CN116087918A

CN116087918A - Ranging method, ranging device, terminal equipment and computer readable storage medium

Info

Publication number: CN116087918A
Application number: CN202211650910.5A
Authority: CN
Inventors: 张可心; 张雪薇; 王泮义
Original assignee: Wuhan Wanji Photoelectric Technology Co Ltd
Current assignee: Wuhan Wanji Photoelectric Technology Co Ltd
Priority date: 2022-12-21
Filing date: 2022-12-21
Publication date: 2023-05-09

Abstract

The application is applicable to the technical field of radars, and provides a ranging method, a ranging device, terminal equipment and a computer readable storage medium, wherein the ranging method comprises the following steps: extracting signal characteristics of an original echo signal; determining a target ranging timing value according to the signal characteristics; and calculating the distance of the target object according to the target distance measurement timing value, extracting signal characteristics capable of representing the autocorrelation degree of the signal intensity in each signal segment, and performing threshold detection by using the signal characteristics to further calculate the target distance measurement timing value for calculating the distance of the target object. The method and the device can increase the detection distance of the laser radar in a low signal-to-noise ratio scene and improve the ranging performance of the laser radar in a long-distance detection scene.

Description

Ranging method, ranging device, terminal equipment and computer readable storage medium

Technical Field

The application belongs to the technical field of radars, and particularly relates to a ranging method, terminal equipment and a computer readable storage medium.

Background

The laser radar is detection equipment for detecting the space environment, and is commonly used for various scenes such as automatic driving, public intelligent transportation, building three-dimensional modeling, topographic mapping and the like due to the advantages of high resolution, high sensitivity, strong anti-interference capability, no influence of dark conditions and the like.

On the premise that the transmitting module and the receiving module are completely consistent, the strength of the echo signal returned by the received target object is weakened along with the increase of the distance between the laser radar and the target object, and the lower the signal-to-noise ratio of the received echo signal is, the poorer the detection performances such as the ranging capability and the ranging precision of the laser radar are.

The detection distance of the lidar is generally increased by increasing the peak power of the emitted laser light or increasing the aperture of the receiving lens. However, increasing the peak power of the emitted laser increases the performance loss of the lidar, increases the burden on the lidar apparatus as a whole, and the laser emitting too high peak power may impair the vision of the operator; increasing the aperture of the receiving lens increases the overall volume and weight of the laser radar, and as the aperture of the receiving lens increases, more interference signals are received, and the signal-to-noise ratio of the received echo signals may be reduced.

Disclosure of Invention

The embodiment of the application provides a ranging method, a ranging device, terminal equipment and a computer readable storage medium, so as to solve the problem that the detection performance of a laser radar is reduced in a long-distance scene.

In a first aspect, an embodiment of the present application provides a ranging method, including:

extracting signal characteristics of an original echo signal; the signal characteristics are the autocorrelation degree of the signal intensity of each signal segment in the original echo signal;

determining a target ranging timing value according to the signal characteristics;

and calculating the distance of the target object according to the target distance measurement timing value.

In an implementation manner of the first aspect, the extracting a signal feature of the original echo signal includes: (1) selecting signal segments based on a sliding window manner; (2) Calculating a signal characteristic value of the selected signal segment based on the short-time average autocorrelation function; (3) And traversing the original echo signal by a sliding window, and outputting a signal characteristic curve of the original echo signal.

In an implementation manner of the first aspect, the determining a target ranging timer value according to the signal characteristic includes: (1) Traversing the signal characteristic curve, and determining the rising edge triggering moment of the signal characteristic curve; (2) And determining the rising edge trigger moment as the target ranging timer value.

In an implementation manner of the first aspect, traversing the signal characteristic curve, determining a rising edge trigger time of the signal characteristic curve includes:

determining a starting position index of the signal characteristic curve according to a first preset threshold, wherein the starting position index is used for threshold detection, and the starting position index is a position index of the signal characteristic curve, the first position index of which is not more than the first preset threshold;

creating a rising edge cache list and a falling edge cache list, wherein the rising edge cache list is used for storing rising edge trigger time, and the falling edge trigger time is used for caching falling edge trigger time;

traversing the signal characteristic curve from the initial position index, if the signal characteristic is larger than the first preset threshold value and the length of the rising edge cache list is equal to that of the falling edge cache list, performing linear interpolation based on the current position index and the position index before the current position index, calculating to obtain a rising edge trigger time, and storing the rising edge trigger time into the rising edge cache list;

if the signal characteristic is smaller than the first preset threshold value and the rising edge cache list length is 1 longer than the falling edge cache list length, linear interpolation is carried out based on the current position index and a position index which is the next position index of the current position index, and a falling edge trigger time is obtained through calculation;

and if the time difference between the falling edge trigger time and the last rising edge trigger time in the rising edge cache list is greater than or equal to a first preset pulse width, storing the falling edge trigger time into the falling edge cache list, otherwise deleting the last rising edge trigger time in the rising edge cache list.

In an implementation manner of the first aspect, the extracting a signal feature of the original echo signal includes:

searching a zero crossing segment of the original echo signal;

screening zero crossing fragments of the original echo signals based on a continuous zero crossing threshold value;

and calculating the signal characteristics of the zero crossing signal fragments obtained by screening.

In an implementation manner of the first aspect, the determining a target ranging timer value according to the signal characteristic includes:

determining rising edge trigger time according to the signal characteristics of the zero crossing signal segment;

and determining the rising edge triggering moment as a target ranging timing value.

In an implementation manner of the first aspect, the determining a rising edge trigger time according to a signal characteristic of the zero crossing signal segment includes:

judging whether the signal characteristics of the zero crossing signal segments are larger than a first preset threshold value or not;

if the signal characteristics of the zero crossing signal segments are larger than a first preset threshold value, linear interpolation is carried out based on the first zero crossing index position of the zero crossing segments and the index position before the first zero crossing index position, and rising edge trigger time is obtained through calculation.

In a second aspect, embodiments of the present application provide a ranging apparatus, comprising:

the characteristic extraction module is used for extracting signal characteristics of the original echo signals; the signal characteristic is the degree of autocorrelation of the signal strength of the signal segment;

a timing value determining module, configured to determine a target ranging timing value according to the signal characteristic;

and the distance calculating module is used for calculating the distance of the target object according to the target distance measurement timing value.

In a third aspect, embodiments of the present application provide a terminal device comprising a processor, a memory and a computer program stored in the memory and executable on the processor, the processor implementing the ranging method according to the first aspect or any of the alternatives of the first aspect when executing the computer program.

In a fourth aspect, embodiments of the present application provide a computer-readable storage medium storing a computer program which, when executed by a processor, implements the ranging method according to the first aspect or any of the alternatives of the first aspect.

In a fifth aspect, embodiments of the present application provide a computer program product for, when run on a terminal device, causing the terminal device to perform the ranging method of the first aspect or any of the alternatives of the first aspect.

Compared with the prior art, the embodiment of the application has the beneficial effects that:

the ranging method, the terminal equipment, the computer readable storage medium and the computer program product provided by the embodiment of the application have the following beneficial effects:

according to the ranging method provided by the embodiment of the application, the signal characteristics capable of representing the correlation degree of the signal intensity inside each signal segment are extracted, the target ranging timing value for calculating the distance between the target object and the target object is determined by utilizing the signal characteristics, the detection distance of the laser radar in a low signal-to-noise ratio scene can be increased, and the ranging performance of the laser radar in a long-distance detection scene can be improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required for the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic illustration of an application scenario of a time-of-flight approach;

fig. 2 is a schematic flowchart of an implementation of a ranging method according to an embodiment of the present application;

fig. 3 is a schematic implementation flow chart of S201 in the ranging method provided in the embodiment of the present application;

FIG. 4 is a schematic diagram of signal eigenvalues of respective signal segments of an original echo signal in an embodiment of the present application;

fig. 5 is a schematic flowchart of an implementation of S202 in the ranging method provided in the embodiment of the present application;

fig. 6 is a schematic flowchart of an implementation of S201 in a ranging method according to another embodiment of the present application;

fig. 7 is a schematic structural diagram of a ranging device according to an embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of a terminal device according to an embodiment of the present application.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

It should be understood that the term "and/or" as used in this specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations. In addition, in the description of the present application and the appended claims, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and are not to be construed as indicating or implying relative importance.

It should also be appreciated that references to "one embodiment" or "some embodiments" or the like described in this specification mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

The laser radar is an automatic remote sensing device which uses a laser as an emission light source and adopts a photoelectric detection technology for detection. The working principle of the laser radar is that the detection laser is emitted to the target object, the target object reflects the detection laser after the detection laser strikes the target object to form an echo signal, the receiving array can receive the echo signal, and the received echo signal is processed to obtain information such as the distance, the size, the speed, the reflectivity and the like of the target object.

The Time of flight (TOF) is a distance measurement method commonly used at present, and the distance between the laser radar and the target object can be obtained by continuously transmitting laser to the target object to detect the target object, receiving an echo signal returned by the target object through a sensor, and multiplying the light velocity by half of the flight round trip Time of the echo signal. Because the time-of-flight ranging method is simple in implementation principle and easy to implement, the time-of-flight ranging method is widely applied to various ranging scenes.

Referring to fig. 1, fig. 1 shows a schematic view of an application scenario of a time-of-flight method. As shown in fig. 1, the automobile 11 is mounted with a laser radar 12, the laser radar 12 emits a detection laser (continuously transmits an optical pulse signal) to a target object 13, the target object 13 reflects an echo after the detection laser strikes the target object 13, a receiving device of the laser radar 12 receives the echo signal reflected by the target object 13, and the distance between the target to be measured and the laser source can be obtained by multiplying half τ/2 of the flight round trip time by the optical speed c by the flight round trip time τ of the detection optical pulse signal.

The signal strength of the received echo signal decreases with the increase of the distance between the laser radar and the target object, and the signal-to-noise ratio of the received echo signal decreases, so that the detection performance such as the ranging capability and the ranging accuracy of the laser radar are affected.

In order to solve the problem that the detection performance of the laser radar is reduced in a long-distance scene, the embodiment of the application provides a ranging method, which is characterized in that signal characteristics capable of representing the correlation degree of the signal intensity inside each signal segment are extracted, the signal characteristics are utilized to determine a target ranging timing value for calculating the distance between the target object and the target ranging timing value, the detection distance of the laser radar in a low signal-to-noise ratio scene can be increased, and the ranging performance of the laser radar in the long-distance detection scene can be improved.

The ranging method provided in the embodiment of the present application will be described in detail below:

referring to fig. 2, fig. 2 is a flow chart of a ranging method according to an embodiment of the present application. The execution main body of the ranging method provided by the embodiment of the application can be a laser radar, a signal processing system inside the laser radar, or a terminal device in communication connection with the laser radar. The terminal equipment can be mobile terminals such as smart phones, tablet computers or wearable equipment, and also can be equipment such as computers, cloud servers and radar auxiliary computers in various application scenes. The following description will be made by taking an execution subject as a laser radar as an example:

as shown in fig. 2, the ranging method provided in the embodiment of the present application may include S201 to S203, which are described in detail as follows:

s201: and extracting signal characteristics of the original echo signals.

In this embodiment of the present application, the signal feature is a degree of correlation of signal intensities of respective signal segments in the original echo signal.

In an embodiment of the present application, a short-time average autocorrelation function may be selected as the signal characteristic of each signal segment in the original echo signal.

It should be noted that, the signal characteristics of each signal segment may also be calculated using other functions capable of representing the degree of correlation of the signal intensities of the signal segments, for example, using an autocorrelation function, a short-time autocorrelation function, a cross-correlation function, and the like, which is not limited in this application.

Referring to fig. 3, fig. 3 is a schematic diagram illustrating an implementation flow of S201 in the ranging method according to an embodiment of the present application. As shown in fig. 3, S201 in the embodiment of the present application may include the following steps:

s301: the signal segments are selected based on a sliding window.

In a specific application, a signal segment is selected by taking the window length as a preset window length threshold value w, and the signal segment is marked as S _t1:t1+w-1 。

It should be noted that, for the sake of convenience in calculation, the preset window length w is selected to be an odd number.

In a specific application, the preset window length threshold w may be set according to a pulse width of a pulse signal emitted by the lidar.

For example, the preset window length threshold w may be set to a pulse width of a transmission pulse signal of the lidar; for another example, if the pulse width of the transmitted pulse signal of the lidar is an even number, the preset window length threshold w is set to be the pulse width of the transmitted pulse signal plus a certain preset length. Specifically, the preset width may be an odd number of lengths such as 1, 3, 5, etc., which is not limited in this application.

S302: and calculating the signal characteristic value of the selected signal segment based on the short-time average autocorrelation function.

In a specific application, the signal segment S is calculated based on a short-time average autocorrelation function _t1:t1+w-1 Signal characteristic value of intermediate position of (2)

The calculation formula is as follows:

wherein R (t) is a signal segment S _t1:t1+w-1 Can be expressed as:

s303: and traversing the original echo signal by the sliding window to obtain the signal characteristic curve corresponding to the original echo signal.

Referring to fig. 4, fig. 4 is a schematic diagram showing signal characteristic values of respective signal segments of an original echo signal in an embodiment of the present application. As shown in FIG. 4, the sliding window sliding progress length can be set to 1, and the signal segment S is obtained _t1:t1+w-1 Signal characteristic value of intermediate position of (2)

Then, the sliding window enters the next moment, and the signal segment S is selected by the sliding window _t2:t2+w-1 The method comprises the steps of carrying out a first treatment on the surface of the Recalculating the signal segment S _t2:t2+w-1 Signal characteristic value of the middle position of +.>

Signal characteristic value +.>

Determined as signal segment S _t2:t2+w-1 Signal characteristic values of (2); repeating the above operation until the original echo signal is traversed. And obtaining signal characteristic values of all the signal segments at the moment, namely obtaining a signal characteristic curve corresponding to the original echo signal.

S202: and determining a target ranging timing value according to the signal characteristics.

In the embodiment of the present application, after determining the signal characteristics of the original echo signal, the target ranging timing value may be determined according to the signal characteristic curve.

In a specific application, when the laser emitted by the laser radar detects a target object, the target object will reflect and return a heavy echo signal, and when the laser emitted by the laser radar detects a plurality of target objects, the original echo signal received by the laser radar will contain multiple echo signals.

Referring to fig. 5, fig. 5 is a schematic flowchart of an implementation of S202 in the ranging method according to an embodiment of the present application.

As shown in fig. 5, when a signal characteristic curve corresponding to the original echo signal is output based on the short-time average autocorrelation function, S202 may include the steps of:

s501: and traversing the signal characteristic curve, and determining the rising edge triggering moment of the signal characteristic curve.

In this embodiment of the present application, the rising edge trigger time of the signal characteristic curve is the time when the target object reflects the echo signal, and when the original echo signal includes multiple echo signals returned by multiple target objects, the obtained signal characteristic curve includes multiple rising edge trigger times.

For example, when two objects (hereinafter referred to as a first target object and a second target object) are detected by the laser emitted by the laser radar, the first target object reflects a first echo signal, the second target object reflects a second echo signal, and the original echo signal received by the laser radar includes the first echo signal and the second echo signal, and accordingly, a first rising edge trigger time corresponding to the first echo signal and a second rising edge trigger time corresponding to the second echo signal can be calculated according to a signal characteristic curve.

In the embodiment of the present application, the step S501 may include the following steps:

determining a starting position index of the signal characteristic curve for threshold detection according to a first preset threshold;

In a specific application, the first preset threshold may be set according to an actual scenario and performance of the lidar, which is not limited in this application.

In a specific application, the determining the initial position index of the signal characteristic curve according to the first preset threshold value specifically includes: and traversing a first time point of which the first signal characteristic value is not more than a first preset threshold value from the starting end of the signal characteristic curve, and determining the time point as a starting position index of the signal characteristic curve.

In a specific application, a rising edge cache list and a falling edge cache list are created first, wherein the rising edge cache list is used for storing the found rising edge trigger time, and the falling edge cache list is used for storing the found falling edge trigger time.

In a specific application, index t from the starting position ₀ Is the next time t of (a) ₀₊₁ Starting traversing the signal characteristic curve, judging whether the signal characteristic value is larger than the first preset threshold value, if the signal characteristic value is larger than the first preset threshold value, searching the rising edge trigger time by a linear interpolation method, storing the determined rising edge trigger time into the rising edge cache list, continuously judging whether the signal characteristic value is smaller than the first preset threshold value, if the signal characteristic value is smaller than the first preset threshold value and the rising edge cache list length is larger than the falling edge cache list length by 1, searching the falling edge trigger time by a linear interpolation method, and searching a rising edge trigger time and a falling edge trigger timeThe detection of a double echo is completed at the moment of transmission. If the received original echo signal contains echo signals reflected by a plurality of target objects, a plurality of rising edge trigger moments and a plurality of falling edge trigger moments can be detected from the signal characteristic curve.

The length of the rising edge buffer list refers to the number of rising edge trigger times included in the rising edge buffer list, and the length of the falling edge buffer list refers to the number of falling edge trigger times included in the falling edge buffer list.

After finding a falling edge trigger time, judging whether the time difference between the found falling edge trigger time and the last rising edge trigger time in the rising edge cache list is larger than or equal to a first preset pulse width, and storing the found falling edge trigger time into the falling edge cache list only when the time difference between the found falling edge trigger time and the last rising edge trigger time in the rising edge cache list is larger than or equal to the first preset pulse width; if the time difference between the found falling edge trigger time and the last rising edge trigger time in the rising edge cache list is smaller than the first preset pulse width, the signal segment corresponding to the found rising edge trigger time to the falling edge trigger time is considered to be an interference signal, and at the moment, the last rising edge trigger time is deleted from the rising edge cache list, so that interference of the interference signal can be effectively avoided, and the detection accuracy is improved.

It should be noted that the first preset pulse width may be set according to a pulse width of an interference signal existing in an application scenario of the laser radar, which is not limited in this application.

S502: and determining the rising edge triggering moment as a target ranging timing value.

In a specific application, the target ranging timer value is determined by the rising edge trigger time saved in the rising edge cache list. And if a plurality of rising edge trigger moments exist in the rising edge cache list, determining each rising edge trigger moment as a target ranging timing value of a corresponding target object.

For example, assuming that after the laser radar emits laser light, two target objects (a first target object and a second target object respectively) are detected, the first target object may reflect a first echo signal, the second target object may reflect a second echo signal, and since there is a time difference between the time when the laser light detects the first target object and the time when the laser light detects the second target object, the laser radar receives the echo signals, there are two echoes, that is, a first heavy echo signal reflected by the first target object and a second heavy echo signal reflected by the second target object, so that there are two rising edge trigger moments on a signal characteristic curve corresponding to the original echo signals, that is, there are two rising edge trigger moments in a rising edge buffer list. And if the laser detects the first target object, the first rising edge trigger time in the rising edge cache list is the target ranging timing value of the first target object, and the second rising edge trigger time in the rising edge cache list is the target ranging timing value of the second target object.

S203: and calculating the distance of the target object according to the target timing value.

In a specific application, the distance of the laser radar from the target object can be obtained by multiplying half of the target timing value by the speed of light.

In a specific application, the distance between the laser radar and each target object can be obtained by multiplying half of the target timing value corresponding to each target object by the speed of light.

It should be noted that, through experimental simulation, in a low signal-to-noise ratio scene, the detection distance of the ranging method provided by the embodiment of the application is improved by about 9.67m compared with that of the traditional ranging method.

As can be seen from the foregoing, in the ranging method provided by the embodiment of the present application, by extracting the signal features that can represent the correlation degree of the signal intensities inside the signal segments, the signal features are used to determine the target ranging timing value for calculating the distance between the target object and the target ranging timing value, so that the ranging distance of the laser radar in the low signal-to-noise ratio scene can be improved, and the ranging performance of the laser radar in the long-distance probing scene can be improved.

Because the short-time average autocorrelation function needs to perform sliding window calculation, the loss of system resources in the calculation process can be increased, the calculation time can be prolonged, and the ranging efficiency can be reduced. Referring to fig. 6, fig. 6 is a schematic diagram illustrating an implementation flow of S201 in a ranging method according to another embodiment of the present application. As shown in fig. 6, S201 in the embodiment of the present application may include the following steps:

s601: searching for a zero crossing signal segment of the original echo signal;

s602: screening zero crossing segments of the original echo signals based on a continuous zero crossing segment length threshold;

s603: and calculating the signal characteristics of the zero crossing signal fragments obtained by screening.

In a specific application, the initial position index t of the original echo signal can be determined according to a first preset threshold ₀ Index t from the start position ₀ Is the next time t of (a) ₀₊₁ Traversing the original echo signal, if t ₀₊₁ When the signal intensity of the original echo signal at the moment is greater than 0, t is set ₀₊₁ Determining the time as a first zero-crossing index position, then continuing traversing the original echo signal until the time with the signal intensity smaller than 0 is found, judging whether the time difference between the time before the time when the current signal is smaller than 0 and the first zero-crossing index position exceeds a second preset pulse width (namely, a continuous zero-crossing segment length threshold), and determining the signal segment from the first zero-crossing index position to the time before the time when the current signal is smaller than 0 as a zero-crossing signal segment if the time difference between the time before the time when the current signal is smaller than 0 and the first zero-crossing index position exceeds the second preset pulse width. Traversing the original echo signals until all zero crossing signal fragments contained in the original echo signals are found out.

After all the zero-crossing signal fragments contained in the original echo signal are determined, calculating a short-time average autocorrelation function of each zero-crossing signal fragment, and obtaining the signal characteristic value of each zero-crossing signal fragment.

Accordingly, the step S202 may include the steps of:

In an embodiment of the present application, the determining the rising edge trigger time according to the signal characteristics of the zero crossing signal segment may include the following steps:

and if the signal characteristic of the zero crossing signal segment is larger than a first preset threshold value, determining the first zero crossing index position of the zero crossing segment as the rising edge trigger time.

In a specific application, a first zero-crossing index cache list and a rising edge cache list can be created first, after a zero-crossing signal segment is determined, whether the signal characteristic of the zero-crossing signal segment exceeds a first preset threshold value is calculated, if the signal characteristic of the zero-crossing signal segment exceeds the first preset threshold value, a first zero-crossing index position in the first zero-crossing index cache list is stored into the rising edge cache list as a rising edge trigger time, and the first zero-crossing index cache list is emptied; if the signal characteristics of the zero-crossing signal segment do not exceed a first preset threshold value, directly emptying the first zero-crossing index cache list, and repeating the steps until the original echo signal is traversed.

It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic of each process, and should not limit the implementation process of the embodiment of the present application in any way.

Based on the ranging method provided by the above embodiment, the embodiment of the invention further provides an embodiment of a ranging device for implementing the above method embodiment.

Referring to fig. 7, fig. 7 is a schematic structural diagram of a ranging apparatus according to an embodiment of the present disclosure. In this embodiment, the ranging device includes units for performing the steps in the embodiments corresponding to fig. 2 to 6. Please refer to fig. 2 to fig. 6 and the related descriptions in the corresponding embodiments of fig. 2 to fig. 6. For convenience of explanation, only the portions related to the present embodiment are shown. As shown in fig. 7, the distance measuring device 7 includes: a feature extraction module 71, a timing value determination module 72, and a distance calculation module 73. Wherein:

the feature extraction module 71 is used for extracting signal features of the original echo signals; the signal characteristic is the degree of autocorrelation of the signal strength of each signal segment in the original echo signal.

The timer value determination module 72 is configured to determine a target ranging timer value based on the signal characteristics.

The distance calculating module 73 is configured to calculate the distance of the target object according to the target ranging timing value.

In one embodiment of the present application, the feature extraction module 71 may include a selection unit, a calculation unit, and a traversal unit.

The selecting unit is used for selecting the signal fragments based on a sliding window mode;

the calculating unit is used for calculating the signal characteristic value of the selected signal segment based on the short-time average autocorrelation function;

the traversing unit is used for traversing the original echo signal through a sliding window and outputting the signal characteristic curve of the original echo signal.

In one embodiment of the present application, the timing value determining module 72 includes a first determining unit and a second determining unit.

The first determining unit is used for traversing the signal characteristic curve and determining the rising edge triggering moment of the signal characteristic curve.

The second determining unit is configured to determine the rising edge trigger time as the target ranging timing value.

In an embodiment of the present application, the first determining unit is specifically configured to determine, according to a first preset threshold, a starting position index of the signal characteristic curve, where the starting position index is used for threshold detection, and the starting position index is a position index of the signal characteristic curve that is first not greater than the first preset threshold;

creating a rising edge cache list and a falling edge cache list, wherein the rising edge cache list is used for storing rising edge trigger time, and the falling edge cache list is used for storing falling edge trigger time;

traversing the signal characteristic curve from the initial position index, if the signal characteristic is larger than the first preset threshold value and the length of the rising edge cache list is equal to that of the falling edge cache list, performing linear interpolation based on the current position index and the previous position index, calculating to obtain a rising edge trigger time, and storing the rising edge trigger time into the rising edge cache list;

if the signal characteristic is smaller than the first preset threshold value and the rising edge cache list length is 1 longer than the falling edge cache list length, linear interpolation is carried out based on the current position index and the subsequent position index, and the falling edge trigger time is obtained through calculation;

and if the time difference between the falling edge trigger time and the last rising edge trigger time in the rising edge cache list is greater than or equal to a first preset pulse width, storing the falling edge trigger time into the falling edge cache list, otherwise, deleting the last rising edge trigger time in the rising edge cache list.

In one embodiment of the present application, the feature extraction module 71 includes a search unit, a screening unit, and a calculation unit.

The searching unit is used for searching the zero crossing segment of the original echo signal.

The screening unit is used for screening zero crossing fragments of the original echo signal based on the continuous zero crossing fragment length threshold value.

The calculation unit is used for calculating the signal characteristics of the zero crossing signal fragments obtained by screening.

In one embodiment of the present application, the timing value determining module 72 further includes a third determining unit.

And the third determining unit is used for determining the rising edge trigger moment according to the signal characteristics of the zero crossing signal segment.

In one embodiment of the present application, the third determining unit is specifically configured to determine whether a signal characteristic of the zero-crossing signal segment is greater than a first preset threshold; and if the signal characteristics of the zero crossing signal segment are larger than a first preset threshold value, determining the first zero crossing index position of the zero crossing segment as the rising edge trigger time.

It should be noted that, because the content of information interaction and execution process between the above units is based on the same concept as the method embodiment of the present application, specific functions and technical effects thereof may be referred to the method embodiment specifically, and will not be described herein again.

Fig. 8 is a schematic structural diagram of a terminal device according to another embodiment of the present application. As shown in fig. 8, the terminal device 8 provided in this embodiment includes: a processor 80, a memory 81 and a computer program 82, such as a ranging program, stored in the memory 81 and executable on the processor 80. The steps of the various ranging method embodiments described above, such as S201-S203 shown in fig. 2, are implemented when the processor 80 executes the computer program 82. Alternatively, the processor 80, when executing the computer program 82, performs the functions of the modules/units in the embodiments of the terminal device described above.

By way of example, the computer program 82 may be partitioned into one or more modules/units that are stored in the memory 81 and executed by the processor 80 to complete the present application. The one or more modules/units may be a series of computer program instruction segments capable of performing the specified functions describing the execution of the computer program 82 in the terminal device 8. For example, the computer program 82 may be divided into a plurality of units, and the specific functions of each unit are described with reference to the corresponding embodiment of fig. 7, which is not repeated herein.

The terminal device may include, but is not limited to, a processor 80, a memory 81. It will be appreciated by those skilled in the art that fig. 8 is merely an example of the terminal device 8 and does not constitute a limitation of the terminal device 8, and may include more or less components than illustrated, or may combine certain components, or different components, e.g., the terminal device may further include an input-output device, a network access device, a bus, etc.

The processor 80 may be a central processing unit (Central Processing Unit, CPU), other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 81 may be an internal storage unit of the terminal device 8, such as a hard disk or a memory of the terminal device 8. The memory 81 may be an external storage device of the terminal device 8, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card) or the like, which are provided on the terminal device 8. Further, the memory 81 may also include both an internal storage unit and an external storage device of the terminal device 8. The memory 81 is used for storing the computer program as well as other programs and data required by the terminal device. The memory 81 may also be used to temporarily store data that has been output or is to be output.

Embodiments of the present application also provide a computer-readable storage medium. The computer readable storage medium stores a computer program which, when executed by a processor, implements the ranging method described above.

The embodiments of the present application provide a computer program product that, when run on a terminal device, causes the terminal device to implement the ranging method described above.

It will be clearly understood by those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of each functional unit and module is illustrated, and in practical application, the above-mentioned functional allocation may be performed by different functional units and modules, that is, the internal structure of the terminal device is divided into different functional units or modules, so as to perform all or part of the above-mentioned functions. The functional units and modules in the embodiment may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working process of the units and modules in the above system may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference may be made to related descriptions of other embodiments.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims

1. A ranging method, comprising:

2. The ranging method as claimed in claim 1, wherein extracting signal characteristics of the original echo signal comprises:

selecting a signal segment based on a sliding window mode;

calculating a signal characteristic value of the selected signal segment based on the short-time average autocorrelation function;

and traversing the original echo signal by a sliding window, and outputting a signal characteristic curve of the original echo signal.

3. The ranging method as recited in claim 2 wherein determining a target ranging timer value from the signal characteristics comprises:

traversing the signal characteristic curve, and determining the rising edge triggering moment of the signal characteristic curve;

and determining the rising edge trigger moment as the target ranging timer value.

4. A ranging method as claimed in claim 3 wherein said traversing the signal profile to determine the rising edge trigger time of the signal profile comprises:

5. The ranging method as claimed in claim 1, wherein the extracting signal characteristics of the original echo signal comprises:

searching all zero crossing fragments of the original echo signal;

screening zero crossing segments of the original echo signals based on a continuous zero crossing segment length threshold;

6. The ranging method as recited in claim 5 wherein said determining a target ranging timer value from said signal characteristics comprises:

7. The ranging method as defined in claim 6, wherein determining a rising edge trigger time from the signal characteristics of the zero-crossing signal segment comprises:

8. A ranging apparatus, comprising:

the characteristic extraction module is used for extracting signal characteristics of the original echo signals; the signal characteristics are the autocorrelation degree of the signal intensity of each signal segment;

9. A terminal device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer readable instructions, implements the ranging method of any of claims 1 to 7.

10. A computer readable storage medium storing a computer program, characterized in that the computer readable instructions, when executed by a processor, implement the ranging method of any of claims 1 to 7.