A handheld laser rangefinder and a method of testing the same

Abstract

This application relates to the field of handheld laser rangefinder technology, and in particular to a handheld laser rangefinder and its testing method. The handheld laser rangefinder body includes a shell, a dual-wavelength laser emitting module, an ambient light intensity sensor, an FPGA time-domain signal processing unit, a temperature compensation system, an LCD screen, and control buttons. The dual-wavelength laser emitting module includes a laser and a light receiver disposed at the end of the shell, and an 808nm / 905nm dual-band laser diode disposed inside the shell. By incorporating the dual-wavelength laser emitting module, the ambient light intensity sensor, the FPGA time-domain signal processing unit, and the temperature compensation system, the handheld laser rangefinder can switch the main wavelength in real time via the ambient light sensor. The switching logic is as follows: when the ambient light sensor detects an illuminance greater than 5000 lux, the 905nm band is automatically activated; when the illuminance is less than or equal to 5000 lux, the 808nm band is used, thereby reducing sunlight interference.

Description

Technical Field

[0001] This application relates to the field of handheld laser rangefinder technology, and in particular to a handheld laser rangefinder and its testing method. Background Technology

[0002] Laser ranging technology is an advanced technology that measures the distance to objects using lasers. Its core principle is to use the monochromaticity and strong directionality of lasers to calculate the distance by measuring the time or phase difference from the emission to the reflection of the laser. It has been widely used in industries, construction, military and other fields.

[0003] A handheld laser rangefinder is a portable device that measures the distance to a target using laser technology. It features high precision and rapid measurement, calculating distance by emitting a laser beam and measuring the round-trip time difference, achieving millimeter-level accuracy. However, existing handheld laser rangefinders still face challenges such as ambient light interference in practical applications.

[0004] Therefore, this application provides a handheld laser rangefinder and its testing method. Summary of the Invention

[0005] The purpose of this application is to solve at least one technical problem raised in the background art.

[0006] This application provides a handheld laser rangefinder, including a handheld laser rangefinder body, which includes a shell, a dual-wavelength laser emitting module, an ambient light intensity sensor, an FPGA time-domain signal processing unit, a temperature compensation system, an LCD screen, and control buttons.

[0007] The dual-wavelength laser emitting module includes a laser and a light receiver disposed at the end of the housing, and an 808nm / 905nm dual-band laser diode disposed inside the housing;

[0008] The temperature compensation system includes a built-in NTC thermistor and a PID temperature control circuit respectively installed inside the housing, which stabilizes the laser's operating temperature within the range of 25±1℃.

[0009] Preferably, the dual-wavelength laser emitting module, ambient light intensity sensor, FPGA time-domain signal processing unit, temperature compensation system and receiver are all located inside the housing, while the LCD screen and control buttons are located on the surface of the housing.

[0010] Preferably, the dual-wavelength laser emission module uses an 808nm / 905nm dual-band laser diode, and switches the main wavelength in real time through an ambient light sensor to reduce sunlight interference. The switching logic is that when the ambient light sensor detects an illuminance greater than 5000 lux, the 905nm band is automatically activated, and when the illuminance is less than or equal to 5000 lux, the 808nm band is used.

[0011] By adopting the above technical solutions, the goal of reducing solar interference can be achieved.

[0012] Preferably, the FPGA time-domain signal processing unit executes a multi-pulse accumulation algorithm, which specifically includes: continuously emitting 10 sets of laser pulses and receiving echo signals, performing exponential decay weighted fusion on the measurement results, and removing abnormal data that deviate from the mean ±2σ.

[0013] By adopting the above technical solution, the goal of improving measurement stability can be achieved.

[0014] Preferably, the outer shell of the handheld laser rangefinder body is provided with a protective mechanism, which is used to protect the LCD screen when the handheld laser rangefinder body is carried. The protective mechanism includes a protective cover that is slidably disposed on the outer surface of the shell, and a counterweight box fixed to the end of the handheld laser rangefinder body. The counterweight box is provided with two synchronous motors for driving the protective cover to automatically extend and retract, and a controller is provided on the outer surface of the counterweight box.

[0015] By adopting the above technical solution, the LCD screen and control buttons on the outer shell of the handheld laser rangefinder can be effectively protected by a protective cover.

[0016] Preferably, the protective mechanism further includes two strip-shaped grooves symmetrically formed on the outer surface of the outer shell, and threaded screws rotatably disposed on the inner walls of the two strip-shaped grooves respectively. The ends of the two threaded screws extend into the interior of the counterweight box and are fixedly connected to the output ends of the two synchronous motors respectively. Rectangular sliders are slidably disposed on the inner walls of the two strip-shaped grooves, and threaded holes that are threadedly connected to the outer surfaces of the two threaded screws are opened on the surfaces of the two rectangular sliders. The ends of the two rectangular sliders are fixedly connected to the inner wall of the protective cover.

[0017] By adopting the above technical solution, the rotation of the threaded screw can drive the rectangular slider to move, thereby enabling the protective cover to move automatically through the rotation of the threaded screw.

[0018] Preferably, the protective cover is provided with a cleaning mechanism inside for cleaning the LCD screen during the retraction of the protective cover. The cleaning mechanism includes a rotating tube rotatably disposed on the inner wall of the protective cover and cleaning bristles evenly disposed on the surface of the rotating tube. A first connecting rod is rotatably disposed on the inner wall of the protective cover, and a fixing block is fixedly disposed on the inner wall of the protective cover. A second connecting rod is rotatably disposed on the surface of the fixing block, penetrating the fixing block. A toothed disc is fixedly disposed at the bottom end of the second connecting rod, and a straight toothed groove that meshes with the toothed disc is opened on the outer surface of the outer shell. A first bevel gear that meshes with each other is fixedly disposed at the top end of the second connecting rod and the surface of the first connecting rod. A second bevel gear that meshes with each other is fixedly disposed at the end of the first connecting rod and the surface of the rotating tube.

[0019] By adopting the above technical solution, the protective cover can rotate under the action of the straight tooth groove during its movement. The rotation of the toothed disc drives the second connecting rod to rotate. The rotation of the second connecting rod drives the first connecting rod to rotate under the action of the two first bevel gears. The rotation of the first connecting rod drives the rotating tube to rotate under the action of the two second bevel gears. The rotation of the rotating tube drives the cleaning brush bristles to rotate, thereby achieving the purpose of effectively cleaning the surface of the LCD screen and control buttons in sequence during the retraction of the protective cover.

[0020] Preferably, the cleaning mechanism further includes a detachable mounting tube threaded to the outer surface of the protective cover, one end of the rotating tube extending into the interior of the mounting tube, a ventilation mesh fixed to the inner wall of the end of the mounting tube, and a plurality of dust suction holes equally spaced on the surface of the rotating tube.

[0021] By adopting the above technical solution, dust can be effectively collected through the installation of pipes and ventilation nets.

[0022] Preferably, the end of the rotating tube is fixed with two symmetrical mounting rods, and the ends of the two mounting rods are fixed with mounting columns. The outer surface of the mounting columns is arranged in a circumferential array with four suction fan blades.

[0023] By adopting the above technical solution, the rotation of the rotating tube can drive the fan blades to rotate, thereby enabling the rotating tube to effectively adsorb the dust swept up through the dust suction holes.

[0024] This application also provides a testing method for a handheld laser rangefinder, including the following steps:

[0025] S1. Preparation before testing: Hold the handheld laser rangefinder in your hand and start the two synchronous motors through the controller to automatically extend the protective cover, exposing the LCD screen and control buttons on the handheld laser rangefinder.

[0026] S2. To test the distance, point the front of the handheld laser rangefinder at the object being measured, turn on the laser using the control button, and ensure that the laser point emitted by the laser accurately falls on the object being measured. The reflected laser light is received by the optical receiver, and the distance is displayed on the LCD screen on the handheld laser rangefinder and recorded simultaneously.

[0027] S3. Post-test operation: After the test is completed, the controller starts the two synchronous motors to reverse, causing the protective cover to retract. The protective cover covers the LCD screen and control buttons on the main body of the handheld laser rangefinder, thus protecting the LCD screen and control buttons.

[0028] In summary, this application includes at least one of the following beneficial technical effects:

[0029] 1. The handheld laser rangefinder and its testing method described in this application, by setting up a dual-wavelength laser emission module, an ambient light intensity sensor, an FPGA time-domain signal processing unit, and a temperature compensation system, enables the handheld laser rangefinder to switch the main wavelength in real time through the ambient light sensor. The switching logic is that when the ambient light sensor detects an illuminance greater than 5000 lux, it automatically activates the 905nm band, and when the illuminance is less than or equal to 5000 lux, it uses the 808nm band to reduce sunlight interference. At the same time, it continuously emits 10 sets of laser pulses and receives echo signals, performs exponential attenuation weighted fusion on the measurement results, and removes abnormal data that deviate from the mean ±2σ, thereby improving the measurement stability.

[0030] 2. The handheld laser rangefinder and its testing method described in this application, by setting a protective mechanism, enables the handheld laser rangefinder to, after use, be activated by a controller to drive two synchronous motors to rotate two threaded screws. The rotation of the threaded screws drives a rectangular slider to move, thereby causing the protective cover to automatically retract, covering the LCD screen and control buttons on the outer shell of the handheld laser rangefinder. This effectively protects the LCD screen and control buttons on the outer shell of the handheld laser rangefinder and effectively improves the service life of the handheld laser rangefinder.

[0031] 3. The handheld laser rangefinder and its testing method described in this application, by setting up a cleaning mechanism, during the retraction of the protective cover, the movement of the protective cover drives the toothed disc to move on the inner wall of the straight tooth groove, thereby driving the toothed disc to rotate. The rotation of the toothed disc drives the second connecting rod to rotate. The rotation of the second connecting rod, under the action of two first bevel gears, drives the first connecting rod to rotate. The rotation of the first connecting rod, under the action of two second bevel gears, drives the rotating tube to rotate. The rotation of the rotating tube drives the cleaning brush bristles to rotate, thereby achieving the purpose of effectively cleaning the surface of the LCD screen and control buttons in sequence during the retraction of the protective cover. At the same time, during the rotation of the rotating tube, it can drive the suction fan blades to rotate, so that the rotating tube can effectively adsorb the dust swept up through the dust suction hole and collect it through the installation tube. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of this application;

[0033] Figure 2 This is a side view of the structure of Embodiment 1 of this application;

[0034] Figure 3 This is a schematic diagram of the overall structure of Embodiment 2 of this application;

[0035] Figure 4 This is a side view of the structure of Embodiment 2 of this application;

[0036] Figure 5 This is a bottom view of the structure of Embodiment 2 of this application;

[0037] Figure 6 This application Figure 5 Enlarged structural diagram at point A in the middle;

[0038] Figure 7 This is a schematic cross-sectional view of the protective cover in Embodiment 2 of this application;

[0039] Figure 8 This application Figure 7 Enlarged structural diagram at point B;

[0040] Figure 9 This is a schematic diagram of the cross-sectional structure of the installation pipe in Embodiment 2 of this application;

[0041] Figure 10 This application Figure 9 Enlarged structural diagram at point C.

[0042] Explanation of reference numerals in the attached figures:

[0043] 100. Handheld laser rangefinder body; 101. Housing; 102. LCD screen; 103. Control buttons; 104. Laser; 105. Optical receiver;

[0044] 200. Protective mechanism; 201. Protective cover; 202. Counterweight box; 203. Controller; 204. Lead screw; 205. Rectangular slider;

[0045] 300. Cleaning mechanism; 301. Rotating tube; 302. Cleaning bristles; 303. First connecting rod; 304. Second connecting rod; 305. Gear plate; 306. Straight tooth groove; 307. First bevel gear; 308. Second bevel gear; 309. Mounting tube; 3010. Ventilation screen; 3011. Dust suction hole; 3012. Mounting rod; 3013. Mounting column; 3014. Fan blades. Detailed Implementation

[0046] The following combination Figures 1 to 10 This application will be described in further detail below.

[0047] Example 1

[0048] Please refer to the following carefully. Figure 1 , Figure 2 A handheld laser rangefinder and its testing method are disclosed. The handheld laser rangefinder body 100 includes a housing 101, a dual-wavelength laser emitting module, an ambient light intensity sensor, an FPGA time-domain signal processing unit, a temperature compensation system, an LCD display 102, and control buttons 103. The dual-wavelength laser emitting module includes a laser 104 and a light receiver 105 disposed at the end of the housing 101, and an 808nm / 905nm dual-band laser diode disposed inside the housing 101. The temperature compensation system includes a built-in NTC thermistor and a PID temperature control circuit disposed inside the housing 101 to stabilize the operating temperature of the laser 104 within the range of 25±1℃.

[0049] Specifically, the main wavelength is switched in real time by an ambient light sensor. When the ambient light sensor detects an illuminance greater than 5000 lux, the 905nm band is automatically activated, and when the illuminance is less than or equal to 5000 lux, the 808nm band is used to reduce sunlight interference.

[0050] Please refer to this carefully. Figure 1 , Figure 2 The dual-wavelength laser emission module, ambient light intensity sensor, FPGA time-domain signal processing unit, temperature compensation system and receiver are all located inside the housing 101, while the LCD screen 102 and control buttons 103 are located on the surface of the housing 101.

[0051] Specifically, the handheld laser rangefinder body 100 can be conveniently controlled via the LCD screen 102 and control buttons 103.

[0052] Please refer to this carefully. Figure 1 , Figure 2 The dual-wavelength laser emission module uses an 808nm / 905nm dual-band laser diode. The main wavelength is switched in real time by an ambient light sensor to reduce sunlight interference. The switching logic is that when the ambient light sensor detects an illuminance greater than 5000 lux, the 905nm band is automatically activated, and when the illuminance is less than or equal to 5000 lux, the 808nm band is used.

[0053] Specifically, it can achieve the goal of reducing sunlight interference.

[0054] Please refer to this carefully. Figure 1 , Figure 2 The FPGA time-domain signal processing unit executes a multi-pulse accumulation algorithm, which specifically includes: continuously emitting 10 sets of laser pulses and receiving echo signals, performing exponential decay weighted fusion of measurement results, and removing abnormal data that deviate from the mean ±2σ.

[0055] Specifically, it can achieve the goal of improving the stability of measurement results.

[0056] In this embodiment, by setting up a dual-wavelength laser emission module, an ambient light intensity sensor, an FPGA time-domain signal processing unit, and a temperature compensation system, the handheld laser rangefinder can switch the main wavelength in real time through the ambient light sensor. The switching logic is to automatically activate the 905nm band when the ambient light sensor detects an illuminance greater than 5000 lux, and use the 808nm band when the illuminance is less than or equal to 5000 lux, thereby reducing sunlight interference. At the same time, it continuously emits 10 sets of laser pulses and receives echo signals, performs exponential attenuation weighted fusion on the measurement results, and removes abnormal data that deviate from the mean ±2σ, thereby improving the measurement stability.

[0057] Example 2

[0058] Based on Example 1, referring to Figures 3 to 10 And unlike Example 1, the following is true:

[0059] Please refer to this carefully. Figure 3 , Figure 4 The outer shell 101 of the handheld laser rangefinder body 100 is provided with a protective mechanism 200, which is used to protect the LCD screen 102 when the handheld laser rangefinder body 100 is carried. The protective mechanism 200 includes a protective cover 201 that is slidably disposed on the outer surface of the outer shell 101, and a counterweight box 202 fixed to the end of the handheld laser rangefinder body 100. The counterweight box 202 is provided with two synchronous motors for driving the protective cover 201 to automatically extend and retract, and a controller 203 is provided on the outer surface of the counterweight box 202.

[0060] Specifically, the protective cover 201 can effectively protect the LCD screen 102 and control buttons 103 on the outer shell 101 of the handheld laser rangefinder body 100.

[0061] Please refer to this carefully. Figure 4 , Figure 6 The protective mechanism 200 also includes two strip-shaped grooves symmetrically opened on the outer surface of the housing 101, and threaded screws 204 respectively rotatably set on the inner wall of the two strip-shaped grooves. The ends of the two threaded screws 204 extend into the interior of the counterweight box 202 and are fixedly connected to the output ends of the two synchronous motors respectively. Rectangular sliders 205 are slidably arranged on the inner wall of the two strip-shaped grooves, and threaded holes are opened on the surface of the two rectangular sliders 205 to be threadedly connected to the outer surface of the two threaded screws 204. The ends of the two rectangular sliders 205 are fixedly connected to the inner wall of the protective cover 201.

[0062] Specifically, the rotation of the threaded screw 204 can drive the rectangular slider 205 to move, thereby enabling the protective cover 201 to move automatically through the rotation of the threaded screw 204.

[0063] In this invention, by setting up a protective mechanism 200, the handheld laser rangefinder can, after use, be activated by the controller 203 to start two synchronous motors to drive two threaded screws 204 to rotate. The rotation of the threaded screws 204 drives the rectangular slider 205 to move, thereby causing the protective cover 201 to automatically retract, covering the LCD screen 102 and control buttons 103 on the outer shell 101 of the handheld laser rangefinder. This effectively protects the LCD screen 102 and control buttons 103 on the outer shell 101 of the handheld laser rangefinder, and effectively improves the service life of the handheld laser rangefinder.

[0064] Please refer to this carefully. Figure 5 , Figure 6 , Figure 7 , Figure 8 The protective cover 201 is equipped with a cleaning mechanism 300 for cleaning the LCD screen 102 during the retraction of the protective cover 201. The cleaning mechanism 300 includes a rotating tube 301 rotatably mounted on the inner wall of the protective cover 201 and cleaning bristles 302 evenly mounted on the surface of the rotating tube 301. A first connecting rod 303 is rotatably mounted on the inner wall of the protective cover 201, and a fixing block is fixedly mounted on the inner wall of the protective cover 201. A second connecting rod 304 is rotatably mounted on the surface of the fixing block, and a gear plate 305 is fixedly mounted at the bottom end of the second connecting rod 304. A straight tooth groove 306 that meshes with the gear plate 305 is opened on the outer surface of the outer shell 101. A first bevel gear 307 that meshes with each other is fixedly mounted at the top end of the second connecting rod 304 and the surface of the first connecting rod 303. A second bevel gear 308 that meshes with each other is fixedly mounted at the end of the first connecting rod 303 and the surface of the rotating tube 301.

[0065] Specifically, during the movement of the protective cover 201, the gear disk 305 is rotated under the action of the straight tooth groove 306. The rotation of the gear disk 305 drives the second connecting rod 304 to rotate. The rotation of the second connecting rod 304 drives the first connecting rod 303 to rotate under the action of the two first bevel gears 307. The rotation of the first connecting rod 303 drives the rotating tube 301 to rotate under the action of the two second bevel gears 308. The rotation of the rotating tube 301 drives the cleaning bristles 302 to rotate, thereby achieving the purpose of effectively cleaning the surfaces of the LCD screen 102 and the control button 103 in sequence during the retraction of the protective cover 201.

[0066] Please refer to this carefully. Figure 9 , Figure 10 The cleaning mechanism 300 also includes a detachable mounting tube 309 that is threaded to the outer surface of the protective cover 201. One end of the rotating tube 301 extends into the interior of the mounting tube 309. A ventilation mesh 3010 is fixed to the inner wall of the end of the mounting tube 309, and a number of dust suction holes 3011 are equidistantly opened on the surface of the rotating tube 301.

[0067] Specifically, dust can be effectively collected through the installation pipe 309 and the ventilation net 3010.

[0068] Please refer to this carefully. Figure 9 , Figure 10 Two symmetrical mounting rods 3012 are fixed to the end of the rotating tube 301, and mounting posts 3013 are fixed to the ends of the two mounting rods 3012. Four suction fan blades 3014 are arranged in a circumferential array on the outer surface of the mounting posts 3013.

[0069] Specifically, the rotation of the rotating tube 301 can drive the suction fan blades 3014 to rotate, thereby enabling the rotating tube 301 to effectively absorb the dust swept up through the suction hole 3011.

[0070] The cleaning mechanism 300, during the retraction of the protective cover 201, causes the gear disc 305 to move along the inner wall of the straight tooth groove 306, thereby rotating the gear disc 305. The rotation of the gear disc 305 causes the second connecting rod 304 to rotate. The rotation of the second connecting rod 304, under the action of the two first bevel gears 307, causes the first connecting rod 303 to rotate. The rotation of the first connecting rod 303, under the action of the two second bevel gears 308, causes the rotating tube 301 to rotate. The rotation of the rotating tube 301 causes the cleaning bristles 302 to rotate. This achieves the purpose of effectively cleaning the surfaces of the LCD screen 102 and the control buttons 103 sequentially during the retraction of the protective cover 201. At the same time, the rotation of the rotating tube 301 causes the suction fan blades 3014 to rotate, enabling the rotating tube 301 to effectively adsorb the dust swept up through the suction hole 3011 and collect it through the mounting tube 309.

[0071] This application also provides a testing method for a handheld laser rangefinder, including the following steps:

[0072] S1. Preparation before testing: Hold the handheld laser rangefinder body 100 in your hand and start the two synchronous motors through the controller 203 to drive the protective cover 201 to extend automatically, so that the LCD screen 102 and control buttons 103 on the handheld laser rangefinder body 100 are exposed.

[0073] S2. Test distance: Point the front end of the handheld laser rangefinder 100 at the object to be measured, and turn on the laser 104 through the control button 103 so that the laser point emitted by the laser 104 accurately falls on the object to be measured. The reflected laser is received through the light receiver 105, and the distance is displayed on the LCD screen 102 on the handheld laser rangefinder 100 and recorded at the same time.

[0074] S3. Post-test operation: After the test is completed, the controller 203 starts the two synchronous motors to reverse, driving the protective cover 201 to retract, so that the protective cover 201 covers the LCD screen 102 and control buttons 103 on the outer shell 101 of the handheld laser rangefinder body 100, thereby protecting the LCD screen 102 and control buttons 103.

[0075] Working principle:

[0076] In practical use, this handheld laser rangefinder can switch the main wavelength in real time via an ambient light sensor. The switching logic is as follows: when the ambient light sensor detects an illuminance greater than 5000 lux, it automatically activates the 905nm band; when the illuminance is less than or equal to 5000 lux, it uses the 808nm band to reduce sunlight interference. Simultaneously, it continuously emits 10 sets of laser pulses and receives echo signals, performs exponential attenuation weighted fusion of the measurement results, and removes abnormal data deviating from the mean ±2σ, thereby improving measurement stability. After use, the controller 203 activates two synchronous motors to rotate two lead screws 204. The rotation of the lead screws 204 moves the rectangular slider 205, causing the protective cover 201 to automatically retract, covering the LCD screen 102 and control buttons 103 on the handheld laser rangefinder housing 101. The key 103 provides effective protection, significantly extending the lifespan of the handheld laser rangefinder. Simultaneously, during the retraction of the protective cover 201, the movement of the cover 201 causes the gear disc 305 to move along the inner wall of the straight tooth groove 306, thus rotating the gear disc 305. The rotation of the gear disc 305 drives the second connecting rod 304 to rotate. The rotation of the second connecting rod 304, under the action of the two first bevel gears 307, drives the first connecting rod 303 to rotate. The rotation of the first connecting rod 303, under the action of the two second bevel gears 308, drives the rotating tube 301 to rotate. The rotation of the rotating tube 301 drives the cleaning brush bristles 302 to rotate, thereby achieving the purpose of effectively cleaning the surfaces of the LCD screen 102 and the control key 103 sequentially during the retraction of the protective cover 201. Simultaneously, the rotation of the rotating tube 301 drives the suction fan blades 3014 to rotate, enabling the rotating tube 301 to effectively absorb the dust swept up through the suction hole 3011 and collect it through the mounting tube 309.

[0077] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be included within the scope of protection of this application.

Claims

1. A handheld laser rangefinder, characterized in that, The device includes a handheld laser rangefinder body (100), which includes a shell (101), a dual-wavelength laser emission module, an ambient light intensity sensor, an FPGA time-domain signal processing unit, a temperature compensation system, an LCD screen (102), and control buttons (103). The dual-wavelength laser emitting module includes a laser (104) and a light receiver (105) disposed at the end of the housing (101), and an 808nm / 905nm dual-band laser diode disposed inside the housing (101); The temperature compensation system includes a built-in NTC thermistor and a PID temperature control circuit respectively installed inside the housing (101) to stabilize the operating temperature of the laser (104) within the range of 25±1℃.

2. The handheld laser rangefinder according to claim 1, characterized in that, The dual-wavelength laser emission module, ambient light intensity sensor, FPGA time-domain signal processing unit, temperature compensation system and receiver are all located inside the housing (101), and the LCD screen (102) and control buttons (103) are all located on the surface of the housing (101).

3. A handheld laser rangefinder according to claim 1, characterized in that, The dual-wavelength laser emission module uses an 808nm / 905nm dual-band laser diode. The main wavelength is switched in real time by an ambient light sensor to reduce sunlight interference. The switching logic is that when the ambient light sensor detects an illuminance greater than 5000 lux, the 905nm band is automatically activated, and when the illuminance is less than or equal to 5000 lux, the 808nm band is used.

4. A handheld laser rangefinder according to claim 1, characterized in that, The FPGA time-domain signal processing unit executes a multi-pulse accumulation algorithm, which specifically includes: continuously emitting 10 sets of laser pulses and receiving echo signals, performing exponential decay weighted fusion on the measurement results, and removing abnormal data that deviate from the mean ±2σ.

5. A handheld laser rangefinder according to claim 1, characterized in that, The outer shell (101) of the handheld laser rangefinder body (100) is provided with a protective mechanism (200) for protecting the liquid crystal display screen (102) when the handheld laser rangefinder body (100) is carried. The protective mechanism (200) includes a protective cover (201) that is slidably disposed on the outer surface of the outer shell (101) and a counterweight box (202) fixed to the end of the handheld laser rangefinder body (100). The counterweight box (202) is provided with two synchronous motors for automatically extending and retracting the protective cover (201) inside, and a controller (203) is provided on the outer surface of the counterweight box (202).

6. A handheld laser rangefinder according to claim 5, characterized in that, The protective mechanism (200) further includes two strip grooves symmetrically opened on the outer surface of the outer shell (101), and threaded screws (204) rotatably set on the inner walls of the two strip grooves respectively. The ends of the two threaded screws (204) extend into the interior of the counterweight box (202) and are fixedly connected to the output ends of the two synchronous motors respectively. Rectangular sliders (205) are slidably arranged on the inner walls of the two strip grooves, and threaded holes that are threadedly connected to the outer surfaces of the two threaded screws (204) are opened on the surfaces of the two rectangular sliders (205). The ends of the two rectangular sliders (205) are fixedly connected to the inner wall of the protective cover (201).

7. A handheld laser rangefinder according to claim 6, characterized in that, The protective cover (201) is internally equipped with a cleaning mechanism (300) for cleaning the liquid crystal display screen (102) during the retraction of the protective cover (201). The cleaning mechanism (300) includes a rotating tube (301) rotatably disposed on the inner wall of the protective cover (201) and cleaning bristles (302) evenly disposed on the surface of the rotating tube (301). A first connecting rod (303) is rotatably disposed on the inner wall of the protective cover (201), and a fixing block is fixedly disposed on the inner wall of the protective cover (201). The surface of the fixing block rotates... A second connecting rod (304) is movably provided with a through-fixed block. A toothed disc (305) is fixed at the bottom end of the second connecting rod (304), and a straight toothed groove (306) that meshes with the toothed disc (305) is opened on the outer surface of the outer shell (101). A first bevel gear (307) that meshes with each other is fixed at the top end of the second connecting rod (304) and the surface of the first connecting rod (303). A second bevel gear (308) that meshes with each other is fixed at the end of the first connecting rod (303) and the surface of the rotating tube (301).

8. A handheld laser rangefinder according to claim 7, characterized in that, The cleaning mechanism (300) also includes a removable mounting tube (309) threaded to the outer surface of the protective cover (201). One end of the rotating tube (301) extends into the interior of the mounting tube (309). A ventilation mesh (3010) is fixed to the inner wall of the end of the mounting tube (309), and a plurality of dust suction holes (3011) are equidistantly opened on the surface of the rotating tube (301).

9. A handheld laser rangefinder according to claim 8, characterized in that, The rotating tube (301) has two symmetrical mounting rods (3012) fixed at its end, and the two mounting rods (3012) have mounting posts (3013) fixed at their ends. The outer surface of the mounting posts (3013) is provided with four suction fan blades (3014) arranged in a circumferential array.

10. A testing method for a handheld laser rangefinder according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Preparation before testing: Hold the handheld laser rangefinder body (100) in your hand and start the two synchronous motors through the controller (203) to drive the protective cover (201) to extend automatically, so that the LCD screen (102) and control buttons (103) on the handheld laser rangefinder body (100) are exposed. S2. Test distance: Align the front end of the handheld laser rangefinder (100) with the object to be measured, and turn on the laser (104) through the control button (103) so that the laser point emitted by the laser (104) accurately falls on the object to be measured. The reflected laser is received through the light receiver (105), and the distance is displayed on the LCD screen (102) on the handheld laser rangefinder (100) and recorded at the same time. S3. Post-test operation: After the test is completed, the controller (203) starts the two synchronous motors to reverse, driving the protective cover (201) to retract, so that the protective cover (201) covers the LCD screen (102) and control buttons (103) on the outer shell (101) of the handheld laser rangefinder body (100), thereby protecting the LCD screen (102) and control buttons (103).

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