TOF module, depth information acquisition method and mobile robot

Abstract

The invention provides a TOF (Time of Flight) module, a depth information acquisition method and a mobile robot, which can solve the problem that an existing single sensor cannot realize mapping navigation and obstacle avoidance functions at the same time. The TOF module comprises a circuit board assembly, a first projection module, a second projection module and a receiving module. The first projection module comprises a first light-emitting light source, a first diffusion element located on the light-emitting side of the first light-emitting light source and a collimating element located in a light path between the first light-emitting light source and the first diffusion element, and is used for projecting a first output light field. The second projection module comprises a second light-emitting light source and a second diffusion element located on the light-emitting side of the second light-emitting light source and is used for projecting a second output light field with the vertical divergence angle larger than that of the first output light field. The first projection module, the second projection module and the receiving module are arranged on the circuit board assembly at intervals, and the first light-emitting light source and the second light-emitting light source are used for being controlled to be lightened in a time-sharing mode.

Description

Technical Field

[0001] The present invention relates to the field of TOF technology, and in particular to a TOF module, a depth information acquisition method and a mobile robot. Background Art

[0002] The time of flight (TOF) method measures the time interval t from the emission to the reception of the pulse signal emitted by the projection module (often called direct time of flight, Direct TOF, referred to as D-TOF) or the phase generated by the laser going back and forth to the environmental target once (often called indirect time of flight, Indirect TOF, referred to as I-TOF) to measure the three-dimensional structure or three-dimensional contour of the environmental target. As a high-precision distance measuring instrument, the TOF module is widely used in many fields such as body control, behavior analysis, monitoring, autonomous driving, artificial intelligence, machine vision and automatic 3D modeling.

[0003] With the rapid development of mobile robot technology, sweeping robots, service robots and industrial robots have been widely used in life and production. During operation, mobile robots must rely on various sensors to perceive the external environment and then execute various instructions based on environmental information. Obstacle avoidance and positioning and mapping are two of the more critical functions of mobile robots. At present, mobile robots usually need to use lidar sensors with a large detection distance to achieve positioning and mapping functions, while line structured light or TOF sensors with a large detection range are required to achieve obstacle avoidance. This means that existing mobile robots need to use a combination of multiple sensors to achieve both mapping navigation and obstacle avoidance functions, such as a solution that uses a combination of line structured light / TOF sensors and lidar sensors. However, the structural design of this solution is relatively complex and the cost is inevitably high, which is not conducive to promotion and popularization. Summary of the invention

[0004] One advantage of the present invention is that it provides a TOF module, a depth information acquisition method and a mobile robot, which can solve the problem that a single existing sensor cannot simultaneously realize mapping navigation and obstacle avoidance functions, simplify the structure and reduce the cost.

[0005] Another advantage of the present invention is that it provides a TOF module, a depth information acquisition method and a mobile robot. In one embodiment of the present invention, the TOF module can use a dual projection module to project a strong light field and a weak light field respectively, so as to correspondingly obtain navigation depth information and obstacle avoidance depth information, thereby realizing navigation and obstacle avoidance functions at the same time.

[0006] Another advantage of the present invention is that it provides a TOF module, a depth information acquisition method and a mobile robot. In one embodiment of the present invention, the TOF module can project strong light fields and weak light fields in time-sharing to perform mapping navigation and obstacle avoidance in time-sharing, which helps to reduce the impact of mutual multipath interference between strong light fields and weak light fields, improve measurement accuracy, and facilitate improving the effects of mapping and obstacle avoidance.

[0007] Another advantage of the present invention is that it provides a TOF module, a depth information acquisition method and a mobile robot. In one embodiment of the present invention, the TOF module can project a weak light field onto the ground to reduce the multipath interference effect of the weak light spot while reducing the blind spot of the TOF module's field of view and improving the obstacle avoidance effect.

[0008] Another advantage of the present invention is to provide a TOF module, a depth information acquisition method and a mobile robot. In one embodiment of the present invention, the TOF module can concentrate the light spot through a strong light field with a smaller divergence angle, so as to achieve higher light intensity while reducing multipath interference of the strong light spot.

[0009] Another advantage of the present invention is that it provides a TOF module, a depth information acquisition method and a mobile robot. In one embodiment of the present invention, the TOF module can diverge the light spot through a weak light field with a larger divergence angle, which is beneficial to reduce the obstacle avoidance blind spot and prevent the mobile robot from colliding due to the inability to recognize close objects, thereby affecting the user experience.

[0010] Another advantage of the present invention is that it provides a TOF module, a depth information acquisition method and a mobile robot. In one embodiment of the present invention, the TOF module can make the frame rate of the obstacle avoidance depth map greater than the frame rate of the navigation depth map, so as to improve the obstacle avoidance performance while meeting the mapping and navigation requirements.

[0011] Another advantage of the present invention is that it provides a TOF module, a depth information acquisition method and a mobile robot. In one embodiment of the present invention, the mobile robot can achieve mapping navigation and obstacle avoidance functions through only one TOF module, which reduces the design and assembly difficulty of the whole machine, greatly reduces the cost, and facilitates promotion and popularization.

[0012] Another advantage of the present invention is to provide a TOF module, a method for obtaining depth information, and a mobile robot, wherein in order to achieve the above-mentioned purpose, no complex system is required in the present invention. Therefore, the present invention successfully and effectively provides a solution, not only providing a simple TOF module, a method for obtaining depth information, and a mobile robot, but also increasing the practicality and reliability of the TOF module, the method for obtaining depth information, and the mobile robot.

[0013] In order to achieve at least one of the above advantages or other advantages and purposes of the present invention, the present invention provides a TOF module, including:

[0014] Circuit board assembly;

[0015] A first projection module, the first projection module comprising a first light source communicatively connected to the circuit board assembly, a first diffusion element located at a light emitting side of the first light source, and a collimating element located in an optical path between the first light source and the first diffusion element, for projecting a first output light field;

[0016] a second projection module, the second projection module comprising a second light source communicatively connected to the circuit board assembly and a second diffusion element located at a light emitting side of the second light source, for projecting a second output light field having a vertical divergence angle greater than the first output light field; and

[0017] A receiving module, the receiving module comprising a photosensitive component communicatively connected to the circuit board component and a receiving lens located on a photosensitive side of the photosensitive component;

[0018] The first projection module, the second projection module and the receiving module are arranged at intervals on the circuit board assembly, and the first light source and the second light source are controlled to light up in time division.

[0019] According to an embodiment of the present application, a vertical divergence angle of the first output light field is less than 20°, and a vertical divergence angle of the second output light field is greater than or equal to 40° and less than or equal to 100°.

[0020] According to an embodiment of the present application, horizontal divergence angles of the first output light field and the second output light field are both greater than 100°.

[0021] According to one embodiment of the present application, the luminous power of the first light source is greater than the luminous power of the second light source.

[0022] According to an embodiment of the present application, the first projection module, the second projection module and the receiving module are arranged in a straight line.

[0023] According to an embodiment of the present application, the first projection module, the second projection module and the receiving module are arranged along a horizontal or vertical direction.

[0024] According to one embodiment of the present application, the first projection module is located between the second projection module and the receiving module.

[0025] According to an embodiment of the present application, the receiving module is located between the first projection module and the second projection module.

[0026] According to an embodiment of the present application, the first projection module, the second projection module and the receiving module are arranged in a triangle.

[0027] According to an embodiment of the present application, the first projection module and the second projection module are arranged along the horizontal direction, and the receiving module is located on the side of the first projection module and the second projection module.

[0028] According to one embodiment of the present application, the circuit board assembly includes a first circuit board, a second circuit board and a third circuit board electrically connected to each other, the first projection module can be communicatively mounted on the first circuit board, the second projection module can be communicatively mounted on the second circuit board, and the receiving module can be communicatively mounted on the third circuit board.

[0029] According to one embodiment of the present application, the circuit board assembly further includes a raising block fixedly mounted on the third circuit board, the raising block having a first mounting surface and a second mounting surface higher than the first mounting surface, the first circuit board is mounted on the first mounting surface of the raising block, and the second circuit board is mounted on the second mounting surface of the raising block.

[0030] According to an embodiment of the present application, the first circuit board is electrically connected to the second circuit board in an integral manner, and the second circuit board can be electrically plugged into the third circuit board.

[0031] According to another aspect of the present application, the present application further provides a mobile robot, comprising:

[0032] The robot body; and

[0033] Any of the TOF modules described above, wherein the TOF module is mounted on the robot body, and the TOF module is used to provide navigation depth information and obstacle avoidance depth information for the robot body.

[0034] According to another aspect of the present application, the present application further provides a method for obtaining depth information, comprising the steps of:

[0035] Controlling the first projection module and the second projection module respectively to light up the first light source of the first projection module and the second light source of the second projection module in a time-sharing manner;

[0036] When the first light source is lit each time, the first input light field is emitted to the collimating element of the first projection module so as to be collimated and then pass through the first diffusion element of the first projection module to project the first output light field;

[0037] When the second light source is lit each time, emitting a second input light field to the second diffusion element of the second projection module to project a second output light field; and

[0038] The receiving module is controlled to receive the echo light field, so as to obtain navigation depth information when the echo light field corresponding to the first output light field is received, and obtain obstacle avoidance depth information when the echo light field corresponding to the second output light field is received.

[0039] According to an embodiment of the present application, the step of controlling the first projection module and the second projection module respectively to light up the first light source of the first projection module and the second light source of the second projection module in a time-sharing manner comprises the steps of:

[0040] In response to the first driving signal, transmitting a modulated pulse signal to the first light emitting source to light up the first light emitting source once; and

[0041] In response to the second driving signal, a modulated pulse signal is transmitted to the second light emitting source, and the second light emitting source is lit up once or multiple times. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic structural diagram of a mobile robot according to an embodiment of the present application;

[0043] Figure 2 A first example of a TOF module in a mobile robot according to the above embodiment of the present application is shown;

[0044] Figure 3 A schematic top view of the TOF module according to the first example of the present application is shown;

[0045] Figure 4 A cross-sectional schematic diagram of a TOF module according to the first example of the present application is shown;

[0046] Figure 5 A cross-sectional schematic diagram of a first projection module in the TOF module according to the first example of the present application is shown;

[0047] Figure 6 A cross-sectional schematic diagram of a second projection module in the TOF module according to the first example of the present application is shown;

[0048] Figure 7 A second example of a TOF module in a mobile robot according to the above embodiment of the present application is shown;

[0049] Figure 8 A third example of a TOF module in a mobile robot according to the above embodiment of the present application is shown;

[0050] Fig. 9A fourth example of a TOF module in a mobile robot according to the above embodiment of the present application is shown;

[0051] Fig.10 is a flowchart of a method for acquiring depth information according to an embodiment of the present application;

[0052] Fig.11 A schematic flow chart of the light source lighting step in the depth information acquisition method according to the above embodiment of the present application is shown.

[0053] Explanation of main component symbols: 1. TOF module; 10. Circuit board assembly; 11. First circuit board; 12. Second circuit board; 13. Third circuit board; 14. Heightening block; 141. First mounting surface; 142. Second mounting surface; 20. First projection module; 21. First light source; 22. First diffusion element; 23. Collimation element; 30. Second projection module; 31. Second light source; 32. Second diffusion element; 40. Receiving module; 41. Photosensitive component; 42. Receiving lens; 2. Robot body.

[0054] The above description of the main component symbols is combined with the accompanying drawings and specific implementation methods to further illustrate the present invention in detail. DETAILED DESCRIPTION

[0055] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0056] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0057] In the present invention, the term "one" in the claims and the specification should be understood as "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple. Unless it is clearly indicated in the disclosure of the present invention that the number of the element is only one, the term "one" cannot be understood as unique or single, and the term "one" cannot be understood as a limitation on the quantity.

[0058] In the description of the present invention, it should be understood that "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through a medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. 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 one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0060] Considering that existing mobile robots need to use a combination of multiple sensors to achieve both mapping navigation and obstacle avoidance functions, the structural design is relatively complex and the cost is inevitably high, which is not conducive to promotion and popularization. The present application provides a TOF module, a depth information acquisition method and a mobile robot, which can solve the problem that a single existing sensor cannot achieve both mapping navigation and obstacle avoidance functions, simplify the structure and reduce the cost.

[0061] Specifically, refer to the accompanying drawings of the specification of this application. Figures 1 to 9 According to an embodiment of the present application, a mobile robot is provided, which may include a TOF module 1 and a robot body 2. The TOF module 1 is mounted on the robot body 2. The TOF module 1 is used to provide the robot body 2 with long-range depth information and short-range depth information, thereby realizing a mapping navigation function and an obstacle avoidance function. It is understandable that although the robot body 2 of the mobile robot of the present application is taken as an example of a sweeping robot in the accompanying drawings, it is not limited thereto and can also be implemented as other robots that require navigation and obstacle avoidance.

[0062] More specifically, if Figures 2 to 6As shown, the TOF module 1 may include a circuit board assembly 10, a first projection module 20, a second projection module 30, and a receiving module 40. The first projection module 20 includes a first light source 21 communicatively connected to the circuit board assembly 10, a first diffusion element 22 located at the light emitting side of the first light source 21, and a collimating element 23 located in the light path between the first light source 21 and the first diffusion element 22, for projecting a first output light field. The second projection module 30 includes a second light source 31 communicatively connected to the circuit board assembly 10 and a second diffusion element 32 located at the light emitting side of the second light source 31, for projecting a second output light field having a vertical divergence angle greater than the first output light field. The receiving module 40 includes a photosensitive component 41 communicatively connected to the circuit board assembly 10 and a receiving lens 42 located on the photosensitive side of the photosensitive component 41; the first projection module 20, the second projection module 30 and the receiving module 40 are arranged at intervals on the circuit board assembly 10, and the first light source 21 and the second light source 31 are used to be controlled to light up in time.

[0063] In this way, when the first light source 21 is lit, the second light source 31 is not lit; at this time, the light beam emitted by the first light source 21 will first pass through the collimating element 23 to be collimated, and then pass through the first diffusion element 22 to expand in the horizontal direction, thereby projecting a light beam with a smaller divergence angle in the vertical direction and a larger divergence angle in the horizontal direction, that is, the first output light field. When the second light source 31 is lit, the first light source 21 is not lit; at this time, the light beam emitted by the second light source 31 will directly pass through the second diffusion element 32 to expand in the horizontal and vertical directions at the same time, thereby projecting a light beam with a larger divergence angle in both the horizontal and vertical directions, that is, the second output light field. In addition, when the first output light field or the second output light field is projected to the target to be measured, it will be reflected to form an echo light field, and then the echo light field will be modulated by the receiving lens 42 first, and then received by the photosensitive component 41, so as to obtain depth information. It is understood that the horizontal direction mentioned in this application refers to the direction corresponding to the horizontal field of view of the TOF module, such as Figure 5 and Figure 6 The vertical direction mentioned in this application refers to the direction corresponding to the vertical field of view of the TOF module, such as Figure 4 The up and down directions in .

[0064] It is worth noting that, on the one hand, since the first projection module 20 is configured with a collimating element and a first diffusion element 22 for matching design, the first output light field projected by it has a smaller divergence angle in the vertical direction, so that the light beam of the first output light field is more concentrated for long-distance detection. Therefore, the receiving module 40 can obtain long-distance depth information when receiving the echo light field corresponding to the first output light field, so as to realize functions such as mapping, positioning and navigation; at the same time, the first output light field has a larger divergence angle in the horizontal direction, so that each frame of image data of the TOF module 1 can obtain more environmental depth information, which helps to improve the efficiency of mapping and positioning.

[0065] On the other hand, since the second projection module 30 is not equipped with a collimating element, the second output light field it projects has a large divergence angle in both the horizontal and vertical directions, so that the light beam of the second output light field is relatively divergent for close-range detection. Therefore, the receiving module 40 can obtain close-range depth information when receiving the echo light field corresponding to the second output light field, so as to realize functions such as object recognition and obstacle avoidance. It can be understood that the first light source 21 and the second light source 31 mentioned in the present application are lit in time-sharing, which can avoid mutual crosstalk between the first output light field and the second output light field, improve detection accuracy, and facilitate the improvement of mapping and obstacle avoidance effects.

[0066] For example, Figures 4 to 6 As shown, the vertical divergence angle V1 of the first output light field may be less than 20°, that is, V1<20°; the vertical divergence angle V2 of the second output light field may be greater than or equal to 40° and less than or equal to 100°, that is, 40°≤V2≤100°.

[0067] Alternatively, if Figure 5 and Figure 6 As shown, the horizontal divergence angle H1 of the first output light field can be greater than 100°, that is, H1>100°; the horizontal divergence angle H2 of the second output light field can be greater than 100°, that is, H2>100°. It can be understood that in some outdoor scenes, the horizontal divergence angles of the first output light field and the second output light field can also be less than 100°, because to achieve the same detection distance, the outdoor scene requires an output light field with a more concentrated light intensity.

[0068] It is worth noting that, since the vertical divergence angle of the first output light field is smaller than the vertical divergence angle of the second output light field, the light intensity of the first output light field is more concentrated than that of the second output light field. Therefore, the light intensity per unit area of ​​the first output light field is greater than that of the second output light field, so that the first output light field can be projected into a farther area in space relative to the second output light field, which helps to meet the application requirements of map building and navigation. In addition, although the light intensity per unit area of ​​the second output light field is relatively low and can only be projected into a relatively close area in space, it is sufficient to meet the needs of the obstacle avoidance function and can reduce the blind spot of the field of view of the TOF module 1; at the same time, the second output light field with a lower light intensity per unit area can also reduce the light reflection from the ground, and can reduce the multipath interference effect on the obstacle avoidance depth information, which helps to improve the measurement accuracy of the obstacle avoidance depth information and facilitates the improvement of the obstacle avoidance effect.

[0069] Optionally, the luminous power of the first light source 21 is greater than the luminous power of the second light source 31, so that the light intensity of the first output light field is much greater than the light intensity of the second output light field, so as to further increase the projection distance of the first output light field, so that the detection distance of the mapping scene can be improved. It can be understood that the TOF module 1 of the present application uses one of the two independent light sources in combination with the collimating element to increase the detection distance to more than ten meters, which well meets the detection distance requirements for the mapping scene.

[0070] Optionally, the first light source 21 and the second light source 31 may be implemented as vertical cavity surface emitting lasers (VCSELs) but are not limited thereto. It is understandable that the number of laser points on the first light source 21 may be large, so as to achieve the purpose of long-distance mapping; and the number of laser points on the second light source 31 may be small, so as to achieve the purpose of obstacle avoidance.

[0071] Optionally, the first diffusion element 22 and the second diffusion element 32 may be implemented as, but not limited to, a diffuser, a light homogenizer, or a diffractive optical element (DOE), etc. The collimating element 23 may be implemented as, but not limited to, a collimating lens.

[0072] It is worth noting that in some examples of this application, such as Figures 2 to 8 As shown, the first projection module 20 , the second projection module 30 and the receiving module 40 can be arranged in a straight line to facilitate the assembly of the TOF module 1 .

[0073] Alternatively, if Figure 3 and Figure 7As shown, the first projection module 20, the second projection module 30 and the receiving module 40 are arranged along the vertical direction, which helps to shorten the overall width of the TOF module 1. It can be understood that the overall width mentioned in this application refers to the size of the TOF module 1 in the horizontal direction.

[0074] For example, in the first example of this application, Figures 2 to 6 As shown, the first projection module 20 is located between the second projection module 30 and the receiving module 40. In this way, the second projection module 30 is located adjacent to the first projection module 20, so that the circuits of the first projection module 20 and the second projection module 30 can be integrated, which helps to reduce the process and reduce the difficulty of assembly. It is understandable that in other examples of the present application, the positions of the first projection module 20 and the second projection module 30 can be interchanged so as to make the projection blind area of ​​the second projection module 30 smaller, and this application will not repeat them.

[0075] Alternatively, if Figure 2 and Figure 4 As shown, the circuit board assembly 10 may include a first circuit board 11, a second circuit board 12, and a third circuit board 13 electrically connected to each other, the first projection module 20 may be mounted on the first circuit board 11 in a communicative manner, the second projection module 30 may be mounted on the second circuit board 12 in a communicative manner, and the receiving module 40 may be mounted on the third circuit board 13 in a communicative manner. In this way, the TOF module 1 of the present application can not only control the first light source 21 and the second light source 31 to be illuminated in time-sharing through the circuit board assembly 10, but also control the photosensitive component 41 to receive the echo light field corresponding to the first output light field and the second output light field in time-sharing through the circuit board assembly 10, so as to perform image processing and depth calculation to obtain navigation depth information and obstacle avoidance depth information.

[0076] Alternatively, if Figure 2 , Figure 4 , Figure 5 as well as Figure 6As shown, the circuit board assembly 10 may further include a padding block 14 fixed to the third circuit board 13, the padding block 14 having a first mounting surface 141 and a second mounting surface 142 higher than the first mounting surface 141, the first circuit board 11 is mounted on the first mounting surface 141, and the second circuit board 12 is mounted on the second mounting surface 142. In this way, the first projection module 20 and the second projection module 30 are correspondingly raised compared to the receiving module 40, so that the first projection module 20, the second projection module 30 and the receiving module 40 have flush light surfaces to avoid mutual visual interference. It can be understood that the first projection module 20 is higher than the second projection module 30 due to the additional collimating element 23, and the receiving module 40 is higher than the first projection module 20 due to the larger receiving lens 42.

[0077] Alternatively, if Figure 2 and Figure 4 As shown, the first circuit board 11 is electrically connected to the second circuit board 12 in an integral manner, and the second circuit board 12 can be electrically plugged into the third circuit board 13, so that the circuits of the first projection module 20 and the second projection module 30 are made into one, which helps to reduce the process and reduce the difficulty of assembly.

[0078] It is worth noting that, compared with the above first example according to the present application, Figure 7 As shown, the difference of the TOF module 1 according to the second example of the present application is that the receiving module 40 can be located between the first projection module 20 and the second projection module 30; that is, the first projection module 20 and the second projection module 30 are located on opposite sides of the receiving module 40, so that the first projection module 20 and the second projection module 30 both have a smaller projection blind area.

[0079] Optionally, in the second example of the present application, the first circuit board 11 can be electrically plugged into the third circuit board 13 , and the second circuit board 12 can be electrically plugged into the third circuit board 13 , which helps to improve the electrical performance of the circuit board assembly 10 .

[0080] In addition, in other examples of the present application, the first projection module 20, the second projection module 30 and the receiving module 40 can also be arranged in the horizontal direction, which helps to significantly shorten the overall height of the TOF module 1. It is understood that the overall height mentioned in the present application refers to the size of the TOF module 1 in the vertical direction.

[0081] For example, compared to the above first example according to the present application, Figure 8 As shown, the difference of the TOF module 1 according to the third example of the present application is that the first projection module 20, the second projection module 30 and the receiving module 40 can also be arranged along the horizontal direction (such as Figure 8 The TOF module 1 is arranged in the horizontal direction (in the left and right direction), and the receiving module 40 is located between the first projection module 20 and the second projection module 30, so that the horizontal displacement of the projection spot at different distances is small. It can be understood that although the TOF module 1 arranged in the horizontal direction may have more stray light, a barrier can be added between the projection module and the receiving module to reduce the influence of stray light.

[0082] In addition, since the projection module and the receiving module are not coaxial and there is a certain distance between them, the light reflected back from different distances will be offset in the baseline direction (i.e., the direction of the line connecting the projection module and the receiving module); therefore, if the projection module and the receiving module are arranged vertically, the light spot will be offset in the vertical direction; if the projection module and the receiving module are arranged horizontally, the light spot will be offset in the horizontal direction. Since the horizontal field of view of the TOF module 1 of the present application is greater than the vertical field of view, the signal lost after the horizontal offset is greater than the signal lost after the vertical offset, so the present application can choose a horizontal arrangement scheme to reduce the horizontal offset of the light spot.

[0083] It is worth noting that in other examples of the present application, the first projection module 20 , the second projection module 30 and the receiving module 40 may also be arranged in a triangle.

[0084] For example, Fig. 9 As shown, in the fourth example of the present application, the first projection module 20 and the second projection module 30 are arranged in the horizontal direction, and the receiving module 40 is located on the side of the first projection module 20 and the second projection module 30. It can be understood that the receiving module 40 can be arranged in the vertical direction with the first projection module 20 or the second projection module 30 to form an L-shaped structure; or, the receiving module 40 can also be located on the midpoint vertical line between the first projection module 20 and the second projection module 30 to form a T-shaped structure.

[0085] According to the above-mentioned embodiment of the present application, the first projection module 20 can be used to project the first output light field horizontally so as to project it into a farther spatial area, so as to meet the needs of map-building navigation applications. The second projection module 30 can be used to project the second output light field obliquely downward. In this way, the second output light field can be projected onto the ground, which helps to further reduce the blind spot of the field of view of the TOF module 1, and prevent the mobile robot from being hit due to the inability to recognize close objects, thereby affecting the user experience.

[0086] It is worth noting that although the first output light field is projected horizontally forward, it may also form multiple reflections to cause multipath interference, especially under strong light intensity conditions; and the vertical divergence angle of the first output light field projected by the TOF module 1 of the present application is small, which is not only conducive to light spot concentration and achieving higher light intensity, but also can reduce multipath interference of strong light spots, thereby improving the navigation depth measurement accuracy of the TOF module 1 and facilitating the improvement of mapping and navigation effects.

[0087] According to the above-mentioned embodiment of the present application, the first light source 21 and the second light source 31 in the TOF module 1 are preferably alternately lit so that the first output light field projected by the first projection module 20 and the second output light field projected by the second projection module 30 appear alternately.

[0088] Optionally, the circuit board assembly 10 of the TOF module 1 of the present application can control the lighting of the first light source 21 and the second light source 31 through a first drive signal and a second drive signal. The first drive signal and the second drive signal are controlled by a control circuit module on the circuit board assembly 10 to ensure that one and only one light source is lit at the same time.

[0089] It is understandable that according to the above logic, the two light sources are alternately lit to alternately collect strong light frame images and weak light frame images, which can avoid the problem of TOF multipath interference caused by the mutual reflection of light spots between the front wall and the ground below. For example, the image collected by the first drive signal is used to generate the point cloud of the front wall, and the image collected by the second drive signal is used to generate the point cloud of the ground below; at this time, the two point cloud data without multipath interference are fused to obtain a complete three-dimensional point cloud map, which has both information about the front wall for map navigation and information about ground obstacles for obstacle avoidance. It is understandable that when the first light source 21 is lit, the second light source 31 is not lit, and the image frame information collected at this time is a strong light frame image; and when the second light source 31 is lit, the first light source 21 is not lit, and the image frame information collected at this time is a strong light frame image.

[0090] Furthermore, the exposure time of the first driving signal when collecting point clouds is fixed, and a larger exposure is used, so that the optical power of the first light source 21 can be sufficient to illuminate the wall in a farther area, achieving a better map construction and navigation effect; the exposure time of the second driving signal when collecting point clouds can be automatically adjusted according to the actual scene, that is, automatic exposure is used, so that different obstacles on the ground will not be overexposed, and can be stably detected to achieve a better obstacle avoidance effect. It can be understood that in other examples of the present application, when the first driving signal collects point clouds, the first light source 21 can be automatically exposed, as long as it can meet the map construction and navigation requirements, and this application will not go into details.

[0091] Optionally, in order to simplify circuit control, the TOF module 1 of the present application is in the process of alternately collecting strong light frame images and weak light frame images: when a strong light frame image is collected, it is necessary to set a suitable automatic exposure value for the next weak light frame, and this suitable automatic exposure value is given by the last weak light frame depth calculation and will be temporarily stored in the memory; and when a weak light frame image is collected, a fixed exposure value will be set for the next strong light frame. At the same time, when the point cloud data of the two frames of images (i.e., the strong light frame image and the weak light frame image) are calculated, they will be fused and output; this cycle is repeated to obtain navigation depth information and obstacle avoidance depth information in real time.

[0092] It is worth noting that in the TOF module 1 according to the above embodiment of the present application, the first light source 21 and the second light source 31 can be controlled to light up alternately and cyclically one by one, that is, in each cycle, the first light source 21 is only lit once, the second light source 31 is also only lit once, and the first light source 21 and the second light source 31 are lit up in time. In other words, the alternating light emission mode of the light source is implemented as: one frame of weak light → one frame of strong light → one frame of weak light → one frame of strong light; this is conducive to reducing the impact of multipath interference, improving the accuracy of depth information, and facilitating map navigation and obstacle avoidance. However, since the first light source 21 and the second light source 31 are lit up in time, the frame rate of the strong light frame image and the frame rate of the weak light frame image collected by the TOF module 1 will be reduced, which may affect the obstacle avoidance effect of the mobile robot.

[0093] However, considering that obstacle avoidance has a relatively high frame rate requirement for the depth map (i.e., higher than the frame rate requirement for the depth map for map building and navigation), in other examples of the present application, the first light source 21 and the second light source 31 are alternately cycled and lit one to multiple times, that is, in each cycle, the first light source 21 is only lit once, and the second light source 31 can be lit multiple times. In other words, the alternating light emission mode of the light source can be implemented as: multiple frames of weak light → one frame of strong light → multiple frames of weak light → one frame of strong light; in this way, although the frame rate of the strong light frame image collected by the TOF module 1 will be further reduced, it can still meet the needs of map building and navigation; while the frame rate of the weak light frame image collected by the TOF module 1 will increase, which will help improve the obstacle avoidance effect of the mobile robot.

[0094] It is worth mentioning that Fig.10 A method for acquiring depth information according to an embodiment of the present application is shown, which may include the steps of:

[0095] S100: Controlling the first projection module and the second projection module respectively to light up the first light source of the first projection module and the second light source of the second projection module in a time-sharing manner;

[0096] S200: When the first light source is lit each time, the first input light field is emitted to the collimating element of the first projection module so as to be collimated and then pass through the first diffusion element of the first projection module to project a first output light field;

[0097] S300: When the second light source is lit each time, emitting a second input light field to a second diffusion element of the second projection module to project a second output light field; and

[0098] S400: Control the receiving module to receive the echo light field, so as to obtain navigation depth information when the echo light field corresponding to the first output light field is received, and obtain obstacle avoidance depth information when the echo light field corresponding to the second output light field is received.

[0099] It is worth noting that in some examples of this application, such as Fig.11 As shown, step S100 of the depth information acquisition method may include the following steps:

[0100] S110: in response to the first driving signal, transmitting a modulated pulse signal to the first light source to light up the first light source once; and

[0101] S120: In response to the second driving signal, transmit a modulated pulse signal to the second light source to light up the second light source once or multiple times.

[0102] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A TOF module, characterized in that: include: Circuit board assembly; A first projection module, the first projection module comprising a first light source communicatively connected to the circuit board assembly, a first diffusion element located at a light emitting side of the first light source, and a collimating element located in an optical path between the first light source and the first diffusion element, for projecting a first output light field; a second projection module, the second projection module comprising a second light source communicatively connected to the circuit board assembly and a second diffusion element located at a light emitting side of the second light source, for projecting a second output light field having a vertical divergence angle greater than the first output light field; and A receiving module, the receiving module comprising a photosensitive component communicatively connected to the circuit board component and a receiving lens located on a photosensitive side of the photosensitive component; The first projection module, the second projection module and the receiving module are arranged at intervals on the circuit board assembly, and the first light source and the second light source are controlled to light up in time division.

2. The TOF module according to claim 1, characterized in that: The vertical divergence angle of the first output light field is less than 20°, and the vertical divergence angle of the second output light field is greater than or equal to 40° and less than or equal to 100°.

3. The TOF module according to claim 1, characterized in that: The horizontal divergence angles of the first output light field and the second output light field are both greater than 100°.

4. The TOF module according to claim 1, characterized in that: The luminous power of the first light source is greater than the luminous power of the second light source.

5. The TOF module according to any one of claims 1 to 4, characterized in that: The first projection module, the second projection module and the receiving module are arranged in a straight line.

6. The TOF module according to claim 5, characterized in that: The first projection module, the second projection module and the receiving module are arranged along a horizontal or vertical direction.

7. The TOF module according to claim 5, characterized in that: The first projection module is located between the second projection module and the receiving module.

8. The TOF module according to claim 5, characterized in that: The receiving module is located between the first projection module and the second projection module.

9. The TOF module according to any one of claims 1 to 4, characterized in that: The first projection module, the second projection module and the receiving module are arranged in a triangle.

10. The TOF module according to claim 9, characterized in that: The first projection module and the second projection module are arranged along the horizontal direction, and the receiving module is located on the sides of the first projection module and the second projection module.

11. The TOF module according to any one of claims 1 to 4, characterized in that: The circuit board assembly includes a first circuit board, a second circuit board and a third circuit board electrically connected to each other, the first projection module can be communicatively mounted on the first circuit board, the second projection module can be communicatively mounted on the second circuit board, and the receiving module can be communicatively mounted on the third circuit board.

12. The TOF module according to claim 11, characterized in that: The circuit board assembly further includes a raising block fixed to the third circuit board, the raising block having a first mounting surface and a second mounting surface higher than the first mounting surface, the first circuit board is mounted on the first mounting surface of the raising block, and the second circuit board is mounted on the second mounting surface of the raising block.

13. The TOF module according to claim 11, characterized in that: The first circuit board is electrically connected to the second circuit board in one piece, and the second circuit board can be electrically plugged into the third circuit board.

14. A mobile robot, characterized in that include: Robot body; and The TOF module as described in any one of claims 1 to 13, wherein the TOF module is mounted on the robot body, and the TOF module is used to provide navigation depth information and obstacle avoidance depth information for the robot body.

15. A method for obtaining depth information, characterized in that: Includes steps: Controlling the first projection module and the second projection module respectively to light up the first light source of the first projection module and the second light source of the second projection module in a time-sharing manner; When the first light source is lit each time, the first input light field is emitted to the collimating element of the first projection module so as to be collimated and then pass through the first diffusion element of the first projection module to project the first output light field; When the second light source is lit each time, the second input light field is emitted to the second diffusion element of the second projection module to project the second output light field; as well as The receiving module is controlled to receive the echo light field, so as to obtain navigation depth information when the echo light field corresponding to the first output light field is received, and obtain obstacle avoidance depth information when the echo light field corresponding to the second output light field is received.

16. The depth information acquisition method according to claim 15, characterized in that: The step of controlling the first projection module and the second projection module respectively to light up the first light source of the first projection module and the second light source of the second projection module in a time-sharing manner comprises the following steps: In response to the first driving signal, a modulated pulse signal is transmitted to the first light source to light up the first light source once; and In response to the second driving signal, a modulated pulse signal is transmitted to the second light emitting source, and the second light emitting source is lit up once or multiple times.

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