation prism; 8: Optical path four dispersion compensation prism; 9: Optical path three imaging plane; 10: Optical path four imaging plane; 11: Shell. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Examples, such as Figure 4 As shown, optical path 1 and optical path 2 are the two core optical paths of the 3D structured light measurement system. The larger the angle between the two optical paths, the more significant the parallax, which is more beneficial for improving the accuracy of 3D measurement. Figure 4 As shown, whether using a dual-path passive imaging optical structure or a "one-projection-one-receiver" 3D imaging system where "one optical path projects a specific pattern, such as a grating fringe pattern, and another optical path receives the fringe deformation image," the imaging essence is the same, and both can be used... Figure 4 describe.

[0016] This embodiment provides a polychromatic structured light three-dimensional imaging system, such as... Figure 1 and Figure 3 As shown, the system includes a housing 11, within which an optical path for the light beam to pass is provided. There are two optical paths: optical path 3 and optical path 4, which are distributed in parallel. Both optical paths 3 and 4 employ a central field of view for imaging or projection.

[0017] One end of the housing 11 is a handheld end, and the bottom wall of the other end is equipped with an object surface 6, which is used to probe into the patient's mouth. The object surface 6 is located at the front end of the housing 11.

[0018] It also includes a refracting prism 5, located at the front end of the optical path and positioned at the object plane 6. The refracting prism 5 is used to refract the light beam emitted from the optical path. The light beams from optical path 3 and optical path 4 respectively enter and exit into the corresponding refracting prisms 5. The wedge angle of the refracting prism 5 is adjustable. Figure 2 and Figure 3 As shown, optical path 3 and optical path 4 are placed in parallel. This structure can significantly compress the width of the optical system. However, the disadvantage of parallel optical paths is obvious: they are not conducive to generating parallax, i.e., 3D measurement is impossible. Therefore, by adding a refracting prism 5 to deflect the light, parallax can be achieved. Figure 4 The optical path layout shown has an equivalent optical parallax that, while reducing the optical path width, still has a sufficiently large parallax angle, thus ensuring measurement accuracy.

[0019] However, the refracting prism 5 introduces chromatic aberration due to light path deflection, making it unsuitable for polychromatic light systems. To address this problem, the present invention introduces a compensating prism in front of the image in the optical system to counteract the additional chromatic aberration introduced by the refracting prism 5. Figure 2and Figure 3 As shown, there are two compensation prisms, namely the optical path trichromatic dispersion compensation prism 7 and the optical path tetrachromatic dispersion compensation prism 8; the wedge angles of the optical path trichromatic dispersion compensation prism 7 and the optical path tetrachromatic dispersion compensation prism 8 are adjustable, and their thicknesses can be adjusted according to the imaging optical path.

[0020] The compensating prism is located at the rear end of the optical path. Specifically, it also includes a three-image plane 9 and a four-image plane 10. The three-image plane 9 is located at the rear end of the three-dispersion compensating prism 7, and the four-dispersion compensating prism 10 is located at the rear end of the four-dispersion compensating prism 8. The compensating prism is located between the object plane 6 and the optical path. The compensating prism can cancel the chromatic aberration introduced by the refracting prism 5, forming a polychromatic light system.

[0021] The specific working principle is as follows: Among the light rays scattered from the six corresponding points on the object surface, there are always rays such as... Figure 3 The two beams of light shown enter the refracting prisms 5 corresponding to optical paths 3 and 4, respectively. The refraction of prism 5 causes these two beams of light to be deflected and enter optical paths 3 and 4, respectively. This deflection process introduces additional chromatic aberration, which is difficult to compensate for through subsequent conventional optical paths. Therefore, a three-way dispersion compensation prism 7 and a four-way dispersion compensation prism 8 are added in front of the image, with their wedge angle rotated 180 degrees relative to the refracting prisms, and their thickness adjustable according to the imaging optical path. These three-way dispersion compensation prisms 7 and four-way dispersion compensation prisms 8 can effectively eliminate the chromatic aberration introduced by the refracting prism 5, thus making the system suitable for polychromatic light systems. In addition, the polychromatic light system also includes a binocular structured light system with one emitter and one receiver for monochromatic light systems, the principle of which is the same as that of the polychromatic light system.

[0022] For example, such as Figure 3 As shown, the object surface 6 extends into the patient's mouth to perform a 3D scan of the oral cavity, acquiring data such as the patient's teeth and gums. To achieve this slender structure, the oral 3D scanner employs techniques such as... Figure 3 The optical layout shown features two optical lenses, 3 and 4, placed parallel to each other, significantly reducing the lateral width of the oral cavity 3D scanner. The refracting prism 5 breaks the parallelism of the two light paths, deflecting them to create optical parallax, thus achieving structured light 3D scanning. Optical paths 3 and 4 eliminate the chromatic aberration introduced by the refracting prism 5. This method reduces the lateral optical width, maintains the structured light parallax capability, and eliminates chromatic aberration. This method is suitable for polychromatic structured light 3D scanning and can obtain colored texture data.

[0023] The advantages of this system are: it compresses the system volume by arranging parallel optical paths, meets the measurement accuracy requirements by adjusting the angle of the refracting prism, and eliminates chromatic aberration by using a compensation prism, thus extending to polychromatic light applications.

[0024] Transforming the traditional angled, intersecting imaging system into a parallel arrangement provides an effective solution for the compact optical design of structured light 3D scanners. In applications such as 3D endoscopic optical systems where radial dimensions are strictly limited, this optical layout is particularly advantageous for significantly reducing the system's radial dimensions while maintaining the same accuracy as the intersecting layout.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A polychromatic structured light three-dimensional imaging system, characterized in that, include: The housing (11) has an optical path for the light beam to pass through inside. One end of the housing (11) is a handheld end, and the bottom wall of the other end is equipped with an object surface (6). The object surface (6) is used to probe into the patient's oral cavity. The object surface (6) is located at the front end of the housing (11). A refracting prism (5) is located at the front end of the optical path. The refracting prism (5) is disposed at the object surface (6) end. The refracting prism (5) is used to refract the light beam emitted from the optical path. The compensating prism is located at the rear end of the optical path and between the object plane (6) and the optical path. The compensating prism can cancel the chromatic aberration introduced by the refracting prism (5) to form a polychromatic light system.

2. The polychromatic structured light three-dimensional imaging system according to claim 1, characterized in that, The optical path includes two optical paths, namely optical path three (3) and optical path four (4), which are distributed in parallel; the light beams in optical path three (3) and optical path four (4) enter and exit into the corresponding refracting prisms (5); Both optical path three (3) and optical path four (4) use the central field of view for imaging or projection; The wedge angle of the refracting prism (5) is adjustable.

3. The polychromatic structured light three-dimensional imaging system according to claim 1, characterized in that, The compensation prism is provided in two parts, namely a three-color dispersion compensation prism (7) and a four-color dispersion compensation prism (8). The wedge angles of the optical path trichromatic dispersion compensation prism (7) and the optical path tetrachromatic dispersion compensation prism (8) are adjustable, and their thicknesses can be adjusted according to the imaging optical path.

4. The polychromatic structured light three-dimensional imaging system according to claim 1, characterized in that, It also includes a three-image plane (9) and a four-image plane (10), the three-image plane (9) being located at the rear end of the three-dispersion compensation prism (7), and the four-image plane (10) being located at the rear end of the four-dispersion compensation prism (8).

5. The polychromatic structured light three-dimensional imaging system according to claim 1, characterized in that, The polychromatic light system is used for polychromatic binocular three-dimensional imaging.

6. The polychromatic structured light three-dimensional imaging system according to claim 1, characterized in that, The polychromatic light system also includes a transmit-receive binocular structured light system for use in monochromatic light systems.

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