A laser ranging method and a handheld laser rangefinder

Abstract

This invention relates to a laser ranging method and a handheld laser rangefinder, comprising: during laser ranging, finding a first target voltage value from one of a gain voltage set and an emission voltage set, and continuing to find a second target voltage value from the other set of the gain voltage set and the emission voltage set; obtaining a final amplified laser signal based on the first and second target voltage values, and calculating the measurement distance between the laser signal and the target object based on the time point of the peak of the final amplified laser signal; finding the target offset distance corresponding to the target gain voltage value from the offset distance set, and adjusting the measurement distance using the target offset distance to obtain the final measurement distance, thereby improving measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of laser ranging technology, and more particularly to a laser ranging method and a handheld laser rangefinder. Background Technology

[0002] In existing technologies, the APD receiving module in handheld laser rangefinders typically adjusts the receiving voltage of the APD to improve the signal reception strength when receiving optical signals. However, the usual approach is a fixed voltage level mode, where a pre-input voltage value is directly provided to increase the gain when an increase in voltage is needed, thereby enabling the acquisition of reflected signals from distant objects.

[0003] However, this method cannot perform targeted gain, so the obtained waveform is not the optimal ranging waveform. A more accurate distance value can only be obtained after a complex algorithm. The complex algorithm increases the computational load of the MCU, affects the measurement efficiency, and the accuracy cannot be guaranteed. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a laser ranging method and a handheld laser rangefinder, which solves the technical problem of low measurement accuracy in the prior art.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0008] In a first aspect, embodiments of the present invention provide a laser ranging method, which is applied to a control module in a handheld laser rangefinder. The handheld laser rangefinder includes a control module and a data storage module controlled by the control module. The data storage module pre-stores a gain voltage set, a transmission voltage set, and an offset distance set. The gain voltage set includes multiple gain voltage values, the transmission voltage set includes multiple transmission voltage values, and the offset distance set includes an offset distance corresponding to each of the multiple gain voltage values. The laser ranging method includes:

[0009] During laser ranging, a first target voltage value is found from one of the voltage sets, the gain voltage set and the emission voltage set, and a second target voltage value is found from the other set of the gain voltage set and the emission voltage set. The first target voltage value and the second target voltage value are both used to make the pulse width of the final amplified laser signal approach zero and the waveform amplitude of the final amplified laser signal greater than a preset waveform amplitude. One of the first target voltage value and the second target voltage value is the target gain voltage value.

[0010] Based on the first target voltage value and the second target voltage value, the final amplified laser signal is obtained, and the measurement distance between the laser signal and the target is calculated based on the time point of the peak of the final amplified laser signal.

[0011] Find the target offset distance corresponding to the target gain voltage value from the offset distance set, and adjust the measurement distance using the target offset distance to obtain the final measurement distance.

[0012] In one possible embodiment, each of the multiple gain voltage values ​​ranges from 60 to 120V, and no two of the multiple gain voltage values ​​are equal.

[0013] In one possible embodiment, each of the plurality of transmit voltage values ​​ranges from 10 to 60V, and no two transmit voltage values ​​are equal.

[0014] In one possible embodiment, the gain voltage set includes multiple gain voltage values ​​sorted according to their magnitude. When the first target voltage value is the target emission voltage value and the second target voltage value is the target gain voltage value, an emission voltage value is first selected from the emission voltage set as a preset emission voltage value, and then the target gain voltage value is obtained from the gain voltage set. The process of obtaining the target gain voltage value includes the following steps: First, when a gain voltage value in the middle of the gain voltage set is selected, a laser signal is emitted according to the preset emission voltage value. Then, the laser signal returned by the object under test is received according to the selected current gain voltage value, and the waveform state of the currently received laser signal is determined. If the waveform of the currently received laser signal is saturated, a gain voltage value is re-obtained in the direction of the minimum gain voltage value in the gain voltage set, and the re-obtained gain voltage value in the direction of the minimum gain voltage value is the intermediate value between the current gain voltage value and the minimum gain voltage value or the previous gain voltage value of the current gain voltage value, until the waveform of the obtained laser signal meets the preset conditions to obtain the target gain voltage.

[0015] In one possible embodiment, the process of obtaining the target gain voltage value further includes the following steps: if the waveform amplitude of the currently received laser signal is less than a preset waveform amplitude, then a gain voltage value is re-obtained in the direction of the maximum gain voltage value of the gain voltage set, and the gain voltage value re-obtained in the direction of the maximum gain voltage value is the intermediate value between the current gain voltage and the maximum gain voltage value or the previous gain voltage value of the current gain voltage value, until the waveform of the obtained laser signal meets the preset conditions, so as to obtain the target gain voltage value.

[0016] In one possible embodiment, the laser ranging method further includes: during the process of acquiring the target gain voltage value, if the minimum gain voltage value is still saturated or the maximum gain voltage value is still less than the preset waveform amplitude, then the minimum gain voltage value or the maximum gain voltage value is selected as the target gain voltage value, and then a qualified emission voltage value is selected from the emission voltage set as the target emission voltage value.

[0017] In one possible embodiment, the laser ranging method further includes: during the process of acquiring a target gain voltage value, if the acquired current gain voltage value and the previous gain voltage value are two adjacent voltage values, and the laser signal waveform saturates when one of the two adjacent voltage values ​​is used, and the laser signal waveform amplitude is less than a preset waveform amplitude when the other of the two adjacent voltage values ​​is used, then the gain voltage value whose laser signal waveform amplitude is less than the preset waveform amplitude is taken as the target gain voltage, and then the transmit voltage value that meets the conditions is selected from the transmit voltage set as the target transmit voltage value.

[0018] In one possible embodiment, the laser ranging method further includes: when the first target voltage value and the second target voltage value are both the maximum voltage values ​​in the corresponding voltage set and the reflected laser signal obtained using them is still less than the preset waveform amplitude, reducing the preset waveform amplitude to obtain a target distance set corresponding to the reduced threshold that meets the conditions; comparing the target distance set with the standard waveform signal within the target distance range to obtain the target waveform, and using the distance corresponding to the target waveform as the measured distance between the target object and the target object.

[0019] In a second aspect, embodiments of the present invention provide a handheld laser rangefinder, including a control module, the control module being used to execute the laser ranging method described in any one of the first aspects.

[0020] (III) Beneficial Effects

[0021] The beneficial effects of this invention are:

[0022] This application provides a laser ranging method. During laser ranging, a first target voltage value is found from one of the voltage sets (gain voltage set and emission voltage set), and a second target voltage value is found from the other set. Both the first and second target voltage values ​​are used to ensure that the pulse width of the final amplified laser signal approaches zero and the waveform amplitude of the final amplified laser signal is greater than a preset waveform amplitude. One of the first and second target voltage values ​​is a target gain voltage value. Subsequently, the final amplified laser signal is obtained based on the first and second target voltage values. The measurement distance to the target object is calculated based on the time point of the peak of the final amplified laser signal. Finally, the target offset distance corresponding to the target gain voltage value is found from the offset distance set, and the measurement distance is adjusted using the target offset distance to obtain the final measurement distance. Compared with existing technologies, this application not only improves measurement efficiency but also measurement accuracy.

[0023] To make the above-mentioned objectives, features and advantages to be achieved by the embodiments of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of a handheld laser rangefinder provided in an embodiment of this application is shown;

[0026] Figure 2 A flowchart of a laser ranging method provided in an embodiment of this application is shown;

[0027] Figure 3 This illustration shows a schematic diagram of a method provided in this application to first find the target gain voltage and then find the target transmission voltage. Detailed Implementation

[0028] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] In existing technologies, the main approach of using automatic gain control (ABD) and automatic drive voltage adjustment is to address the significant impact of ambient temperature on the APD, which can affect measurement accuracy. Therefore, voltage compensation at different temperatures is used to reduce measurement errors. Furthermore, most existing technologies obtain the bias voltage through voltage compensation based on the linear relationship between temperature and voltage. Some technologies also aim to find the optimal voltage or gain for the APD to improve ranging performance and protect it from damage.

[0030] However, in the existing technology, there is no way to adjust the APD gain to adjust the received waveform so that the received waveform is in the optimal identification waveform state, and then calculate the actual distance.

[0031] Based on this, this application provides a laser ranging method. It establishes a set for gain voltage, emission voltage, and offset distance, and during laser ranging, finds a first target voltage value from one of the voltage sets (gain voltage set and emission voltage set) and a second target voltage value from the other set. Both the first and second target voltage values ​​are used to ensure that the pulse width of the final amplified laser signal approaches zero and the waveform amplitude of the final amplified laser signal is greater than a preset waveform amplitude. One of the first and second target voltage values ​​is a target gain voltage value. The final amplified laser signal is then obtained based on the first and second target voltage values. The measurement distance to the target object is calculated based on the time point of the peak of the final amplified laser signal. Finally, the target offset distance corresponding to the target gain voltage value is found from the offset distance set, and the measurement distance is adjusted using the target offset distance to obtain the final measurement distance. Compared with existing technologies, this application not only improves measurement efficiency but also measurement accuracy.

[0032] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0033] Please see Figure 1 , Figure 1 A schematic diagram of a handheld laser rangefinder provided in an embodiment of this application is shown. Figure 1As shown, the laser measuring instrument may include a laser emitting module, an APD receiving module, a signal amplification module, a data storage module, and a control module. The APD receiving module and the signal amplification module are connected, and the laser emitting module, the signal amplification module, and the data storage module are all connected to the control module.

[0034] It should be noted here that... Figure 1 The handheld laser rangefinder may also include more modules, and this application is not limited to this.

[0035] exist Figure 1 On the basis of, such as Figure 2 As shown, Figure 2 A flowchart of a laser ranging method provided in an embodiment of this application is shown. Figure 2 As shown, this laser ranging method can be applied to, for example... Figure 1 The control module in the handheld laser rangefinder shown includes a control module and a data storage module controlled by the control module. The data storage module pre-stores a gain voltage set, a transmission voltage set, and an offset distance set. The gain voltage set includes multiple gain voltage values, the transmission voltage set includes multiple transmission voltage values, and the offset distance set includes the offset distance corresponding to each of the multiple gain voltage values. The data in the above three sets can be sorted in ascending order. Specifically, the laser ranging method includes:

[0036] Step S210: During laser ranging, a first target voltage value is found from one of the voltage sets, the gain voltage set and the emission voltage set, and a second target voltage value is found from the other set. Both the first and second target voltage values ​​are used to ensure that the pulse width of the final amplified laser signal approaches zero and the waveform amplitude of the final amplified laser signal is greater than a preset waveform amplitude. One of the first and second target voltage values ​​is a target gain voltage value.

[0037] It should be understood that the specific number of all gain voltage values ​​in the gain voltage set and the specific value of each gain voltage value can be set according to actual needs, and the embodiments of this application are not limited thereto.

[0038] Optionally, the gain voltage set may include y gain voltage values, where each of the y gain voltage values ​​ranges from 60 to 120V, and no two gain voltage values ​​are equal. Here, y is a preset positive integer. Furthermore, the gain voltage set can be different for handheld laser rangefinders with different ranges; that is, the number of gain voltages in the gain voltage set and the specific voltage value of each gain voltage are preset according to the range of the handheld laser rangefinder.

[0039] Furthermore, the step value between two adjacent gain voltage values ​​in the gain voltage set can be 1V or 2V, etc., that is, the step value can be set according to actual needs, as long as the step value is an integer. The embodiments of this application are not limited to this.

[0040] Furthermore, the data storage module of this application pre-stores an offset distance set, which also includes y offset distances, and each of the y offset distances corresponds to a gain voltage value. That is, any offset distance in the offset distance set corresponds to a gain voltage value in the gain voltage set. Thus, after the target gain voltage is selected, the measurement distance can be adjusted by using the target offset distance corresponding to the selected target gain voltage when calculating the final measurement distance, thereby enabling the final measurement distance.

[0041] It should be noted that the specific value of each offset distance in the y offset distance set can be set at the factory, and it can be obtained through precise measurement.

[0042] It should also be understood that the specific number of all transmit voltage values ​​in the transmit voltage set and the specific voltage value of each transmit voltage value can be set according to actual needs, and the embodiments of this application are not limited thereto.

[0043] Optionally, the set of emitted voltages may include m emitted voltage values, each of which ranges from 10 to 60V, and no two emitted voltage values ​​are equal. Here, m is a preset positive integer. Furthermore, the set of emitted voltages can be different for handheld laser rangefinders with different ranges; that is, the number of emitted voltage values ​​in the set and the specific voltage value of each emitted voltage value are preset according to the range of the handheld laser rangefinder.

[0044] Furthermore, the step value between two adjacent transmit voltage values ​​in the transmit voltage set can be 1V or 2V, etc., that is, the step value can also be set according to actual needs, as long as the step value is an integer. The embodiments of this application are not limited to this.

[0045] It should also be understood that the specific process of finding the first target voltage value from one of the voltage sets of the gain voltage set and the transmit voltage set, and then finding the second target voltage value from the other set of the gain voltage set and the transmit voltage set, can be set according to actual needs, and the embodiments of this application are not limited thereto.

[0046] Optionally, if the first target voltage value is the target gain voltage and the second target voltage value is the target transmission voltage, the target gain voltage can be found first from the gain voltage set, and then the target transmission voltage can be found from the transmission voltage set.

[0047] Optionally, if the first target voltage value is the target transmit voltage and the second target voltage value is the target gain voltage, the target transmit voltage can be found first from the set of transmit voltages, and then the target gain voltage can be found from the set of gain voltages.

[0048] To facilitate understanding of the embodiments of this application, the following description will take the example of first finding the target gain voltage from the gain voltage set and then finding the target transmission voltage from the transmission voltage set.

[0049] Specifically, first, a transmission voltage value is selected from the set of transmission voltages as the preset transmission voltage value, and then the target gain voltage value is obtained from the set of gain voltages; the process of obtaining the target gain voltage value includes the following steps:

[0050] If the middle gain voltage value in the gain voltage set is selected first, a laser signal is emitted according to the preset emission voltage value. Then, the laser signal returned by the object under test is received according to the selected current gain voltage value, and the waveform state of the currently received laser signal is determined.

[0051] If the waveform of the currently received laser signal is saturated, a new gain voltage value is acquired in the direction of the minimum gain voltage value in the gain voltage set. The new gain voltage value acquired in the direction of the minimum gain voltage value is the midpoint between the current gain voltage value and the minimum gain voltage value or the previous gain voltage value of the current gain voltage value. This process continues until the waveform of the acquired laser signal meets the preset conditions to obtain the target gain voltage. Waveform saturation refers to a waveform amplitude greater than a preset waveform amplitude and a pulse width greater than a first preset pulse width. The specific amplitude of the preset waveform amplitude and the specific width of the first preset pulse width can be set according to actual needs, and this application embodiment is not limited to this.

[0052] For example, when reacquiring a gain voltage value in the direction of minimum gain voltage, if the previous gain voltage value is between the current gain voltage value and the minimum gain voltage value, then the gain voltage value reacquiring in the direction of minimum gain voltage is the midpoint between the current gain voltage value and the previous gain voltage value; if the previous gain voltage value is outside the voltage range between the current gain voltage value and the minimum gain voltage value, then the gain voltage value reacquiring in the direction of minimum gain voltage is the midpoint between the current gain voltage value and the minimum gain voltage value, until the pulse width of the acquired laser signal waveform is less than the first preset pulse width and the amplitude of the final gained laser signal waveform is greater than the preset waveform amplitude, then it can be determined as the target gain voltage value. See [link to documentation] for details. Figure 3 Related descriptions;

[0053] If the waveform amplitude of the currently received laser signal is less than the preset waveform amplitude, then a new gain voltage value is obtained in the direction of the maximum gain voltage value in the gain voltage set. The new gain voltage value obtained in the direction of the maximum gain voltage value is the midpoint between the current gain voltage and the maximum gain voltage value or the previous gain voltage value of the current gain voltage value, until the waveform of the acquired laser signal meets the preset conditions to obtain the target gain voltage.

[0054] For example, when reacquiring a gain voltage value in the direction of the maximum gain voltage value, if the previous gain voltage value is between the current gain voltage value and the maximum gain voltage value, then the gain voltage value reacquiring in the direction of the maximum gain voltage value is the midpoint between the current gain voltage value and the previous gain voltage value; if the previous gain voltage value is outside the voltage range between the current gain voltage value and the maximum gain voltage value, then the gain voltage value reacquiring in the direction of the maximum gain voltage value is the midpoint between the current gain voltage value and the maximum gain voltage value, until the pulse width of the acquired laser signal waveform is less than the first preset pulse width and the waveform amplitude of the final gained laser signal is greater than the preset waveform amplitude, then it can be determined as the target gain voltage value. See [link to documentation] for details. Figure 3 Related descriptions.

[0055] It should be noted that if the waveform amplitude of the current signal is greater than the preset waveform amplitude, then the waveform of the current signal can be considered saturated.

[0056] In addition, during the process of obtaining the target gain voltage value, if the minimum gain voltage value is still saturated or the maximum gain voltage value is still less than the preset waveform amplitude, the minimum gain voltage value or the maximum gain voltage value is selected as the target gain voltage value, and then the transmit voltage value that meets the conditions is selected from the transmit voltage set as the target transmit voltage value.

[0057] For example, if the minimum gain voltage value is still saturated, the minimum gain voltage value can be selected as the target gain voltage value, and then a suitable transmit voltage value can be selected from the transmit voltage set as the target transmit voltage value; as another example, if the maximum gain voltage value is still less than the preset waveform amplitude, the maximum gain voltage value can be selected as the target gain voltage value, and then a suitable transmit voltage value can be selected from the transmit voltage set as the target transmit voltage value.

[0058] In addition, during the process of obtaining the target gain voltage value, if the current gain voltage value and the previous gain voltage value are adjacent to each other, and the laser signal waveform saturates when one of the two adjacent gain voltage values ​​is used, and the laser signal waveform amplitude is less than the preset waveform amplitude when the other of the two adjacent gain voltage values ​​is used, then the gain voltage value among the two adjacent voltage values ​​that makes the laser signal waveform amplitude less than the preset waveform amplitude is taken as the target gain voltage. Then, the emission voltage value that meets the conditions is selected from the emission voltage set as the target emission voltage value.

[0059] It should be noted that after obtaining the target gain voltage value, a further target emission voltage value can be selected from the emission voltage set that makes the width of the laser signal reflected by the object under test closer to zero, while keeping the target gain voltage value fixed. Furthermore, the process of obtaining the target emission voltage value is similar to the process of obtaining the target gain voltage; please refer to the relevant description of the target gain voltage acquisition process above for details.

[0060] To facilitate understanding of the embodiments of this application, the process of obtaining the target transmission voltage value is described below through specific embodiments.

[0061] Specifically, with a fixed target gain voltage value, a laser signal is emitted according to the current emission voltage value, and then the laser signal returned by the object under test is received according to the target gain voltage value, and the waveform state of the currently received laser signal is determined.

[0062] If the amplitude of the currently received laser signal is greater than a preset waveform amplitude and the pulse width of the currently received laser signal is greater than a second preset pulse width (at which point it can be considered still saturated), then a new emission voltage value is acquired in the direction of the minimum emission voltage value in the emission voltage set. The new emission voltage value acquired in the direction of the minimum emission voltage value is the midpoint between the current emission voltage value and the minimum emission voltage value, or between the current emission voltage value and the previous emission voltage value, until the acquired laser signal waveform meets the preset conditions to obtain the target emission voltage. The specific width of the second preset pulse width can be set according to actual needs, as long as the second preset pulse width is less than the first preset pulse width. This embodiment is not limited to this. Furthermore, when the pulse width of the waveform is less than the second preset pulse width, the pulse width of the laser signal can be considered to approach zero.

[0063] For example, when reacquiring the emission voltage value in the direction of the minimum emission voltage value, if the previous emission voltage value is between the current emission voltage value and the minimum emission voltage value, then the emission voltage value reacquiring in the direction of the minimum emission voltage value is the midpoint between the current emission voltage value and the previous emission voltage value; if the previous emission voltage value is outside the voltage range between the current emission voltage value and the minimum emission voltage value, then the emission voltage value reacquiring in the direction of the minimum emission voltage value is the midpoint between the current emission voltage value and the minimum emission voltage value, until the pulse width of the acquired laser signal waveform is less than the second preset pulse width (at which point its width can be considered to be closer to zero) and the waveform amplitude of the final amplified laser signal is greater than the preset waveform amplitude (that is, it can be considered to meet the preset conditions), then it can be determined as the target emission voltage value. For details, please refer to [link to relevant documentation]. Figure 3 Related descriptions;

[0064] If the waveform amplitude of the currently received laser signal is less than the preset waveform amplitude, then the emission voltage value is reacquired in the direction of the maximum emission voltage value in the emission voltage set, and the emission voltage value reacquired in the direction of the maximum emission voltage value is the midpoint between the current emission voltage and the maximum emission voltage value or the previous emission voltage value of the current emission voltage value, until the waveform of the acquired laser signal meets the preset conditions to obtain the target emission voltage.

[0065] For example, when re-acquiring the emission voltage value in the direction of the maximum emission voltage value, if the previous emission voltage value is between the current emission voltage value and the maximum emission voltage value, then the emission voltage value re-acquired in the direction of the maximum emission voltage value is the midpoint between the current emission voltage value and the previous emission voltage value; if the previous emission voltage value is outside the voltage range between the current emission voltage value and the maximum emission voltage value, then the emission voltage value re-acquired in the direction of the maximum emission voltage value is the midpoint between the current emission voltage value and the maximum emission voltage value, until the pulse width of the acquired laser signal waveform is less than the second preset pulse width and the amplitude of the final amplified laser signal waveform is greater than the preset waveform amplitude, then it can be determined as the target emission voltage value. See [link to documentation] for details. Figure 3 Related descriptions.

[0066] Furthermore, in the process of obtaining the target transmission voltage value, if the minimum transmission voltage value is still greater than the preset waveform amplitude and its corresponding pulse width is still greater than the second preset pulse width, or if the maximum transmission voltage value is still less than the preset waveform amplitude, then the minimum transmission voltage value or the maximum transmission voltage value shall be selected as the target transmission voltage value.

[0067] For example, if the minimum transmit voltage value is still greater than the preset waveform amplitude and its corresponding pulse width is still greater than the second preset pulse width, then the minimum transmit voltage value can be selected as the target transmit voltage value; as another example, if the maximum transmit voltage value is still less than the preset waveform amplitude, then the maximum transmit voltage value can be selected as the target transmit voltage value.

[0068] In addition, during the process of obtaining the target emission voltage value, if the current emission voltage value and the previous emission voltage value are two adjacent voltage values, and the amplitude of the laser signal waveform is greater than the preset waveform amplitude and the corresponding pulse width is greater than the second preset pulse width when one of the two adjacent voltage values ​​is used, and the amplitude of the laser signal waveform is less than the preset waveform amplitude when the other of the two adjacent voltage values ​​is used, then the emission voltage value among the two adjacent voltage values ​​that makes the amplitude of the laser signal waveform less than the preset waveform amplitude is taken as the target emission voltage.

[0069] Furthermore, if both the first target voltage value and the second target voltage value are the maximum voltage values ​​in the corresponding voltage sets and the reflected laser signal obtained using them is still less than the preset waveform amplitude, the preset waveform amplitude is reduced to obtain the target distance set corresponding to the reduced threshold that meets the conditions; the target distance set is compared with the standard waveform signal within the target distance range to obtain the target waveform, and the distance corresponding to the target waveform is used as the measured distance between the target object and the target.

[0070] For example, if the obtained gain voltage and emission voltage correspond to the maximum voltage value in the voltage set, and the obtained reflected laser signal is still less than the preset waveform amplitude, then the currently returned laser signal is determined to be a weak signal.

[0071] Furthermore, when the received signal is determined to be a weak signal, the processing steps for the weak signal include:

[0072] The laser signal is emitted multiple times continuously using the maximum emission voltage, and the returned laser signal is received using the maximum gain voltage.

[0073] Since the waveform amplitude of the weak signal cannot reach the preset waveform amplitude, after entering the weak signal processing mode, the preset waveform amplitude is first adjusted, and the first intermediate value between the preset waveform amplitude and zero amplitude (i.e., within the range of 0 to the preset waveform amplitude) is taken, and then the laser is emitted multiple times.

[0074] The steps for determining the target distance set are as follows: If, in each acquired return laser signal, there is a valid signal with a waveform amplitude greater than the first intermediate value, and the number of valid signals is within a first preset range, then the distance of the valid signal in a single received signal is calculated. Multiple distance data points measured from each received laser signal are then grouped into a set. The distances that appear most frequently in all sets or appear most frequently within a preset error distance range are taken as the target distances, forming the target distance set. The specific range of the first preset range can be set according to actual needs. For example, the first preset range can be 3 to 10. Furthermore, the preset waveform amplitude can be adjusted by the control module through the ADC interface of the handheld laser rangefinder.

[0075] It should be noted that the specific principle is as follows: the obtained signal contains the target signal and the interference signal. Since the interference signal is a variable signal and the signal returned by the object being measured is a fixed signal, after calculating the distance in the signal multiple times, the signal that appears most frequently is the signal returned by the object being measured, and the corresponding distance is the target distance.

[0076] If in each acquired return laser signal there is no valid signal with a waveform amplitude greater than the first intermediate value, or the number of valid signals is less than the minimum boundary value of the first preset range (for example, it can be 3), then the second intermediate value between the first intermediate value and zero amplitude is taken, and the subsequent processing method in the target distance set determination step is repeated; if in each acquired return laser signal there are more valid signals greater than the first intermediate value than the maximum boundary value of the first preset range (for example, it can be 10), then the intermediate value between the first intermediate value and the preset waveform amplitude is taken and determined as the third intermediate value, and the subsequent processing method in the target distance set determination step is repeated.

[0077] Furthermore, the acquired target distance set is compared with standard waveform signals within that distance range to ultimately obtain the target waveform, calculate the distance, and output it. Specifically, this includes:

[0078] Let the set of target distances be denoted as X = {x1, x2, ..., x}. n}, which includes 1 to n signals (where n is a natural number), and then the average value of the n signals is calculated. ,Right now ;

[0079] Subsequently, according to the formula below, the value of each waveform signal x in the filtered signal is calculated sequentially. i Compared with the average The mean square error is used as the waveform feature CH of each waveform signal. i Let i be any natural number from 1 to n, and let CH be the waveform characteristic of the i-th waveform signal. i The calculation expression is as follows:

[0080] ;

[0081] In the formula, CH i This represents the waveform characteristics of the i-th waveform signal; Let p represent the j-th data in the i-th waveform signal, and let p represent the total number of data in the i-th waveform signal.

[0082] Subsequently, the waveform characteristics CH of the i-th waveform signal are calculated. i Waveform characteristics of standard signals CH s The ratio of CH i / CH s Then, the waveform signal corresponding to the ratio greater than a preset value is taken as the final valid signal. For example, the preset value can be in the range of 0.5 to 0.8, and preferably, the preset value is in the range of 0.7 to 0.8.

[0083] Step S220: Based on the first target voltage value and the second target voltage value, the final amplified laser signal is obtained, and the measurement distance between the laser signal and the target is calculated based on the time point where the peak of the final amplified laser signal is located.

[0084] Specifically, after determining the target gain voltage value and the target emission voltage value, the final amplified laser signal is obtained based on the target gain voltage value and the target emission voltage value, and the measurement distance between the laser signal and the target is calculated based on the time point of the peak of the final amplified laser signal.

[0085] Step S230: Find the target offset distance corresponding to the target gain voltage value from the offset distance set, and adjust the measurement distance using the target offset distance to obtain the final measurement distance.

[0086] Specifically, the target offset distance corresponding to the target gain voltage value is found from the offset distance set, and the measurement distance is adjusted using the target offset distance to obtain the final measurement distance.

[0087] Therefore, by means of the above technical solution, this application can realize automatic adjustment of the full-range gain voltage and automatic adjustment of the transmission voltage, so that the acquired full-range waveform can automatically gain and quickly reach the expected waveform. Then, based on the peak value of the acquired expected waveform, the time point of the waveform peak can be obtained, which can more accurately obtain the time point of the peak of the target object's reflected signal, thereby improving the ranging accuracy.

[0088] It should be understood that the above laser ranging method is merely exemplary, and those skilled in the art can make various modifications based on the above method, and the modified solutions also fall within the protection scope of this application.

[0089] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0090] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions.

[0091] It should be noted that the word "a" or "an" preceding a component does not preclude the existence of multiple such components. This invention can be implemented using hardware comprising several different components and using a suitably programmed computer. Among the listed devices, several of these devices may be embodied by the same hardware. The use of terms such as "first," "second," "third," etc., is merely for convenience and does not indicate any order. These terms can be understood as part of the component names.

[0092] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0093] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the technical solution should be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0094] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the invention's technical solutions and their equivalents, then the invention should also include these modifications and variations.

Claims

1. A laser ranging method, characterized in that, The laser ranging method is applied to a control module in a handheld laser rangefinder. The handheld laser rangefinder includes the control module and a data storage module controlled by the control module. The data storage module pre-stores a gain voltage set, a transmission voltage set, and an offset distance set. The gain voltage set includes multiple gain voltage values, the transmission voltage set includes multiple transmission voltage values, and the offset distance set includes an offset distance corresponding to each of the multiple gain voltage values. The laser ranging method includes: During laser ranging, a first target voltage value is found from one of the voltage sets, the gain voltage set and the emission voltage set, and a second target voltage value is found from the other set of the gain voltage set and the emission voltage set. Both the first and second target voltage values ​​are used to make the pulse width of the final amplified laser signal approach zero and the waveform amplitude of the final amplified laser signal greater than a preset waveform amplitude. One of the first and second target voltage values ​​is a target gain voltage value. Based on the first target voltage value and the second target voltage value, the final amplified laser signal is obtained, and the measurement distance between the laser signal and the target is calculated based on the time point of the peak of the final amplified laser signal. Find the target offset distance corresponding to the target gain voltage value from the offset distance set, and adjust the measurement distance using the target offset distance to obtain the final measurement distance.

2. The laser ranging method according to claim 1, characterized in that, The range of each of the plurality of gain voltage values ​​is 60~120V, and no two of the plurality of gain voltage values ​​are equal.

3. The laser ranging method according to claim 1, characterized in that, The range of each of the plurality of transmission voltage values ​​is 10~60V, and no two of the plurality of transmission voltage values ​​are equal.

4. The laser ranging method according to claim 1, characterized in that, The gain voltage set includes multiple gain voltage values ​​sorted by gain voltage magnitude; when the first target voltage value is the target transmit voltage value and the second target voltage value is the target gain voltage value, a transmit voltage value is first selected from the transmit voltage set as a preset transmit voltage value, and then the target gain voltage value is obtained from the gain voltage set. The process of obtaining the target gain voltage value includes the following steps: If a gain voltage value in the middle of the gain voltage set is selected first, a laser signal is emitted according to the preset emission voltage value. Then, the laser signal returned by the object under test is received according to the selected current gain voltage value, and the waveform state of the currently received laser signal is determined. If the waveform of the currently received laser signal is saturated, a new gain voltage value is obtained in the direction of the minimum gain voltage value of the gain voltage set. The new gain voltage value obtained in the direction of the minimum gain voltage value is the intermediate value between the current gain voltage value and the minimum gain voltage value or the previous gain voltage value of the current gain voltage value, until the waveform of the acquired laser signal meets the preset conditions to obtain the target gain voltage value.

5. The laser ranging method according to claim 4, characterized in that, The process of obtaining the target gain voltage value further includes the following steps: If the waveform amplitude of the currently received laser signal is less than the preset waveform amplitude, then a gain voltage value is reacquired in the direction of the maximum gain voltage value of the gain voltage set, and the gain voltage value reacquired in the direction of the maximum gain voltage value is the intermediate value between the current gain voltage and the maximum gain voltage value or the previous gain voltage value of the current gain voltage value, until the waveform of the acquired laser signal meets the preset condition to obtain the target gain voltage.

6. The laser ranging method according to claim 5, characterized in that, The laser ranging method further includes: In the process of obtaining the target gain voltage value, if the minimum gain voltage value is still saturated or the maximum gain voltage value is still less than the preset waveform amplitude, then the minimum gain voltage value or the maximum gain voltage value is selected as the target gain voltage value, and then a transmission voltage value that meets the conditions is selected from the transmission voltage set as the target transmission voltage value.

7. The laser ranging method according to claim 5, characterized in that, The laser ranging method further includes: In the process of obtaining the target gain voltage value, if the current gain voltage value and the previous gain voltage value are two adjacent voltage values, and the laser signal waveform saturates when one of the two adjacent voltage values ​​is used, and the laser signal waveform amplitude is less than a preset waveform amplitude when the other of the two adjacent voltage values ​​is used, then the gain voltage value whose laser signal waveform amplitude is less than the preset waveform amplitude is taken as the target gain voltage. Then, the emission voltage value that meets the conditions is selected from the emission voltage set as the target emission voltage value.

8. The laser ranging method according to claim 1, characterized in that, The laser ranging method further includes: If both the first target voltage value and the second target voltage value are the maximum voltage values ​​in the corresponding voltage set, and the reflected laser signal obtained using them is still less than the preset waveform amplitude, the preset waveform amplitude is reduced to obtain the target distance set corresponding to the reduced threshold that meets the conditions. The target distance set is compared with the standard waveform signal within the target distance range to obtain the target waveform, and the distance corresponding to the target waveform is used as the measured distance between the target object and the target object.

9. A handheld laser rangefinder, characterized in that, It includes a control module, which is used to execute the laser ranging method according to any one of claims 1 to 8.

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