Ranging device and mobile platform

Abstract

A ranging device (100) comprising: a light source (110) for emitting a sequence of light pulses; a scanning module (120), the scanning module (120) comprising a rotatable first optical element (121), a second optical element (122) and a third optical element (123), wherein the first optical element (121) and the second optical element (122) rotate at the same speed in opposite directions; the scanning module (120) is configured to refract the sequence of light pulses through the first optical element (121), the second optical element (122) and the third optical element (123) to scan an external environment; wherein the scanning pattern of the ranging device (100) in a frame duration has a higher point cloud density in the middle than at both ends in the vertical direction of the central region, thereby meeting the user's demand for high-precision identification and detection of the central region.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of target detection, and in particular to a ranging device and a mobile platform. BACKGROUND

[0002] A laser radar can be used to detect a target object. Specifically, it can emit a laser beam, and after receiving a laser beam reflected back from the target object, it can compare and process the reflected laser beam with the emitted laser beam, thereby obtaining information about the position reached by the laser beam. With the popularization of laser radars, people have gradually put forward higher demands for laser radars. SUMMARY

[0003] Therefore, one of the purposes of the present application is to provide a ranging device to solve the problem that the scan pattern obtained by the existing laser radar scanning does not meet the user's demand in point cloud density.

[0004] The first aspect of the present application provides a ranging device, comprising:

[0005] a light source for emitting a light pulse sequence;

[0006] a scanning module, the scanning module comprising a rotatable first optical element, a second optical element and a third optical element, wherein the first optical element and the second optical element rotate at the same speed in opposite directions;

[0007] The scanning module is used to refract the light pulse sequence through the first optical element, the second optical element and the third optical element to scan the external environment; wherein the point cloud density in the middle of the scan pattern of the ranging device in a frame length in the vertical direction of the central region is higher than that at both ends.

[0008] The second aspect of the present application provides a mobile platform, comprising a mobile platform body and a ranging device mounted on the mobile platform body;

[0009] The ranging device comprises:

[0010] a light source for emitting a light pulse sequence;

[0011] a scanning module, the scanning module comprising a rotatable first optical element, a second optical element and a third optical element, wherein the first optical element and the second optical element rotate at the same speed in opposite directions;

[0012] The scanning module is configured to refract the light pulse sequence through the first optical element, the second optical element and the third optical element to scan the external environment; wherein the point cloud density of the middle of the scanning pattern of the ranging device in a frame length is higher than the point cloud density of the two ends in the vertical direction of the central region.

[0013] The ranging device provided by the embodiment of the present application comprises a light source configured to emit a light pulse sequence; and a scanning module configured to refract the light pulse sequence through a first optical element, a second optical element and a third optical element to scan an external environment; wherein the point cloud density of the middle of the scanning pattern of the ranging device in a frame length is higher than the point cloud density of the two ends in the vertical direction and / or the horizontal direction of the central region, thereby meeting the requirement of high-precision identification and detection of the central region. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0015] Figure 1 FIG. 1 is a structural schematic diagram of a ranging device provided by an embodiment of the present application.

[0016] Figure 2 FIG. 2 is a scanning pattern provided by an embodiment of the present application.

[0017] Figure 3A FIG. 3 is a basic pattern corresponding to the ranging device provided by an embodiment of the present application. Figure 2

[0018] Figure 3B , Figure 3C and Figure 3D are respectively a first basic pattern, a second basic pattern and a third basic pattern corresponding to the ranging device provided by an embodiment of the present application.

[0019] Figure 4 FIG. 4 is a scanning pattern formed by the ranging device when the deflection angle of the third optical element to the light pulse sequence is too small.

[0020] Figure 5 FIG. 5 is a scanning pattern of the ranging device provided by an embodiment of the present application in a frame length.

[0021] Figure 6 FIG. 6 is another scanning pattern of the ranging device provided by an embodiment of the present application in a frame length. DETAILED DESCRIPTION​

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0023] With the popularization of laser radars, users gradually put forward higher demands on laser radars. First, users hope that the field of view (FOV) of the laser radar is large enough to be able to detect a wider range. Second, users hope that the point cloud density and coverage in the entire field of view are high enough, so as to have higher accuracy in target identification and other related applications. However, it is very difficult to meet the above demands of users at the same time, because the laser radar itself is limited by the number of laser lines, the emission frequency, the device capability and the safety specification, etc.

[0024] The applicant finds that the user's demand for identification and detection accuracy (or accuracy) in different areas in the entire field of view is different. Generally speaking, the user has higher accuracy requirements for the identification and detection of the central area. For example, in the scenario of autonomous driving, the four-lane corresponding to the horizontal field of view angle of 100m is actually in the central area within 12 degrees, so this 12-degree area needs to have higher identification and detection accuracy. Relatively speaking, other areas outside the 12-degree area do not need such high identification and detection accuracy.

[0025] If the identification and detection accuracy is high, the area to be identified and detected needs to have a high enough point cloud density. For the central area, it requires higher identification and detection accuracy, so it needs to have a high enough point cloud density, and the edge area does not need too high identification and detection accuracy, so it does not need too high point cloud density.

[0026] It should be noted that the so-called central area can be an area containing the center point of the entire field of view. The specific boundary and area of the area can be set by a person skilled in the art according to the needs, which is not limited here.

[0027] The embodiment of the present application provides a ranging device. The ranging device can be a device for measuring distance, which can be used to scan the external environment to obtain the point cloud data corresponding to the external environment.

[0028] The point cloud data can contain a plurality of point cloud points, and each point cloud point can include one or more information such as distance, orientation, reflection intensity, speed, and energy.

[0029] In the application level, the ranging device can be applied to remote sensing, obstacle avoidance, surveying, modeling, navigation and other businesses.

[0030] In one example, the ranging device can be a laser radar, of course, the ranging device can also be other electronic devices that use other types of light to achieve ranging.

[0031] As to the ranging principle of the ranging device, in one embodiment, the ranging device can calculate the distance from the ranging device to the object by measuring the time of flight of light between the ranging device and the object, i.e., the time of flight (TOF) of light. Alternatively, the ranging device can also achieve ranging by other techniques, such as a ranging method based on phase shift measurement, or a ranging method based on frequency shift measurement, without limitation.

[0032] Reference can be made below Figure 1 , Figure 1 is a structural schematic diagram of a ranging device provided by an embodiment of the present application. The ranging device 100 can include a light source 110 and a scanning module 120.

[0033] The light source can be used to emit a light pulse sequence, where the light pulse sequence is a collection of light beams emitted by the light source at a certain frequency within a period of time. In one example, the emitted light pulse sequence can be a laser pulse sequence, of course, it can also be a pulse sequence of other light.

[0034] In one embodiment, the light source can include at least two light emitting chips, where each light emitting chip can emit a light pulse sequence along a different light path, which can be parallel or not parallel between different light paths. In one example, the distance between the light emitting chips is any distance between 200um and 800um.

[0035] The scanning module 120 can include a first optical element 121, a second optical element 122, and a third optical element 123. Wherein the first optical element 121, the second optical element 122, and the third optical element 123 can all be rotated. The first optical element, the second optical element, and the third optical element can be disposed on the emission light path of the light pulse sequence, so that the light pulse sequence emitted from the light source can pass through the first optical element, the second optical element, and the third optical element. Again, since the first optical element, the second optical element, and the third optical element are rotating all the time when the light source emits the light pulse sequence, the refraction direction of each light beam in the light pulse sequence is different, so that different light beams can reach different positions.

[0036] As to the rotation of the first optical element, the second optical element and the third optical element, there are various ways in implementation. In one embodiment, a driver can be provided for each optical element, by which the optical element can be driven to rotate around the rotation axis. The driver corresponding to each optical element can be connected to the controller respectively, and the controller can control the rotation speed, rotation direction and other parameters of each driver respectively.

[0037] The rotation axes around which the optical elements rotate can be the same or different, as long as the rotation of the optical elements does not cause the light pulse sequence to be unable to pass through the optical element at some time. Of course, as shown in the example, the first optical element, the second optical element and the third optical element can be rotated around the same central axis. Figure 1

[0038] As to the rotation of the optical elements, the first optical element and the second optical element can rotate at the same speed in opposite directions, so that the scanning track of the light pulse sequence can be roughly a straight line back and forth. It should be noted that the same speed mentioned in this application does not mean that the rotation speeds of the first optical element and the second optical element are absolutely equal (it is actually difficult to achieve such control precision in engineering), but a certain degree of deviation is allowed, as long as the deviation does not exceed the reasonable range set, it can be considered that the two are rotating at the same speed. As to the opposite direction, it means that when the first optical element rotates clockwise, the second optical element rotates counterclockwise, or when the first optical element rotates counterclockwise, the second optical element rotates clockwise. The third optical element is not limited in rotation direction, which can rotate clockwise or counterclockwise.

[0039] The first optical element and the second optical element can rotate at a high speed, and the third optical element can rotate at a low speed. It should be noted that the rotation speed of the first optical element and the rotation speed of the third optical element can be coordinated with each other, and the rotation speed of the third optical element should not be too fast or too slow. In one embodiment, the rotation speed of the first optical element (which can also be said to be the rotation speed of the second optical element, because the first optical element and the second optical element rotate at the same speed) can be 10 to 20 times the rotation speed of the third optical element. For example, the rotation speed of the first optical element can be between 7000 rpm (Round Per Minute) and 10000 rpm, and the rotation speed of the third optical element can be between 580 rpm and 850 rpm.

[0040] As to the front-back order of the first optical element, the second optical element and the third optical element in the optical path, there are various setting ways in implementation. In one embodiment, as shown in Figure 1 ​As shown, the first optical element, the second optical element and the third optical element are arranged in sequence, so that the light pulse sequence passes through the first optical element, the second optical element and the third optical element in sequence. In another embodiment, the third optical element can be arranged in front of the first optical element and the second optical element, so that the light pulse sequence passes through the third optical element first, and then passes through the first optical element and the second optical element.

[0041] In an embodiment, the ranging device can further include a collimating element 130 and a receiver (not shown in the figure). The collimating element 130 can be arranged between the light source 210 and the scanning module 220, and is configured to collimate the light pulse sequence emitted by the light source. The receiver can be configured to receive the light pulse sequence reflected by the object, and can be arranged at the end of a light path (hereinafter referred to as a receiving light path) through which the reflected light pulse sequence passes. In an embodiment, the ranging device can use a coaxial light path, i.e., the emission light path and the receiving light path of the light pulse sequence can share at least part of the light path. In another embodiment, the emission light path and the receiving light path can also be a heteroaxial light path.

[0042] Through the light source 110, the collimating element 130, the scanning module 120 and the receiver, the ranging device can complete the scanning of the external environment. Specifically, each light beam (light pulse sequence) emitted at the light source can reach different positions of the target object after being refracted by the first optical element, the second optical element and the third optical element rotating in the scanning module. The light beams reflected from different positions can be received by the receiver, and each received light beam can be converted into an electrical signal through photoelectric conversion. By sampling and operating the electrical signal, the information of the point reached by the light beam can be calculated, so as to generate a point cloud point in the scanning pattern. The information of the points (positions) reached by all the light beams emitted by the light source within a frame duration constitutes a point cloud map, i.e., a scanning pattern within a frame duration, which can also be referred to as a point cloud frame.

[0043] For a frame duration, it can be different in different application scenarios, such as any duration between 0.04s and 0.2s. In an example, the frame duration can be set to any of the following values: 0.1s, 0.9s, 0.8s, 0.7s, 0.6s, 0.5s, 1.1s, 1.2s, 1.3s, 1.4s, 1.5s. The setting of the frame duration can be determined according to the required output frame rate (real-time performance) of the point cloud frame and / or the required point cloud density of the point cloud frame.

[0044] In an embodiment, the ranging device provided by the embodiments of the present application can scan to obtain a scanning pattern as shown in the following figure within a frame duration. Figure 2 By analyzing the scanning pattern, the ranging device can obtain the information of the object, such as the distance between the ranging device and the object, the shape of the object, the size of the object, the color of the object, the texture of the object, etc.Figure 2 As shown in the scanning pattern, it can be found that the point cloud density of the scanning pattern is denser in the middle than at both ends in the horizontal direction, but the point cloud density of the scanning pattern is sparser in the middle than at both ends in the vertical direction through the central region. In other words, in the vertical direction through the central region, more point cloud points do not fall in the central region but fall in the edge regions at both upper and lower ends, so that the point cloud density of the central region is not high enough to meet the user's demand for high-precision identification and detection of the central region.

[0045] As known from the foregoing, the rotation speed of the third optical element is much slower than that of the first optical element and the second optical element, so from a relatively short time, the first optical element and the second optical element have rotated many times, while the third optical element has only a small angular displacement. Therefore, if the effect of the third optical element is not considered or the third optical element in the distance measuring device is temporarily removed (not actually removed, but only a condition that there is no third optical element but only the first optical element and the second optical element), the light pulse sequence can also scan to form a scanning pattern after being refracted by the first optical element and the second optical element rotating at a constant speed in opposite directions. For convenience, this scanning pattern formed without considering the third optical element can be referred to as a basic pattern. After considering the effect of the third optical element, the reference point of the basic pattern can move along a certain trajectory.

[0046] For the scanning pattern as shown in Figure 2 If the effect of the third optical element is not considered, the basic pattern corresponding to the scanning pattern as shown in Figure 3A is in the shape of "∞" (the basic pattern scanned by six light emitting chips is shown in the figure). After considering the effect of the third optical element, i.e., the reference point of the "∞" basic pattern moves along a circular trajectory (which can be a circle, an ellipse, or a circle-like shape), a scanning pattern as shown in Figure 2 can be scanned within one frame.

[0047] The applicant found through analysis that the reason why the scanning pattern as shown in Figure 2 is sparser in the middle than at both ends in the vertical direction through the central region is that the basic pattern "∞" causes it. Since the middle part of the basic pattern is inwardly contracted in the vertical direction (i.e., the middle intersection part), when the reference point of the basic pattern moves along the circular trajectory, when it moves near the top and bottom of the circle, the middle contraction of the "∞" basic pattern causes the scanning trajectory not to pass through the central region of the entire field of view, thereby causing the scanning trajectory to intersect less in the central region, resulting in the problem that the point cloud density at both upper and lower ends is higher and the point cloud density in the middle is lower.

[0048] Through further research, it can be found that the basic pattern corresponding to the ranging device is in the shape of "∞" because Figure 2 In the corresponding embodiment, the same first optical element and second optical element are used, so that the deflection angles formed by the first optical element and the second optical element on the optical pulse sequence (light beam) are the same.

[0049] Therefore, in order to avoid the basic pattern corresponding to the ranging device being a pattern such as "∞" whose middle part shrinks inward in the vertical direction, in one embodiment, the first optical element and the second optical element may be different, so that the deflection angles formed by the first optical element and the second optical element for the light pulse sequence are different.

[0050] The optical element may be one or a combination of lenses, prisms, liquid crystals, optical phased arrays, etc. In one embodiment, the first optical element and the second optical element may both be wedge-shaped prisms. The wedge-shaped prisms may be prisms with varying thickness. In one embodiment, the first optical element and the second optical element may be wedge-shaped prisms. Figure 1 As shown, the vertical surfaces (the surfaces perpendicular to the optical axis) of the first and second optical elements can face each other. In another embodiment, the first and second optical elements can be arranged so that the inclined surfaces face each other, with the vertical surfaces at either end. Of course, for the first and second optical elements, both surfaces through which the light beam passes need not be perpendicular to the optical axis, and it is not necessary for one surface to be perpendicular to the optical axis.

[0051] The deflection angle of a light beam formed by a wedge prism can be calculated using the formula δ = α(n-1). Here, δ is the deflection angle, n is the refractive index, which is related to the material used for the wedge prism, and α is the wedge angle. Therefore, to ensure that the first and second optical elements form different deflection angles for the sequence of light pulses, in one embodiment, the first and second optical elements may have the same wedge angle but different materials. In another embodiment, the first and second optical elements may have the same material but different wedge angles. In yet another embodiment, the first and second optical elements may have different wedge angles and different materials.

[0052] When the deflection angles formed by the first optical element and the second optical element on the light pulse sequence are different, the scanning pattern (i.e., the basic pattern) formed by the light pulse sequence after being refracted by the rotating first optical element and the second optical element is no longer Figure 3A The pattern with the middle part shrinking inward in the vertical direction can be elliptical as a whole. Taking the light source as six lines, that is, the light source includes six light-emitting chips, when the first optical element and the second optical element have different deflection angles for the light pulse sequence, the basic pattern can be as follows Figure 3B, Figure 3C or Figure 3D an elliptical pattern.

[0053] Further, if the point cloud points in the scanning pattern of the distance measuring device are not horizontally straight, the edge lines of the regular object in the scanning pattern are also not straight, which results in great difficulty in subsequent algorithm adaptation and unnatural visual effects for users. Therefore, in an embodiment, the point cloud points of the scanning pattern of the distance measuring device within a frame duration can be made to be horizontally straight.

[0054] Since the scanning pattern finally output by the distance measuring device is obtained through the joint action of the first optical element, the second optical element, and the third optical element, whether the scanning pattern of the distance measuring device within a frame duration is straight is also affected by the joint action of the three optical elements. However, in an embodiment, if the refractive ability of the third optical element is weak, the influence of the third optical element on whether the point cloud points are straight can be ignored, as long as the point cloud points of the scanning pattern formed by the scanning of the basic pattern, i.e., the light pulse sequence after being refracted by the first optical element and the second optical element, are horizontally straight, such as Figure 3D .

[0055] In another embodiment, if the refractive ability of the third optical element is strong, even if the point cloud points of the basic pattern are horizontally straight, after the combination of the refraction of the third optical element, the point cloud points of the final scanning pattern will not be straight. For this case, the deflection angles of the three optical elements need to be coordinated by taking into account the comprehensive action of the three optical elements.

[0056] In an embodiment, the difference between the deflection angle of the light pulse sequence formed by the first optical element and the deflection angle of the light pulse sequence formed by the second optical element (for convenience, this difference is referred to as the deflection angle difference hereinafter) can be between 2 degrees and 10 degrees, so that the point cloud points of the obtained basic pattern can be horizontally straight.

[0057] It should be noted that the straightness mentioned in the present application refers to absolute straightness. Even if the vertical heights of the point cloud points are slightly different, as long as the slight difference is within a reasonable range (which is set by the person skilled in the art according to experience), it is still considered to be straight.

[0058] In the working of the ranging device, the first optical element and the second optical element are in a rotating state, and in the rotating process, the deflection angle of the first optical element to the light pulse sequence in the vertical plane remains unchanged at least in part of the time, and correspondingly, the deflection angle of the second optical element to the light pulse sequence in the vertical plane also remains unchanged at least in part of the time, so that the deflection angle difference between the first optical element and the second optical element can also remain unchanged in the rotating process. The vertical plane is a plane perpendicular to the horizontal plane, which can be a vertical plane facing the light source and perpendicular to the collimated light sequence pulse.

[0059] When there is a deflection angle difference between the first optical element and the second optical element, as described above, the basic pattern as a whole is elliptical, and as Figure 3B , Figure 3C , Figure 3D . Similarly, as described above, the third optical element can make the reference point of the basic pattern move along a circular trajectory. The specific shape of the circular trajectory is related to the deflection capability of the third optical element. If the deflection angle of the third optical element to the light pulse sequence is too small, the range of the circular trajectory is also small, and when the reference point of the basic pattern moves along the circular trajectory, since the basic pattern as a whole is elliptical and has a larger blank at the center, the final scanning will form a scanning pattern with no points at the center, as shown in Figure 4 . Therefore, in an embodiment, the deflection angle of the third optical element to the light pulse sequence can be greater than the deflection angle difference between the first optical element and the second optical element, thereby avoiding the above problem.

[0060] In an embodiment, the third optical element can also be a wedge-angle prism together with the first optical element and the second optical element, and the aperture of the third optical element can be greater than the aperture of the first optical element to increase the light receiving aperture. As described above, the wedge angles of the first optical element and the second optical element can be the same or different, and in an embodiment, the wedge angle of the third optical element can be smaller than the wedge angle of the first optical element or the second optical element. Specifically, in an example, the wedge angle of the third optical element can be less than half of the wedge angle of the first optical element or the second optical element.

[0061] In an embodiment, an antireflection film can be coated on each optical element.

[0062] In an embodiment, a filter layer can be coated on the surface of the optical element, or a filter can be arranged on the light beam propagation path for transmitting the wave band of the light beam emitted by the light source and reflecting other wave bands to reduce the noise of the ambient light to the receiver.

[0063] For example, Figure 5 , Figure 5is a scanning pattern of the ranging device in a frame duration provided by an embodiment of the present application, and the scanning pattern is shown in FIG. 1. The scanning pattern shown in FIG. 1 is only an example. The scanning pattern provided by the embodiment of the present application can be a scanning pattern shown in FIG. 2, a scanning pattern shown in FIG. 3, or a scanning pattern shown in FIG. 4. Figure 5 The scanning pattern shown in FIG. 1 is only an example. The scanning pattern provided by the embodiment of the present application can be a scanning pattern shown in FIG. 2, a scanning pattern shown in FIG. 3, or a scanning pattern shown in FIG. 4. Figure 5 The ranging device corresponding to the scanning pattern, the light source of the ranging device includes six light emitting chips. The deflection angles of the first optical element and the second optical element formed by the light pulse sequence are different, and the difference between the deflection angles remains unchanged during the equal-speed reverse rotation of the two. The driving parameter of the controller to the optical element is configured, so that the rotation speed of the first optical element is between 7000 rpm and 10000 rpm, and the rotation speed of the third optical element is between 580 rpm and 850 rpm.

[0064] It can be seen that the scanning pattern of the ranging device provided by the embodiment of the present application has a high point cloud density in the central region than in the surrounding region (including up, down, left and right). And the scanning pattern has a large enough field of view, wherein the horizontal field of view is greater than the vertical field of view, and the scanning pattern is a rectangle in the example shown in FIG. 1. Figure 5 In the example shown in FIG. 1, the horizontal field of view can be more than twice the vertical field of view, and the scanning pattern as a whole is rectangular.

[0065] Another example of a ranging device can also be provided. In this example, the light source of the ranging device can include 12 light emitting chips, that is, 12 line light sources. The first optical element, the second optical element and the third optical element in the scanning module can all be wedge-angle prisms, and the materials of the three optical elements can be HK9, HZF6 and HZK9B respectively. The wedge angles can be 24 degrees, 24 degrees and 10 degrees respectively. The rotation speed of the first optical element can be 7522 rpm, the second optical element can be equal-speed reverse, and the rotation speed can be -7522 rpm, and the rotation speed of the third optical element can be +632 rpm or -632 rpm. In this way, the scanning pattern of the ranging device in a frame duration can refer to FIG. 4. Figure 6 The scanning pattern has very high point cloud density in the entire field of view, and the maximum gap is below 0.2 degrees, and the point cloud coverage rate is extremely high.

[0066] The above is a detailed description of the ranging device provided by the embodiment of the present application. The ranging device provided by the embodiment of the present application includes a light source for emitting a light pulse sequence; a scanning module including a rotatable first optical element, a second optical element and a third optical element, wherein the first optical element and the second optical element rotate at equal speed in opposite directions. The scanning module is used to refract the light pulse sequence through the first optical element, the second optical element and the third optical element to scan the external environment. The scanning pattern of the ranging device in a frame duration is higher than the point cloud density of the two ends in the vertical direction and / or the horizontal direction through the central region, so as to meet the high-precision identification and detection requirements of the central region.

[0067] It should be noted that the above provides various embodiments of the ranging device, and as long as there is no conflict or contradiction between different embodiments, those skilled in the art can freely combine according to actual conditions. However, there are too many ways to combine, and this application file cannot exhaust all combinations, so it does not expand the description of the embodiments obtained by all combinations, but it can be understood that these combinations also belong to the scope disclosed in this application file.

[0068] The application further provides a mobile platform, which can include a mobile platform body and a ranging device carried on the mobile platform body. The mobile platform can include at least one of an unmanned aerial vehicle, a car, a remote control car, a robot, and a camera. When the ranging device is applied to the unmanned aerial vehicle, the mobile platform body is the fuselage of the unmanned aerial vehicle. When the ranging device is applied to the car, the mobile platform body is the car body. The car can be an automatic driving car or a semi-automatic driving car, which is not limited here. When the ranging device is applied to the remote control car, the mobile platform body is the car body of the remote control car. When the ranging device is applied to the robot, the mobile platform body is the robot. When the ranging device is applied to the camera, the mobile platform body is the camera itself.

[0069] Consistent with the foregoing, the ranging device can include:

[0070] a light source for emitting a light pulse sequence;

[0071] a scanning module, the scanning module including a rotatable first optical element, a second optical element, and a third optical element, wherein the first optical element and the second optical element rotate at the same speed in opposite directions;

[0072] The scanning module is configured to refract the light pulse sequence through the first optical element, the second optical element, and the third optical element to scan the external environment; wherein the point cloud density of the scanning pattern of the ranging device in a frame duration is higher in the middle than at both ends in the vertical direction of the central region.

[0073] Optionally, the first optical element and the second optical element form different deflection angles for the light pulse sequence.

[0074] Optionally, the scanning pattern formed by scanning the light pulse sequence after being refracted by the rotating first optical element and the second optical element is overall elliptical.

[0075] Optionally, the point cloud points of the scanning pattern of the ranging device in a frame duration are distributed flatly in the horizontal direction.

[0076] Optionally, the point cloud points of the scanning pattern formed by the light pulse sequence after being refracted by the first optical element and the second optical element are horizontally distributed in a straight line.

[0077] Optionally, the difference between the deflection angles of the light pulse sequence formed by the first optical element and the second optical element is between 2 degrees and 10 degrees.

[0078] Optionally, the deflection angles of the light pulse sequence formed by the first optical element and the second optical element in the vertical plane remain unchanged at least for part of the rotation time.

[0079] Optionally, the first optical element and the second optical element are wedge angle prisms, and the wedge angles and / or refractive indices of the first optical element and the second optical element are different.

[0080] Optionally, the deflection angle of the light pulse sequence formed by the third optical element is greater than the difference between the deflection angles of the light pulse sequence formed by the first optical element and the second optical element.

[0081] Optionally, the rotation speed of the first optical element is 10-20 times the rotation speed of the third optical element.

[0082] Optionally, the rotation speed of the first optical element is between 7000 rpm and 10000 rpm.

[0083] Optionally, the rotation speed of the third optical element is between 580 rpm and 850 rpm.

[0084] Optionally, the first optical element, the second optical element, and the third optical element rotate around the same central axis.

[0085] Optionally, the first optical element, the second optical element, and the third optical element are all wedge angle prisms, and the aperture of the third optical element is greater than the aperture of the first optical element.

[0086] Optionally, the wedge angles of the first optical element and the second optical element are the same; and / or,

[0087] The wedge angle of the third optical element is smaller than the wedge angle of the first optical element or the second optical element.

[0088] Optionally, the wedge angle of the third optical element is less than half of the wedge angle of the first optical element or the second optical element.

[0089] Optionally, the first optical element and the second optical element are arranged opposite to each other in the vertical plane or the inclined plane.

[0090] Optionally, the frame duration is between 0.04s and 0.2s.

[0091] Optionally, the point cloud density of the central region of the scanning pattern of the ranging device in a frame duration is higher than that of the surrounding region.

[0092] Optionally, the horizontal field of view of the scanning pattern of the ranging device in a frame duration is greater than the vertical field of view.

[0093] Optionally, the scanning pattern of the ranging device in a frame duration is in a rectangular shape.

[0094] Optionally, the horizontal field of view of the scanning pattern of the ranging device in a frame duration is greater than twice the vertical field of view.

[0095] Optionally, the light source comprises at least two light emitting chips for emitting light pulse sequences along different light paths respectively.

[0096] Optionally, the distance between the at least two light emitting chips is between 200um and 800um.

[0097] The mobile platform provided by the embodiments of the present application has the ranging device mounted thereon, and the scanning pattern of the ranging device in a frame duration has a higher point cloud density in the middle than in the two ends in the vertical and / or horizontal direction through the central region, thereby meeting the high-precision identification and detection requirements of the central region.

[0098] The specific implementation of the various embodiments of the mobile platform provided above can refer to the related description of the ranging device in the foregoing, which will not be described here again.

[0099] It should be noted that, in this document, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. The terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0100] The device provided by the embodiment of the present application is described in detail above, and the principle and implementation manner of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manner and application range will be changed, and the above description should not be understood as a limitation on the present application.

Claims

1. A distance measuring device, characterized in that: include: a light source for emitting a sequence of light pulses; a scanning module comprising a rotatable first optical element, a second optical element, and a third optical element, wherein the first optical element and the second optical element rotate in opposite directions at the same speed; and the first optical element and the second optical element form different deflection angles for the light pulse sequence; The scanning module is used to refract the light pulse sequence through the first optical element, the second optical element, and the third optical element to scan the external environment. The scanning pattern of the ranging device within one frame duration has a higher point cloud density in the vertical direction of the central area than at both ends. Moreover, the point cloud points of the scanning pattern are flatly distributed in the horizontal direction.

2. The distance measuring device according to claim 1, characterized in that After the light pulse sequence is refracted by the rotating first optical element and the second optical element, a scanning pattern formed by scanning is elliptical as a whole.

3. The distance measuring device according to claim 1, wherein After the light pulse sequence is refracted by the rotating first optical element and the second optical element, the point cloud points of the scanning pattern formed by scanning are distributed flatly in the horizontal direction.

4. The distance measuring device according to claim 1, wherein: The difference between the deflection angles formed by the first optical element and the second optical element for the light pulse sequence is between 2 degrees and 10 degrees.

5. The distance measuring device according to claim 1, wherein: The deflection angles formed by the first optical element and the second optical element on the vertical plane for the light pulse sequence respectively remain unchanged for at least a portion of the duration during the rotation.

6. The distance measuring device according to claim 1, characterized in that The first optical element and the second optical element are wedge-angle prisms, and the first optical element and the second optical element have different wedge angles and / or refractive indices.

7. The distance measuring device according to claim 1, characterized in that The deflection angle formed by the third optical element on the light pulse sequence is greater than the difference between the deflection angles formed by the first optical element and the second optical element on the light pulse sequence respectively.

8. The distance measuring device according to claim 1, wherein: The rotation speed of the first optical element is 10 to 20 times that of the third optical element.

9. The distance measuring device according to claim 1, characterized in that The rotation speed of the first optical element is between 7000 rpm and 10000 rpm.

10. The distance measuring device according to claim 1, characterized in that: The rotation speed of the third optical element is between 580 rpm and 850 rpm.

11. The distance measuring device according to claim 1, characterized in that: The first optical element, the second optical element, and the third optical element rotate around the same central axis.

12. The distance measuring device according to claim 1, characterized in that The first optical element, the second optical element and the third optical element are all wedge-shaped prisms, and the aperture of the third optical element is larger than that of the first optical element.

13. The distance measuring device according to claim 12, characterized in that: The wedge angles of the first optical element and the second optical element are the same; and / or, A wedge angle of the third optical element is smaller than a wedge angle of the first optical element or the second optical element.

14. The distance measuring device according to claim 13, characterized in that: A wedge angle of the third optical element is smaller than half of a wedge angle of the first optical element or the second optical element.

15. The distance measuring device according to claim 12, characterized in that: The vertical surfaces or inclined surfaces of the first optical element and the second optical element are arranged opposite to each other.

16. The distance measuring device according to claim 1, characterized in that The duration of one frame is between 0.04s and 0.2s.

17. The distance measuring device according to claim 1, wherein: The point cloud density of the central area of ​​the scanning pattern of the ranging device within one frame time is higher than the point cloud density of the surrounding areas.

18. The distance measuring device according to claim 1, characterized in that The horizontal field angle of the scanning pattern of the distance measuring device within one frame duration is greater than the vertical field angle.

19. The distance measuring device according to claim 18, characterized in that The scanning pattern of the distance measuring device within one frame duration is rectangular as a whole.

20. The distance measuring device according to claim 18, characterized in that The horizontal field angle of the scanning pattern of the distance measuring device in one frame time is greater than twice the vertical field angle.

21. The distance measuring device according to claim 1, characterized in that The light source includes at least two light-emitting chips, which are used to emit light pulse sequences along different light paths respectively.

22. The distance measuring device according to claim 21, characterized in that The distance between the at least two light-emitting chips is between 200um and 800um.

23. A mobile platform, characterized in that: It includes a mobile platform body and a distance measuring device mounted on the mobile platform body; The distance measuring device comprises: a light source for emitting a sequence of light pulses; a scanning module comprising a rotatable first optical element, a second optical element, and a third optical element, wherein the first optical element and the second optical element rotate in opposite directions at the same speed; and the first optical element and the second optical element form different deflection angles for the light pulse sequence; The scanning module is used to refract the light pulse sequence through the first optical element, the second optical element, and the third optical element to scan the external environment. The scanning pattern of the ranging device within one frame duration has a higher point cloud density in the vertical direction of the central area than at both ends. Moreover, the point cloud points of the scanning pattern are flatly distributed in the horizontal direction.

24. The mobile platform according to claim 23, wherein: After the light pulse sequence is refracted by the rotating first optical element and the second optical element, a scanning pattern formed by scanning is elliptical as a whole.

25. The mobile platform according to claim 23, wherein: After the light pulse sequence is refracted by the rotating first optical element and the second optical element, the point cloud points of the scanning pattern formed by scanning are distributed flatly in the horizontal direction.

26. The mobile platform according to claim 23, wherein: The difference between the deflection angles formed by the first optical element and the second optical element for the light pulse sequence is between 2 degrees and 10 degrees.

27. The mobile platform according to claim 23, wherein: The deflection angles formed by the first optical element and the second optical element on the vertical plane for the light pulse sequence respectively remain unchanged for at least a portion of the duration during the rotation.

28. The mobile platform according to claim 23, wherein: The first optical element and the second optical element are wedge-angle prisms, and the first optical element and the second optical element have different wedge angles and / or refractive indices.

29. The mobile platform according to claim 23, wherein: The deflection angle formed by the third optical element on the light pulse sequence is greater than the difference between the deflection angles formed by the first optical element and the second optical element on the light pulse sequence respectively.

30. The mobile platform according to claim 23, wherein: The rotation speed of the first optical element is 10 to 20 times that of the third optical element.

31. The mobile platform according to claim 23, wherein: The rotation speed of the first optical element is between 7000 rpm and 10000 rpm.

32. The mobile platform according to claim 23, wherein: The rotation speed of the third optical element is between 580 rpm and 850 rpm.

33. The mobile platform according to claim 23, wherein: The first optical element, the second optical element, and the third optical element rotate around the same central axis.

34. The mobile platform according to claim 23, wherein: The first optical element, the second optical element and the third optical element are all wedge-shaped prisms, and the aperture of the third optical element is larger than that of the first optical element.

35. The mobile platform according to claim 34, wherein: The wedge angles of the first optical element and the second optical element are the same; and / or, A wedge angle of the third optical element is smaller than a wedge angle of the first optical element or the second optical element.

36. The mobile platform according to claim 35, characterized in that A wedge angle of the third optical element is smaller than half of a wedge angle of the first optical element or the second optical element.

37. The mobile platform according to claim 36, wherein: The vertical surfaces or inclined surfaces of the first optical element and the second optical element are arranged opposite to each other.

38. The mobile platform according to claim 23, wherein: The duration of one frame is between 0.04s and 0.2s.

39. The mobile platform according to claim 23, wherein: The point cloud density of the central area of ​​the scanning pattern of the ranging device within one frame time is higher than the point cloud density of the surrounding areas.

40. The mobile platform according to claim 23, wherein: The horizontal field angle of the scanning pattern of the distance measuring device within one frame duration is greater than the vertical field angle.

41. The mobile platform according to claim 40, wherein: The scanning pattern of the distance measuring device within one frame duration is rectangular as a whole.

42. The mobile platform according to claim 40, wherein: The horizontal field angle of the scanning pattern of the distance measuring device in one frame time is greater than twice the vertical field angle.

43. The mobile platform according to claim 23, wherein: The light source includes at least two light-emitting chips, which are used to emit light pulse sequences along different light paths respectively.

44. The mobile platform according to claim 43, wherein: The distance between the at least two light-emitting chips is between 200um and 800um.

Images