CN112526485B

CN112526485B - Fault detection method and device, equipment and storage medium

Info

Publication number: CN112526485B
Application number: CN201910883251.1A
Authority: CN
Inventors: 王路
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2019-09-18
Filing date: 2019-09-18
Publication date: 2024-04-09
Anticipated expiration: 2039-09-18
Also published as: CN112526485A

Abstract

The embodiment of the application discloses a fault detection method, a fault detection device, equipment and a storage medium, wherein the method comprises the following steps: receiving an opening instruction, wherein the opening instruction is used for indicating to open a ranging module of the electronic equipment; responding to the starting instruction, and before controlling a light wave emitter in the ranging module to emit working pulses at first regular intervals, controlling the light wave emitter to emit at least one test pulse so as to perform fault detection on the ranging module and obtain a detection result; the working pulse is used for measuring the distance between the ranging module and the target object; and controlling the working state of the ranging module according to the detection result.

Description

Fault detection method and device, equipment and storage medium

Technical Field

Embodiments of the present application relate to electronic technology, and relate to, but are not limited to, fault detection methods and apparatuses, devices, and storage media.

Background

Currently, time of Flight (TOF) ranging methods are widely used in motion sensing interaction and control, three-dimensional (3 d) object recognition and sensing, intelligent environment sensing, dynamic map construction, and the like. The electronic equipment can utilize TOF range finding module to confirm the distance with the target object, and the specific mode is: and controlling a laser transmitter in the TOF ranging module to transmit laser working pulse, and after receiving the laser reflected by the target object, determining the distance between the laser and the target object by calculating the phase difference between the transmitting time and the receiving time of the laser.

However, if the components in the TOF ranging module fail, the laser light emitted by the laser transmitter may cause some damage to the human eye and skin. Therefore, the TOF ranging module is subjected to fault detection, so that the risk of injury to eyes and skin of the TOF ranging module is reduced, and the TOF ranging module has important significance.

Disclosure of Invention

In view of this, embodiments of the present application provide a fault detection method, a fault detection device, a fault detection apparatus, and a storage medium. The technical scheme of the embodiment of the application is realized as follows:

in a first aspect, an embodiment of the present application provides a fault detection method, where the method includes: receiving an opening instruction, wherein the opening instruction is used for indicating to open a ranging module of the electronic equipment; responding to the starting instruction, and before controlling a light wave emitter in the ranging module to emit working pulses at first regular intervals, controlling the light wave emitter to emit at least one test pulse so as to perform fault detection on the ranging module and obtain a detection result; the working pulse is used for measuring the distance between the ranging module and the target object; and controlling the working state of the ranging module according to the detection result.

In a second aspect, an embodiment of the present application provides a fault detection device, including: the receiving module is configured to receive an opening instruction, wherein the opening instruction is used for indicating to open a ranging module of the device; the control module is configured to respond to the starting instruction and control the light wave emitter in the ranging module to emit at least one test pulse before controlling the light wave emitter to emit working pulses at first regular intervals so as to perform fault detection on the ranging module and obtain a detection result; the working pulse is used for measuring the distance between the ranging module and the target object; and the control module is further configured to control the working state of the ranging module according to the detection result.

In a third aspect, an embodiment of the present application provides an electronic device, including a memory and a processor, where the memory stores a computer program that can be run on the processor, and the processor implements steps in the fault detection method provided in the embodiment of the present application when the processor executes the program.

In a fourth aspect, embodiments of the present application provide a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements steps in a fault detection method provided by embodiments of the present application.

In the embodiment of the application, after receiving the opening instruction, responding to the opening instruction, and before controlling a light wave emitter in the ranging module to emit working pulses at first regular intervals, controlling the light wave emitter to emit at least one test pulse so as to perform fault detection on the ranging module to obtain a detection result; according to the detection result, controlling the working state of the ranging module; in this way, the risk of injury to the human eye and skin by light waves can be reduced.

Drawings

FIG. 1A is a schematic diagram of a TOF ranging module according to an embodiment of the present disclosure;

fig. 1B is a schematic structural diagram of an infrared emission unit in a TOF ranging module according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of an implementation flow of a fault detection method according to an embodiment of the present application;

FIG. 3A is a schematic diagram of a pulse signal according to an embodiment of the present application;

FIG. 3B is a signal diagram of the working pulse transmitted by the first rule according to the embodiment of the present application;

FIG. 4 is a schematic flow chart of another implementation of a fault detection method according to an embodiment of the present application;

FIG. 5 is a schematic flow chart of another implementation of a fault detection method according to an embodiment of the present application;

FIG. 6 is a schematic diagram illustrating an implementation flow of a fault detection method according to another embodiment of the present application;

FIG. 7 is a schematic diagram of another pulse signal according to an embodiment of the present application;

FIG. 8 is a schematic diagram of a pulse signal according to an embodiment of the present application;

FIG. 9 is a schematic diagram of an implementation flow of another fault detection method according to an embodiment of the present application;

FIG. 10 is a schematic diagram of a pulse signal according to an embodiment of the present disclosure;

FIG. 11 is a schematic flow chart of a method for detecting whether a diffusion sheet falls off according to an embodiment of the present application;

FIG. 12 is a schematic diagram of a structure of a fault detection device according to an embodiment of the present disclosure;

fig. 13 is a schematic diagram of a hardware entity of an electronic device according to an embodiment of the present application.

Detailed Description

For the purposes, technical solutions and advantages of the embodiments of the present application to be more apparent, the specific technical solutions of the present application will be described in further detail below with reference to the accompanying drawings in the embodiments of the present application. The following examples are illustrative of the present application, but are not intended to limit the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of the present application only and is not intended to be limiting of the present application.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is to be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with one another without conflict.

It should be noted that the term "first\second\third" in relation to the embodiments of the present application is merely to distinguish different objects and does not represent a specific ordering for the objects, it being understood that the "first\second\third" may be interchanged in a specific order or sequence, where allowed, to enable the embodiments of the present application described herein to be implemented in an order other than illustrated or described herein.

Firstly, taking a ranging module as a TOF ranging module as an example, the structure and the working principle of the TOF ranging module are explained. As shown in fig. 1A, the module 10 includes an infrared emission unit 11, an infrared receiving unit 12, and a controller 15; the controller 15 controls the infrared emitting unit 11 to emit modulated near infrared light 13, the modulated near infrared light is projected onto the target object 14, reflected by the target object 14 and received by the infrared receiving unit 12, and the controller 15 calculates a time difference or a phase difference ΔΦ between the emitting time and the receiving time of the light, so as to obtain a distance between the module 10 and the target object 14, thereby generating depth information.

The structure of the infrared emission unit 11 is shown in fig. 1B, and the unit 11 includes a vertical cavity surface laser emitter (Vertical Cavity Surface Emitting Laser, VCSEL) 111, a light diffusion sheet 112, and a photodiode 113 (PD) as a detector; wherein the VCSEL 111 is configured to emit a laser pulse with a certain energy, which is reflected to the infrared receiving unit 12 after being projected onto the target object 14. The laser pulse has a wavelength of 940 nanometers (nm), belongs to near infrared light, has certain energy, and is invisible to naked eyes. According to the definition of the international electrotechnical commission standard IEC60825-2014 for eye safety, the laser energy emitted by the VCSEL 111 needs to be controlled to meet the requirements of safety in use.

The PD 113 is configured to receive laser energy reflected by the emitted laser after passing through the light diffusion sheet 112, and to convert the received laser energy into a photocurrent, thereby monitoring and determining whether the laser energy is changed according to the magnitude of the photocurrent.

The embodiment of the application provides a fault detection method, which can be applied to electronic equipment comprising a ranging module, wherein the electronic equipment can be equipment with ranging capability such as a mobile phone, a tablet personal computer, a notebook computer, a robot and an unmanned aerial vehicle. The functions implemented by the fault detection method may be implemented by a processor in the electronic device calling a program code, which may of course be stored in a computer storage medium, it being seen that the electronic device comprises at least a processor and a storage medium.

Fig. 2 is a schematic implementation flow chart of a fault detection method according to an embodiment of the present application, as shown in fig. 2, the method at least includes the following steps S201 to S203:

step S201, receiving an opening instruction, wherein the opening instruction is used for indicating to open a ranging module of the electronic equipment. For example, when an electronic device receives an instruction to instruct to open a camera application, it is determined that the open instruction is received. For example, a touch instruction is received on an icon of a camera application, or a voice instruction indicating that the camera application is started is received.

Step S202, responding to the starting instruction, and before controlling a light wave emitter in the ranging module to emit working pulses at first regular intervals, controlling the light wave emitter to emit at least one test pulse so as to perform fault detection on the ranging module and obtain a detection result; the working pulse is used for measuring the distance between the ranging module and the target object.

In the embodiment of the present application, the type of the optical wave emitter is not limited, and the optical wave emitter may be a lamp for emitting optical waves such as ultrasonic waves, infrared rays, near infrared rays, and the like, for example, the optical wave emitter is a laser emitter.

For example, as shown in fig. 3A, after receiving the turn-on command, the electronic device does not directly control the light wave transmitter in the ranging module to transmit the working pulses 301 to 30m at first regular intervals, where m is an integer greater than 1; the light wave emitter is controlled to emit 4 test pulses 311 to 314 to perform fault detection on the ranging module, so that damage of light waves (such as laser) to human eyes and skin can be greatly reduced. This is because, after receiving the on command, the electronic device directly controls the optical wave emitter to emit the working pulse, and in this process, the working pulse emitted by the optical wave emitter starts to be safely tested, and since the testing process needs a certain time (for example, 0.5 seconds) to complete, the width of the working pulse is usually much smaller than 0.5 seconds (for example, the width of the working pulse is 1 to 20 nanoseconds), so that during the period of time of performing the safety test, the electronic device already emits a large number of working pulses by the optical wave emitter, and if the components in the ranging module are abnormal (for example, the driving circuit is short-circuited or the diffusion sheet falls off), the optical power of these working pulses is greatly enhanced, which is enough to cause injury to human eyes and skin. The working pulse shown in fig. 3A is a pulse signal that is emitted by the optical wave emitter under the premise that the electronic device determines that the component of the ranging module is not obstructed.

Based on this, in the embodiment of the present application, after receiving the start instruction, the electronic device does not directly transmit a working pulse, but transmits at least one test pulse in advance, so as to perform fault detection on the ranging module, and then, according to the result of the fault detection, controls the working state of the ranging module; in this way, the risk of injury to the health of the human eye and skin can be greatly reduced.

It should be noted that the first rule defines that the optical wave transmitter needs to transmit the working pulse according to a specific pulse frequency, pulse width and duty cycle, and the configuration of these parameters is in accordance with the eye safety specification. For example, as shown in fig. 3B, the optical wave transmitter is controlled to transmit the operation pulses at intervals of 100 Megahertz (MHZ), a Duty Cycle (DC) of 33%, a phase time of 350 microseconds (us), and a frame length of 33.3 milliseconds (ms); wherein, according to the pulse frequency and the duty ratio, the pulse width of the operation pulse can be determined to be 33 nanoseconds (ns).

Step S203, controlling the working state of the ranging module according to the detection result.

The working states of the corresponding ranging modules are different according to different detection results. For example, the working state of the ranging module is controlled by the following steps S505, S507, or S509. That is, in case that the detection result is that the component in the ranging module is not failed, controlling the ranging module to input the working current of the optical wave emitter to the driving circuit, so that the driving circuit drives the optical wave emitter to emit the working pulse at the first regular intervals; closing the ranging module when the detection result is that the diffusion sheet is detached, so as to inhibit the light wave emitter from emitting the working pulse; and under the condition that the detection result is that the driving circuit is short-circuited, the ranging module is closed, or the ranging module is controlled to input other currents smaller than the working current to the driving circuit, so that the driving circuit drives the light wave emitter to emit working pulses at second regular intervals.

The embodiment of the application further provides a fault detection method, which at least comprises the following steps S301 to S303:

step S301, receiving an opening instruction, where the opening instruction is used to instruct to open a ranging module of the electronic device.

Step S302, responding to the starting instruction, before controlling a light wave emitter in the ranging module to emit working pulses at first regular intervals, sequentially inputting a plurality of instantaneous currents to a driving circuit in the ranging module, so that the driving circuit drives the light wave emitter to sequentially emit a plurality of test pulses, and fault detection is carried out on the ranging module to obtain a detection result; the working pulse is used for measuring the distance between the ranging module and the target object.

The electronic device may implement step S302 through steps S402 to S404 in the following embodiment, that is, a plurality of instantaneous currents are sequentially input to the driving circuit, and then a detection result is determined based on a relationship between each detected photocurrent and a preset threshold value range; the electronic device may further implement step S302 by inputting an instantaneous current to the driving circuit to drive the optical wave emitter to emit a test pulse, detecting whether the photocurrent generated by the photoelectric conversion element under the reflection of the test pulse is within a corresponding threshold range, and if so, continuing to input the next instantaneous current to the driving circuit; otherwise, the lightwave transmitter is disabled from transmitting test pulses or operating pulses, or a smaller operating current is input, so that the lightwave transmitter transmits operating pulses of smaller energy.

The number and the magnitude of the plurality of instantaneous currents are not limited here. Generally, at least two instantaneous currents are sequentially input to the driving circuit, so that the accuracy of the detection result can be improved, and the false positive probability can be reduced. When implemented, the magnitudes of the plurality of instantaneous currents may be the same or different. However, each instantaneous current must be less than or equal to the maximum operating current of the lightwave emitter to meet eye safety regulations, avoiding damage to the human eye and skin from excessive instantaneous currents.

Step S303, according to the detection result, controlling the working state of the ranging module.

In the embodiment of the application, in response to an opening instruction, before controlling a light wave emitter in a ranging module to emit working pulses at first regular intervals, a plurality of instantaneous currents are sequentially input to a driving circuit, so that the driving circuit drives the light wave emitter to sequentially emit a plurality of test pulses to perform fault detection on the ranging module; thus, compared with a method of directly inputting constant current to a driving circuit to drive a light wave emitter to emit working pulses and carrying out safety detection based on the working pulses, the method has the following technical effects: first, damage to the human eye and skin can be reduced; second, power consumption can be saved; third, the risk of burning out the component due to the abnormality of the component of the ranging module can be reduced, because the constant current (i.e., the working current) is directly conducted under the condition that whether the component of the ranging module is abnormal is not yet determined, and the risk of burning out the component exists.

An embodiment of the present application further provides a fault detection method, and fig. 4 is a schematic implementation flow diagram of another fault detection method according to an embodiment of the present application, as shown in fig. 4, where the method at least includes the following steps S401 to S405:

step S401, receiving an opening instruction, where the opening instruction is used to instruct to open a ranging module of the electronic device.

Step S402, in response to the on command, before controlling the light wave emitter in the ranging module to emit working pulses at first regular intervals, sequentially inputting a plurality of instantaneous currents to a driving circuit in the ranging module, so that the driving circuit drives the light wave emitter to sequentially emit the plurality of test pulses.

Step S403, detecting photocurrent generated by the photoelectric conversion element in the ranging module when each test pulse is transmitted.

And step S404, determining the detection result according to the relation between each photocurrent and the corresponding threshold range so as to realize fault detection of the ranging module.

It will be appreciated that when the magnitude of the instantaneous current is different, the energy of the test pulse emitted by the driving light wave emitter is also different, so that the photon density reflected onto the photoelectric conversion element by the diffusion sheet is also different, and thus the photocurrent generated by the photoelectric conversion element is also different. Thus, different instantaneous currents correspond to different threshold ranges, i.e., each photocurrent corresponds to a threshold range; of course, different instantaneous currents may also correspond to the same threshold range. For example, when the component of the ranging module is not faulty, the photocurrent corresponding to the minimum operating current of the optical wave emitter is the lower limit value of the threshold range, and the photocurrent corresponding to the maximum operating current is the upper limit value of the threshold range. In implementation, the lower limit value may also be set to a current value close to 0.

The electronic apparatus may determine different detection results through step S504, step S506, and step S508 of the following embodiments.

Step S405, controlling the working state of the ranging module according to the detection result.

In the embodiment of the application, a plurality of instant currents are sequentially input to a driving circuit in the ranging module, so that the driving circuit drives the light wave emitter to sequentially emit the plurality of test pulses; detecting photocurrent generated by a photoelectric conversion element in the ranging module when each test pulse is transmitted; and determining the detection result according to the relation between each photocurrent and the corresponding threshold range, so that the electronic equipment can more rapidly realize fault detection on the ranging module.

An embodiment of the present application further provides a fault detection method, and fig. 5 is a schematic implementation flow diagram of another fault detection method according to an embodiment of the present application, as shown in fig. 5, where the method at least includes the following steps S501 to S509:

step S501, an opening instruction is received, where the opening instruction is used to instruct to open a ranging module of the electronic device.

Step S502, in response to the on command, before controlling the light wave emitter in the ranging module to emit working pulses at first regular intervals, sequentially inputting a plurality of instantaneous currents to a driving circuit in the ranging module, so that the driving circuit drives the light wave emitter to sequentially emit the plurality of test pulses.

Step S503, detecting a photocurrent generated by the photoelectric conversion element in the ranging module when each of the test pulses is transmitted.

Step S504, where each photocurrent belongs to a corresponding threshold range, determining that the detection result is that no component in the ranging module has failed, and then proceeding to step S505.

For example, 2A of instantaneous current is input into the driving circuit, and in the case that the component in the ranging module has no fault, the corresponding photoelectric current value is 30 microamps (uA), and its corresponding threshold range may be set to [1uA,50uA ] when implemented.

Step S505, controlling the ranging module to input the working current of the optical wave emitter to the driving circuit, so that the driving circuit drives the optical wave emitter to emit the working pulse at the first regular intervals.

For example, the light wave emitter has an operating current of 1 Ampere (a) to 3A, and when implemented, an operating current of 2A is input to the driving circuit.

In other embodiments, during the process of the light wave emitter emitting the working pulses at the first regular intervals, the electronic device may further detect a photocurrent generated by the photoelectric conversion element when emitting each working pulse, and if at least one photocurrent is greater than a preset threshold value or less than the preset threshold value, the current working current may be adjusted according to a difference between the photocurrent and the preset threshold value, so as to keep the optical power of the working pulse emitted by the light wave emitter within a specific range, so as to solve the problem of inconsistent light intensities emitted by the plurality of electronic devices.

Step S506, when at least one of the photocurrents is greater than the upper limit value of the corresponding threshold value range, determining that the detection result is that the driving circuit has been shorted, and proceeding to step S507.

It will be appreciated that if the driving circuit is shorted, even if a small current is input to the driving circuit, the driving circuit will output a large current, thereby triggering the light wave emitter to emit a light wave with very strong energy, and further increasing the photon density on the photoelectric conversion element, and generating a large photocurrent.

And S507, closing the ranging module to prohibit the light wave emitter from emitting the working pulse, so as to prevent the light wave emitter from emitting a large amount of strong light and damaging human eyes and skin health.

In other embodiments, the electronic device may further control the ranging module to input other currents smaller than the operating current to the driving circuit when detecting that the driving circuit has been shorted, so that the driving circuit drives the optical wave emitter to emit the operating pulse at second regular intervals. Here, the second rule may be the same as or different from the first rule; at different times, parameters such as pulse frequency, pulse width or duty ratio in the second rule are smaller, so that the light wave transmitter can transmit working pulses with smaller power.

In other embodiments, the electronic device may further output a prompt message to prompt the user to lengthen the distance between the ranging module and the target object when detecting that the driving circuit has been shorted. For example, when the user opens the camera to perform self-timer shooting, a prompt message is popped up on the image preview interface to prompt the user that the camera is farther away from the user.

Step S508, determining that the detecting result is that the diffusion sheet in the ranging module has fallen off when each photocurrent is smaller than the lower limit value of the corresponding threshold value range, and entering step S509.

It will be appreciated that if the diffusion sheet falls off, two problems will result: first, the power density of the emitted pulse signal increases, which can cause injury to the human eye and skin; second, no photons are reflected to the photoelectric conversion element, which results in a small photocurrent, nearly close to 0, generated by the photoelectric conversion element. Therefore, when the electronic device is implemented, in order to avoid interference of other optical signals with the detection result, the lower limit value is generally set to a non-zero value, for example, the lower limit value is set to 1uA.

Step S509, closing the ranging module to prohibit the light wave emitter from emitting the working pulse, thereby reducing the risk of injury to human eyes and skin health.

In the embodiment of the application, a specific detection result is determined according to the relation between each photocurrent and the corresponding threshold range, so that a basis condition is provided for better control of the working state of the ranging module subsequently.

An embodiment of the present application further provides a fault detection method, and fig. 6 is a schematic implementation flow chart of another fault detection method according to an embodiment of the present application, as shown in fig. 6, where the method at least includes the following steps S601 to S610:

step S601, receiving an opening instruction, where the opening instruction is used to instruct to open a ranging module of the electronic device.

Step S602, in response to the start instruction, inputs N instantaneous currents into a driving circuit in the ranging module in sequence before controlling the optical wave transmitter in the ranging module to transmit working pulses at first regular intervals, so that the driving circuit drives the optical wave transmitter to transmit the N test pulses in sequence, where N is an integer greater than 1.

When the electronic device implements step S602, N instantaneous currents may be sequentially input to the driving circuit in order from small to large. For example, the minimum operating current Ia of the lightwave transmitter is input to the driving circuit as a first instantaneous current, and then, after a certain interval, the typical operating current Ityp of the lightwave transmitter is input to the driving circuit as a second instantaneous current. Therefore, 2 instantaneous currents are sequentially input to the driving circuit, so that false detection can be avoided, and the obtained detection result is more accurate; on the other hand, the second instantaneous current uses the maximum operating current of the optical wave emitter, and the detection sensitivity can be improved. In other examples, the first instantaneous current is less than the second instantaneous current, which may be less than the maximum operating current of the lightwave emitter.

The value of N is not limited here, that is, 2 or 3 or more instantaneous currents may be sequentially input into the driving circuit when implemented.

Step S603, determining whether the characteristic of the transmitted Nth test pulse meets the condition; if not, executing step S604; if so, step S605 is performed.

The electronic apparatus can determine whether the characteristic of the transmitted nth test pulse satisfies the condition by step S703, step S704, step S706, and step S708 in the following embodiments. Namely, detecting photocurrent generated by the photoelectric conversion element in the ranging module when the nth test pulse is transmitted; under the condition that the photocurrent belongs to a corresponding threshold range, determining that the characteristic of the Nth test pulse meets a condition; otherwise, under the condition that the photocurrent is not in the corresponding threshold range, determining that the characteristic of the Nth test pulse does not meet the condition; if the condition is not satisfied, it indicates that there may be an abnormality (e.g., a short circuit of the driving circuit, a falling off of the diffusion sheet, etc.) in a certain component of the ranging module, step S604 is executed, and the next instantaneous current is prohibited from being input to the driving circuit, so as to reduce the damage to human eyes and skin caused by the fault detection process.

Step S604, prohibiting the next instantaneous current from being input to the driving circuit, ending the fault detection on the ranging module, obtaining the detection result, and then executing step S609 or step S610 according to the detection result.

The electronic device may determine the detection result based on a relationship between the photocurrent generated by the photoelectric conversion element when the nth test pulse is transmitted and the corresponding threshold value range. The detection result is determined, for example, by step S704 or step S706 of the following embodiment.

Step S605, the next instantaneous current is continuously input to the driving circuit, so that the driving circuit drives the optical wave emitter to emit the next test pulse.

The electronic device may continue to input the typical operating current of the optical wave emitter to the driving circuit while implementing step S605; thus, first, the reliability of the detection result can be increased; second, the detection result is made more valuable as the operating current input to the driving circuit is the typical operating current at the time of the subsequent transmission of the operating pulse. For example, a typical operating current of 2A is input to the driving circuit.

Step S606 of determining whether a photocurrent generated by the photoelectric conversion element at the time of transmitting the next test pulse satisfies a condition; if yes, go to step S607; if not, step S608 is performed.

In step S607, the ranging module is controlled to input the working current of the optical wave emitter to the driving circuit, so that the driving circuit drives the optical wave emitter to emit the working pulse at the first regular intervals.

In other embodiments, if it is determined in step S606 that the photocurrent generated by the photoelectric conversion element at the time of transmitting the next test pulse also satisfies the condition, an instantaneous current is continuously input to the driving circuit, so that the driving circuit drives the optical wave transmitter to transmit a test pulse again, and further, fault detection is completed, so that reliability of the detection result can be increased.

Step S608, ending the fault detection on the ranging module, obtaining the detection result, and then executing step S609 or step S610 according to the detection result.

And step S609, closing the ranging module to prohibit the light wave emitter from emitting the working pulse when the detection result is that the diffusion sheet is detached.

And step S610, closing the ranging module or controlling the ranging module to input other currents smaller than the working current to the driving circuit when the detection result is that the driving circuit is short-circuited, so that the driving circuit drives the light wave emitter to emit working pulses at second regular intervals.

The embodiment of the application further provides a fault detection method, which at least comprises the following steps S701 to S703:

step S701, receiving an opening instruction, where the opening instruction is used to instruct to open a ranging module of the electronic device.

Step S702, in response to the start instruction, before controlling the light wave emitter in the ranging module to emit working pulses at first regular intervals, sequentially inputting N instantaneous currents to a driving circuit in the ranging module, so that the driving circuit drives the light wave emitter to sequentially emit the N test pulses, where N is an integer greater than 1;

step S703, detecting a photocurrent generated by the photoelectric conversion element in the ranging module when the nth test pulse is transmitted;

step S704, at least if the photocurrent is greater than the upper limit value of the corresponding threshold range, determining that the characteristic of the nth test pulse does not meet the condition, prohibiting the next instantaneous current from being input to the driving circuit, ending the fault detection on the ranging module, determining that the driving circuit is shorted, and entering step S705.

For example, if the photocurrent generated by the photoelectric conversion element when the nth test pulse is transmitted is greater than the upper limit value of the corresponding threshold value range, it is determined that the characteristic of the nth test pulse does not satisfy the condition, the next instantaneous current is prohibited from being input to the driving circuit, so as to end the fault detection on the ranging module, and it is determined that the detection result is that the driving circuit has been shorted. For another example, if the photocurrent generated by the photoelectric conversion element at the time of transmitting each of the N test pulses is greater than the upper limit value of the corresponding threshold value range, the result in step S704 is obtained.

Step S705, turning off the ranging module, or controlling the ranging module to input other currents smaller than the working current to the driving circuit, so that the driving circuit drives the optical wave emitter to emit working pulses at second regular intervals.

Step S706, at least when the photocurrent is smaller than the lower limit value of the corresponding threshold range, determines that the characteristic of the nth test pulse does not meet the condition, and determines that the detection result is that the diffusion sheet in the ranging module has fallen, and proceeds to step S707.

Step S707, closing the ranging module to prohibit the light wave emitter from emitting the working pulse.

Step S708, at least if the photocurrent belongs to the corresponding threshold value range, continuing to input a next instantaneous current to the driving circuit, so that the driving circuit drives the optical wave emitter to emit a next test pulse;

step S709 of determining whether a photocurrent generated by the photoelectric conversion element at the time of transmitting the next test pulse satisfies a condition; if yes, go to step S710; if not, executing step S711;

step S710, controlling the ranging module to input the working current of the optical wave emitter to the driving circuit, so that the driving circuit drives the optical wave emitter to emit the working pulse at the first regular intervals.

Step S711, the fault detection on the ranging module is finished, the detection result is obtained, and then step S705 or step S707 is performed according to the detection result.

With the development of technologies and markets such as somatosensory interaction and control, 3D object recognition and perception, intelligent environment perception, dynamic map construction and the like, various large application scenes nowadays start to generate increasingly strong interests and increasingly vigorous demands on 3D vision and recognition technologies.

Technically, the advantages of the TOF ranging method in practical applications are self-evident compared to the other two schemes of 3D depth vision. For example, post-processing is not needed when the depth of field is calculated after the picture is shot, so that time delay can be avoided, and related cost caused by a powerful post-processing system can be saved; moreover, the TOF ranging scale has large elasticity, and the ranging scale can be adjusted by only changing the light source intensity, the optical field of view and the pulse frequency of the laser transmitter in most cases; in addition, due to the fact that the TOF ranging module has the advantages of being not prone to being interfered by external light, small in size, high in response speed, high in identification accuracy and the like, the TOF ranging module becomes a first-choice technical scheme of 3D vision in application fields such as mobile terminals and vehicle-mounted applications.

When the TOF ranging module is used on mobile equipment such as a mobile phone, the TOF ranging module can be used for measuring distance and size, performing three-dimensional modeling on objects in a scene, taking photos and blurring, performing motion sensing games, and performing corresponding application by matching with augmented reality (Augmented Reality, AR) glasses.

In TOF range finding module, influence the factor of the laser energy that infrared emission unit launched mainly includes: supply current, pulse Frequency (Frequency), pulse width, and duty cycle; wherein:

pulse frequency: a laser transmitter (i.e. one example of such a light wave transmitter) emits a modulated pulse signal, the modulation speed of which is frequency, typically between 20MHZ and 100 MHZ;

pulse width: the inverse of the pulse frequency is called the period, the period-by-duty cycle is the pulse width, and is usually 1-20ns;

duty cycle: pulse width/period, typically between 10% and 50%;

the pulse frequency, pulse width and duty cycle are configuration parameters of the driving circuits of the TOF sensor and the VCSEL, which are usually fixed after setting.

The power supply current of the driving circuit is a direct factor affecting the laser energy, and in general, the TOF ranging module has an overcurrent protection mechanism, and the specific principle is as follows: the photodiode PD of the infrared emission unit converts the received and reflected laser energy into corresponding photocurrent, and whether the laser energy emitted by the laser emitter is changed or not is judged based on the magnitude of the photocurrent. For example, a current threshold of the PD is set in advance according to the maximum driving current of the laser emitter, and if the photocurrent of the PD exceeds the current threshold during operation, a protection mechanism is triggered to turn off the laser emitter.

The TOF safety detection and protection mechanisms in the related art are all performed after the laser transmitter starts to work, if an abnormal condition is encountered, such as a short circuit occurs in a driving circuit of the laser transmitter, the laser transmitter is at a higher current level when the laser transmitter is just powered on, so that the energy of the initially emitted laser becomes large, and at the moment, the use of the laser has the eye safety risk.

The relevant laser energy monitoring scheme is performed after the laser transmitter starts to work, and the laser energy of the initial transmission is not monitored. The driving circuit of the laser transmitter is not found to continue to use the TOF ranging module after abnormality occurs, and a certain human eye safety risk exists.

Based on this, an exemplary application of the embodiments of the present application in one practical application scenario will be described below.

According to the embodiment of the application, on the basis of related laser energy monitoring, the laser transmitters are driven by different currents to pre-transmit a plurality of pulse signals (namely the test pulse), and whether a driving circuit is normal or not is judged by the photocurrent of the PD, so that monitoring of the laser energy of initial transmission is realized.

The specific implementation method is as follows, taking a TOF ranging module of 100MHz as an example for illustration, and the implementation method is as follows:

1) According to the safety standard, aiming at a TOF ranging module of 100MHZ, calculating the maximum laser current acceptable by human eye safety, and recording as Ia;

2) Setting a corresponding current threshold range of the PD according to the working current range of the laser transmitter; for example, the operating current range of the laser transmitter is [ Imin, imax ], with a typical value being Ityp; the current value range corresponding to PD is [ imin, imax ];

3) Setting 4-gear driving current (i.e. instantaneous current), namely first current (Imin), second current (Ia), third current (Ityp) and fourth current (Ityp), and respectively generating a first pulse signal, a second pulse signal, a third pulse signal and a fourth pulse signal as shown in fig. 7, wherein the third pulse signal and the fourth pulse signal are the same, and the purpose of the third current is to verify the stability of the third current; part of energy of the 4-gear pulse signal is reflected to the PD through the diffusion sheet, and the PD corresponds to 4 current values;

4) Before the phase work is started, 4 low-frequency pulse signals are respectively transmitted according to 4-gear current drive;

5) If the 4-stage drive currents can be respectively corresponding to the current threshold values of the PDs, judging that: the driving current of the laser transmitter is normal, and the phase operation is started at this time, as shown in fig. 7, and the transmission of a phase pulse signal (i.e., the operation pulse) is started;

6) As shown in fig. 8, if the PD current value corresponding to the second pulse signal exceeds the upper limit value of the current threshold range, it is determined that the current is too large, and the phase operation is stopped;

as shown in fig. 9, the electronic device may include the following steps S901 to S906 when executing the above method:

step S901, turn on the TOF ranging module, and then enter step S902;

step S902, driving a laser emitter to emit 4 low-frequency pulse signals according to a preset 4-gear driving current;

step S903, reading a PD current value corresponding to the pulse signal at the 4-speed drive current;

step S904, judging whether each PD current value is within a corresponding threshold range; if so, step S905 is performed; otherwise, step S906 is performed;

step S905, driving the laser transmitter with the working current of the laser transmitter to intermittently transmit working pulses (i.e. start-phase working) according to the pre-configured parameters;

in step S906, if the PD current value corresponding to the second pulse signal exceeds the upper limit value of the current threshold range, it is determined that the current is too large, and the phase operation is stopped at this time.

In the embodiment of the application, on one hand, the monitoring of initial laser energy is realized, the abnormality of a driving circuit is found in advance, a protection mechanism is triggered timely, and a laser transmitter is turned off; on the other hand, the emission energy of the laser can be effectively controlled in the working process.

In the embodiment of the application, a plurality of pulse signals are pre-emitted through different current driving, and whether the current driving is normal or not is judged through the current of the PD so as to realize monitoring of the laser energy of initial emission.

In other embodiments, the 4-speed current driving may be further set to a first current (I0), a second current (I1), a third current (I2), and a fourth current (I3) in sequence, where the 4-speed current increases in sequence, and as shown in fig. 10, a first pulse signal, a second pulse signal, a third pulse signal, and a fourth pulse signal are generated respectively; the amplitude corresponding to the first pulse signal to the fourth pulse signal is smaller than the amplitude corresponding to the maximum current.

If the 4-gear driving current can be corresponding to the current threshold value of the PD, judging that the laser driving current is normal, and starting the phase operation at the moment as shown in FIG. 10; otherwise, the phase operation is not started.

In other embodiments, this approach may also be used to detect in advance whether the diffusion sheet is detached; specifically, the state of the diffuser (diffuser) is unknown prior to use of the laser transmitter. 1) If the diffuser is in a falling state at this time, the laser transmitter transmits laser according to normal setting, and the transmitted laser can cause damage to human eyes and skin in the period of detecting and judging that the diffuser falls off; 2) If the diffusion does not fall off at this time, but the current becomes large due to the abnormality of the driving circuit of the laser emitter, the laser emitter emits laser according to the normal setting, the optical pulse power also becomes large, and the emitted laser can cause damage to human eyes and skin.

Therefore, the state of the diffuser can be judged by transmitting 3 low-frequency pulse signals, and then whether the phase operation is started or not is determined. As shown in fig. 11, after the TOF ranging module is turned on, 3 low-frequency pulse signals are transmitted to determine whether the PD current value is smaller than a first threshold; if the PD current values of the 3 times are smaller than the first threshold value, judging that the diffuser falls off, and not starting the phase work; and if the PD current value for 3 times is larger than the first threshold value and smaller than the second threshold value, judging that the diffuser is normal, and starting the phase operation when the laser current is also normal.

Based on the foregoing embodiments, the embodiments of the present application provide a fault detection device, where the fault detection device includes each module included, and each unit included in each module may be implemented by a processor in an electronic device; of course, the method can also be realized by a specific logic circuit; in an implementation, the processor may be a Central Processing Unit (CPU), a Microprocessor (MPU), a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), or the like.

Fig. 12 is a schematic structural diagram of a fault detection device according to an embodiment of the present application, as shown in fig. 12, where, the device 120 includes a receiving module 121 and a control module 122, where:

A receiving module 121 configured to receive an opening instruction, where the opening instruction is used to instruct to open the ranging module of the device 120;

the control module 122 is configured to respond to the starting instruction, and control the light wave emitter in the ranging module to emit at least one test pulse before controlling the light wave emitter to emit working pulses at first regular intervals so as to perform fault detection on the ranging module and obtain a detection result; the working pulse is used for measuring the distance between the ranging module and the target object;

the control module 122 is further configured to control the working state of the ranging module according to the detection result.

In other embodiments, the control module 122 is configured to, in response to the on command, input a plurality of transient currents to a driving circuit in the ranging module in sequence before controlling the optical wave emitter in the ranging module to emit the working pulse at a first regular interval, so that the driving circuit drives the optical wave emitter to emit the plurality of test pulses in sequence, so as to perform fault detection on the ranging module, and obtain the detection result.

In other embodiments, the control module 122 includes: the first driving unit is configured to sequentially input a plurality of instantaneous currents to a driving circuit in the ranging module, so that the driving circuit drives the light wave emitter to sequentially emit the plurality of test pulses; a first detection unit configured to detect a photocurrent generated by a photoelectric conversion element in the ranging module when each of the test pulses is transmitted; and the first determining unit is configured to determine the detection result according to the relation between each photocurrent and the corresponding threshold range so as to realize fault detection on the ranging module.

In other embodiments, the first determining unit is configured to: under the condition that each photocurrent belongs to a corresponding threshold range, determining that the detection result is that no fault occurs to a component in the ranging module; under the condition that at least one photocurrent is larger than the upper limit value of the corresponding threshold value range, determining that the detection result is that the driving circuit is short-circuited; and under the condition that each photocurrent is smaller than the lower limit value of the corresponding threshold range, determining that the detection result is that the diffusion sheet in the ranging module is fallen off.

In other embodiments, the control module 122 includes: the second driving unit is configured to sequentially input N instantaneous currents to a driving circuit in the ranging module, so that the driving circuit drives the light wave emitter to sequentially emit the N test pulses, and N is an integer greater than 1; and the second determining unit is configured to prohibit the next instantaneous current from being input to the driving circuit to finish fault detection on the ranging module and obtain the detection result under the condition that the characteristic of the transmitted Nth test pulse does not meet the condition.

In other embodiments, the second determining unit is configured to: detecting photocurrent generated by a photoelectric conversion element in the ranging module when the Nth test pulse is transmitted; at least under the condition that the photocurrent is larger than the upper limit value of the corresponding threshold value range, determining that the characteristic of the Nth test pulse does not meet the condition, and determining that the detection result is that the driving circuit is short-circuited; and at least under the condition that the photocurrent is smaller than the lower limit value of the corresponding threshold range, determining that the characteristic of the Nth test pulse does not meet the condition, and determining that the detection result is that the diffusion sheet in the ranging module is fallen.

In other embodiments, the control module 122 is configured to: when the detection result shows that the components in the ranging module are not in failure, controlling the ranging module to input the working current of the light wave emitter to the driving circuit, so that the driving circuit drives the light wave emitter to emit the working pulse at the first regular intervals; closing the ranging module when the detection result is that the diffusion sheet is detached, so as to inhibit the light wave emitter from emitting the working pulse; and under the condition that the detection result is that the driving circuit is short-circuited, the ranging module is closed, or the ranging module is controlled to input other currents smaller than the working current to the driving circuit, so that the driving circuit drives the light wave emitter to emit working pulses at second regular intervals.

The description of the apparatus embodiments above is similar to that of the method embodiments above, with similar advantageous effects as the method embodiments. For technical details not disclosed in the device embodiments of the present application, please refer to the description of the method embodiments of the present application for understanding.

It should be noted that, in the embodiment of the present application, if the fault detection method is implemented in the form of a software functional module, and is sold or used as a separate product, the fault detection method may also be stored in a computer readable storage medium. Based on such understanding, the technical solution of the embodiments of the present application may be embodied essentially or in a part contributing to the related art, in the form of a software product stored in a storage medium, including several instructions for causing an electronic device (which may be a mobile phone, a tablet computer, a notebook computer, a robot, a drone, etc.) to perform all or part of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read Only Memory (ROM), a magnetic disk, an optical disk, or other various media capable of storing program codes. Thus, embodiments of the present application are not limited to any specific combination of hardware and software.

Correspondingly, an electronic device is provided in the embodiment of the present application, fig. 13 is a schematic diagram of a hardware entity of the electronic device in the embodiment of the present application, and as shown in fig. 13, the hardware entity of the electronic device 130 includes: comprising a memory 131 and a processor 132, said memory 131 storing a computer program executable on the processor 132, said processor 132 implementing the steps of the fault detection method provided in the above-mentioned embodiments when said program is executed.

The memory 131 is configured to store instructions and applications executable by the processor 132, and may also cache data (e.g., image data, audio data, voice communication data, and video communication data) to be processed or processed by the respective modules in the processor 132 and the electronic device 130, and may be implemented by a FLASH memory (FLASH) or a random access memory (Random Access Memory, RAM).

Accordingly, embodiments of the present application provide a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps in the fault detection method provided in the above embodiments.

It should be noted here that: the description of the storage medium and apparatus embodiments above is similar to that of the method embodiments described above, with similar benefits as the method embodiments. For technical details not disclosed in the embodiments of the storage medium and the apparatus of the present application, please refer to the description of the method embodiments of the present application for understanding.

It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in various embodiments of the present application, the sequence numbers of the foregoing processes do not mean the order of execution, and the order of execution of the processes should be determined by the functions and internal logic thereof, and should not constitute any limitation on the implementation process of the embodiments of the present application. The foregoing embodiment numbers of the present application are merely for describing, and do not represent advantages or disadvantages of the embodiments.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above described device embodiments are only illustrative, e.g. the division of the units is only one logical function division, and there may be other divisions in practice, such as: multiple units or components may be combined or may be integrated into another system, or some features may be omitted, or not performed. In addition, the various components shown or discussed may be coupled or directly coupled or communicatively coupled to each other via some interface, whether indirectly coupled or communicatively coupled to devices or units, whether electrically, mechanically, or otherwise.

The units described above as separate components may or may not be physically separate, and components shown as units may or may not be physical units; can be located in one place or distributed to a plurality of network units; some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may be separately used as one unit, or two or more units may be integrated in one unit; the integrated units may be implemented in hardware or in hardware plus software functional units.

Those of ordinary skill in the art will appreciate that: all or part of the steps for implementing the above method embodiments may be implemented by hardware related to program instructions, and the foregoing program may be stored in a computer readable storage medium, where the program, when executed, performs steps including the above method embodiments; and the aforementioned storage medium includes: a mobile storage device, a Read Only Memory (ROM), a magnetic disk or an optical disk, or the like, which can store program codes.

Alternatively, the integrated units described above may be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product. Based on such understanding, the technical solution of the embodiments of the present application may be embodied essentially or in a part contributing to the related art, in the form of a software product stored in a storage medium, including several instructions for causing an electronic device (which may be a mobile phone, a tablet computer, a notebook computer, a robot, a drone, etc.) to perform all or part of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a removable storage device, a ROM, a magnetic disk, or an optical disk.

The methods disclosed in the several method embodiments provided in the present application may be arbitrarily combined without collision to obtain a new method embodiment.

The features disclosed in the several product embodiments provided in the present application may be combined arbitrarily without conflict to obtain new product embodiments.

The features disclosed in the several method or apparatus embodiments provided in the present application may be arbitrarily combined without conflict to obtain new method embodiments or apparatus embodiments.

The foregoing is merely an embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of fault detection, the method comprising:

receiving an opening instruction, wherein the opening instruction is used for indicating to open a ranging module of the electronic equipment;

responding to the starting instruction, and before controlling a light wave emitter in the ranging module to emit working pulses at first regular intervals, controlling the light wave emitter to emit at least one test pulse so as to perform fault detection on the ranging module and obtain a detection result; the working pulse is used for measuring the distance between the ranging module and the target object;

according to the detection result, controlling the working state of the ranging module;

wherein, according to the detection result, the working state of the ranging module is controlled, including: when the detection result shows that the components in the ranging module are not in failure, controlling the ranging module to input working current of the light wave emitter to a driving circuit, so that the driving circuit drives the light wave emitter to emit the working pulse at the first regular intervals;

Closing the ranging module when the detection result is that the diffusion sheet is detached, so as to inhibit the light wave emitter from emitting the working pulse; or,

and under the condition that the detection result is that the driving circuit is short-circuited, the ranging module is closed, or the ranging module is controlled to input other currents smaller than the working current to the driving circuit, so that the driving circuit drives the light wave emitter to emit working pulses at second regular intervals.

2. The method of claim 1, wherein controlling the optical wave emitter to emit at least one test pulse to perform fault detection on the ranging module to obtain a detection result comprises:

and sequentially inputting a plurality of instantaneous currents to a driving circuit in the ranging module, so that the driving circuit drives the light wave emitter to sequentially emit a plurality of test pulses, and fault detection is performed on the ranging module to obtain a detection result.

3. The method according to claim 2, wherein the sequentially inputting the plurality of instantaneous currents to the driving circuit in the ranging module, so that the driving circuit drives the optical wave emitter to sequentially emit the plurality of test pulses, so as to perform fault detection on the ranging module, and obtain a detection result, includes:

Sequentially inputting a plurality of instantaneous currents to a driving circuit in the ranging module, so that the driving circuit drives the light wave emitter to sequentially emit a plurality of test pulses;

detecting photocurrent generated by a photoelectric conversion element in the ranging module when each test pulse is transmitted;

and determining the detection result according to the relation between each photocurrent and the corresponding threshold range so as to realize fault detection of the ranging module.

4. A method according to claim 3, wherein said determining the detection result from the relationship between each of the photocurrents and the corresponding threshold value range comprises:

under the condition that each photocurrent belongs to a corresponding threshold range, determining that the detection result is that no fault occurs to a component in the ranging module;

under the condition that at least one photocurrent is larger than the upper limit value of the corresponding threshold value range, determining that the detection result is that the driving circuit is short-circuited;

and under the condition that each photocurrent is smaller than the lower limit value of the corresponding threshold range, determining that the detection result is that the diffusion sheet in the ranging module is fallen off.

5. The method according to claim 2, wherein the sequentially inputting the plurality of instantaneous currents to the driving circuit in the ranging module, so that the driving circuit drives the optical wave emitter to sequentially emit the plurality of test pulses, so as to perform fault detection on the ranging module, and obtain the detection result, includes:

sequentially inputting N instantaneous currents to a driving circuit in the ranging module, so that the driving circuit drives the light wave emitter to sequentially emit N test pulses, wherein N is an integer greater than 1;

and under the condition that the characteristic of the transmitted Nth test pulse does not meet the condition, prohibiting the next instantaneous current from being input into the driving circuit, ending the fault detection on the ranging module, and obtaining the detection result.

6. The method according to claim 5, wherein the obtaining the detection result in the case where the characteristic of the nth test pulse transmitted does not satisfy the condition includes:

detecting photocurrent generated by a photoelectric conversion element in the ranging module when the Nth test pulse is transmitted;

and at least under the condition that the photocurrent is larger than the upper limit value of the corresponding threshold range, determining that the characteristic of the Nth test pulse does not meet the condition, and determining that the detection result is that the driving circuit is short-circuited.

7. The method of claim 6, wherein the method further comprises:

and at least under the condition that the photocurrent is smaller than the lower limit value of the corresponding threshold range, determining that the characteristic of the Nth test pulse does not meet the condition, and determining that the detection result is that the diffusion sheet in the ranging module is fallen.

8. A fault detection device, the device comprising:

the receiving module is configured to receive an opening instruction, wherein the opening instruction is used for indicating to open a ranging module of the device;

the control module is configured to respond to the starting instruction and control the light wave emitter in the ranging module to emit at least one test pulse before controlling the light wave emitter to emit working pulses at first regular intervals so as to perform fault detection on the ranging module and obtain a detection result; the working pulse is used for measuring the distance between the ranging module and the target object;

the control module is further configured to control the working state of the ranging module according to the detection result; wherein, according to the detection result, the working state of the ranging module is controlled, including: when the detection result shows that the components in the ranging module are not in failure, controlling the ranging module to input working current of the light wave emitter to a driving circuit, so that the driving circuit drives the light wave emitter to emit the working pulse at the first regular intervals;

9. An electronic device comprising a memory and a processor, the memory storing a computer program executable on the processor, characterized in that the processor implements the steps of the fault detection method of any of claims 1 to 7 when the program is executed.