Three-dimensional imaging device, method and electronic equipment based on structured light

Abstract

This application discloses a three-dimensional imaging device, method, and electronic device based on structured light. The device includes a transmitting module and a receiving module. The transmitting module is configured to emit structured light with a predetermined polarization direction. The receiving module is configured to receive both ambient light and structured light from the target's environment. The predetermined polarization direction of the structured light is the same as the polarization direction of the weakest light intensity in the ambient light received by the receiving module. Based on the technical solutions provided in the embodiments of this application, the three-dimensional imaging device improves the imaging signal-to-noise ratio.

Description

Technical Field

[0001] The present application generally relates to the field of optics, and more specifically to a three-dimensional imaging device, method, and electronic device based on structured light. Background Art

[0002] With the deepening of research on three-dimensional imaging based on structured light and the expansion of application needs, three-dimensional imaging has been widely used in depth detection and other aspects.

[0003] Traditional structured light-based 3D imaging devices for depth detection consist of a light source, an image sensor, and a processor. The light source emits structured light toward a target; the image sensor forms an image of the structured light reflected by the target; and the processor calculates the target's distance by determining the time difference between the structured light being emitted, reflected by the target, and then received by the image sensor based on the image and other information.

[0004] As can be seen from the above, the existing technology has at least the following problems: the environment where the target object is located generally has a large amount of interfering light, which will seriously affect the signal-to-noise ratio of the three-dimensional imaging device. Summary of the Invention

[0005] In view of the problem of low signal-to-noise ratio of existing three-dimensional imaging devices based on structured light, the present application proposes a three-dimensional imaging device, method and electronic equipment based on structured light, which can improve the imaging signal-to-noise ratio.

[0006] In a first aspect, an embodiment of the present application provides a three-dimensional imaging device based on structured light, the device comprising:

[0007] Transmitter module and receiver module;

[0008] The transmitting module is used to transmit structured light in a predetermined polarization direction;

[0009] The receiving module is used to receive ambient light and structured light in the environment where the target object is located. The predetermined polarization direction of the structured light is the same as the polarization direction of the light with the weakest intensity in the ambient light received by the receiving module.

[0010] Optionally, the receiving module includes a first infrared image sensor and a first optical analyzer, and the first optical analyzer covers a light receiving surface close to the first infrared image sensor.

[0011] Optionally, the receiving module further includes a second infrared image sensor and a second optical analyzer, the second optical analyzer covers the light receiving surface of the second infrared image sensor, and the analysis directions of the second optical analyzer and the first optical analyzer are perpendicular to each other.

[0012] Optionally, the emission module includes a high-contrast grating laser and a diffraction optical element, and the diffraction optical element is arranged on a side where the high-contrast grating laser emits light.

[0013] Optionally, the high-contrast grating laser is a high-contrast grating vertical cavity surface emitting laser.

[0014] Optionally, the transmitting module further includes a rotating component connected to the high-contrast grating laser and configured to rotate the high-contrast grating laser to change the polarization direction of the structured light emitted by the high-contrast grating laser.

[0015] Optionally, the emission module further includes a collimator lens, which is arranged on the side where the high-contrast grating laser emits light, and is used to reduce the divergence angle of the light emitted by the high-contrast grating laser.

[0016] In a second aspect, an embodiment of the present application provides a structured light three-dimensional imaging method, the method comprising:

[0017] emitting structured light in a predetermined polarization direction;

[0018] receiving ambient light and structured light in an environment where the target object is located, wherein the predetermined polarization direction of the structured light is the same as the polarization direction of the light with the weakest intensity in the received ambient light;

[0019] Imaging is performed based on the received ambient light and structured light.

[0020] Optionally, the polarization direction of the light with the weakest intensity in the ambient light is determined by the following method:

[0021] acquiring a first image of the environment by means of a first infrared image sensor and a first optical analyzer;

[0022] acquiring a second image of the environment by using a second infrared image sensor and a second optical analyzer, wherein the second optical analyzer is perpendicular to the first optical analyzer;

[0023] The polarization direction of the light with the weakest light intensity in the environment is determined according to the first image and the second image.

[0024] In a third aspect, an embodiment of the present application provides an electronic device, which includes any one of the three-dimensional imaging devices described in the first aspect.

[0025] In summary, the three-dimensional imaging device provided in the embodiment of the present application determines the polarization direction of the light with the weakest intensity in the environment, and enables the transmitting module to emit structured light with the same polarization direction as the light with the weakest intensity, so that when the receiving module receives the structured light, the influence of ambient light on it is reduced, the interference information of the imaging is reduced, and the signal-to-noise ratio is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly describes the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings are only for the purpose of illustrating preferred implementation methods and are not to be considered as limiting the present invention. It should also be noted that, for ease of description, the drawings only show portions relevant to the present invention, not all of them.

[0027] Figure 1 is a schematic diagram of a three-dimensional imaging device based on structured light according to an embodiment of the present application;

[0028] Figure 2 Another three-dimensional imaging device based on structured light is shown in an embodiment of the present application;

[0029] Figure 3 is a schematic diagram of a receiving module according to an embodiment of the present application;

[0030] Figure 4 is a schematic diagram of a receiving module according to an embodiment of the present application;

[0031] Figure 5 is a schematic diagram of another receiving module according to an embodiment of the present application;

[0032] Figure 6 is a schematic diagram of a transmitting module according to an embodiment of the present application;

[0033] Figure 7 is a schematic diagram of a high contrast grating according to an embodiment of the present application;

[0034] Figure 8 1 is a schematic diagram of a high-contrast grating vertical cavity surface emitting laser according to an embodiment of the present application;

[0035] Figure 9 1 is a schematic diagram of an output light field of a high-contrast grating laser according to an embodiment of the present application;

[0036] Figure 10 This is a schematic diagram of the light field emitted from a single aperture of a high-contrast grating laser according to an embodiment of the present application;

[0037] Figure 11 This is a schematic diagram of a three-dimensional imaging method based on structured light according to an embodiment of the present application. DETAILED DESCRIPTION

[0038] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the invention are shown in the accompanying drawings.

[0039] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] Figure 1 FIG is a schematic diagram of a three-dimensional imaging device based on structured light according to an embodiment of the present application. Figure 1 As shown, the device includes: a transmitting module 110 and a receiving module 120.

[0041] The transmitting module 110 is configured to transmit structured light in a predetermined polarization direction.

[0042] The receiving module 120 is used to receive ambient light and structured light in the environment where the target object 150 is located. The predetermined polarization direction of the structured light is the same as the polarization direction of the light with the weakest intensity in the ambient light received by the receiving module 120 .

[0043] Since the predetermined polarization direction of the structured light is the same as the polarization direction of the weakest light in the ambient light received by the receiving module 120, the polarization direction of the weakest light in the ambient light needs to be determined in advance before the transmitting module 110 transmits the structured light with the predetermined polarization direction.

[0044] Of course, the predetermined polarization direction may also be determined according to actual needs. For example, the predetermined polarization direction may be determined as the polarization direction of light that is neither the weakest nor the strongest in the environment.

[0045] Furthermore, the polarization direction of the light with the weakest intensity in the ambient light can be determined by the receiving module 120. Figure 3 The receiving module 120 includes a first infrared image sensor 121 and a first optical analyzer 122. The first optical analyzer 122 covers the light receiving surface of the first infrared image sensor 121. The method for determining the polarization direction of the light with the weakest light intensity in the environment is as follows:

[0046] Step 1: Acquire a first image of the environment through the first infrared image sensor 121 and the first optical analyzer 122;

[0047] Step 2: Rotate the directions of the first infrared image sensor 121 and the first optical analyzer 122 so that an angle exists between them and their directions before rotation, and acquire a second image of the environment;

[0048] Step 3: Determine the polarization direction of the light with the weakest light intensity in the environment based on the first image and the second image.

[0049] The angle obtained by the rotation can be of any size, such as 90 degrees. When the angle is 90 degrees, any polarization direction of light in the environment can be decomposed into two directions with an angle of 90 degrees, thereby improving the accuracy of the received ambient light, thereby improving the accuracy of the first image and the second image, and further improving the accuracy of the polarization direction of the light with the weakest light intensity in the environment.

[0050] The first image and the second image may be one or more images. When there are multiple images, the average value may be calculated multiple times to improve the accuracy of determining the polarization direction of the light with the weakest light intensity in the environment.

[0051] Step 3 may be as follows:

[0052] 1. Calculate the brightness difference between the two images;

[0053] 2. Determine the polarization direction of the two analyzers;

[0054] 3. Calculate the intensity of each light in the ambient light and its corresponding polarization direction based on the brightness difference and polarization direction;

[0055] 4. Select the light with the weakest intensity and determine the polarization direction corresponding to the light with the weakest intensity.

[0056] Optionally, the receiving module 120 further includes a second infrared image sensor 131 and a second optical analyzer 132. The second optical analyzer 132 covers the light receiving surface of the second infrared image sensor 131, and the second optical analyzer 132 has a different analysis direction than the first optical analyzer 121. Optionally, the two analysis directions are perpendicular to each other. Compared to other different angles, similar to the above principle, the perpendicularity can improve the accuracy of determining the polarization direction of the weakest light intensity in the environment.

[0057] Optionally, combined Figure 2 and Figure 5 The second infrared image sensor 131 and the second optical analyzer 132 may be provided in the receiving module 120 , or may be separately provided in another receiving module 130 .

[0058] Furthermore, when the receiving module 120 further includes a second infrared image sensor 131 and a second optical analyzer 132, the method for determining the polarization direction of the light with the weakest light intensity in the environment is as follows:

[0059] Step 1: Acquire a first image of the environment through the first infrared image sensor 121 and the first optical analyzer 122;

[0060] Step 2: Acquire a second image of the environment through the second infrared image sensor 131 and the second optical analyzer 132;

[0061] Step 3: Determine the polarization direction of the light with the weakest light intensity in the environment based on the first image and the second image.

[0062] Among them, determining the polarization direction of the light with the weakest light intensity in the environment is similar to the above method and will not be described in detail here.

[0063] In addition, it should be noted that the receiving module 120 does not necessarily include only the above two cases. The number of TOF image sensors and optical polarizers can also be set according to actual conditions. For example, a third TOF image sensor and a third optical polarizer can be set, or more can be set, which are not described one by one here.

[0064] After determining the polarization direction of the light with the weakest light intensity in the environment, the polarization direction of the light with the weakest light intensity is determined as the predetermined polarization direction, and the light source in the transmitting module 110 emits structured light with the predetermined polarization direction.

[0065] See also Figure 6 The transmitting module 110 includes a laser 111. The laser 111 is a structured light laser, and further can be a high-contrast grating laser. The high-contrast grating laser consists of a high-contrast grating (English full name: High-Contrast Gratings; English abbreviation: HCG) and a laser. Figure 7 , is a schematic diagram of a high-contrast grating according to the present embodiment, wherein the high-contrast grating can analyze the polarization direction of light projected thereon, and only allows light with the same polarization direction as the analysis direction to pass through. Therefore, the light-emitting surface of the structured light laser is covered with a high-contrast grating with a predetermined analysis direction, and the structured light is analyzed to emit structured light with a preset polarization direction.

[0066] In addition, the high-contrast grating can also modulate the angle, wavelength, etc. of the structured light to emit high-quality structured light.

[0067] Optionally, the laser is a vertical cavity surface emitting laser (VCSEL), and the high-contrast grating laser is a high-contrast grating vertical cavity surface emitting laser (HCG-VCSEL). VCSELs have the advantages of small size, high power, and stable operation, and thus can not only reduce the size of a 3D imaging device but also improve its imaging accuracy.

[0068] Optionally, the structure of the HCG-VCSEL includes an N-electrode layer, an N-type DBR layer, an active layer, a P-type DBR layer, HCG, and a P-electrode layer.

[0069] Further, see Figure 8The structure of the HCG-VCSEL includes an N-electrode layer 310 , a substrate layer 320 , an N-type DBR layer 330 , an active layer 340 , an oxide layer 350 , a P-type DBR layer 360 , an oxide layer 370 , an HCG 380 , and a P-electrode layer 390 .

[0070] See also Figure 9 , which is a schematic diagram of the polarization of the light field emitted by the HCG-VCSEL in this embodiment. Compared with the traditional DBR-VCSEL, the HCG-VCSEL in this embodiment can emit structured light polarized in the same direction.

[0071] See also Figure 10 , is a schematic diagram of the polarization of the output light field of a single light-emitting hole of the HCG-VCSEL in this embodiment. The angle between its polarization direction and the horizontal direction is α, and α can be any value from 0 to 180 degrees.

[0072] Further, see Figure 4 The transmitting module 110 further includes a diffractive optical element 113 , which is disposed on a side where the laser 111 emits light, and is used to expand the viewing angle of the light emitted by the laser 111 to project a speckle pattern 160 with a large field of view.

[0073] Optionally, the transmitting module 110 may further include a rotating component connected to the high-contrast grating laser and configured to rotate the high-contrast grating laser to change the polarization direction of the structured light emitted by the high-contrast grating laser.

[0074] In addition, the laser 111 can be designed to have a fixed polarization direction and also to rotate, wherein the rotation can also be achieved by other methods, such as setting the laser 111 itself to rotate.

[0075] Compared with a high-contrast grating with a predetermined polarization direction set in advance according to the polarization direction of the weakest light intensity in the environment, after setting the rotating component, the rotating component can be rotated to obtain a high-contrast grating with any predetermined polarization direction. In different environments, it is only necessary to rotate the rotating component according to the predetermined polarization direction, so that it can be applied to different environments and improves the convenience of use.

[0076] Alternatively, see Figure 6 The transmitting module 110 further includes a collimator 112 , which is disposed between the high-contrast grating laser and the diffraction optical element 113 and is used to reduce the divergence angle of light emitted by the high-contrast grating laser.

[0077] Because transmitting module 110 emits structured light with the same polarization direction as the weakest light intensity in the environment, receiving modules 120 and / or 130 also receive structured light with the same polarization direction as the weakest light intensity in the environment. This reduces the impact of the light with this polarization direction on the structured light, reduces noise, and improves the signal-to-noise ratio. Furthermore, when the signal-to-noise ratio of a three-dimensional imaging device based on structured light is improved, the accuracy of distance detection can be improved.

[0078] Furthermore, when the three-dimensional imaging device includes only one receiving module, that is, only the receiving module 120, the first optical polarizer 122 can be rotated before receiving the structured light so that the polarization direction of the first optical polarizer 122 is the same as the polarization direction of the structured light emitted by the transmitting module 110, so that light with other polarization directions in the environment cannot pass through the first optical polarizer 122, thereby filtering the ambient light, reducing the impact of the ambient light on the received structured light, reducing noise, and improving the signal-to-noise ratio.

[0079] The structured light-based 3D imaging device has a high signal-to-noise ratio and can be used for depth detection of objects. Furthermore, the structured light is emitted from the transmitting module 110, reflected by the target object, and then reaches the receiving module 120. The receiving module 120 captures the reflected image and obtains information such as the triangular parallax change of the structured light from the image. By calculating this information, the depth information of the environment is obtained.

[0080] Alternatively, see Figure 1 Or 2, the three-dimensional imaging device further includes a circuit board 140 , which includes a control circuit and a processor to share part of the control and data processing operations of the transmitting module 110 , the receiving module 120 , and the receiving module 130 .

[0081] For example, the circuit board 140 is used to control the transmission module 110 to turn on so that the light source therein emits light. It is also used to receive images sent from the receiving module 120 or 130 and calculate the polarization direction of the weakest light intensity in the environment or the depth of the target object based on the image.

[0082] To summarize, the three-dimensional imaging device based on structured light provided in the embodiment of the present application determines the polarization direction of the light with the weakest intensity in the environment, and enables the transmitting module to emit structured light with the same polarization direction as the light with the weakest intensity, so that when the receiving module receives the structured light, the influence of ambient light on it is reduced, the interference information of the imaging is reduced, and the signal-to-noise ratio is improved.

[0083] Figure 11 FIG. 1 is a flow chart of a three-dimensional imaging method based on structured light according to an embodiment of the present application. Figure 11 As shown, the method includes:

[0084] Step 201, emitting structured light in a predetermined polarization direction;

[0085] Step 202 , receiving ambient light and structured light from an environment where the target object is located, wherein the predetermined polarization direction of the structured light is the same as the polarization direction of the light with the weakest intensity in the received ambient light;

[0086] Step 203: Imaging based on the received ambient light and structured light.

[0087] Optionally, the polarization direction of the light with the weakest intensity in the ambient light is determined by the following method:

[0088] acquiring a first image of the environment by means of a first infrared image sensor and a first optical analyzer;

[0089] Acquire a second image of the environment by using a second infrared image sensor and a second optical analyzer, wherein the analyzing directions of the second optical analyzer and the first optical analyzer are perpendicular to each other;

[0090] The polarization direction of the light with the weakest light intensity in the environment is determined according to the first image and the second image.

[0091] In addition, it should be noted that for the relevant content in the method embodiment, please refer to the device embodiment and will not be repeated here.

[0092] To summarize, the three-dimensional imaging method based on structured light provided in the embodiment of the present application determines the polarization direction of the light with the weakest intensity in the environment, and enables the transmitting module to emit structured light with the same polarization direction as the light with the weakest intensity, so that when the receiving module receives the structured light, the influence of ambient light on it is reduced, the interference information of the imaging is reduced, and the signal-to-noise ratio is improved.

[0093] An electronic device shown in an embodiment of the present application includes any three-dimensional imaging device shown in the above embodiments and the accompanying drawings.

[0094] Among them, the electronic device may be a handheld terminal, a wearable terminal, a fixed terminal, etc.

[0095] Optionally, the device includes:

[0096] One or more processors;

[0097] A memory for storing one or more programs;

[0098] When one or more programs are executed by one or more processors, the one or more processors implement any of the methods described in the above method embodiments.

[0099] Optionally, the electronic device includes a readable storage medium having a computer program stored thereon, the computer program being configured to:

[0100] When the computer program is executed by a processor, it implements any of the methods described in the above method embodiments.

[0101] To sum up, the electronic device provided in the embodiment of the present application determines the polarization direction of the light with the weakest intensity in the environment, and enables the transmitting module to emit structured light with the same polarization direction as the light with the weakest intensity, so that when the receiving module receives the structured light, the influence of ambient light on it is reduced, the interference information of the imaging is reduced, and the signal-to-noise ratio is improved.

[0102] The embodiments in this specification are described in a progressive manner, and similar parts between the various embodiments refer to each other. The embodiments under each step focus on the specific method under that step. The above-described implementation scheme is merely illustrative, and the specific embodiments are merely examples for illustrating the present invention. Technicians in the technical field to which the present invention belongs can also make several improvements and refinements without departing from the principles described in the embodiments of the present invention, and these improvements should also be regarded as the scope of protection of the present invention.

[0103] The above is merely a description of the preferred embodiments of the present application and the technical principles employed. Those skilled in the art should understand that the scope of the invention herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the above-mentioned inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features having similar functions disclosed in this application.

Claims

1. A three-dimensional imaging device based on structured light, characterized in that: The device comprises: Transmitter module and receiver module; The transmitting module is used to transmit structured light in a predetermined polarization direction; The receiving module is used to receive the ambient light of the environment where the target object is located and the structured light, and the predetermined polarization direction of the structured light is the same as the polarization direction of the light with the weakest light intensity in the ambient light received by the receiving module. The receiving module includes a first infrared image sensor and a first optical polarizer, the first optical polarizer covers a light receiving surface close to the first infrared image sensor, the receiving module also includes a second infrared image sensor and a second optical polarizer, the second optical polarizer covers the light receiving surface of the second infrared image sensor, and the polarization directions of the second optical polarizer and the first optical polarizer are perpendicular to each other.

2. The three-dimensional imaging device according to claim 1, wherein: The emission module includes a high-contrast grating laser and a diffraction optical element, and the diffraction optical element is arranged on a side where the high-contrast grating laser emits light.

3. The three-dimensional imaging device according to claim 2, wherein: The high-contrast grating laser is a high-contrast grating vertical cavity surface emitting laser.

4. The three-dimensional imaging device according to claim 2 or 3, characterized in that: The transmitting module further includes a rotating component connected to the high-contrast grating laser and configured to rotate the high-contrast grating laser to change the polarization direction of the structured light emitted by the high-contrast grating laser.

5. The three-dimensional imaging device according to claim 2 or 3, characterized in that: The emission module further includes a collimator lens, which is arranged on a side where the high-contrast grating laser emits light and is used to reduce the divergence angle of the light emitted by the high-contrast grating laser.

6. A three-dimensional imaging method, characterized in that: The method comprises: emitting structured light in a predetermined polarization direction; receiving ambient light and the structured light from an environment where the target object is located, wherein the predetermined polarization direction of the structured light is the same as the polarization direction of the light with the weakest light intensity in the received ambient light; Imaging is performed based on the received ambient light and the structured light.

7. The three-dimensional imaging method according to claim 6, characterized in that: The polarization direction of the light with the weakest intensity in the ambient light is determined by the following method: acquiring a first image of the environment by using a first infrared image sensor and a first optical analyzer; acquiring a second image of the environment by using a second infrared image sensor and a second optical analyzer, wherein the second optical analyzer is perpendicular to the first optical analyzer; The polarization direction of the light with the weakest light intensity in the environment is determined according to the first image and the second image.

8. An electronic device, characterized in that: The electronic device includes the three-dimensional imaging device according to any one of claims 1 to 6.

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