Ground material identification method and distance measurement method based on ground material identification method

Abstract

The invention relates to the field of distance detection, and particularly provides a ground material identification method and a distance measurement method based on the ground material identification method. The ground material identification method comprises the following steps that S1, first light intensity and second light intensity are obtained, the first light intensity is light field intensity in the vertical reflection direction, and the second light intensity is light field intensity in the mirror reflection direction; s2, determining a ground material according to the difference between the first light intensity and the second light intensity, and obtaining a surface correction factor A; and determining the ground material according to the surface correction factor. On the basis, the distance measurement method further comprises the step S3 of obtaining a distance L to be measured according to the surface correction factor A, the first light intensity and the second light intensity. According to the invention, the surface correction factor A is introduced for correcting the interference of the reflection characteristics of different materials on the light intensity measurement, the detection error caused by the material difference is reduced, and the distance measurement accuracy is improved.

Description

Technical Field

[0001] This application relates to the field of distance detection. Specifically, it relates to a method for identifying ground materials and a ranging method based on the same. Background Art

[0002] A floor sweeper is a device that realizes sweeping and mopping in an operating environment. During the operation process, it is necessary to accurately identify changes in the ground height to ensure the coherence and safety of the cleaning process. If there are pits, steps, or protrusions on the ground, and the distance recognition is inaccurate, the floor sweeper may fall into the pit, get stuck on the obstacle, or be damaged due to falling, affecting normal operation.

[0003] In the prior art, floor sweepers generally use infrared sensors, laser ranging devices, or optical sensors based on the time-of-flight principle for distance measurement to achieve the perception of ground height changes, obstacles, and boundaries. These detection devices emit light beams with specific wavelengths and receive the signals reflected from the surface of the target object. Based on the time delay or light intensity change between transmission and reception, the distance to the object is calculated. Due to its simple structure and fast response speed, the optical detection method is widely used in floor sweepers.

[0004] However, during actual use, due to the large differences in the reflection characteristics of different ground materials (such as polished floors, rough carpets, frosted tiles, metal components, etc.) for light signals, the intensity of the reflected light signals detected at the receiving end fluctuates significantly, resulting in optical path energy loss and reception distortion. Specifically, some high-reflection materials may cause the echo signal to be too strong and cause saturation, while low-reflection materials may cause signal attenuation or even failure to detect an effective echo, resulting in deviation of the ranging result. Due to the above reasons, the existing optical distance detection solutions are difficult to ensure stable and accurate distance perception in an application environment with frequent material changes and complex surface conditions, and are prone to problems such as the floor sweeping robot falling, getting stuck, and missing cleaning, affecting the overall cleaning effect and equipment reliability.

[0005] Therefore, there is a need for a method that can effectively suppress the influence of ground material differences on the detection result to improve the accuracy of ground condition recognition. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for identifying ground materials and a ranging method based on the same to solve the problem in the prior art that ground material differences affect distance detection and the ground condition recognition is inaccurate, aiming at the deficiencies in the above-mentioned prior art.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows: The present application provides a ranging method based on ground material recognition, and the method includes the following steps (wherein, steps S1 and S2 can be used for ground material recognition): S1. Obtain a first light intensity and a second light intensity, where the first light intensity is the light field intensity in the direction of vertical reflection, and the second light intensity is the light field intensity in the direction of specular reflection; S2. Determine the ground material by using the difference between the first light intensity and the second light intensity, and obtain a surface correction factor A; S3. Obtain a distance L to be measured according to the surface correction factor A, the first light intensity, and the second light intensity.

[0008] In the present application, the first light intensity is the light intensity of the vertical reflection or diffuse reflection component, and the second light intensity is the light field intensity in the direction of specular reflection, with a relatively strong directivity. Since the intensity of specularly reflected light is very sensitive to the reflection path length, when the distance between the device and the ground changes, the angle and intensity of the reflected light returning to the second light detector will change significantly, so that the light intensity received by the second light detector shows an obvious distance dependence. The diffuse reflected light received by the first light detector is relatively evenly distributed, and the amplitude of its light intensity change with distance is small. That is, based on the inverse law of light intensity, the light intensity is related to the distance, and the change of the light intensity with different angles and reflection characteristics with distance can be used to detect the change of the distance.

[0009] In order to improve the ranging accuracy under various ground material conditions, it is proposed to introduce a surface correction factor A to dynamically compensate for the interference of different surface reflection characteristics on the light intensity. Since the differences in ground materials will significantly affect the distribution characteristics of the reflected light. For example, smooth tiles are mainly specularly reflected, while rough carpets produce a large amount of diffuse reflection. The reflection differences unrelated to the distance will cause the signal received by the light detector to shift, thus affecting the distance estimation based on the light intensity. Specifically, a smooth surface will enhance the specularly reflected light, resulting in an overestimated distance; while a rough surface weakens the specularly reflected light in the specular direction and enhances the diffuse reflection, causing an underestimated distance. By introducing a correction factor A associated with the surface reflection characteristics, the final distance calculation result is corrected: when the surface is rough and the estimated value is small, the amplification factor A is set to a larger value to compensate for the false "distance contraction" caused by insufficient reflection energy; when the surface is smooth and the estimated value is large, the amplification factor A is set to a smaller value to suppress the "distance amplification" caused by excessive reflection. By introducing the surface reflection information into the correction factor model, the systematic error caused by material differences can be significantly reduced, making the ranging result more accurate and improving the adaptability in complex ground environments. The present application is based on the "inverse law of light intensity", and through the analysis of the difference in light intensity between two channels, combined with surface adaptive correction, it reduces the influence of different floor materials on the distance detection result and provides a method for accurately identifying the distance.

[0010] Furthermore, the surface correction factor A is determined by the following expression: where e is the base of the natural logarithm, , I1 is the first light intensity, and I2 is the second light intensity. The introduced surface correction factor A does not adopt a fixed value or a simple piecewise setting. Instead, a continuous and smooth non-linear function model is constructed based on the light intensity reflectance ratio, enabling the factor to adaptively and dynamically adjust with the change of the ground reflection characteristics. This function has the property of being continuously differentiable, enabling a smooth transition between a rough diffuse reflection surface and a smooth specular reflection surface, thus effectively avoiding the numerical jump problem caused by traditional linear interpolation methods at the parameter mutation, significantly reducing the systematic error caused by surface reflection differences, and making the distance detection more accurate.

[0011] Furthermore, the distance L to be measured is determined by the following expression: where A is the surface correction factor, I1 is the first light intensity, I2 is the second light intensity, and C1 and C2 are compensation parameters. On the one hand, a distance calculation model based on the difference and normalized ratio of the two light intensities is adopted. This model takes the difference between the first light intensity and the second light intensity as the core variable reflecting the change of the ground distance, and at the same time introduces the sum of the two as the normalized denominator to eliminate the interference caused by the fluctuation of the light source intensity, different surface reflectivities, or environmental brightness changes to the measurement result. On the other hand, the main difference part is dynamically amplified or compressed by setting the surface correction factor, enabling the entire ranging calculation process to automatically adapt to the reflection characteristics of different types of ground. On the other hand, compensation parameters are also introduced into the calculation model to correct the systematic deviation caused by device structure offset, optical path error, or material refraction. It can enhance the ranging adaptability of the system to various ground environments, effectively reduce the error caused by light intensity change and material difference, and improve the accuracy of non-contact distance recognition.

[0012] Furthermore, the first light intensity and the second light intensity are detected by the following device: The device includes a housing body. A detection hole is provided on the bottom surface of the housing body, and a light source, a first light detector, and a second light detector are fixedly provided on the inner side of the top wall of the housing body; the light field intensity received by the first light detector is the first light intensity, and the light field intensity received by the second light detector is the second light intensity.

[0013] Furthermore, the first light detector is arranged directly above the detection hole, and the light source and the second light detector are symmetrically arranged on both sides of the first light detector. In this way, the first light detector receives the light field intensity in the vertical reflection direction, and the second light detector receives the light field intensity in the specular reflection direction.

[0014] Furthermore, an infrared transparent sheet is fixedly arranged on the inner wall of the detection hole, and the plane where the infrared transparent sheet is located is perpendicular to the straight line where the central axis of the detection hole is located. The infrared transparent sheet can perform selective transmission of light waves in a specific wavelength band, and only allows infrared light in the working band to pass through, thereby avoiding the contamination of the light intensity detection result by other wavelength clutter. It can effectively limit the external stray light and ambient visible light from entering the detection cavity from non-normal incident directions without obstructing the vertical transmission path of the infrared light, improving the anti-light interference ability of the system.

[0015] Furthermore, the light-emitting surface of the light source and the light-receiving surface of the second light detector both face the direction where the detection hole is located. This makes the emitted light and the main receiving path have a clear and symmetric geometric relationship, which helps to stably form a specular reflection path. The infrared light emitted by the light source can directly irradiate the ground target area with a small divergence angle and be reflected at a specific angle. Since the second light detector faces the same direction, the ranging error caused by angle deviation or unstable reflection path is reduced, and the receiving efficiency of the reflected light is improved.

[0016] Furthermore, polarizing sheets are arranged on the light-emitting surface of the light source, the light-receiving surface of the first light detector, and the light-receiving surface of the second light detector. Since different ground materials have different reflection behaviors for infrared light, specular reflection usually has strong polarization, while diffuse reflection has a lower degree of polarization. By setting a polarizing sheet with a specific polarization direction at the light source end, the emitted light has a unified polarization state, which can enhance the controllability of the reflection characteristics; while setting a polarizing sheet at the receiving end can selectively receive the reflected light with a specific polarization direction, thereby filtering out some stray light and non-target reflections and improving the signal purity.

[0017] Furthermore, the emission wavelength band of the light source is 850 - 950 nm. Infrared light has a long wavelength, good penetrability, and low scattering characteristics, and can stably propagate in an environment with dust, smoke, or low illuminance, reducing the interference of external light sources on the detection result. At the same time, the infrared band is in the range invisible to the human eye, avoiding the interference of visible light reflection on the system's vision sensor or human-machine interaction interface, and enhancing the concealment and use safety of the system.

[0018] Furthermore, S2 and S3 are implemented in a program manner through an embedded MCU, FPGA, or DSP.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This application combines the double light intensity difference with a dynamic correction mechanism to provide a distance measurement solution with high-precision performance even under complex surface conditions. A surface correction factor A is introduced to dynamically correct the interference caused by the reflection characteristics of different materials to the light intensity measurement. When the surface is rough and the ranging value is small, A is set to a larger value to amplify the reflection signal; when the surface is smooth and the estimated value is large, A is set to a smaller value to suppress errors. By introducing the reflection characteristic information to correct the distance calculation process in real time, this application reduces the detection error caused by material differences and improves the accuracy of ground condition recognition. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a method for identifying ground materials provided by the present invention and a ranging method based on the same; Figure 2 is a schematic diagram of a device for detecting the first light intensity and the second light intensity in a method for identifying ground materials provided by the present invention and a ranging method based on the same; Figure 3 is a schematic diagram of another device for detecting the first light intensity and the second light intensity in a method for identifying ground materials provided by the present invention and a ranging method based on the same.

[0021] Reference numerals: 1 - housing body; 2 - light source; 3 - first light detector; 4 - second light detector; 5 - infrared light transmissive sheet; 6 - circuit board. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To make the implementation process of the present invention clearer, the following will be described in detail with reference to the accompanying drawings.

[0023] This application provides a ranging method based on ground material identification. As Figure 1 shown, the method includes the following steps: S1, obtaining a first light intensity I1 and a second light intensity I2. The first light intensity I1 is the light field intensity in the direction perpendicular to the reflection direction, and the second light intensity I2 is the light field intensity in the specular reflection direction. Specifically, the first light intensity I1 and the second light intensity I2 are detected by the following device: As Figure 2 shown, the device includes a housing body 1. A detection hole is provided on the bottom surface of the housing body 1. A light source 2, a first light detector 3, and a second light detector 4 are fixedly arranged on the inner side of the top wall of the housing body 1. The emission wavelength band of the light source 2 is 850 - 950 nm. Preferably, it can be 850 nm or 940 nm. The first light detector 3 and the second light detector 4 are light intensity detectors capable of detecting the intensity of the light field propagating in the direction where they are located. The light field intensity received by the first light detector 3 is the first light intensity I1, and the light field intensity received by the second light detector 4 is the second light intensity I2.

[0024] Specifically, the first light detector 3 is arranged directly above the detection hole with its light-receiving surface facing downward for direct detection, so as to receive the light field intensity in the vertical direction of the detection surface. The greater the detected light field intensity, the greater the diffuse reflection degree of the detected surface. The light source 2 and the second light detector 4 are symmetrically arranged on both sides of the first light detector 3, and the distances from the light source 2 and the second light detector 4 to the middle first light detector 3 are equal. The light-emitting surface of the light source 2 and the light-receiving surface of the second light detector 4 both face the direction where the detection hole is located. The light emitted by the light source 2 passes through the detection hole, irradiates on the surface to be measured, and after being reflected by the surface to be measured, the reflected light enters the second light detector 4, so that the second light detector 4 can receive the light field intensity in the specular reflection direction. The larger the value, the higher the specular reflection degree and the smoother the surface of the surface to be measured. The diameter of the detection hole needs to not affect the light field propagation among the light source 2, the first light detector 3, and the second light detector 4. The diameter of the detection hole is related to the size of the device. Preferably, the diameter of the detection hole is one-fifth to one-third of the ground diameter of the housing body 1, and is specifically related to factors such as the size of the device and the distance between the light source 2 and the first light detector 3. The included angle between the connection line of the light source 2 and the detection hole and the central axis direction of the detection hole is 40-50°. The specular reflection efficiency is relatively high within this range, the degree of change of the light intensity with distance is greater, and the detection of distance change is more sensitive. This application does not make specific limitations on the size of the device, mainly regarding the arrangement of the components inside the housing body 1.

[0025] Further, the light source 2 can be a pulsed light source with a pulse frequency of 10 kHz to 100 kHz, which is specifically set according to the sampling ability and delay of the MCU. By outputting high-intensity infrared light in a short time and combining with a synchronous sampling mechanism, the pulsed light source can effectively suppress the background interference generated by ambient light on the detector, thereby improving the signal-to-noise ratio and ensuring that the received light intensity signal is more pure and has high credibility. On the other hand, when facing surfaces with low reflectivity such as dark carpets and rough floor tiles, the high peak intensity of the pulsed light helps to increase the probability of the reflected light returning to the detector, enhancing the detection ability of the system under weak signal conditions and avoiding the occurrence of a "ranging blind spot". On the other hand, the pulsed signal has clear time-domain characteristics, making it easier for the system to perform time-domain filtering, multi-frame averaging, and dynamic compensation, thereby reducing the fluctuations caused by random noise and improving the smoothness and consistency of the ranging output. Through the cooperation of periodic light emission and synchronous sampling, the system can focus on the effective signal corresponding to the pulse period, improving the response accuracy of the difference between the first light intensity and the second light intensity. The pulsed light source not only improves the response ability of the system to the weak reflection characteristics of the ground, but also enhances the detection accuracy of the entire system in low-reflection materials, strong light interference, and dynamic change environments.

[0026] To avoid the interference of external stray light, an infrared light-transmitting sheet 5 is fixedly arranged on the inner wall of the detection hole. The plane where the infrared light-transmitting sheet 5 is located is perpendicular to the straight line where the central axis of the detection hole is located. The infrared light-transmitting sheet 5 can only transmit light in the infrared band, and visible light outside the device cannot pass through, so that the change in the light field received by the light detector only comes from the change in the intensity of the infrared light caused by the change in distance, and thus the detection result is more accurate.

[0027] Preferably, as Figure 3 shown, the first light detector 3, the light source 2, and the second light detector 4 are fixedly arranged on the top wall of the housing body 1 through the circuit board 6. Specifically, the circuit board 6 is fixedly arranged on the top wall of the housing body 6, and the first light detector 3, the light source 2, and the second light detector 4 are fixedly arranged on the side of the circuit board 6 away from the edge of the housing body 1. In this way, it is easy to fabricate, and by changing the shape of the edge of the circuit board 6, it is convenient to adjust the positions and angles of the first light detector 3, the light source 2, and the second light detector 4 to increase the reception efficiency of the optical signal. To increase the reception angle of the light incident on the bottom surface, the bottom surface of the housing body 1 is a detection hole, and the infrared light-transmitting sheet 5 is arranged at the edge of the detection hole, that is, the bottom surface of the housing body 1 is the infrared light-transmitting sheet 5, which can make the light emitted by the light source 1 fully irradiate on the surface to be detected; at the same time, the optical signal reflected by the surface to be detected can also enter the light detector. Figure 3 The middle in

[0028] Furthermore, polarizers are provided on the light-emitting surface of the light source 2, the light-receiving surface of the first light detector 3, and the light-receiving surface of the second light detector 4. Specifically, the polarizer can convert light into linearly polarized light, making the light have a single polarization direction. The polarizer at the light source 2 can be vertically polarized; when vertically polarized light encounters the ground surface, the reflection behavior is closely related to the surface smoothness and the incident angle. A smooth surface is more likely to produce specular reflection with the polarization direction retained, while a rough surface causes a change in the polarization state or depolarization effect. The light emitted by the light source 1 is vertically polarized, and the reflection type can be judged according to the degree of polarization retention of the reflected light at the detector end, thereby enhancing the system's ability to separate the specular and diffuse reflection components. The light-receiving surface of the first light detector 3 is provided with a polarizer having the same polarization direction as the light source 2 to enhance its ability to receive specular reflected light in the same direction as the emitted light direction, thereby improving the sensitivity to the direct reflection component; the light-receiving surface of the second light detector 4 is provided with a polarizer perpendicular to the polarization direction of the light source 2 to suppress the specular reflection component and enhance the detection ability for non-polarized or low-polarized diffuse reflected light. The design of the differential configuration of the polarization direction utilizes the physical difference in polarization characteristics between specular reflection and diffuse reflection to set the polarization direction differently. In this way, the first light detector 3 can more accurately respond to the directional reflection related to the distance, while the second light detector 4 is more sensitive to the scattering change caused by the surface material. Effectively distinguish the change in light intensity caused by the distance change from the change in the reflection distribution caused by the material difference, so as to achieve more accurate distance estimation and material judgment under complex ground conditions, and improve the sensitivity, stability and recognition accuracy of the overall detection system.

[0029] S2. Determine the ground material by using the difference between the first light intensity I1 and the second light intensity I2 to obtain the surface correction factor A; The surface correction factor A is determined by the following expression: where e is the base of the natural logarithm, , I1 is the first light intensity and I2 is the second light intensity. R reflects the reflection characteristics of the surface to infrared light: a smooth surface produces strong specular reflection, I2 is greater than I1, resulting in R approaching 1; while a rough surface is mainly diffuse reflection, I2 is similar to I1, and R approaches 0. When the value of R is small, the surface correction factor A has a large value to amplify the signal under low reflection and compensate for the error of underestimated distance; when the value of R is large, the surface correction factor A has a small value to avoid the distance estimation amplification effect caused by high reflection, realizing real-time adaptive correction of ground material differences, improving the accuracy of distance detection, and making the detection of ground conditions more accurate. For smooth floor tiles or glass, the surface correction factor A is 0.8 - 1.2; for ordinary wooden floors or plastic floors, the surface correction factor A is 1.0 - 1.5; for rough floor tiles or carpets, the surface correction factor A is 1.5 - 2.5. Steps S1 and S2 in the method of this application can be used to identify floor materials; the surface correction factors of different floor materials are different.

[0030] S3. Obtain the distance L to be measured according to the surface correction factor A, the first light intensity, and the second light intensity.

[0031] The distance L to be measured is determined by the following expression: where A is the surface correction factor, I1 is the first light intensity, I2 is the second light intensity, and C1 and C2 are compensation parameters. The formula comprehensively considers the relationship between the first light intensity I1, the second light intensity I2, and the surface correction factor A to improve the ranging accuracy under different ground material conditions. Taking the difference between I2 and I1 as the core variable reflects the sensitivity of the reflected light intensity to distance changes. Among them, I2 mainly receives specular reflection light with strong directivity and is significantly affected by distance changes, while I1 receives diffuse reflection light and changes relatively little. By introducing the normalization term , it can effectively eliminate the light intensity offset caused by the intensity fluctuation of the light source 2 or different surface reflectivities, and improve the accuracy of distance detection. C1 can be 5% - 10% of the minimum effective light intensity within the light intensity sensing range; to improve the numerical stability and noise resistance under weak signal conditions. In practical applications, if the light intensity values of I1 and I2 are both at a low level, for example, on a dark carpet or a rough surface with strong diffuse reflection, the denominator will appear as a minimum value, resulting in the calculated distance value being abnormally amplified, thus causing ranging errors or data jumps. To avoid this problem, C1 is set as a constant bias to "support the bottom" of the denominator, limit its minimum value, and ensure that the algorithm still has good numerical performance under low light intensity conditions. Setting C1 to 5% - 10% of the minimum effective signal within the light intensity sensing range can not only avoid the non-linear amplification effect caused by too small a denominator but also not disturb the distance output within the normal range, thus improving the overall stability of the system while ensuring the sensitivity of the algorithm. C2 is the distance from the bottom surface to the optical center, which only affects the absolute value of the distance and does not affect the relative change of the distance. That is, this parameter has no impact on the recognition of the ground condition and can also be set to 0 at the beginning; during use, it can be calibrated according to actual needs. In this application, S2 and S3 are implemented in a programmatic manner through an embedded MCU, FPGA, or DSP.

[0032] Furthermore, to improve the ranging accuracy under low light conditions, a non-linear exponential enhancement factor is introduced to amplify and compensate the reflected signal under low light intensity conditions. The exponential amplification coefficient enables the non-linear enhancement of the light intensity difference signal under weak reflection conditions, thereby improving the response sensitivity of the system to distance changes. The specific expression is as follows: Among them, is the enhancement amplitude coefficient, is the exponential decay coefficient, A is the surface correction factor, I1 is the first light intensity, I2 is the second light intensity, and C1 and C2 are compensation parameters. Specifically, in the calculation of the distance to be measured, the original reflected light intensity difference part is multiplied by an exponential function that varies with the total light intensity, thereby realizing the dynamic amplification of weak light signals on low reflectivity grounds such as carpets and dark plastics. This enhancement factor varies with The total light intensity increases and then decreases exponentially, approaching 1 under sufficient light or on highly reflective materials, with little impact on distance measurement; while it approaches the maximum amplification value in low light conditions to enhance low-reflection signals. The weaker the diffuse reflection ability of the ground material, the less light is reflected back, and the smaller the signal amplitude received by the detector. Due to the minimum sensing threshold of the detector, such weak signals are easily submerged by noise or distorted before amplification, resulting in unstable or even ineffective distance measurement. By introducing an exponential amplification factor, without changing the hardware gain, weak signals can be given an additional boost at the algorithm level, thereby improving the detector's response ability to low-reflection ground and enhancing the correspondence between light intensity and distance. This method effectively alleviates the non-linear compression problem of distance estimation under weak signals and improves the distance detection accuracy in low light conditions.

[0033] In use, the system also includes an ADC sampling module and an embedded control unit. The ADC sampling module and the embedded control unit together form the core circuit part for signal processing and algorithm execution, respectively undertaking the tasks of digital conversion of light intensity signals and real-time calculation of distance measurement algorithms. Specifically, after the infrared light emitted by the light source irradiates the ground, the first light detector 3 and the second light detector 4 respectively receive the reflected light signals in the directions of vertical reflection and specular reflection, and output corresponding analog voltage signals representing the first light intensity I1 and the second light intensity I2. The ADC sampling module performs high-precision analog-to-digital conversion on the two signals, converts them into digital signals and transmits them to the embedded control unit. The embedded control unit can be an MCU, FPGA or DSP chip, and is responsible for executing all algorithm processes including surface correction factor calculation, distance estimation formula solution, filtering and compensation processing, and at the same time controls the emission cycle and sampling timing of the light source 2. This module communicates and controls with the light source 2, the detector, and the ADC module through the IO port to achieve closed-loop acquisition and processing of optoelectronic signals, ensuring that the system can stably output high-precision distance information under different ground materials, reflection characteristics or lighting conditions. These are not limitations to the solution.

[0034] The method of this application can also be used in other devices that operate autonomously and need to adapt to changing ground environments, such as unmanned delivery robots, automatic warehouse transfer vehicles, robotic dogs, automatic lawn mowers, and so on.

[0035] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for identifying floor materials, characterized in that, The method includes the following steps: S1. Obtain a first light intensity and a second light intensity, where the first light intensity is the light field intensity in the direction of vertical reflection, and the second light intensity is the light field intensity in the direction of specular reflection; S2. Determine the ground material by using the difference between the first light intensity and the second light intensity to obtain a surface correction factor A; Determine the ground material according to the surface correction factor.

2. The ground material identification method according to claim 1, characterized in that The surface correction factor A is determined by the following expression: where e is the base of the natural logarithm, , I1 is the first light intensity, and I2 is the second light intensity.

3. A ranging method based on ground material recognition, characterized in that, The method includes the following steps: S1. Obtain a first light intensity and a second light intensity, where the first light intensity is the light field intensity in the direction of vertical reflection, and the second light intensity is the light field intensity in the direction of specular reflection; S2. Determine the ground material by using the difference between the first light intensity and the second light intensity to obtain a surface correction factor A; S3. Obtain a distance L to be measured according to the surface correction factor A, the first light intensity, and the second light intensity.

4. The ranging method based on ground material recognition according to claim 3, wherein, The surface correction factor A is determined by the following expression: where e is the base of the natural logarithm, , I1 is the first light intensity, and I2 is the second light intensity.

5. The ranging method based on ground material recognition according to claim 4, wherein The distance L to be measured is determined by the following expression: Where A is the surface correction factor, I1 is the first light intensity, I2 is the second light intensity, and C1 and C2 are compensation parameters.

6. The ranging method based on ground material recognition according to claim 5, characterized in that, The first light intensity and the second light intensity are detected by the following device: The device includes a housing body, a detection hole is provided on the bottom surface of the housing body, and a light source, a first light detector, and a second light detector are fixedly arranged on the inner side of the top wall of the housing body; the light field intensity received by the first light detector is the first light intensity, and the light field intensity received by the second light detector is the second light intensity.

7. The ranging method based on ground material recognition according to claim 6, characterized in that, The first light detector is arranged directly above the detection hole, and the light source and the second light detector are symmetrically arranged on both sides of the first light detector.

8. The ranging method based on ground material recognition according to claim 7, wherein An infrared light-transmitting sheet is fixedly arranged on the inner wall of the detection hole, and the plane where the infrared light-transmitting sheet is located is perpendicular to the straight line where the central axis of the detection hole is located.

9. The ranging method based on ground material recognition according to claim 8, wherein The light-emitting surface of the light source and the light-receiving surface of the second light detector both face the direction where the detection hole is located.

10. The ranging method based on ground material recognition according to claim 9, characterized in that, The light-emitting band of the light source is 850 - 950 nm.

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