Combined optical distance measuring device, laser radar and use method thereof

Abstract

The invention discloses a combined optical ranging device, a laser radar and a use method thereof, and relates to the technical field of optical ranging. The device comprises at least two optical ranging systems which are sequentially arranged according to the ranging ranges from large to small, ranging optical paths of the at least two optical ranging systems coincide, and the ranging optical paths of the at least two optical ranging systems are overlapped through relation limitation and working method limitation on attributes such as ranging precision and ranging errors of the ranging systems. The obtained combined optical ranging scheme has the characteristic of wide range of the foremost optical ranging system and the characteristic of high precision of the last optical ranging system, so that the purposes of large range and high precision are achieved, and due to the fact that the combined optical ranging scheme is realized based on the existing optical ranging system combination, the combined optical ranging scheme can also have the characteristic of low cost. And practical application and popularization are facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical ranging, and in particular relates to a combined optical ranging device, a laser radar and a method of using the same. Background Art

[0002] In the field of optical ranging technology, there are many different optical ranging methods, such as the pulse method, phase method (including single-frequency phase method, dual-frequency phase method, and multi-frequency phase method), triangulation method, 3D vision method, and Frequency Modulated Continuous Wave (FMCW) method. These ranging methods generally have ranging accuracy of decimeters, centimeters, or millimeters, with some reaching sub-millimeter levels. The ranging range can range from meters to kilometers, thousands of kilometers, or even longer. High-precision optical ranging measurement methods, such as interferometry (including single-wavelength interferometry, dual-wavelength interferometry, and multi-wavelength interferometry), can achieve nanometer or even sub-nanometer accuracy. However, the range of single-wavelength interferometry is often only on the micrometer level, and the range of dual-wavelength interferometry and multi-wavelength interferometry is often only on the millimeter level.

[0003] Traditional distance measurement methods typically have either a large range but low accuracy, or high accuracy but a small range. None of these methods offer the advantages of both a large range and high accuracy. While the recently developed dual-comb ranging method is capable of measuring distances over long distances, large scales, and with extremely high accuracy, its extremely high implementation cost significantly limits its commercial application.

[0004] In addition, some specific applications (such as surface inspection of high-precision optical lens surfaces, such as those for extreme ultraviolet lithography mirrors, large astronomical telescopes, or gravitational wave detectors) often require a range of meters and sub-nanometer accuracy, but current traditional optical ranging methods are unable to achieve high-precision measurements at such a large range. Furthermore, for some large structural components, whose scale reaches tens of meters, the surface scanning accuracy of the structural components needs to reach the sub-micron level, or the alignment accuracy of the installation needs to reach the sub-micron level, but current traditional optical ranging solutions cannot measure these. Summary of the Invention

[0005] The purpose of the present invention is to provide a combined optical ranging device, a laser radar and a method of using the same, so as to solve the problem that existing optical ranging solutions cannot achieve a large range and high accuracy.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, a combined optical ranging device is provided, comprising at least two optical ranging systems arranged in descending order of ranging range, wherein the ranging optical paths of the at least two optical ranging systems overlap, the ranging optical path being the optical path from a ranging starting point to a measured object, and the optical ranging systems comprising systems that use light waves or electromagnetic waves for ranging;

[0008] Any pair of adjacently ordered optical ranging systems, the preceding optical ranging system and the following optical ranging system, in the at least two optical ranging systems, meets the following conditions: the preceding optical ranging system and the following optical ranging system are two optical ranging systems using different ranging principles; the ranging accuracy of the preceding optical ranging system is lower than the ranging accuracy of the following optical ranging system; the ranging error of the preceding optical ranging system is smaller than the difference between the ranging range and the ranging error of the following optical ranging system; the ranging range of the following optical ranging system has periodic usability, wherein the ranging error is equal to twice the absolute value of the ranging accuracy; the periodic usability means that the ranging range l0, the true distance L, and the ranging value d satisfy L=N×l0+d, where N is a natural number and represents an unknown number of ranging ranges in use;

[0009] The working method of the combined optical distance measuring device includes:

[0010] At least two ranging values corresponding to the at least two optical ranging systems are obtained by measuring the at least two optical ranging systems;

[0011] According to the at least two ranging values, a final ranging value is determined according to the following steps S21 to S24:

[0012] S21. Initialize the variable k to 1, and then execute step S22;

[0013] S22. Based on the ranging accuracy and ranging value of the kth optical ranging system in the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system in the at least two optical ranging systems, updating the ranging value of the k+1th optical ranging system, and then executing step S23;

[0014] S23 determines whether k+1 is equal to the total number of the at least two optical ranging systems. If so, proceed to step S24. Otherwise, k is incremented by 1, and then the process returns to step S22.

[0015] S24. Taking the current distance measurement value of the k+1th optical distance measurement system as the final distance measurement value.

[0016] Based on the above invention, a combined optical ranging solution based on multiple different optical ranging systems is provided, namely, it includes at least two optical ranging systems arranged in order from large to small ranging range, wherein the ranging optical paths of the at least two optical ranging systems overlap, and by limiting the relationship between these ranging systems in terms of properties such as ranging accuracy and ranging error, as well as the working methods, the resulting combined optical ranging solution can have both the large range characteristics of the foremost optical ranging system and the high precision characteristics of the rearmost optical ranging system, thereby achieving the purpose of large range and high precision. Moreover, since it is implemented based on a combination of existing optical ranging systems, it can also have the characteristics of low cost, which is convenient for practical application and promotion.

[0017] In one possible design, when the k+1th optical ranging system among the at least two optical ranging systems is a single-frequency optical ranging system, updating the ranging value of the k+1th optical ranging system according to the ranging accuracy and ranging value of the kth optical ranging system among the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system among the at least two optical ranging systems includes:

[0018] According to the distance measurement accuracy ±μ of the kth optical distance measurement system among the at least two optical distance measurement systems k and the distance value d k , determine the range of distance measurement value [d k -μ k ,d k +μ k ];

[0019] According to the distance measuring range l of the k+1th optical distance measuring system among the at least two optical distance measuring systems 0,k+1 and the distance value d k+1 , update the distance value of the k+1th optical ranging system to belong to the distance value range [d k -μ k ,d k +μ k ] an optional distance value D k+1 =n×l 0,k+1 +d k+1 , where n represents a natural number.

[0020] In one possible design, when the k+1th optical ranging system among the at least two optical ranging systems is a dual-frequency optical ranging system, updating the ranging value of the k+1th optical ranging system according to the ranging accuracy and ranging value of the kth optical ranging system among the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system among the at least two optical ranging systems includes:

[0021] According to the distance measurement accuracy ±μ of the kth optical distance measurement system among the at least two optical distance measurement systems k and the distance value d k , determine the range of distance measurement value [d k -μ k ,d k +μ k ];

[0022] According to the ranging range l of the first single-frequency optical ranging subsystem in the dual-frequency optical ranging system 1,0,k+1 and the distance value d 1,k+1 , determine the range of the distance value [d k -μ k ,d k +μ k ] the first optional distance value D 1,k+1 =n1×l 1,0,k+1 +d 1,k+1 , where n1 represents a natural number;

[0023] According to the distance measurement range l of the second single-frequency optical distance measurement subsystem in the dual-frequency optical distance measurement system 2,0,k+1 and the distance value d 2,k+1 , determine the range of the distance value [d k -μ k ,d k +μ k ] second optional distance value D 2,k+1 =n2×l 2,0,k+1 +d 2,k+1 , where n2 represents a natural number;

[0024] Based on all the first optional distance values and all the second optional distance values, the absolute difference of each pair of distance values is calculated according to the following formula:

[0025] ΔD i,j =|D 1,i,k+1 -D 2,j,k+1 |

[0026] Wherein, i is an integer and 1≤i≤I, I represents the total number of distance values of all the first optional distance values, j represents an integer and 1≤j≤J, J represents the total number of distance values of all the second optional distance values, D 1,i,k+1 Indicates the i-th distance value among all the first optional distance values, D 2,j,k+1 represents the jth distance value among all the second optional distance values, ΔD i,j represents the absolute difference between the i-th distance value and the j-th distance value;

[0027] Determine a pair of distance values with the smallest absolute difference from the absolute differences of the pairs of distance values;

[0028] Update the distance value of the k+1th optical distance measurement system to the average distance value of the pair of distance values, any distance value in the pair of distance values, any distance value between the pair of distance values, or any distance value within the range With range Any distance value within the intersection range of , where represents the first optional distance value in the pair of distance values and corresponding to the first single-frequency optical ranging subsystem, ±μ 1,k+1 represents the ranging accuracy of the first single-frequency optical ranging subsystem, represents the second optional distance value in the pair of distance values and corresponding to the second single-frequency optical ranging subsystem, ±μ 2,k+1 Represents the ranging accuracy of the second single-frequency optical ranging subsystem.

[0029] In one possible design, when the k+1th optical ranging system among the at least two optical ranging systems is a multi-frequency optical ranging system, updating the ranging value of the k+1th optical ranging system according to the ranging accuracy and ranging value of the kth optical ranging system among the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system among the at least two optical ranging systems includes:

[0030] According to the distance measurement accuracy ±μ of the kth optical distance measurement system among the at least two optical distance measurement systems k and the distance value d k , determine the range of distance value (d k -μ k ,d k +μ k );

[0031] For each single-frequency optical ranging subsystem in the multi-frequency optical ranging system, according to the corresponding ranging range and ranging value, the corresponding ranging value that belongs to the ranging value range [d k -μ k ,d k +μ k ] Optional distance values:

[0032] D m,k+1 =n m ×l m,0,k+1 +d m,k+1

[0033] Wherein, m is a positive number and 1≤m≤M, M represents the total number of single-frequency optical ranging subsystems in the multi-frequency optical ranging system, lm,0,k+1 represents the ranging range of the mth single-frequency optical ranging subsystem in the multi-frequency optical ranging system, d m,k+1 represents the distance measurement value of the mth single-frequency optical ranging subsystem, n m represents the natural number corresponding to the mth single-frequency optical ranging subsystem, D m,k+1 represents the mth single-frequency optical ranging subsystem and belongs to the ranging value range [d k -μ k ,d k +μ k ] optional distance value;

[0034] Based on the distance value sets of each single-frequency optical ranging subsystem, the absolute difference amplitude of each set of distance values is calculated according to the following formula:

[0035] ΔD S =D S,max -D S,min

[0036] Where S represents any set of distance values in the above distance values and has i m is an integer with 1≤i m ≤I m , I m represents the mth single-frequency optical ranging subsystem and belongs to the ranging value range [d k -μ k ,d k +μ k ], the total number of distance values of all said optional distance values, Indicates that the m-th single-frequency optical ranging subsystem and belongs to the ranging value range [d k -μ k ,d k +μ k ] among all the optional distance values m distance value, D S,max Indicates the maximum distance value in any set of distance values, D S,min Indicates the minimum distance value in any set of distance values, ΔD S represents the absolute difference magnitude of any set of distance values;

[0037] Determining a group of distance values having the smallest absolute difference magnitude from the absolute difference magnitudes of the groups of distance values;

[0038] Update the distance value of the k+1th optical distance measurement system to the average distance value of the certain group of distance values, the median distance value of the certain group of distance values, any distance value in the certain group of distance values, or a distance value within the range …、 and Any distance value within the intersection range of , where represents an optional distance value in the set of distance values and corresponding to the mth single-frequency optical ranging subsystem, ±μ m,k+1 represents the ranging accuracy of the m-th single-frequency optical ranging subsystem.

[0039] In one possible design, the optical ranging system in the front order adopts a pulse optical ranging system, a single-frequency phase optical ranging system, a dual-frequency phase optical ranging system, a multi-frequency phase optical ranging system, a single-wavelength interference optical ranging system, a dual-wavelength interference optical ranging system, a multi-wavelength interference optical ranging system, a triangulation optical ranging system, a frequency-modulated continuous wave optical ranging system or a 3D vision ranging system.

[0040] In one possible design, the sorted optical ranging system adopts a single-frequency phase method optical ranging system, a dual-frequency phase method optical ranging system, a multi-frequency phase method optical ranging system, a single-wavelength interference method optical ranging system, a dual-wavelength interference method optical ranging system or a multi-wavelength interference method optical ranging system.

[0041] In one possible design, the at least two optical ranging systems achieve the overlap of the ranging optical paths through a light combining and splitting device, wherein the light combining and splitting device is used to combine light of different wavelengths in a forward direction and split light in a retroreflective direction, the forward direction refers to the direction toward the object to be measured, and the retroreflective direction refers to the direction from the object to be measured.

[0042] In one possible design, the detectors of the pulse optical ranging system or the phase optical ranging system in the at least two optical ranging systems are optical fiber type devices or space type devices.

[0043] In one possible design, the at least two optical ranging systems use optical fiber or spatial optical path to achieve the overlap of the ranging optical paths.

[0044] In a second aspect, a laser radar is provided, comprising a spatial scanning device and a combined optical ranging device as described in the first aspect or any possible design in the first aspect, wherein the spatial scanning device is installed at the front end of the spatial light path in the combined optical ranging device.

[0045] In a third aspect, a method for using the laser radar as described in the second aspect is provided. When the ranging range of the laser radar also has the periodic usability, the method for using the laser radar includes the following steps:

[0046] Using a 3D visual odometry method to measure a first distance value from a starting point to each point in a target area, wherein a ranging range of the 3D visual odometry method is greater than a ranging range of the laser radar, a ranging accuracy of the 3D visual odometry method is lower than a ranging accuracy of the laser radar, and a ranging error of the 3D visual odometry method is less than a difference between the ranging range of the laser radar and the ranging error;

[0047] Using the laser radar to measure and obtain a second distance value from the starting point to each of the points;

[0048] For each of the points, the final distance value from the starting point to the corresponding point is updated according to the ranging accuracy of the 3D visual ranging method and the first distance value from the starting point to the corresponding point, as well as the ranging range of the laser radar and the second distance value from the starting point to the corresponding point.

[0049] Beneficial effects of the above scheme:

[0050] (1) The present invention creatively provides a combined optical ranging solution based on multiple different optical ranging systems, namely, comprising at least two optical ranging systems arranged in descending order of ranging range, wherein the ranging optical paths of the at least two optical ranging systems overlap, and by limiting the relationship between these ranging systems in terms of properties such as ranging accuracy and ranging error, as well as the working methods, the resulting combined optical ranging solution can have both the large range characteristic of the foremost optical ranging system and the high precision characteristic of the rearmost optical ranging system, thereby achieving the purpose of large range and high precision. Moreover, since it is implemented based on a combination of existing optical ranging systems, it can also have the characteristic of low cost, which is convenient for practical application and promotion.

[0051] (2) Theoretically, the combined optical ranging solution can easily achieve ranging of hundreds of meters, kilometers, or even longer distances, that is, it can even reach a range of several kilometers to tens of kilometers, or even hundreds of kilometers, with an accuracy of nanometers or even sub-nanometers. It is particularly suitable for surface detection applications of high-precision optical lens surfaces such as reflectors of extreme ultraviolet lithography machines, large astronomical telescopes, or reflectors of gravitational wave detectors, as well as for scenarios where large structural parts are scanned or aligned with high precision.

[0052] (3) Based on the large range and high precision characteristics of the combined optical ranging device, the laser radar can achieve extremely high precision in a large range when measuring distances in different directions;

[0053] (4) It is also possible to combine the use of laser radar and 3D visual ranging method, which can not only have the characteristics of large-scale measurement of 3D imaging, but also can achieve extremely high accuracy in distance measurement of each point. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0055] Figure 1 A schematic flow chart of a general working method of a combined optical ranging device provided in an embodiment of the present application.

[0056] Figure 2 A schematic diagram of the specific structure of the first combined optical ranging device provided in an embodiment of the present application.

[0057] Figure 3 A schematic diagram of the specific structure of the second combined optical ranging device provided in an embodiment of the present application.

[0058] Figure 4 A schematic diagram of the specific structure of the third combined optical ranging device provided in an embodiment of the present application.

[0059] Figure 5 A schematic diagram of the specific structure of the fourth combined optical ranging device provided in an embodiment of the present application.

[0060] Figure 6 A schematic diagram of the partial specific structure of the fifth combined optical ranging device provided in an embodiment of the present application.

[0061] Figure 7 A schematic diagram of the partial specific structure of the sixth combined optical ranging device provided in an embodiment of the present application.

[0062] In the above figures: 1- single-frequency phase method optical ranging system; 2- single-wavelength interferometry method optical ranging system; 3- dual-wavelength interferometry method optical ranging system; 4- dual-frequency phase method optical ranging system; 6- pulse method optical ranging system. DETAILED DESCRIPTION

[0063] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the embodiments of the present application will be briefly introduced below in conjunction with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the present application. For those of ordinary skill in the art, other embodiment descriptions can be obtained based on these embodiment descriptions without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0064] It should be understood that although the terms first, second, etc. may be used herein to describe various objects, these objects should not be limited by these terms. These terms are merely used to distinguish one object from another. For example, a first object can be referred to as a second object, and similarly, a second object can be referred to as a first object without departing from the scope of the exemplary embodiments of the present application.

[0065] It should be understood that the term "and / or" that may appear in this document is merely a description of the association relationship between associated objects, indicating that there may be three relationships. For example, A and / or B can indicate three situations: A exists alone, B exists alone, or A and B exist at the same time. For another example, A, B and / or C can indicate the existence of any one of A, B and C or any combination of them. The term "or and" that may appear in this document describes another relationship between associated objects, indicating that there may be two relationships. For example, A or and B can indicate two situations: A exists alone or A and B exist at the same time. In addition, the character " / " that may appear in this document generally indicates that the previous and next associated objects are in an "or" relationship.

[0066] Example 1

[0067] like Figures 1-2 As shown, the first combined optical ranging device provided by this embodiment includes but is not limited to the following at least two optical ranging systems arranged in descending order of ranging range: a single-frequency phase method optical ranging system 1 and a single-wavelength interferometry method optical ranging system 2, wherein the ranging optical paths of the single-frequency phase method optical ranging system 1 and the single-wavelength interferometry method optical ranging system 2 overlap, and the ranging optical path refers to the optical path from the ranging starting point to the object being measured. Figure 2 As shown, the distance measurement optical paths of the above two systems can be overlapped in the following manner, but not limited to: the single-frequency phase method optical distance measurement system 1 adopts a modulation wavelength of λ M,1The single-wavelength interference optical ranging system 2 is exemplified by a Michelson interferometer and uses light with a wavelength of λ1. The single-frequency phase method optical ranging system 1 and the single-wavelength interference method optical ranging system 2 use light with different wavelengths. The two lights of different wavelengths are combined through a wavelength division multiplexer WDM (Wavelength Division Multiplexing), and then emitted to the object to be measured through the collimator 2 of the Michelson interferometer measuring arm, and are received by the collimator 2 when returning, and then return to the optical fiber and are separated again at the wavelength division multiplexer WDM. In this way, the end face of the collimator 2 can be used as the starting point of ranging, so that the ranging optical paths of the two systems are both the optical paths between the end face of the collimator 2 and the object to be measured, thereby achieving the purpose of overlapping the ranging optical paths through the wavelength division multiplexer used as a light combining and splitting device. The aforementioned light combining and splitting device is used to combine light of different wavelengths in the forward direction and split it in the return direction, thereby achieving overlap of the ranging optical paths, where the forward direction refers to the direction toward the object being measured, and the return direction refers to the direction from the object being measured. Furthermore, the light combining and splitting device may also employ, but is not limited to, a spatial dichroic mirror, grating, or prism in place of the wavelength division multiplexer to achieve overlap of the ranging optical paths.

[0068] The single-frequency phase-based optical ranging system 1 serves as the first-order optical ranging system, and the single-wavelength interference-based optical ranging system 2 serves as the last-order optical ranging system. In order to ensure that the entire first combined optical ranging device has the advantages of large range and high precision, the first-order optical ranging system and the last-order optical ranging system must meet the following conditions: the first-order optical ranging system and the last-order optical ranging system are two optical ranging systems using different ranging principles; the ranging accuracy of the first-order optical ranging system is lower than the ranging accuracy of the last-order optical ranging system; the ranging error of the first-order optical ranging system is less than the difference between the ranging range and the ranging error of the last-order optical ranging system; the ranging range of the last-order optical ranging system has periodic usability, wherein the ranging error is equal to twice the absolute value of the ranging accuracy; the periodic usability means that the ranging range l0, the true distance L, and the ranging value d satisfy L=N×l0+d, where N is a natural number and represents the number of unknown ranging ranges used. The distance measurement range of the single-frequency phase method optical distance measurement system 1 is generally λ M,1 / 2 (which is common knowledge); the ranging accuracy of the single-frequency phase method optical ranging system 1 is generally ±η×(λ M,1 / 2) (which is common knowledge, η represents the internal phase discrimination accuracy of the single-frequency phase method optical ranging system 1, which is generally one thousandth, or has a higher accuracy); the ranging error of the single-frequency phase method optical ranging system 1 is generally η×λ M,1(i.e., equal to the ranging accuracy ±η×(λ M,1 The single-wavelength interferometry optical ranging system 2 has a ranging range of λ1 / 2 (which is common knowledge); the ranging accuracy of the single-wavelength interferometry optical ranging system 2 is generally ±γ×(λ1 / 2) (which is common knowledge, where γ represents the internal phase demodulation accuracy of the single-wavelength interferometry optical ranging system 2, which is generally one thousandth, or has a higher accuracy); the ranging error of the single-wavelength interferometry optical ranging system 2 is generally γ×λ1 (i.e., equal to twice the absolute value of the ranging accuracy ±γ×(λ1 / 2)).

[0069] Based on the existing working principle of the single-wavelength interferometry optical ranging system 2, it can be inferred that: if the actual distance L exceeds the ranging range λ1 / 2, it will enter the next level of interference fringes, making it impossible for the system to distinguish which level each interference fringes is in (this is like using a very high-precision ruler to measure length. Its accuracy is very high, reaching the nanometer level, but the range is very short, only sub-micron level. If the length to be measured exceeds the range of this ruler, although it can still be measured with this ruler, it is impossible to determine how many times the measurement has been repeated with this ruler). Therefore, another measurement system is needed to first determine which level of interference fringes the single-wavelength interferometry optical ranging system 2 with the periodic usability range is in (that is, how many times this high-precision ruler has been repeatedly measured). The single-frequency phase method optical ranging system 1 in this embodiment is used as another measurement system mentioned above. If the ranging error of the single-frequency phase method optical ranging system 1 is greater than or equal to the difference between the ranging range and the ranging error of the single-wavelength interferometry optical ranging system 2, then it will be impossible to uniquely determine which level of interference fringes the single-wavelength interferometry optical ranging system 2 is in (that is, it is impossible to uniquely determine what N is equal to), and there is no way to achieve the purpose of high precision. Therefore, the ranging error of the single-frequency phase method optical ranging system 1 is less than the difference between the ranging range and the ranging error of the single-wavelength interferometry optical ranging system 2 (that is, η×λ M,1 <λ1 / 2-γ×λ1), which is one of the necessary conditions for the first combined optical distance measuring device to have the advantages of large range and high precision (in this embodiment, the wavelength of the single-wavelength interferometry method is generally in the micron order, so the measurement accuracy of the single-frequency phase method should also reach the micron order. The modulated wave is preferably loaded with a modulation frequency of several tens of GHz so that its modulated wavelength reaches the mm order, and the demodulation accuracy η of the single-frequency phase method is preferably also able to reach or even better than one ten-thousandth of an accuracy, so as to meet the condition η×λ M,1<λ1 / 2-γ×λ1). In addition, the ranging accuracy of the single-frequency phase method optical ranging system 1 is lower than that of the single-wavelength interferometry optical ranging system 2, which is also one of the necessary conditions for the first combined optical ranging device to have the advantages of a large range and high precision. Otherwise, the combination is meaningless (that is, the single-frequency phase method optical ranging system 1 can be used directly for measurement without using the single-wavelength interferometry optical ranging system 2).

[0070] like Figure 1 As shown, the working method of the first combined optical distance measuring device includes but is not limited to the following steps S1 to S2.

[0071] S1. Obtain at least two ranging values corresponding one-to-one to the at least two optical ranging systems through the at least two optical ranging systems.

[0072] In the step S1, specifically, the first distance value can be measured by the single-frequency phase method optical ranging system 1, and the second distance value can be measured by the single-wavelength interference method optical ranging system 2. The measurement process of the above two systems can be implemented by existing conventional technical means, such as Figure 2 As shown, the light with wavelength λ1 returns to the fiber coupler 1 of the interferometer and interferes with the light returning through the reference arm. By measuring this interference signal, a very high-precision measurement result (i.e., the second distance measurement value) can be obtained, but the measurement range is limited; while the modulation wavelength is λ M,1 The light will return to the phase method measurement part (i.e., the part composed of the optical fiber coupler 2, the phase method detector 1 and the phase method detector 2), and through phase resolution, the distance result (i.e., the first ranging value) is obtained. The accuracy of this measurement result is not high, but the ranging range is large.

[0073] S2. Determine a final ranging value according to the at least two ranging values according to the following steps S21 to S24.

[0074] S21. Initialize the variable k to 1, and then execute step S22.

[0075] S22. Update the ranging value of the k+1th optical ranging system according to the ranging accuracy and ranging value of the kth optical ranging system in the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system in the at least two optical ranging systems, and then execute step S23.

[0076] In step S22, since the at least two optical ranging systems of this embodiment only include the single-frequency phase method optical ranging system 1 and the single-wavelength interference method optical ranging system 2, the k-th optical ranging system is the single-frequency phase method optical ranging system 1, and the k+1-th optical ranging system is the single-wavelength interference method optical ranging system 2 (which is a single-frequency optical ranging system), so that the ranging value of the k+1-th optical ranging system can be updated according to the ranging accuracy and ranging value of the k-th optical ranging system in the at least two optical ranging systems and the ranging range and ranging value of the k+1-th optical ranging system in the at least two optical ranging systems, according to the following steps S2211 to S2212.

[0077] S2211. According to the ranging accuracy ±μ of the kth optical ranging system in the at least two optical ranging systems. k and the distance value d k , determine the range of distance measurement value [d k -μ k ,d k +μ k ].

[0078] S2212. According to the ranging range l of the k+1th optical ranging system in the at least two optical ranging systems. 0,k+1 and the distance value d k+1 , update the distance value of the k+1th optical ranging system to belong to the distance value range [d k -μ k ,d k +μ k ] an optional distance value D k+1 =n×l 0,k+1 +d k+1 , where n represents a natural number.

[0079] In the above steps S2211 to S2212, for example, assuming that the ranging accuracy of the single-frequency phase method optical ranging system 1 is ±0.4 μm and the ranging value is 10.5 μm, then the ranging value range can be determined to be [10.1, 10.9] μm, and further assuming that the ranging range of the single-wavelength interferometry optical ranging system 2 is 1.00 μm and the ranging accuracy is ±0.01 μm, if the ranging value of the single-wavelength interferometry optical ranging system 2 is 0.15 μm, then there are multiple optional distance values as follows: 0.15 μm ± 0.01 μm, 1.1 5μm±0.01μm, 2.15μm±0.01μm, 3.15μm±0.01μm, 4.15μm±0.01μm, 5.15μm±0.01μm, 6.15μm±0.01μm, 7.15μm±0.01μm, 8.15μm±0.01μm, 9.15μm±0.01μm, 10.15μm±0.01μm and 11.15μm±0.01μm, etc. Since only 10.15μm±0.01μm belongs to [10.1,10.9]μm, the above The distance measurement value of the single-wavelength interferometry optical ranging system 2 is updated to 10.15μm±0.01μm (±0.01μm represents the distance measurement accuracy at this time); for another example, assuming that the distance measurement accuracy of the single-frequency phase method optical ranging system 1 is ±0.4μm and the distance measurement value is 10.2μm, then the distance measurement value range can be determined to be [9.8,10.6]μm, and assuming that the distance measurement range of the single-wavelength interferometry optical ranging system 2 is 1.00μm and the distance measurement accuracy is ±0.01μm, if the distance measurement value of the single-wavelength interferometry optical ranging system 2 is 0.85 μm, there are multiple optional distance values as follows: 6.85μm±0.01μm, 7.85μm±0.01μm, 8.85μm±0.01μm, 9.85μm±0.01μm, 10.85μm±0.01μm and 11.85μm±0.01μm, etc. Since only 9.85μm±0.01μm belongs to [9.8,10.6]μm, the ranging value of the single-wavelength interferometry optical ranging system 2 can be updated to 9.85μm±0.01μm (±0.01μm represents the ranging accuracy at this time).

[0080] S23. Determine whether k+1 is equal to the total number of the at least two optical ranging systems. If so, execute step S24; otherwise, increment k by 1, and then return to execute step S22.

[0081] In step S23, since the at least two optical ranging systems of this embodiment only include the single-frequency phase method optical ranging system 1 and the single-wavelength interference method optical ranging system 2, step S24 will be directly executed without executing step S22 again.

[0082] S24. Taking the current distance measurement value of the k+1th optical distance measurement system as the final distance measurement value.

[0083] In step S24, this embodiment uses the updated result of the second ranging value as the final ranging value.

[0084] Based on the specific structure and working method of the aforementioned first combined optical ranging device, the single-frequency phase method optical ranging system 1 and the single-wavelength interference method optical ranging system 2 can be combined together, so that the entire first combined optical ranging device has both the large range characteristics of the single-frequency phase method optical ranging system 1 and the high precision characteristics of the single-wavelength interference method optical ranging system 2, thereby achieving the purpose of large range and high precision. Moreover, because it is based on the combination of existing optical ranging systems, it can also have the characteristics of low cost, which is convenient for practical application and promotion. In addition, Figure 2 The positions of components such as the wavelength division multiplexer WDM and the second optical fiber coupler CP2 are not limited to the positions in the figure, and can also be arranged in other forms as long as the purpose of combining the two optical ranging systems can be achieved.

[0085] In summary, the first combined optical distance measuring device and its working method provided by this embodiment have the following technical effects:

[0086] (1) This embodiment provides a combined optical ranging solution based on a single-frequency phase method optical ranging system and a single-wavelength interferometry optical ranging system, that is, it includes at least two optical ranging systems arranged in descending order of ranging range: a single-frequency phase method optical ranging system and a single-wavelength interferometry optical ranging system, wherein the ranging optical paths of the single-frequency phase method optical ranging system and the single-wavelength interferometry optical ranging system overlap, and by limiting the relationship between the two ranging systems in terms of properties such as ranging accuracy and ranging error, as well as limiting the working methods, the obtained combined optical ranging solution can have both the large range characteristics of the single-frequency phase method optical ranging system and the high precision characteristics of the single-wavelength interferometry optical ranging system, thereby achieving the purpose of large range and high precision, and because it is based on the combination of existing optical ranging systems, it can also have the characteristics of low cost, which is convenient for practical application and promotion.

[0087] Example 2

[0088] like Figure 3As shown, this embodiment further provides the second combined optical ranging device based on the technical solution of the first embodiment, which is different from the first embodiment in that: the single-wavelength interferometry optical ranging system 2 is replaced by a dual-wavelength interferometry optical ranging system 3, wherein the ranging range of the dual-wavelength interferometry optical ranging system 3 is generally (λ′1×λ′2) / (2×(λ′1-λ′2)) (which is existing common knowledge, the dual-wavelength interferometry optical ranging system 3 uses two lights with wavelengths of λ′1 and λ′2 for distance measurement), and also has the said periodic usability; the ranging accuracy of the dual-wavelength interferometry optical ranging system 3 is generally ±γ′×((λ′1+λ′2) / 4) (which is existing common knowledge, γ′ represents the internal The phase demodulation accuracy is generally one thousandth, or has higher accuracy); the ranging error of the dual-wavelength interferometry optical ranging system 3 is generally γ′×((λ′1+λ′2) / 2) (that is, equal to twice the absolute value of the ranging accuracy ±γ′×((λ′1+λ′2) / 4)); and in the step S22, since the k+1th optical ranging system is the dual-wavelength interferometry optical ranging system 3 (which is a dual-frequency optical ranging system), the ranging value of the k+1th optical ranging system can be updated according to the ranging accuracy and ranging value of the kth optical ranging system in the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system in the at least two optical ranging systems, according to the following steps S2221 to S2226.

[0089] S2221. According to the ranging accuracy ±μ of the kth optical ranging system in the at least two optical ranging systems. k and the distance value d k , determine the range of distance measurement value [d k -μ k ,d k +μ k ].

[0090] In the step S2221, for example, assuming that the ranging accuracy of the single-frequency phase method optical ranging system 1 is ±2.5 μm and the ranging value is 10.0 μm, the ranging value range can be determined to be [7.5, 12.5] μm.

[0091] S2222. According to the first single-frequency optical ranging subsystem in the dual-frequency optical ranging system ranging range l 1,0,k+1 and the distance value d 1,k+1 , determine the range of the distance value [d k -μ k ,d k +μ k ] the first optional distance value D1,k+1 =n1×l 1,0,k+1 +d 1,k+1 , where n1 represents a natural number.

[0092] In the step S2222, for example, it is also assumed that the ranging range of the first single-frequency optical ranging subsystem in the dual-wavelength interferometry optical ranging system 3 is 1.00 μm and the ranging accuracy is 0.03 μm. If the ranging value of the first single-frequency optical ranging subsystem is 0.28 μm, it can be determined that the following first optional distance values belong to [7.5, 12.5] μm: 8.28 μm, 9.28 μm, 10.28 μm, 11.28 μm and 12.28 μm.

[0093] S2223. According to the second single-frequency optical ranging subsystem in the dual-frequency optical ranging system ranging range l 2,0,k+1 and the distance value d 2,k+1 , determine the range of the distance value [d k -μ k ,d k +μ k ] second optional distance value D 2,k+1 =n2×l 2,0,k+1 +d 2,k+1 , where n2 represents a natural number.

[0094] In the step S2223, for example, it is also assumed that the ranging range of the second single-frequency optical ranging subsystem in the dual-wavelength interferometry optical ranging system 3 is 0.84 μm and the ranging accuracy is 0.03 μm. If the ranging value of the second single-frequency optical ranging subsystem is 0.37 μm, it can be determined that there are the following second optional distance values belonging to [7.5, 12.5] μm: 7.93 μm, 8.77 μm, 9.61 μm, 10.45 μm, 11.29 μm and 12.13 μm.

[0095] S2224. Based on all the first optional distance values and all the second optional distance values, calculate the absolute difference of each pair of distance values according to the following formula:

[0096] ΔD i,j =|D 1,i,k+1 -D 2,j,k+1 |

[0097] Wherein, i is an integer and 1≤i≤I, I represents the total number of distance values of all the first optional distance values, j represents an integer and 1≤j≤J, J represents the total number of distance values of all the second optional distance values, D 1,i,k+1 Indicates the i-th distance value among all the first optional distance values, D 2,j,k+1represents the jth distance value among all the second optional distance values, ΔD i,j represents the absolute difference between the i-th distance value and the j-th distance value.

[0098] In the step S2224, for example, based on all the first optional distance values (i.e., 8.28μm, 9.28μm, 10.28μm, 11.28μm and 12.28μm) and all the second optional distance values (7.93μm, 8.77μm, 9.61μm, 10.45μm, 11.29μm and 12.13μm), the following absolute differences can be determined: |8.28-7.93|μm, |8.28-8.77|μm, ..., |8.28-12.13|μm, |9.28-7.93|μm, ..., |10.28-11.29|μm, ..., |12.28-11.29|μm and |12.28-12.13|μm, totaling 5×6=30 absolute differences.

[0099] S2225. Determine a pair of distance values having the smallest absolute difference from the absolute differences of the pairs of distance values.

[0100] In step S2225, for example, among the above 30 absolute differences, the minimum absolute difference is |11.28-11.29|μm=0.01μm, and a pair of distance values with this minimum absolute difference is 11.28μm and 11.29μm. Since the minimum absolute difference |11.28-11.29|μm=0.01μm<0.03μm (theoretically, the minimum absolute difference must be within the accuracy range of the ranging system. In actual measurement, if it is not within the accuracy range, it may be that the system error exceeds the tolerance, indicating that the ranging system is unreliable and the product is unqualified. If the system is not wrong, this minimum absolute value must be within the accuracy range of the k+1th optical ranging system), therefore, this pair of distance values is the true distance.

[0101] S2226. Update the distance value of the k+1th optical distance measurement system to the average distance value of the pair of distance values, any distance value in the pair of distance values, any distance value between the pair of distance values, or any distance value within the range With range Any distance value within the intersection range of , where represents the first optional distance value in the pair of distance values and corresponding to the first single-frequency optical ranging subsystem, ±μ 1,k+1 represents the ranging accuracy of the first single-frequency optical ranging subsystem, represents the second optional distance value in the pair of distance values and corresponding to the second single-frequency optical ranging subsystem, ±μ2,k+1 Represents the ranging accuracy of the second single-frequency optical ranging subsystem.

[0102] In step S2226, for example, if a pair of distance values with the minimum absolute difference is 11.28 μm and 11.29 μm, the ranging value of the dual-wavelength interferometry optical ranging system 3 can be updated to 11.285 μm, 11.28 μm, 11.29 μm, 11.287 μm or any distance value within the intersection range [11.26, 11.31] μm of the range 11.28±0.03 μm and the range 11.29±0.03 μm.

[0103] exist Figure 3 In the embodiment, the single-frequency phase optical ranging system 1 also serves as the optical ranging system in the front order, and the dual-wavelength interference optical ranging system 3 serves as the optical ranging system in the back order. Similarly, as long as the two ranging systems meet the following conditions: the optical ranging system in the front order and the optical ranging system in the back order adopt different ranging principles, the ranging accuracy of the optical ranging system in the front order is lower than the ranging accuracy of the optical ranging system in the back order, the ranging error of the optical ranging system in the front order is less than the difference between the ranging range and the ranging error of the optical ranging system in the back order, and the ranging range of the optical ranging system in the back order has periodic usability, then the working method described in the first embodiment can be combined to make the entire second combined optical ranging device have both the large range characteristics of the single-frequency phase optical ranging system 1 and the high precision characteristics of the dual-wavelength interference optical ranging system 3, thereby achieving the purpose of large range and high precision. In addition, the dual-wavelength interferometry optical ranging system 3 can also be extended to a multi-frequency optical ranging system (for example, a multi-frequency phase method optical ranging system or a multi-wavelength interferometry optical ranging system, etc.). At this time, the ranging value of the k+1th optical ranging system can be updated according to the ranging accuracy and ranging value of the kth optical ranging system in the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system in the at least two optical ranging systems, according to the following steps S2231 to S2235.

[0104] S2231. According to the ranging accuracy ±μ of the kth optical ranging system in the at least two optical ranging systems. k and the distance value d k , determine the range of distance value (d k -μ k ,d k +μ k ).

[0105] S2232. For each single-frequency optical ranging subsystem in the multi-frequency optical ranging system, according to the corresponding ranging range and ranging value, determine the corresponding and belonging to the ranging value range according to the following formula [d k -μ k ,d k +μ k ] Optional distance values:

[0106] D m,k+1 =n m ×l m,0,k+1 +d m,k+1

[0107] Wherein, m is a positive number and 1≤m≤M, M represents the total number of single-frequency optical ranging subsystems in the multi-frequency optical ranging system, l m,0,k+1 represents the ranging range of the mth single-frequency optical ranging subsystem in the multi-frequency optical ranging system, d m,k+1 represents the distance measurement value of the mth single-frequency optical ranging subsystem, n m represents the natural number corresponding to the mth single-frequency optical ranging subsystem, D m,k+1 represents the mth single-frequency optical ranging subsystem and belongs to the ranging value range [d k -μ k ,d k +μ k ] is an optional distance value.

[0108] The specific details of the above steps S2231 to S2232 can be obtained by referring to the conventional derivation of the above steps S2221 to S2223, and will not be repeated here.

[0109] S2233. Based on the distance value sets of each single-frequency optical ranging subsystem, the absolute difference amplitude of each set of distance values is calculated according to the following formula:

[0110] ΔD S =D S,max -D S,min

[0111] Where S represents any set of distance values in the above distance values and has i m is an integer with 1≤i m ≤I m , I m represents the mth single-frequency optical ranging subsystem and belongs to the ranging value range [d k -μ k ,d k +μ k ], the total number of distance values of all said optional distance values, Indicates that the m-th single-frequency optical ranging subsystem and belongs to the ranging value range [d k -μ k ,d k +μ k ] among all the optional distance values m distance value, D S,max Indicates the maximum distance value in any set of distance values, D S,min Indicates the minimum distance value in any set of distance values, ΔD S Represents the absolute difference magnitude of any set of distance values.

[0112] In step S2233 , for example, if a set of distance values is 11.27 μm, 11.28 μm, and 11.29 μm, then the absolute difference amplitude of the set of distance values can be calculated to be 11.29 μm-11.27 μm=0.02 μm.

[0113] S2234. Determine a group of distance values having the smallest absolute difference amplitude from the absolute difference amplitudes of the distance values of each group.

[0114] S2235. Update the distance value of the k+1th optical distance measurement system to the average distance value of the certain group of distance values, the median distance value of the certain group of distance values, any distance value in the certain group of distance values, or any distance value in the range and Any distance value within the intersection range of , where represents an optional distance value in the set of distance values and corresponding to the mth single-frequency optical ranging subsystem, ±μ m,k+1 represents the ranging accuracy of the m-th single-frequency optical ranging subsystem.

[0115] The technical details and technical effects of this embodiment can be derived with reference to the aforementioned embodiment 1 and will not be described in detail here.

[0116] Example 3

[0117] like Figure 4 As shown, this embodiment further provides the third combined optical ranging device based on the technical solution of the second embodiment. The difference between this embodiment and the second embodiment is that the single-frequency phase method optical ranging system 1 is replaced by a dual-frequency phase method optical ranging system 4, wherein the ranging range of the dual-frequency phase method optical ranging system 4 is generally (λ′ M,1 ×λ′ M,2 ) / (2×(λ′ M,1 -λ′ M,2 )) It is common knowledge that the dual-frequency phase optical ranging system 4 uses modulation wavelengths of λ′M,1 and λ′ M,2 The dual-frequency phase method optical ranging system 4 generally has a ranging accuracy of ±η′×((λ′ M,1 +λ′ M,2 ) / 4)(It is common knowledge, η′ represents the internal phase discrimination accuracy of the dual-frequency phase method optical ranging system 4, which is generally one thousandth, or has a higher accuracy); the ranging error of the dual-frequency phase method optical ranging system 4 is generally η′×((λ′ M，1 +λ′ M，2 ) / 2)(that is, equal to the ranging accuracy ±η′×((λ′ M,1 +λ′ M,2 ) / 4) twice the absolute value).

[0118] exist Figure 4 In the embodiment, the dual-frequency phase optical ranging system 4 serves as the optical ranging system in the front order, and the dual-wavelength interference optical ranging system 3 serves as the optical ranging system in the back order. Similarly, as long as the two ranging systems meet the following conditions: the optical ranging system in the front order and the optical ranging system in the back order adopt different ranging principles, the ranging accuracy of the optical ranging system in the front order is lower than the ranging accuracy of the optical ranging system in the back order, the ranging error of the optical ranging system in the front order is less than the difference between the ranging range and the ranging error of the optical ranging system in the back order, and the ranging range of the optical ranging system in the back order has periodic usability, then the working method described in the first embodiment can be combined to make the entire third combined optical ranging device have both the large range characteristics of the dual-frequency phase optical ranging system 4 and the high precision characteristics of the dual-wavelength interference optical ranging system 3, thereby achieving the purpose of large range and high precision. In addition, the dual-frequency phase-based optical ranging system 4 may also be extended to a multi-frequency optical ranging system (eg, a multi-frequency phase-based optical ranging system or a multi-wavelength interferometry optical ranging system, etc.).

[0119] The technical details and technical effects of this embodiment can be derived with reference to the aforementioned embodiment 1 and will not be described in detail here.

[0120] Example 4

[0121] like Figure 5As shown, this embodiment further provides the fourth combined optical ranging device based on the technical solution of the second embodiment. This device differs from the second embodiment in that a pulse optical ranging system 6 (which uses light with a wavelength of λ0) is added. The ranging range of the pulse optical ranging system 6 is greater than the ranging range of the single-frequency phase optical ranging system 1, and the ranging accuracy of the pulse optical ranging system 6 is lower than the ranging accuracy of the single-frequency phase optical ranging system 1. In this way, at least two optical ranging systems are obtained, arranged in descending order of ranging range: the pulse optical ranging system 6, the single-frequency phase optical ranging system 1, and the dual-wavelength interferometry optical ranging system 3. The ranging optical paths of these three ranging systems are also overlapped by, for example, a wavelength division multiplexer serving as the light combining and splitting device. In addition, the ranging range of the pulse optical ranging system 6 is theoretically infinite; the ranging accuracy of the pulse optical ranging system 6 is generally ±ΔT×(c / 2) (which is common knowledge, ΔT represents the internal time difference measurement accuracy of the pulse optical ranging system 6, and c represents the speed of light); the ranging error of the pulse optical ranging system 6 is generally ΔT×c (that is, equal to twice the absolute value of the ranging accuracy ±ΔT×(c / 2)).

[0122] exist Figure 6In the embodiment, the pulse method optical ranging system 6 and the single-frequency phase method optical ranging system 1 serve as the first pair of the optical ranging system in front and the optical ranging system in the back that are adjacently arranged in the at least two optical ranging systems (i.e., the pulse method optical ranging system 6 serves as the optical ranging system in front, and the single-frequency phase method optical ranging system 1 serves as the optical ranging system in the back); the single-frequency phase method optical ranging system 1 and the dual-wavelength interferometry optical ranging system 3 serve as the second pair of the optical ranging system in front and the optical ranging system in the back that are adjacently arranged in the at least two optical ranging systems (i.e., the single-frequency phase method optical ranging system 1 serves as the optical ranging system in front, and the dual-wavelength interferometry optical ranging system 3 serves as the optical ranging system in the back). Similarly, as long as these two pairs of the optical ranging system in front and The optical ranging systems ordered last satisfy the following conditions: the optical ranging system ordered first and the optical ranging system ordered last are two optical ranging systems using different ranging principles; the ranging accuracy of the optical ranging system ordered first is lower than the ranging accuracy of the optical ranging system ordered last; the ranging error of the optical ranging system ordered first is less than the difference between the ranging range and the ranging error of the optical ranging system ordered last; the ranging range of the optical ranging system ordered last has cyclical usability, which can be combined with the working methods described in Example 1 and Example 2 (at this time, the variable k will be incremented once, and step S22 will be executed twice), so that the entire fourth combined optical ranging device has both the large range characteristics of the pulse method optical ranging system 6 (theoretically infinite) and the high precision characteristics of the dual-wavelength interference method optical ranging system 3, thereby achieving the purpose of large range and high precision. Since the ranging range of the pulse optical ranging system 6 does not have the periodic usability, it is not suitable as the optical ranging system that is sorted later, and the pulse optical ranging system 6 can also be replaced by other ranging systems that do not have the periodic usability, such as the triangulation optical ranging system, the FMCW (Frequency Modulated Continuous Wave) optical ranging system or the 3D vision ranging system (these ranging systems do not have periodic repeatability and can only be used as the first level). In addition, considering that light waves are essentially electromagnetic waves, the pulse optical ranging system 6 can also be replaced by a system that uses electromagnetic waves for ranging, such as the currently popular microwave ranging system, the millimeter wave ranging system, or a system that uses a mixture of electromagnetic waves and light waves for ranging, and the single-frequency phase method optical ranging system 1 and the dual-wavelength interference method optical ranging system 3 can also be replaced by systems that have the periodic usability and use electromagnetic waves for ranging.

[0123] The technical details and technical effects of this embodiment can be derived with reference to the aforementioned embodiments 1 and 2, and will not be described in detail here.

[0124] Example 5

[0125] like Figure 6 As shown, this embodiment further provides the fifth combined optical ranging device based on the technical solution of the fourth embodiment. The difference between this fifth combined optical ranging device and the fourth embodiment is that the detectors of the pulse optical ranging system or the phase optical ranging system in the at least two optical ranging systems are spatial devices rather than optical fiber devices (that is, in the aforementioned embodiments one to four, the detectors of the pulse optical ranging system and the phase optical ranging system are both optical fiber devices). Specifically, Figure 6 In the figure, A represents a dichroic mirror 3, which is used to modulate the wavelength λ M,1 The dichroic mirror 5 is used to semi-transmit and semi-reflect light with a wavelength of λ0 and allow all other light to pass through. (The starting point of the distance measurement is now the location of the dichroic mirror 5.) Furthermore, the dispersion of the collimator should also be considered. This is especially true when measuring long distances. This dispersion will prevent light of different wavelengths from being fully collimated, causing the beam to diverge and introduce errors. Therefore, the collimator must be achromatic.

[0126] In addition, the installation method of the space type device is not unique, and can also be different from Figure 6 other forms of .

[0127] The technical details and technical effects of this embodiment can be derived with reference to the aforementioned fourth embodiment and will not be described in detail here.

[0128] Example 6

[0129] like Figure 7As shown, this embodiment further provides the sixth combined optical ranging device based on the technical solution of the fourth embodiment. The difference between the sixth combined optical ranging device and the fourth embodiment is that the at least two optical ranging systems use a spatial optical path method rather than an optical fiber method to achieve the overlap of the ranging optical paths (i.e., in the aforementioned embodiments one to four, the at least two optical ranging systems use an optical fiber method to achieve the overlap of the ranging optical paths). Specifically, although the optical fiber method can make the light of various different ranging systems accurately overlap and travel through the same optical path (i.e., considering combining various different optical ranging systems together, to ensure that the ranging optical paths of the various different ranging systems are the same, optical fiber devices can make this combination easier, because ordinary single-mode optical fibers have only one mode, which ensures that each different light travels through the same path and is the same mode), it is also possible to not use the optical fiber method, for example, use a spatial optical path method to combine several types of light together (this requires a good optical path design) to ensure that each light beam accurately overlaps. Figure 7 This is a partial schematic diagram of the phase method and pulse method using a spatial optical path combined with the interferometer's measuring arm. Specifically, Figure 7 In the figure, A represents a dichroic mirror 3, which is used to reflect the modulated wavelength λ M,1 , and allows other light to pass through completely; B represents a semi-transparent and semi-reflective mirror; C represents a dichroic mirror 5, which is used to reflect light with a wavelength of λ0 and allow other light to pass through completely (in this case, the starting point of the ranging is changed to the position of the dichroic mirror 5); D represents another semi-transparent and semi-reflective mirror. Figure 7 The method of combining the spatial optical path with the measuring arm of the interferometer is not unique, and other similar optical paths can also be used.

[0130] The technical details and technical effects of this embodiment can be derived with reference to the aforementioned fourth embodiment and will not be described in detail here.

[0131] Example 7

[0132] This embodiment, based on the technical solutions of any of Examples 1 through 6, further provides a laser radar, comprising a spatial scanning device and the combined optical ranging device described in any of Examples 1 through 6, wherein the spatial scanning device is installed at the front end of the spatial optical path of the combined optical ranging device. The spatial scanning device is implemented using existing structures and can be installed at the front end of the spatial optical path of the combined optical ranging device using existing installation methods. This allows the laser radar to achieve extremely high accuracy over a wide range when measuring distances in different directions, leveraging the wide range and high precision of the combined optical ranging device.

[0133] Preferably, the laser radar can also be used in combination with the 3D visual ranging method, that is, when the ranging range of the laser radar also has the periodic usability (for example, the first optical ranging system among the at least two optical ranging systems is a phase method optical ranging system rather than a pulse method optical ranging system), the method of using the laser radar includes but is not limited to the following steps S100 to S300.

[0134] S100. Use a 3D visual ranging method to measure and obtain a first distance value from a starting point to each point in a target area, wherein a ranging range of the 3D visual ranging method is greater than a ranging range of the laser radar, a ranging accuracy of the 3D visual ranging method is lower than a ranging accuracy of the laser radar, and a ranging error of the 3D visual ranging method is less than a difference between a ranging range and a ranging error of the laser radar (specifically, the first optical ranging system among the at least two optical ranging systems).

[0135] In step S100, the 3D visual ranging method uses two or more cameras installed at different positions to perform large-scale imaging of the target area to be measured, and uses the difference in imaging of each point in the measurement area by cameras at different positions to calculate the distance of each point; the advantage of this ranging method is that it can image a large area at the same time, but the accuracy is not high. Therefore, the 3D visual ranging method can be combined with the laser radar ranging method to achieve new technical effects.

[0136] S200. Use the laser radar to measure and obtain a second distance value from the starting point to each of the points.

[0137] S300. For each of the points, update the final distance value from the starting point to the corresponding point based on the ranging accuracy of the 3D visual ranging method and the first distance value from the starting point to the corresponding point, as well as the ranging range of the laser radar and the second distance value from the starting point to the corresponding point.

[0138] In step S300, the 3D visual ranging method is similar to the optical ranging system in the first to sixth embodiments, and the ranging method of the laser radar is similar to the optical ranging system in the last order in the first to sixth embodiments. Therefore, the specific update details can be obtained by referring to the conventional derivation of the aforementioned embodiments one to six, and will not be repeated here.

[0139] Therefore, based on the above steps S100 to S300, the laser radar and the 3D visual ranging method can be used in combination, which can not only have the characteristics of large-scale measurement of 3D imaging, but also can achieve extremely high accuracy in distance measurement of each point.

[0140] The technical effects of this embodiment, in addition to the technical effects of the aforementioned embodiments one to six, also include: (1) based on the large-range and high-precision characteristics of the combined optical ranging device, the laser radar can achieve extremely high precision within a large range when measuring distances in different directions; (2) it can also be combined with the 3D visual ranging method to have the characteristics of large-range measurement of 3D imaging and achieve extremely high precision in distance measurement of each point.

[0141] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A combined optical distance measuring device, characterized in that: The invention comprises at least two optical ranging systems arranged in descending order of ranging range, wherein the ranging optical paths of the at least two optical ranging systems overlap, the ranging optical path being the optical path from the ranging starting point to the measured object, and the optical ranging system comprising a system using light waves or electromagnetic waves for ranging; Any pair of adjacently ordered optical ranging systems, the preceding optical ranging system and the following optical ranging system, in the at least two optical ranging systems, meets the following conditions: the preceding optical ranging system and the following optical ranging system are two optical ranging systems using different ranging principles; the ranging accuracy of the preceding optical ranging system is lower than the ranging accuracy of the following optical ranging system; the ranging error of the preceding optical ranging system is smaller than the difference between the ranging range and the ranging error of the following optical ranging system; the ranging range of the following optical ranging system has periodic usability, wherein the ranging error is equal to twice the absolute value of the ranging accuracy; the periodic usability means that the ranging range l0, the true distance L, and the ranging value d satisfy L=N×l0+d, where N is a natural number and represents an unknown number of ranging ranges in use; The working method of the combined optical distance measuring device includes: At least two ranging values corresponding to the at least two optical ranging systems are obtained by measuring the at least two optical ranging systems; According to the at least two ranging values, a final ranging value is determined according to the following steps S21 to S24: S21. Initialize the variable k to 1, and then execute step S22; S22. Based on the ranging accuracy and ranging value of the kth optical ranging system in the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system in the at least two optical ranging systems, updating the ranging value of the k+1th optical ranging system, and then executing step S23; S23 determines whether k+1 is equal to the total number of the at least two optical ranging systems. If so, proceed to step S24. Otherwise, k is incremented by 1, and then the process returns to step S22. S24. Taking the current distance measurement value of the k+1th optical distance measurement system as the final distance measurement value.

2. The combined optical distance measuring device according to claim 1, wherein: When the k+1th optical ranging system among the at least two optical ranging systems is a single-frequency optical ranging system, updating the ranging value of the k+1th optical ranging system according to the ranging accuracy and ranging value of the kth optical ranging system among the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system among the at least two optical ranging systems comprises: According to the distance measurement accuracy ±μ of the kth optical distance measurement system among the at least two optical distance measurement systems k and the distance value d k , determine the range of distance measurement value [d k -μ k ,d k +μ k ]; According to the distance measuring range l of the k+1th optical distance measuring system among the at least two optical distance measuring systems 0,k+1 and the distance value d k+1 , update the distance value of the k+1th optical ranging system to belong to the distance value range [d k -μ k ,d k +μ k ] an optional distance value D k+1 =n×l 0,k+1 +d k+1 , where n represents a natural number.

3. The combined optical distance measuring device according to claim 1, wherein: When the k+1th optical ranging system among the at least two optical ranging systems is a dual-frequency optical ranging system, updating the ranging value of the k+1th optical ranging system according to the ranging accuracy and ranging value of the kth optical ranging system among the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system among the at least two optical ranging systems comprises: According to the distance measurement accuracy ±μ of the kth optical distance measurement system among the at least two optical distance measurement systems k and the distance value d k , determine the range of the distance value [d k -μ k ,d k +μ k ]; According to the ranging range l of the first single-frequency optical ranging subsystem in the dual-frequency optical ranging system 1,0,k+1 and the distance value d 1,k+1 , determine the range of the distance value [d k -μ k ,d k +μ k ] the first optional distance value D 1,k+1 =n1×l 1,0,k+1 +d 1,k+1 , where n1 represents a natural number; According to the distance measurement range l of the second single-frequency optical distance measurement subsystem in the dual-frequency optical distance measurement system 2,0,k+1 and the distance value d 2,k+1 , determine the range of the distance value [d k -μ k ,d k +μ k ] second optional distance value D 2,k+1 =n2×l 2,0,k+1 +d 2,k+1 , where n2 represents a natural number; Based on all the first optional distance values and all the second optional distance values, the absolute difference of each pair of distance values is calculated according to the following formula: ΔD i,j =|D 1,i,k+1 -D 2,j,k+1 | Wherein, i is an integer and 1≤i≤I, I represents the total number of distance values of all the first optional distance values, j represents an integer and 1≤j≤J, J represents the total number of distance values of all the second optional distance values, D 1,i,k+1 Indicates the i-th distance value among all the first optional distance values, D 2,j,k+1 represents the jth distance value among all the second optional distance values, ΔD i,j represents the absolute difference between the i-th distance value and the j-th distance value; Determine a pair of distance values with the smallest absolute difference from the absolute differences of the pairs of distance values; Update the distance value of the k+1th optical distance measurement system to the average distance value of the pair of distance values, any distance value in the pair of distance values, any distance value between the pair of distance values, or any distance value within the range With range Any distance value within the intersection range of , where represents the first optional distance value in the pair of distance values and corresponding to the first single-frequency optical ranging subsystem, ±μ 1,k+1 represents the ranging accuracy of the first single-frequency optical ranging subsystem, represents the second optional distance value in the pair of distance values and corresponding to the second single-frequency optical ranging subsystem, ±μ 2,k+1 Represents the ranging accuracy of the second single-frequency optical ranging subsystem.

4. The combined optical distance measuring device according to claim 1, wherein: When the k+1th optical ranging system among the at least two optical ranging systems is a multi-frequency optical ranging system, updating the ranging value of the k+1th optical ranging system according to the ranging accuracy and ranging value of the kth optical ranging system among the at least two optical ranging systems and the ranging range and ranging value of the k+1th optical ranging system among the at least two optical ranging systems comprises: According to the distance measurement accuracy ±μ of the kth optical distance measurement system among the at least two optical distance measurement systems k and the distance value d k , determine the range of distance measurement value (d k -μ k ,d k +μ k ); For each single-frequency optical ranging subsystem in the multi-frequency optical ranging system, according to the corresponding ranging range and ranging value, the corresponding ranging value that belongs to the ranging value range [d k -μ k ,d k +μ k ] Optional distance values: D m,k+1 =n m ×l m,0,k+1 +d m,k+1 Wherein, m is a positive number and 1≤m≤M, M represents the total number of single-frequency optical ranging subsystems in the multi-frequency optical ranging system, l m,0,k+1 represents the ranging range of the mth single-frequency optical ranging subsystem in the multi-frequency optical ranging system, d m,k+1 represents the distance measurement value of the mth single-frequency optical ranging subsystem, n m represents the natural number corresponding to the mth single-frequency optical ranging subsystem, D m,k+1 represents the mth single-frequency optical ranging subsystem and belongs to the ranging value range [d k -μ k ,d k +μ k ] optional distance value; Based on the distance value sets of each single-frequency optical ranging subsystem, the absolute difference amplitude of each set of distance values is calculated according to the following formula: ΔD S =D S,max -D S,min Where S represents any set of distance values in the above distance values and has i m is an integer with 1≤i m ≤I m , I m represents the mth single-frequency optical ranging subsystem and belongs to the ranging value range [d k -μ k ,d k +μ k ], the total number of distance values of all said optional distance values, Indicates that the m-th single-frequency optical ranging subsystem and belongs to the ranging value range [d k -μ k ,d k +μ k ] among all the optional distance values m distance value, D S,max Indicates the maximum distance value in any set of distance values, D S,min Indicates the minimum distance value in any set of distance values, ΔD S represents the absolute difference magnitude of any set of distance values; Determining a group of distance values having the smallest absolute difference magnitude from the absolute difference magnitudes of the groups of distance values; Update the distance value of the k+1th optical distance measurement system to the average distance value of the certain group of distance values, the median distance value of the certain group of distance values, any distance value in the certain group of distance values, or a distance value within the range and Any distance value within the intersection range of represents an optional distance value in the set of distance values and corresponding to the mth single-frequency optical ranging subsystem, ±μ m,k+1 represents the ranging accuracy of the m-th single-frequency optical ranging subsystem.

5. The combined optical distance measuring device according to claim 1, wherein: The optical ranging system in the preceding order adopts a pulse optical ranging system, a single-frequency phase optical ranging system, a dual-frequency phase optical ranging system, a multi-frequency phase optical ranging system, a single-wavelength interferometry optical ranging system, a dual-wavelength interferometry optical ranging system, a multi-wavelength interferometry optical ranging system, a triangulation optical ranging system, a frequency modulated continuous wave optical ranging system or a 3D vision ranging system; And / or, the optical ranging system in the latter order adopts a single-frequency phase method optical ranging system, a dual-frequency phase method optical ranging system, a multi-frequency phase method optical ranging system, a single-wavelength interferometry optical ranging system, a dual-wavelength interferometry optical ranging system or a multi-wavelength interferometry optical ranging system.

6. The combined optical distance measuring device according to claim 1, wherein: The at least two optical ranging systems achieve the overlap of the ranging optical paths through a light combining and splitting device, wherein the light combining and splitting device is used to combine light of different wavelengths in the forward direction and split light in the retroreflective direction, the forward direction refers to the direction toward the object to be measured, and the retroreflective direction refers to the direction from the object to be measured.

7. The combined optical distance measuring device according to claim 1, wherein: The detectors of the pulse method optical ranging system or the phase method optical ranging system in the at least two optical ranging systems are optical fiber type devices or space type devices.

8. The combined optical distance measuring device according to claim 1, wherein: The at least two optical ranging systems use an optical fiber method or a spatial optical path method to achieve the overlap of the ranging optical paths.

9. A laser radar, characterized in that: The invention comprises a spatial scanning device and a combined optical ranging device as claimed in any one of claims 1 to 8, wherein the spatial scanning device is installed at the front end of the spatial light path in the combined optical ranging device.

10. A method for using the laser radar according to claim 9, characterized in that: When the ranging range of the laser radar also has the periodic usability, the method of use includes the following steps: Using a 3D visual odometry method to measure a first distance value from a starting point to each point in a target area, wherein a ranging range of the 3D visual odometry method is greater than a ranging range of the laser radar, a ranging accuracy of the 3D visual odometry method is lower than a ranging accuracy of the laser radar, and a ranging error of the 3D visual odometry method is less than a difference between the ranging range of the laser radar and the ranging error; Using the laser radar to measure and obtain a second distance value from the starting point to each of the points; For each of the points, the final distance value from the starting point to the corresponding point is updated according to the ranging accuracy of the 3D visual ranging method and the first distance value from the starting point to the corresponding point, as well as the ranging range of the laser radar and the second distance value from the starting point to the corresponding point.

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