Structured light projection device and 3D measurement system

Abstract

The utility model relates to a structured light projection device and a 3D measurement system. The projection device comprises a light-emitting part and a projection part. The light-emitting part comprises a strip-shaped light-emitting area and a stripe generation structure. The length of the strip-shaped light-emitting area is larger than the width. The stripe generation structure covers the front side of the strip-shaped light-emitting area, the stripe generation structure is configured to generate a sine stripe image from light emitted by the strip-shaped light-emitting area, and the sine stripe image has periodic light intensity change in the length direction of the strip-shaped light-emitting area. The multiple light-emitting parts are arrayed at intervals in the width direction of the strip-shaped light-emitting area. Each sine fringe image at least has two frequencies and three initial phases. The projection part is arranged on the front side of all the light-emitting parts and is configured to project the sine fringe images outwards. Compared with the prior art, according to the scheme, mechanical motion is not generated, high repetition precision is achieved, the 3D shape of the surface of the to-be-measured object is measured through the multi-frequency multi-step phase shift projection method, and the measurement precision is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of structured light measurement, in particular to a structured light projection device and a 3D measurement system. Background Art

[0002] Fringe Projection Profilometry (FPP) is a structured light 3D measurement technology that uses a projection device to project a sinusoidal fringe image onto the surface of the object to be measured. An image acquisition device then captures and analyzes the reflected fringes on the surface to determine the 3D shape of the surface. Projecting multiple sinusoidal fringe images onto the surface of the object using projection methods with multiple frequencies and / or phases can improve measurement accuracy. For example, the two-frequency, three-step phase shift method requires the sequential projection of six sinusoidal fringe images, each with two fringe frequencies and three phases.

[0003] In related technologies, a mask with a preset frequency pattern is typically used to generate a sinusoidal fringe image with an initial phase. A mechanical structure is then used to shift the piezoelectric ceramic to change this initial phase, thereby generating multiple sinusoidal fringe images with different phases. On the one hand, the mechanical structure makes it difficult to ensure system repeatability over long-term use, making it difficult to meet the repeatability requirements of structured light products for projected images, hindering commercial applications. On the other hand, this solution can only produce sinusoidal fringe images with a single frequency and cannot achieve multi-frequency, multi-step phase-shift projection, resulting in poor measurement accuracy. Utility Model Content

[0004] In view of the above problems, the present invention is proposed to provide a structured light projection device and a 3D measurement system to overcome the above problems or at least partially solve the above problems, which can not only meet the requirements for the repeatability accuracy of the projected image, but also realize multi-frequency and multi-step phase shift projection.

[0005] Specifically, the present invention provides the following technical solutions:

[0006] A structured light projection device comprises a light emitting portion and a projection portion.

[0007] The light-emitting portion includes a strip-shaped light-emitting area and a stripe generating structure. The strip-shaped light-emitting area is longer than its width. The stripe generating structure is disposed over the front side of the strip-shaped light-emitting area and is configured to generate a sinusoidal stripe pattern from the light emitted by the strip-shaped light-emitting area. The sinusoidal stripe pattern has periodic intensity variations along the length of the strip-shaped light-emitting area. There are multiple light-emitting portions, spaced apart in an array along the width of the strip-shaped light-emitting area. Each sinusoidal stripe pattern has at least two frequencies and three initial phases.

[0008] The projection unit is arranged in front of all the light-emitting units and is configured to project each of the sinusoidal fringe images outward.

[0009] Optionally, the plurality of light-emitting portions include M first light-emitting portions and N second light-emitting portions.

[0010] The M is greater than or equal to 3. The frequencies of the first sinusoidal fringe images emitted by the first light-emitting units are equal, and the initial phases of the first sinusoidal fringe images differ by 2π / M.

[0011] The N is greater than or equal to 3. The frequencies of the second sinusoidal fringe images emitted by the second light-emitting units are equal, and the initial phases of the second sinusoidal fringe images differ by 2π / N.

[0012] The frequencies of the first sinusoidal fringe image and the second sinusoidal fringe image are different.

[0013] Optionally, the plurality of light-emitting units further include P third light-emitting units, where P is greater than or equal to 3. The frequencies of the third sinusoidal fringe images emitted by the third light-emitting units are equal, and the initial phases of the third sinusoidal fringe images differ by 2π / P.

[0014] The frequencies of the first sinusoidal fringe image, the second sinusoidal fringe image and the third sinusoidal fringe image are all different.

[0015] Optionally, an optical isolation structure is provided between two adjacent light-emitting parts.

[0016] Optionally, an optical isolation structure is provided between two adjacent strip-shaped light-emitting areas.

[0017] Optionally, the light-emitting portion further includes a light-homogenizing structure, and the light-homogenizing structure is provided between the strip-shaped light-emitting area and the stripe generating structure to homogenize the light emitted by the strip-shaped light-emitting area.

[0018] Optionally, the stripe generating structure includes a pattern mask, which is provided with a binary pattern or a grayscale pattern arrayed along the length direction of the strip-shaped light-emitting area to generate the sinusoidal stripe image with a preset frequency and / or initial phase by changing the amount of light passing through.

[0019] Optionally, the fringe generating structure includes an optical shaping plate, and the optical shaping plate is configured to diffract or refract the passing light to generate the sinusoidal fringe image with a preset frequency and / or initial phase.

[0020] Optionally, when the stripe generating structure includes the pattern mask, the projection device further includes a substrate, the substrate is arranged in front of all the strip-shaped light-emitting areas, and all the pattern masks are arranged on the substrate.

[0021] Optionally, a ratio of the length to the width of the strip-shaped light-emitting area is greater than or equal to 10.

[0022] The projection unit includes a first lens configured to uniformly stretch the sinusoidal fringe image in a width direction of the strip-shaped light-emitting area. The first lens is a cylindrical lens or a quasi-cylindrical lens.

[0023] Optionally, the projection device further includes a back panel, on which one or more reflective structures are provided, and all of the strip-shaped light-emitting areas are provided on the reflective structures.

[0024] All the strip-shaped light-emitting areas form a light-emitting region, and the ratio of the length to the width of the light-emitting region is greater than or equal to 2.

[0025] In another aspect, the present invention further provides a 3D measurement system comprising an image acquisition device and the aforementioned projection device, wherein the angle between the projection optical axis of the projection device and the incident optical axis of the image acquisition device is non-zero.

[0026] The utility model relates to a structured light projection device, which can generate a sinusoidal stripe image with periodic light intensity changes by arranging a stripe-shaped light-emitting area and a stripe generating structure in the light-emitting part, and then project it onto the surface of the object to be measured through the projection part. By arranging multiple light-emitting parts at intervals and presetting different structures in each stripe generating structure, multiple sinusoidal stripe images with different frequency and initial phase combinations can be generated. By controlling the light-emitting and extinguishing states of each stripe-shaped light-emitting area in a time-sharing manner, multiple sinusoidal stripe images with at least two frequencies and three initial phase combinations can be projected onto the surface of the object to be measured in sequence. Compared with the existing technology, this solution does not generate mechanical motion, achieves higher repeatability, and realizes the measurement of the 3D shape of the surface of the object to be measured by a multi-frequency and multi-step phase shift projection method, thereby improving the measurement accuracy.

[0027] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0029] Figure 1 is a schematic front view of multiple light-emitting parts of a projection device according to one embodiment of the present invention;

[0030] Figure 2 is a schematic cross-sectional view of multiple light-emitting parts of a projection device according to one embodiment of the present invention;

[0031] Figure 3 is a schematic cross-sectional view of multiple light-emitting parts of a projection device according to one embodiment of the present invention;

[0032] Figure 4 is a schematic cross-sectional view of multiple light-emitting parts of a projection device according to one embodiment of the present invention;

[0033] Figure 5 is a schematic cross-sectional view of multiple light-emitting parts of a projection device according to one embodiment of the present invention;

[0034] Figure 6 is a schematic cross-sectional view of multiple light-emitting parts of a projection device according to one embodiment of the present invention;

[0035] Figure 7 is a schematic cross-sectional view of multiple light-emitting parts of a projection device according to one embodiment of the present invention;

[0036] Figure 8 is a schematic partial cross-sectional view of multiple light-emitting parts of a projection device according to one embodiment of the present invention;

[0037] Figure 9 is a schematic front view of a pattern mask of a projection device according to one embodiment of the present invention;

[0038] Figure 10 is a schematic front view of a pattern mask of a projection device according to one embodiment of the present invention;

[0039] Figure 11 is a schematic diagram of 12 sinusoidal fringe images projected by a projection device according to one embodiment of the present invention;

[0040] Figure 12 is a schematic structural diagram of a projection device according to one embodiment of the present utility model;

[0041] Figure 13 is a schematic structural diagram of a projection device according to one embodiment of the present utility model;

[0042] Figure 14 is a schematic structural diagram of a 3D measurement system according to one embodiment of the present utility model;

[0043] Figure 15It is a schematic flow chart of a control method of a 3D measurement system according to an embodiment of the present invention.

[0044] List of Figure Numbers:

[0045] 100, 3D measurement system; 200, projection device; 202, projection optical axis; 210, light-emitting unit; 211, strip-shaped light-emitting area; 212a, pattern mask; 212b, optical shaping sheet; 213, light-homogenizing structure; 213a, optical film; 213b, microlens; 220, projection unit; 221, first lens; 230, optical isolation structure; 240, substrate; 250, backplane; 270, first light-emitting unit; 272, first pattern mask; 280, second light-emitting unit; 282, second pattern mask; 290, third light-emitting unit; 292, third pattern mask; 300, image acquisition device; 302, incident optical axis; 402, surface of the object to be measured. DETAILED DESCRIPTION

[0046] Refer to the following Figures 1 to 15 To describe the structured light projection device and 3D measurement system of the embodiment of the present utility model. In the description of this embodiment, it should be understood that the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features, that is, include one or more of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. When a feature "includes or contains" one or some of the features it covers, unless otherwise specifically described, this indicates that other features are not excluded and other features may be further included.

[0047] Unless otherwise expressly specified or limited, terms such as "disposed," "installed," "connected," "connected," "fixed," and "coupled" should be interpreted broadly. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two elements or interaction between two elements, unless otherwise expressly limited. A person of ordinary skill in the art should be able to understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0048] In addition, in the description of this embodiment, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact via another feature between them. That is, in the description of this embodiment, the first feature being "above," "above," and "above" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below," "below," or "below" the second feature may mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0049] In the description of the present embodiment, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in any one or more embodiments or examples.

[0050] Figure 1 is a schematic front view of multiple light-emitting parts of a projection device according to an embodiment of the present invention, as shown in FIG. Figure 1 As shown, and reference Figures 2 to 15 The embodiment of the present invention provides a structured light projection device 200 . The projection device 200 includes a light emitting unit 210 and a projection unit 220 .

[0051] The light-emitting unit 210 includes a stripe-shaped light-emitting area 211 and a stripe-generating structure. The stripe-shaped light-emitting area 211 has a length L1 greater than its width W1. The stripe-generating structure covers the front of the stripe-shaped light-emitting area 211 and is configured to generate a sinusoidal fringe pattern from the light emitted by the stripe-shaped light-emitting area 211. The sinusoidal fringe pattern exhibits periodic intensity variations along the length of the stripe-shaped light-emitting area 211. There are multiple light-emitting units 210, spaced apart in an array along the width of the stripe-shaped light-emitting area 211. Each sinusoidal fringe pattern has at least two frequencies and three initial phases.

[0052] The projection unit 220 is disposed in front of all the light emitting units 210 and is configured to project each sinusoidal fringe image outward.

[0053] The strip-shaped light-emitting area 211 can be rectangular or elongated in shape, with a light source disposed therein to form a backlight. The light source can be an LED (including mini-LEDs, micro-LEDs, etc.), an OLED, a LD, a VECSEL, a fluorescent lamp, etc. Multiple light sources can be disposed within the strip-shaped light-emitting area 211 to form a strip-shaped light-emitting surface. Multiple light sources can be arranged in a continuous or intermittent array on a backplane 250.

[0054] The stripe generating structure is provided on the front side of the stripe-shaped light-emitting area 211 and is installed or formed on the front side of the stripe-shaped light-emitting area. When light emitted from the stripe-shaped light-emitting area 211 passes through the stripe generating structure, a sinusoidal stripe image is formed. The stripe generating structure can form a sinusoidal stripe image by changing the amount of light passing through (for example, through a pattern mask), diffracting or refracting the light (for example, through an optical shaping sheet), etc. The stripe generating structure can be arrayed with periodically varying structures along the length of the stripe-shaped light-emitting area 211, so that the light passing through forms a sinusoidal periodic light intensity variation along the length of the stripe-shaped light-emitting area 211. By presetting different structures, the stripe generating structure can form sinusoidal stripe images with different frequency (number of periods) and initial phase combinations.

[0055] Multiple light-emitting sections 210 are arranged in an array spaced apart along the width of the strip-shaped light-emitting area 211 to minimize size and position each light-emitting section 210 as close as possible to the incident light axis 302 of the projection section 220, thereby improving projection quality. At least six light-emitting sections 210 can be provided to form a sinusoidal fringe image with two frequencies and three initial phase combinations, meeting the requirements of multi-frequency, multi-step phase-shift projection. Each strip-shaped light-emitting section 211 should be independently controlled (e.g., each connected to a control unit) to enable time-sharing illumination and extinguishing.

[0056] The projection unit 220 may include optical elements, such as one or more lenses, reflectors, etc., for projecting the sinusoidal fringe image onto the surface of the object to be measured 402. For a micro-light-emitting unit 210 (e.g., a strip-shaped light-emitting area 211 having a length L1 of several or tens of millimeters), the projection unit 220 may also need to amplify or stretch the projected image.

[0057] The present invention employs a structured light projection device that, by time-sharingly controlling the on / off states of each strip-shaped light-emitting region 211, can sequentially project multiple sinusoidal fringe images with at least two frequencies and three initial phase combinations onto the surface 402 of the object under test. Compared to existing technologies, this solution does not generate mechanical motion, achieving higher repeatability and enabling the measurement of the 3D shape of the surface 402 of the object under test using a multi-frequency, multi-step phase-shifting projection method, thereby improving measurement accuracy.

[0058] In some embodiments of the projection device of the present invention, such as Figure 1 As shown, the plurality of light emitting sections 210 include M first light emitting sections 270 and N second light emitting sections 280 .

[0059] M is greater than or equal to 3. The frequencies of the first sinusoidal fringe images emitted by each first light-emitting unit 270 are equal, and the initial phases of the first sinusoidal fringe images differ by 2π / M. N is greater than or equal to 3. The frequencies of the second sinusoidal fringe images emitted by each second light-emitting unit 280 are equal, and the initial phases of the second sinusoidal fringe images differ by 2π / N.

[0060] The frequencies of the first sinusoidal fringe image and the second sinusoidal fringe image are different.

[0061] The following example takes M and N as 4 as an example. Figure 11 , Figure 11 (a)-(d) illustrate the four first sinusoidal fringe images projected by the projection device 200 in a time-sharing manner, and (e)-(h) illustrate the four second sinusoidal fringe images projected by the projection device 200 in a time-sharing manner. The fringe structure in the four first sinusoidal fringe images has the same frequency (i.e., the same number of periods, all 16). Compared with (a), the initial phases of the images differ by 0°, 90°, 180°, and 270°, respectively. The fringe structure in the four second sinusoidal fringe images has the same frequency (the number of periods is all 17). Compared with (e), the initial phases of the images differ by 0°, 90°, 180°, and 270°, respectively. By projecting these eight sinusoidal fringe images onto the surface 402 of the object to be measured, the phase at each location on the surface 402 can be analyzed using the two-frequency four-step phase shift method, thereby more accurately determining the 3D shape of the surface 402 of the object to be measured.

[0062] In some embodiments of the projection device of the present invention, such as Figure 1 As shown, the plurality of light emitting units 210 further include P third light emitting units 290, where P is greater than or equal to 3. The frequencies of the third sinusoidal fringe images emitted by the third light emitting units 290 are equal, and the initial phases of the third sinusoidal fringe images differ by 2π / P.

[0063] The frequencies of the first sinusoidal fringe image, the second sinusoidal fringe image and the third sinusoidal fringe image are all different.

[0064] Take P as 4 as an example. Figure 11 , Figure 11Figures (i)-(l) illustrate four third sinusoidal fringe images projected time-sharingly by projection device 200. The fringe structures in these four third sinusoidal fringe images have the same frequency (i.e., the same number of periods, 18). Compared to (i), the initial phases of each image differ by 0°, 90°, 180°, and 270°, respectively. By projecting these 12 sinusoidal fringe images time-sharingly onto the surface 402 of the object under test, the phase at each location on the surface 402 can be analyzed using a three-frequency, four-step phase shifting method, thereby accurately determining the 3D shape of the surface 402. This method achieves higher measurement accuracy than the two-frequency, three-step, or two-frequency, four-step phase shifting methods.

[0065] In some embodiments of the projection device of the present invention, such as Figure 2-4 and Figure 8-10 As shown, the stripe generating structure includes a pattern mask 212a, which is provided with a binary pattern or a grayscale pattern arrayed along the length direction of the strip light-emitting area 211 to generate a sinusoidal stripe image with a preset frequency and / or initial phase by changing the amount of light passing through.

[0066] The pattern mask 212a forms a sinusoidal fringe image by setting a periodic pattern, and may include a binary pattern or a grayscale pattern, etc. The binary pattern or the grayscale pattern may be realized by photolithography, printing, coating, etc.

[0067] Figure 9 A binary pattern mask is illustrated, and its pattern is binary (0 or 1). The black part represents light absorption (corresponding to 0), and the white part represents light transmission (corresponding to 1). Along the length direction of the strip-shaped light-emitting area 211, the width of the light-transmitting area perpendicular to the length varies sinusoidally. Rows 1 to 4 may be a first pattern mask 272, whose sinusoidal distribution has the same frequency, but the initial phase difference is 0°, 90°, 180°, and 270°. Rows 5-8 may be a second pattern mask 282, which has another frequency. Rows 9-12 may be a third pattern mask 292, which has a third frequency. For example, the first pattern mask 272 may be arranged in the first light-emitting portion 270, the second pattern mask 282 may be arranged in the second light-emitting portion 280, and the third pattern mask 292 may be arranged in the third light-emitting portion 290.

[0068] Figure 10 The grayscale pattern mask is shown, with different grayscale shades representing different light transmittances. By directly modulating the light transmittance, the grayscale pattern mask can also achieve sinusoidal modulation of the light transmittance along the length of the strip-shaped light-emitting area 211, thereby generating a sinusoidal fringe image with a preset frequency and / or initial phase.

[0069] The manufacturing process for pattern mask 212a is relatively mature, allowing for convenient fabrication of corresponding patterns as needed, thereby forming a sinusoidal fringe image with a preset frequency and phase. In actual use, different frequencies, phase shifts, and steps can be implemented as needed. For example, dual, quad, quintuple, or hexafrequency frequencies can be employed. Another example is the use of a six-step phase shift, with each phase shift differing by 60°.

[0070] In some embodiments of the projection device of the present invention, such as Figure 3-4 and Figure 9-10 As shown, the stripe generating structure includes a pattern mask 212 a , and the projection device 200 further includes a substrate 240 . The substrate 240 is disposed in front of all the strip-shaped light-emitting areas 211 , and all the pattern masks 212 a are disposed on the substrate 240 .

[0071] The substrate 240 may be made of glass, metal, plastic, ceramic, etc. The pattern mask 212a may be formed or mounted on the substrate 240 by photolithography, printing, coating, etc. The pattern mask 212a may be located on a side of the substrate 240 that is close to or away from the strip-shaped light-emitting area 211, without limitation.

[0072] By placing all pattern masks 212a on a single substrate 240, the relative positions and angles between the pattern masks 212a are highly accurate, thereby improving the projection accuracy of each sinusoidal fringe image and preventing misalignment or offset of the sinusoidal fringe images during projection. This also simplifies the assembly process and improves production efficiency.

[0073] In some embodiments of the projection device of the present invention, such as Figure 2-4 and Figure 8 As shown, the light emitting portion 210 further includes a light homogenizing structure 213 , which is disposed between the strip-shaped light emitting area 211 and the stripe generating structure to homogenize the light emitted by the strip-shaped light emitting area 211 .

[0074] Since the pattern mask 212a generates a sinusoidal fringe image by transmitting light, there are certain requirements for the uniformity of the incident light. In this embodiment, the light homogenization structure 213 is used to homogenize the light emitted by the strip-shaped light-emitting area 211, thereby improving the quality of the sinusoidal fringe image generated by the pattern mask 212a.

[0075] The light uniforming structure 213 may be an optical film 213 a , a micro lens 213 b , or the like.

[0076] The optical film 213a may include a diffusion film / sheet, a prism sheet (BEF or xBEF), a brightness enhancement film (DBEF), and other display devices with similar light uniformity functions. The optical film 213a can be a single film or a stack of multiple display films. After the light emitted by each light source in the strip light-emitting area 211 passes through the optical film 213a, a uniform intensity distribution can be formed in the entire strip light-emitting area 211. The optical film 213a can be arranged at intervals in front of each light source in the strip light-emitting area 211, or on the side of the substrate 240 close to the strip light-emitting area 211.

[0077] Microlenses 213b can be made of polymer, glass, or the like and can be mounted around the front of each light source within strip-shaped light-emitting area 211 or etched therein. Microlenses 213b can achieve uniform light distribution and also provide protection by encapsulating the light sources within strip-shaped light-emitting area 211.

[0078] The light emitting portion 210 may also use a micro lens 213b and an optical film 213a at the same time. Figure 8 As shown, the light uniformity effect is further improved.

[0079] In some embodiments of the projection device of the present invention, such as Figure 5-7 As shown, the fringe generating structure includes an optical shaping sheet 212b, which is configured to diffract or refract the light passing therethrough to generate a sinusoidal fringe image with a preset frequency and / or initial phase.

[0080] The function of the optical shaping sheet 212b is to shape the light emitted by the strip-shaped light-emitting area 211, thereby achieving a specific light intensity distribution on an intermediate image plane (not shown) at a certain distance. The optical shaping sheet 212b can be a diffractive optical element (DOE), a volume holographic grating, a microlens array, a cylindrical lens array, etc. The intermediate image plane can be a real image plane that can be directly observed, or it can be a virtual image plane that cannot be directly observed. The optical shaping sheet 212b can make the integral of the light intensity along the length of the strip-shaped light-emitting area 211 a periodic function similar to a sine distribution, thereby generating a sinusoidal fringe image with a preset frequency and / or initial phase.

[0081] Compared with the solution using the pattern mask 212a, the solution using the optical shaping sheet 212b does not require the light uniforming structure 213, has a simpler structure, and can reduce or prevent optical crosstalk between different light-emitting units 210.

[0082] In particular, if Figure 7 As shown, the optical shaping sheet 212b can be directly covered on the front side of the light source of the strip-shaped light-emitting area 211, which can greatly simplify the structure of the projection device and reduce the manufacturing cost.

[0083] In some embodiments of the projection device of the present invention, such as Figure 2 and Figure 5 As shown, an optical isolation structure 230 is provided between two adjacent light emitting portions 210 .

[0084] The optical isolation structure 230 can be a light-absorbing structure in black or other corresponding colors to absorb the light emitted by the light source, or a reflective structure to reflect the light. The purpose of the optical isolation structure 230 is to avoid or reduce optical crosstalk between different light-emitting units 210.

[0085] In this embodiment, the strip-shaped light-emitting area 211 and the stripe generating structure of each light-emitting portion 210 are independently arranged within the isolation boundary formed by the optical isolation structure 230. Specifically, each optical film 213a, microlens 213b, pattern mask 212a or optical shaping sheet 212b is independently arranged within the isolation boundary formed by the optical isolation structure 230, which can prevent optical crosstalk between adjacent strip-shaped light-emitting areas 211 and stripe generating structures to the greatest extent, thereby improving the projection quality.

[0086] In some embodiments of the projection device of the present invention, such as Figure 3-4 and Figure 6 As shown, an optical isolation structure 230 is provided between two adjacent light-emitting regions 211 .

[0087] like Figure 3 and Figure 6 As shown, the strip-shaped light-emitting area 211, the optical film 213a and the microlens 213b can be independently arranged within the isolation boundary formed by the optical isolation structure 230, and the pattern mask 212a / optical shaping sheet 212b can be arranged outside the optical isolation structure 230. In this way, the pattern mask 212a or the optical shaping sheet 212b of each light-emitting portion 210 can be processed on the same substrate 240, thereby reducing shape and position errors during installation and improving the projection accuracy of each sinusoidal fringe image.

[0088] like Figure 4 As shown, the strip-shaped light-emitting regions 211 can be independently positioned within the isolation boundary formed by the optical isolation structure 230, while the optical film 213a and pattern mask 212a / optical shaping sheet 212b can be positioned outside the optical isolation structure 230. This allows each light-emitting unit 210 to utilize the same optical film 213a, simplifying the assembly process. The pattern mask 212a or optical shaping sheet 212b for each light-emitting unit 210 is fabricated onto the same substrate 240, minimizing geometric and positional errors during assembly and improving the projection accuracy of each sinusoidal fringe image.

[0089] In some embodiments of the projection device of the present invention, such as Figure 1 and Figure 12-13As shown, the ratio L1 / W1 of the length L1 to the width W1 of the strip-shaped light-emitting area 211 is greater than or equal to 10.

[0090] The projection unit 220 includes a first lens 221, and the first lens 221 is configured to uniformly stretch the sinusoidal fringe image in the width direction of the strip-shaped light-emitting area 211. The first lens 221 is a cylindrical lens or a quasi-cylindrical lens.

[0091] In this embodiment, the strip-shaped light-emitting area 211 has a large aspect ratio to form a sinusoidal fringe image with a greater number of periods (displaying more sinusoidal fringes within the same projected area). This increases the frequency of the projected sinusoidal fringe image and thereby improves measurement accuracy. This also reduces the volume of the light-emitting unit 210, thereby reducing the size and cost of the projection device 200.

[0092] Because the aspect ratio of a single strip-shaped light-emitting area 211 is relatively large, a first lens 221 is provided in the projection unit 220 to project an image with approximately the same aspect ratio. The first lens 221, which can be a cylindrical or quasi-cylindrical lens, is used to converge light in the direction of the stripe spacing between the sinusoidal stripes (corresponding to the length of the strip-shaped light-emitting area 211), thereby ensuring that the projected image maintains a one-dimensional luminous flux distribution similar to that of the sinusoidal stripe image in this direction. In the perpendicular direction, i.e., the stripe extension direction (corresponding to the width of the strip-shaped light-emitting area 211), the first lens 221 diverges the light, thereby producing a stretched stripe.

[0093] Please refer to Figure 12-13 . Figure 12 The vertical direction is the extension direction of the sinusoidal stripes (corresponding to the width direction of the strip-shaped light-emitting area 211 ), and the first lens 221 diverges the light in the vertical direction, thereby generating stretched stripes. Figure 13 The upper and lower directions are the stripe spacing directions of the sinusoidal stripes (corresponding to the width direction of the strip-shaped light-emitting area 211). The first lens 221 converges the light in the upper and lower directions, so that the projected image maintains a one-dimensional luminous flux distribution similar to the sinusoidal stripe image in this direction.

[0094] For example, the cylindrical surface of the cylindrical mirror may have the following shape:

[0095]

[0096] Where z is the surface height, y is the coordinate independent variable, c is the surface curvature, k is the cone coefficient, α i is an even-numbered aspheric surface coefficient. When k=0, α i = 0, the curve is a circle. Rotating this projection around a fixed axis yields a cylindrical-like plane. When the axis of rotation is at infinity, the resulting plane is a standard cylinder.

[0097] In this embodiment, by setting a larger aspect ratio in the strip-shaped light-emitting area 211 and cooperating with the first lens 221 , the number of periods of the sinusoidal fringe image can be increased, thereby improving the measurement accuracy.

[0098] In some embodiments of the projection device of the present invention, such as Figure 1 As shown, the projection device 200 further includes a back plate 250 , on which one or more reflective structures (not shown) are disposed, and all the strip-shaped light-emitting areas 211 are disposed on the reflective structures.

[0099] All the strip-shaped light-emitting regions 211 form a light-emitting area, and a ratio L1 / W2 of the length L1 to the width W2 of the light-emitting area is greater than or equal to 2.

[0100] In this embodiment, each light-emitting portion 210 is mounted or formed on the back panel 250. The material of the back panel 250 can be plastic, metal, glass or other composite materials. An optical reflective structure can be provided on one surface of the back panel 250. The reflective structure is composed of an optical reflective material, which can efficiently reflect light, so that the light emitted by the strip-shaped light-emitting area 211 is emitted toward the stripe generating structure. One surface of the back panel 250 can be set as a reflective structure as a whole, or a plurality of reflective structures can be set at intervals in different areas (for example, a reflective structure is set only on the back side of the strip-shaped light-emitting area 211). The back panel 250 can also include a control circuit for the control system of the projection device 200.

[0101] In this embodiment, the luminous area formed by all the strip-shaped luminous areas 211 has an overall rectangular structure, and its aspect ratio L1 / W2 is greater than or equal to 2. This allows the strip-shaped luminous areas 211 at both ends of the luminous area to be as close as possible to the incident light axis 302 of the projection unit 220. This allows the sinusoidal fringe image generated by the strip-shaped luminous area 211 farthest from the incident light axis 302 of the projection unit 220 to be projected onto a predetermined area on the surface 402 of the object to be measured. Furthermore, the co-projection quality is improved, preventing severe image distortion caused by the distance from the incident light axis 302 of the projection unit 220.

[0102] In some embodiments of the projection device of the present invention, the projection device 200 further includes a second lens. The first lens 221 is located on the side of the second lens away from the light-emitting portion 210. There are multiple second lenses. The second lenses are spherical mirrors. The multiple second lenses can be spaced apart along the principal optical axis. The second lens is used to improve projection quality, for example, by collimating and eliminating chromatic aberration. Because the first lens 221 stretches the projected image, placing the first lens 221 away from the display portion can reduce the size of the second lens, thereby reducing the size of the projection device 200 and reducing manufacturing costs.

[0103] In some embodiments of the 3D measurement system of the present invention, Figure 14As shown, the 3D measurement system 100 includes an image acquisition device 300 and a projection device 200 of any one of the above embodiments or a combination of embodiments. The angle α between the projection optical axis 202 of the projection device 200 and the incident optical axis 302 of the image acquisition device 300 is not zero.

[0104] The image acquisition device 300 can be a camera, a video camera, etc., and is used to capture each sinusoidal fringe image projected by the projection device 200 onto the surface 402 of the object to be measured. The image acquisition device 300 can also perform phase separation on the sinusoidal fringe images to obtain measurement results of the surface 402 of the object to be measured. Alternatively, the image acquisition device 300 can be connected to a computing device, which processes the collected data to obtain measurement results of the surface 402 of the object to be measured.

[0105] An angle α (e.g., 45 degrees) is formed between the incident light axis 302 of the image acquisition device 300 and the projection light axis 202 of the projection device 200, thereby being able to capture the sinusoidal fringe image reflected by the surface 402 of the object to be measured, and obtain the 3D shape of the surface 402 of the object to be measured by deformation of the fringes.

[0106] In some embodiments of the 3D measurement system of the present invention, the measurement system may adopt Figure 15 The control directions shown are for image projection and acquisition.

[0107] S8100, start;

[0108] S8111, the first first light-emitting portion emits light;

[0109] S8112, the image acquisition device acquires an image;

[0110] S8113, the first light-emitting portion is turned off;

[0111] S8121, the second first light-emitting portion emits light;

[0112] …

[0113] S8341, the fourth third luminous part emits light;

[0114] S8342, the image acquisition device acquires an image;

[0115] S8343, the fourth third light emitting part goes out;

[0116] S8400, end.

[0117] In this way, a total of 12 sinusoidal fringe images (e.g. Figure 11 The image is projected onto the surface of the object to be measured, and after passing through the image acquisition device, the 3D shape of the surface of the object to be measured can be obtained through calculation and analysis.

[0118] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications consistent with the principles of the present invention can be directly determined or deduced from the contents disclosed herein without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims

1. A structured light projection device, characterized in that: include: a light-emitting portion, the light-emitting portion comprising a stripe-shaped light-emitting area and a stripe generating structure; The length of the strip-shaped light-emitting area is greater than its width; The stripe generating structure is disposed on the front side of the strip-shaped light-emitting area, and is configured to generate a sinusoidal stripe image from the light emitted by the strip-shaped light-emitting area, wherein the sinusoidal stripe image has a periodic light intensity variation along the length direction of the strip-shaped light-emitting area; the light-emitting portions are multiple and spaced in an array along the width direction of the strip-shaped light-emitting area; Each of the sinusoidal fringe images has at least two frequencies and three initial phases; The projection unit is arranged in front of all the light-emitting units and is configured to project each of the sinusoidal fringe images outward.

2. The projection device according to claim 1, wherein: The plurality of light emitting parts include: M first light-emitting units, where M is greater than or equal to 3; the frequencies of the first sinusoidal fringe images emitted by the first light-emitting units are equal, and the initial phases of the first sinusoidal fringe images differ by 2π / M; and N second light-emitting units, where N is greater than or equal to 3; the frequencies of the second sinusoidal fringe images emitted by the second light-emitting units are equal, and the initial phases of the second sinusoidal fringe images differ by 2π / N. The frequencies of the first sinusoidal fringe image and the second sinusoidal fringe image are different.

3. The projection device according to claim 2, wherein: The plurality of light emitting parts further include: P third light-emitting units, where P is greater than or equal to 3; the frequencies of the third sinusoidal fringe images emitted by the third light-emitting units are equal, and the initial phases of the third sinusoidal fringe images differ by 2π / P; The frequencies of the first sinusoidal fringe image, the second sinusoidal fringe image and the third sinusoidal fringe image are all different.

4. The projection device according to claim 1, wherein: An optical isolation structure is provided between two adjacent light-emitting parts; or An optical isolation structure is provided between two adjacent strip-shaped light-emitting areas.

5. The projection device according to claim 1, wherein: The light emitting portion further includes a light uniforming structure, which is provided between the strip-shaped light emitting area and the stripe generating structure to uniformly distribute the light emitted by the strip-shaped light emitting area.

6. The projection device according to claim 1, wherein: The stripe generating structure comprises: a pattern mask provided with a binary pattern or a grayscale pattern arrayed along the length direction of the strip-shaped light-emitting area, so as to generate the sinusoidal fringe image with a preset frequency and / or initial phase by changing the amount of light passing therethrough; or An optical shaping sheet is configured to diffract or refract the light passing therethrough to generate the sinusoidal fringe image with a preset frequency and / or initial phase.

7. The projection device according to claim 6, wherein: In the case where the stripe generating structure includes the pattern mask, the projection device further includes a substrate, which is arranged in front of all the strip-shaped light-emitting areas, and all the pattern masks are arranged on the substrate.

8. The projection device according to claim 1, wherein: The ratio of the length to the width of the strip-shaped light-emitting area is greater than or equal to 10; The projection unit includes a first lens, which is configured to uniformly stretch the sinusoidal stripe image in the width direction of the strip-shaped light-emitting area; the first lens is a cylindrical lens or a quasi-cylindrical lens.

9. The projection device according to claim 8, wherein: The projection device further comprises a back plate, wherein one or more reflective structures are provided on the back plate, and all the strip-shaped light-emitting areas are provided on the reflective structures; All the strip-shaped light-emitting areas form a light-emitting region, and the ratio of the length to the width of the light-emitting region is greater than or equal to 2.

10. A 3D measurement system, characterized in that: The device comprises an image acquisition device and the projection device according to any one of claims 1 to 9; the angle between the projection optical axis of the projection device and the incident optical axis of the image acquisition device is not zero.

Images