Method for determining road surface roughness and sensor device for implementing the method
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- KISTLER HLDG AG
- Filing Date
- 2026-01-06
- Publication Date
- 2026-08-05
Smart Images
Figure 2026127038000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a method for determining the roughness of a road surface and a sensor device for carrying out the method, according to the preamble of an independent claim. [Background technology]
[0002] A sensor device for measuring the relative motion between a vehicle and a road is known from European Patent No. 0101536. In detail, the sensor device is used to measure the speed and direction of travel of a vehicle on a road. For this purpose, the sensor device is mounted on the vehicle. The sensor device comprises a photodetector. The photodetectors are arranged in a grid-like structure and positioned relative to each other at a certain photodetector angle. Each photodetector comprises a plurality of photodiodes. As the vehicle moves, a portion of the road surface is imaged on the photodetector and captured by the plurality of photodiodes. The photodiodes generate a measurement signal for the captured portion of the road surface. Furthermore, the conventional sensor device comprises an evaluation unit for evaluating the measurement signal and determining the speed or direction of the relative motion of the sensor device with respect to the road, respectively, based on the evaluation of the measurement signal.
[0003] Next, it is desirable for vehicle users to be aware of the roughness of the road surface. This is because roughness has a major impact on the functional characteristics of the road, such as performance, safety, convenience, and economic efficiency. Therefore, surface roughness affects the grip and noise generation of tires on a vehicle on the road. Surface roughness can be smooth or rough. Smooth surface roughness reduces tire grip, thereby particularly affecting high-speed driving and cornering. Conversely, rough surface roughness increases tire grip and has a strong impact on driving on wet roads and aquaplaning. [Prior art documents] [Patent Documents]
[0004] [Patent Document 1] European Patent No. 0101536 [Overview of the project] [Problems that the invention aims to solve]
[0005] The objective of the present invention is to further develop the sensor devices of the prior art. In particular, the sensor device is capable of determining the roughness of a road surface. [Means for solving the problem]
[0006] This objective was achieved by the features of the independent claim.
[0007] The present invention relates to a method for determining the roughness of a road surface using a sensor device mounted on a vehicle, wherein the sensor device comprises at least one photodetector, the vehicle is moved over the road surface, a portion of the surface is imaged on the photodetector during this movement, the photodetector generates a measurement signal from the image, in a first step the measurement signal is provided as measurement data, the measurement data having intensity, the intensity including information about the surface roughness and information about the surface luminosity, and the intensity of the measurement data comprising amplitude and offset.
[0008] Furthermore, the present invention relates to a sensor device for carrying out a method for determining the roughness of a road surface, wherein the sensor device comprises at least one photodetector, the sensor device can be mounted on a vehicle, and when mounted on a vehicle, can be moved by the vehicle on a road surface so that a portion of the surface is captured as an image on the photodetector, the photodetector generates a measurement signal from the image, the sensor device comprises at least an evaluation unit, the evaluation unit converts the measurement signal into measurement data, the evaluation unit includes at least an evaluation program, the evaluation program is configured to load and evaluate the measurement data, the measurement data includes intensity, the intensity includes information relating to the roughness of the surface and information relating to the luminosity of the surface, and the intensity of the measurement data consists of amplitude and offset.
[0009] Further advantageous developments of the present invention are claimed in the dependent claims.
[0010] The present invention will be described in more detail below with reference to the figures. [Brief explanation of the drawing]
[0011] [Figure 1] This is a partial side view of a sensor device 10 mounted on a vehicle 1 on a surface 2 having a roughness R. [Figure 2] Figure 1 shows a portion of the surface 2 of road 3 having different roughness levels R2-R2'''. [Figure 3] Figure 1 is a schematic diagram of a part of a first embodiment of the sensor device 10, which has details regarding imaging of the surface 2 on the photodetectors 14 and 15. [Figure 4] Figure 1 is a schematic diagram of a part of a second embodiment of the sensor device 10, which has details regarding imaging of the surface 2 on the photodetectors 14 and 15. [Figure 5] Figure 1 is a schematic diagram of a part of a third embodiment of the sensor device 10, which has details regarding imaging of the surface 2 on the photodetectors 14 and 15. [Figure 6]Figure 3 is a schematic diagram of a part of a first embodiment of the sensor device 10, which has details regarding the generation of measurement data D14 and D15 of the imaged surface 2. [Figure 7] Figure 4 is a schematic diagram of a part of a second embodiment of the sensor device 10, which has details regarding the generation of measurement data D14, D15 and luminosity data D17 of the imaged surface 2. [Figure 8] Figure 5 is a schematic diagram of a part of a third embodiment of the sensor device 10, which has details regarding the generation of measurement data D14, D15 and luminosity data D17' of the imaged surface 2. [Figure 9] Figure 2 shows the measurement data D14 and D15 of the imaged surface 2 having a first roughness R2. [Figure 10] Figure 2 shows the first and second measurement data D14 and D15 of the imaged surface 2 having a second surface roughness R2'. [Figure 11] Figure 2 shows the first and second measurement data D14 and D15 of the imaged surface 2 having a third roughness R2''. [Figure 12] Figure 2 shows the first and second measurement data D14 and D15 of the imaged surface 2 having a fourth roughness R2''. [Figure 13] This is a flowchart including steps S1 to S5 of a first modified form of a method for determining the roughness R of surface 2 according to Figure 1 using the sensor device 10 according to Figures 3 to 8. [Figure 14] This is a flowchart including steps SS1 to SS8 of a second modified form of the method for determining the roughness R of surface 2 according to Figure 1 using the sensor device 10 according to Figures 3 to 8. [Modes for carrying out the invention]
[0012] Throughout the diagram, the same reference number indicates the same object.
[0013] Figure 1 shows a partial side view of the sensor device 10 attached to vehicle 1.
[0014] The sensor device 10 is installed, for example, on the front of the vehicle 1. The vehicle 1 moves on the road 3 at a speed V. The road 3 includes a surface 2. The direction of movement is indicated by an arrow. The sensor device 10 has the function of measuring the roughness R of the surface 2.
[0015] The surface 2 of road 3 has a roughness R. Surface R indicates non-uniformity in the height of surface 2 perpendicular to the planar extension of the surface. The roughness R of surface 2 is stochastic and contains more or less larger structures K. In this regard, Figure 2 illustrates four surfaces 2, each having different roughness R and different sizes of structures K. The roughness R includes a first roughness R2 having a first structure K2, a second roughness R2' having a second structure K2', a third roughness R2'' having a third structure K2'', and a fourth roughness R2''' having a fourth structure K''''. The first roughness R2 contains small first structures K2 in the range of 20 μm to a maximum of 200 μm. The second roughness R2' contains larger second structures K2' in the range of 200 μm to a maximum of 500 μm. The third roughness R2'' includes a large third structure K2'' in the range of 500 μm or more and up to 1000 μm. The fourth roughness R2''' includes a very large fourth structure K2''' in the range of 1000 μm or more and up to 2000 μm. In light of the present invention, the roughness may have five or more sizes of structures. Furthermore, the roughness may also represent other sizes of structures, such as smaller structures and even larger structures.
[0016] Figures 3 to 8 show details of the sensor device 10. The sensor device 10 is configured to detect light 11 reflected from surface 2. In Figures 2 to 4, the edge rays of light 11 are shown as dotted lines. The sensor device 10 comprises at least one optical lens 12, at least one aperture 13, and at least one photodetector 14, 15. From surface 2, light 11 travels to the optical lens 12, where it is focused onto the aperture 13. From the aperture 13, light 11 travels to the photodetectors 14, 15. Surface 2 is imaged onto the photodetectors 14, 15 as image P2. The image of surface 2 on the photodetectors 14, 15 is produced at an image scale M.
[0017] Preferably, the photodetectors 14, 15 comprise a first photodetector 14 and a second photodetector 15. Each of the photodetectors 14, 15 is formed as a grid, the first photodetector 14 includes a first grid constant G14, and the second photodetector 15 includes a second grid constant G15. A symmetry axis 16 extends between the photodetectors 14, 15. The photodetectors 14, 15 are positioned with respect to the symmetry axis 16 at a photodetector angle α of 45°. The symmetry axis 16 extends parallel to the longitudinal axis of the vehicle 1. In light of the present invention, the photodetector angle α may also be any other value, and therefore its value may be 30° or 60°.
[0018] The photodetectors 14 and 15 comprise a plurality of n photodiodes 14i, 15i, i=1...n, where the exponent i is an integer between 1 and n. Preferably, the plurality is equal to 10, 100, etc. The first photodetector 14 comprises a plurality of n first photodiodes 14i, i=1...n. The first photodiodes 14i, i=1...n are arranged at a distance from each other equal to a first lattice constant G14. The second photodetector 15 comprises a plurality of n second photodiodes 15i, i=1...n. The second photodiodes 15i, i=1...n are arranged at a distance from each other equal to a second lattice constant G15. The values of the lattice constants G14 and G15 may be adjusted. Preferably, the values of the lattice constants G14 and G15 are within the range of surface roughness R2 to R2'''. Preferably, the values of the lattice constants G14 and G15 are equal to 400 μm.
[0019] The photodetectors 14 and 15 constitute a spatial frequency filter, where only a portion of the surface 2 is imaged on each of the n photodiodes 14i, 15i, i=1...n. Each of the n photodiodes 14i, 15i, i=1...n generates a measurement signal S14i, S15i, i=1...n for the portion it detects. The first photodiode 14i, i=1...n generates the first measurement signal S14i, i=1...n. The second photodiode 15i, i=1...n generates the second measurement signal S15i, i=1...n. The measurement signals S14i, S15i, i=1...n are analog signals.
[0020] The sensor device 10 detects the vehicle 1 traveling on the road 3 at different points in time t. * , t ** At time t, measurement signals S14i, S15i, i=1...n are generated. * , t ** This is the first time point t * and at least one further point t ** This includes the time t. * , t **occurs according to the measurement frequency of the sensor device 10. Preferably, the measurement frequency of the sensor device 10 is between 500 kHz and 1 MHz. Therefore, at a further time point t ** is the first time point t * at least 10 -6 seconds later. Therefore, for example, during the measurement of the roughness R of the surface 2 that takes 10 -3 seconds, there are 10 3 further time points t ** existing.
[0021] The measurement signals S14i, S_{15i}, i = 1...n are taken out at several signal outputs according to the alternating weighting. - The first even measurement signals S_{14ip}, i = 2...n are taken out at the first signal output of the first photodetector 14. The first even measurement signals S_{14ip} are derived from the first photodiodes 14i having even indices i = 2...n. Since the first photodiodes 14i have different even indices i, the first even measurement signals S_{14ip}, i = 2...n are phase-shifted relative to each other by a certain phase shift. In the case of a photodetector angle α of ±45° with respect to the symmetry axis 16, the phase shift is 90°. - The first odd measurement signals S_{14iu}, i = 1...n are taken out at the second signal output of the first photodetector 14. The first odd measurement signals S_{14iu}, i = 1...n are derived from the first photodiodes 14i having odd indices i = 1...n. Since the first photodiodes 14i have different odd indices i, the first odd measurement signals S_{14iu}, i = 1...n are phase-shifted relative to each other by the above phase shift. - The second even measurement signals S_{15ip}, i = 2...n are taken out at the first signal output of the second photodetector 15. The second even measurement signals S_{15ip}, i = 2...n are derived from the second photodiodes 15i having even indices i = 2...n. Since the second photodiodes 15i have different even indices i, the second even measurement signals S_{15ip}, i = 2...n are phase-shifted relative to each other by the above phase shift. - The second odd measurement signal S15iu, i=1...n is extracted at the second signal output of the second photodetector 15. The second odd measurement signal S15iu, i=1...n is derived from the second photodiode 14i, which has odd exponents i=1...n. Since the second photodiode 15i has a different odd exponent i, the second odd measurement signals S15iu, i=1...n are phase-shifted relative to each other by the phase shift described above.
[0022] The sensor device 10 may include luminosity photodiodes 17, 17' within the photodiodes 14, 15. Such luminosity photodiodes 17, 17' are not strictly necessary to determine the roughness R2 ~ R2''' of the surface 2 of the road 3. Therefore, the photodetectors 14, 15 of the first embodiment of the sensor device 10 according to Figure 3 do not include luminosity photodiodes. However, the sensor device 10 according to the second and third embodiments, as shown in Figures 4 and 5, includes at least one luminosity photodiode 17, 17' within the photodetectors 14, 15. The luminosity photodiodes 17, 17' have only the function of measuring the luminosity L of light 11.
[0023] In the second embodiment of the sensor device 10 shown in Figure 4, the photometric photodiode 17 is one of the components of the photodetectors 14 and 15. Thus, the photometric photodiode 17 is one of several n photodiodes 14i, 15i, i=1...n, which are arranged relative to each other at distances equal to the lattice constants G14 and G15.
[0024] In the third embodiment of the sensor device 10 shown in Figure 5, the photometric photodiode 17' is not a component of the photodetectors 14 and 15. The photometric photodiode 17' is a separate component added to the multiple n photodiodes 14i, 15i, i=1...n, and is spatially separated from the multiple n photodiodes 14i, 15i, i=1...n.
[0025] The photodiodes 17 and 17' generate photointensity signals S17 and S17'. The photointensity signals S17 and S17' are analog signals.
[0026] The sensor device 10 includes at least an evaluation unit 20. The evaluation unit 20 has the function of evaluating measurement signals S14i, S15i, i=1...n and luminous intensity signals S17, S17'. For this purpose, the evaluation unit 20 converts the measurement signals S14i, S15i, i=1...n and luminous intensity signals S17, S17' into measurement data D14, D15 and luminous intensity data D17.
[0027] The evaluation unit 20 receives measurement signals S14i, S15i, i=1...n from multiple n first and second photodiodes 14i, 15i, i=1...n. To achieve this, the multiple n first photodiodes 14i, i=1...n and the evaluation unit 20 are electrically connected in the embodiment of the sensor device 10 shown in Figures 6 to 8. In addition, the multiple n second photodiodes 15i, i=1...n and the evaluation unit 20 are also electrically connected.
[0028] The evaluation unit 20 receives luminosity measurement signals S17 and S17' from the luminosity photodiodes 17 and 17'. To achieve this, the luminosity photodiodes 17 and 17' and the evaluation unit 20 are electrically connected in the embodiment of the sensor device 10 shown in Figures 7 and 8.
[0029] The evaluation unit 20 comprises at least subtractors 21 and 22, at least analog-to-digital converters 23, 24, and 25, at least a data processor 26, at least a data memory 27, at least an input device 28, and at least an output device 29. Furthermore, the evaluation unit 20 comprises several signal inputs. The subtractors 21 and 22 comprise a first subtractor 21 and a second subtractor 22. The analog-to-digital converters 23, 24, and 25 comprise a first analog-to-digital converter 23, a second analog-to-digital converter 24, and a third analog-to-digital converter 25.
[0030] In the embodiment of the sensor device 10 shown in Figures 6 to 8, the first measurement signal S14i, i=1...n is applied to the first signal input of the evaluation unit 20. The first measurement signal S14i, i=1...n includes the first even and odd measurement signals S14ip, S14iu, i=1...n. The first subtractor 21 is configured to subtract the first even and odd measurement signals S14ip, S14iu, i=1...n to obtain the first potential difference X14. The first analog-to-digital converter 23 is configured to digitize the first potential difference X14 to give the first measurement data D14.
[0031] In the embodiment of the sensor device 10 shown in Figures 6 to 8, the second measurement signals S15i, S15i, i=1...n are applied to the second signal input of the evaluation unit 20. The second measurement signals S15i, i=1...n are applied to the second even measurement signal and odd measurement signal S15i + S15i - , including i=1...n. The second subtractor 22 obtains the second even measurement signal and the second odd measurement signal S15i to acquire the second potential difference X15. + S15i - The second analog-to-digital converter 24 is configured to subtract i=1...n. The second analog-to-digital converter 24 is configured to digitize the second potential difference X15 to give the second measurement data D15.
[0032] Measurement data D14 and D15 are from different time points t * , t ** This is derived from the measurement signals S14i, S15i, i=1...n generated by the sensor device 10.
[0033] Measurement data D14 and D15 include intensity I. Measurement data D14 and D15 can be stored in data memory 27.
[0034] In the embodiment of the sensor device 10 shown in Figures 7 and 8, the luminous intensity signals S17, S17' are applied to the third signal input of the evaluation unit 20 and digitized by the third analog-to-digital converter 25 to obtain luminous intensity data D17. The luminous intensity data D17 includes the luminous intensity I17. The luminous intensity data D17 can be stored in the data memory 27.
[0035] The evaluation unit 20 includes at least an evaluation program CP stored in a data memory 27, which can be loaded into the data processor 26. The evaluation program CP loaded into the data processor 26 is configured to evaluate the measurement data D14, D15 and the luminosity data D17.
[0036] The evaluation program CP loaded into the data processor 26 is configured to load the measurement data D14 and D15 into the data processor 26 and evaluate these data by intensity I over time t.
[0037] Figures 9 to 12 show the measurement data D14 and D15 obtained from surfaces 2 having different roughness levels R2 to R2''. In these figures, intensity I is plotted as a vertical coordinate against time t on the horizontal axis. Intensity I consists of amplitude A and offset O. Intensity I includes a first intensity I2, a second intensity I2', a third intensity I2'', and a fourth intensity I2''''. - Figure 9 shows the measurement data D14 and D15 for surface 2 having a first roughness R2. For the first structure K2 in the range of 20 μm to a maximum of 200 μm, the first roughness R2 is considerably smaller than the lattice constants G14 and G15, which are 400 μm. The measurement data D14 and D15 have a rectangular shape and include a first intensity I2 and a first duration T2. The first intensity I2 consists of a first amplitude A2 and a first offset O2. - Figure 10 shows the measurement data D14 and D15 for surface 2 having a second roughness R2'. For the second structure K2' in the range of 200 μm to a maximum of 500 μm, the second roughness R2' is approximately the same as the lattice constants G14 and G15 of 400 μm. The measurement data D14 and D15 have a sinusoidal shape and include a second intensity I2' and a second duration T2'. The second intensity I2' consists of a second amplitude A2' and a second offset O2'. The second amplitude A2' is larger than the first amplitude A2. The second offset O2' is larger than the first offset O2. - Figure 11 shows the measurement data D14, D15 for surface 2 having a third roughness R2''. For the third structure K2'' in the range of 500 μm to a maximum of 1000 μm, the third roughness R2'' is greater than the lattice constants G14, G15 for 400 μm. The measurement data D14, D15 have a sinusoidal shape and include a third intensity I2'' and a third duration T2''. The third intensity I2'' consists of a third amplitude A2'' and a third offset O2''. The third amplitude A2'' is smaller than the first amplitude A2 and the second amplitude A2'. The third offset O2'' is larger than the first offset O2 and the second offset O2'. - Figure 12 shows the measurement data D14, D15 for surface 2 having a fourth roughness R2''. For the fourth structure K2''' in the range of 1000 μm to a maximum of 2000 μm, the fourth roughness R2''' is considerably larger than the lattice constants G14, G15 for 400 μm. The measurement data D14, D15 have a sinusoidal shape and include a fourth intensity I2''' and a fourth duration T2'''. The fourth intensity I2''' consists of a fourth amplitude A2''' and a fourth offset O2'''. The fourth amplitude A2''' is smaller compared to the first amplitude A2, the second amplitude A'', and the third amplitude A''. The fourth offset O2''' is larger compared to the first offset O2, the second offset O2', and the third offset O''.
[0038] From the figures 9 to 12, which show the measurement data D14 and D15 of surface 2 with different roughness levels R2 to R2'', the following results can be derived. - For roughness R within the range of lattice constants G14 and G15, the amplitude A is maximized. - For roughness R smaller than lattice constants G14 and G15, the offset O is small. - For roughness R greater than lattice constants G14 and G15, the offset O increases with the size of the structure K of roughness R.
[0039] The intensity I2~I2''' includes information on the surface roughness R2~R2''' and information on the luminosity L of the surface 2. These two pieces of information overlap within intensity I2~I2'''. The information on the luminosity L of the surface 2 interferes with and disrupts the determination of the surface roughness R2~R2'''. Therefore, the information on the luminosity L of the surface 2 is excluded from intensity I2~I2'''. To achieve this, the evaluation unit 20 includes multiple normalized data ND and calibration data CD~CD'''.
[0040] The normalized data ND is stored in the data memory 27. The normalized data ND includes the maximum amplitude MA of the sensor device 10. The maximum amplitude MA is the maximum amplitude that the analog-to-digital converters 23 and 24 can process when digitizing the potential differences X14 and X15.
[0041] Calibration data CD~CD'' is stored in data memory 27. Calibration data CD~CD'' includes information about different roughnesses R2~R2'''' of surface 2, such as the size of the surface structure K2~K2'''', as well as calibration intensity CI~CI''''. Each calibration intensity CI~CI'''' consists of a calibration amplitude CA~CA''' and a calibration offset CO~CO''''. Calibration intensity CI~CI'''' does not include any information about the luminosity L of surface 2. - The first calibration data CD shows the size of the first structure K2 according to Figure 2, which is in the range of 20 μm to a maximum of 200 μm for the first roughness R2 according to Figure 2. The first calibration data CD also shows the amount and shape of the first calibration amplitude CA of the surface 2 having the first roughness R2. The first calibration data CD also shows the amount of the first calibration offset CO of the surface 2 having the first roughness R2, which has the first structure K2 in the range of 20 μm to a maximum of 200 μm. The first calibration amplitude CA and the first calibration offset O2 give the first calibration intensity CI. Thus, the first calibration amplitude CA corresponds to the first amplitude A2 according to Figure 9, and the first calibration offset O2 corresponds to the first offset O2 according to Figure 9. - The second calibration data CD' shows the size of the second structure K2' according to Figure 2 within the range of 200 μm to a maximum of 500 μm for the second roughness R2' according to Figure 2. The second calibration data CD' also shows the amount and shape of the second calibration amplitude CA' for surface 2 having the second roughness R2'. Furthermore, the second calibration data CD' shows the amount of the second calibration offset CO' for surface 2 having the second roughness R2' with the second structure K2' within the range of 200 μm to a maximum of 500 μm. The second calibration amplitude CA' and the second calibration offset O2' give the second calibration intensity CI'. The second calibration amplitude CA' therefore corresponds to the second amplitude A2' according to Figure 10, and the second calibration offset O2' therefore corresponds to the second offset O2' according to Figure 10. - The third calibration data CD'' shows the size of the third structure K2'' according to Figure 2, within the range of 500 μm to a maximum of 1000 μm for the third roughness R2'' according to Figure 2. The third calibration data CD'' further shows the amount and shape of the third calibration amplitude CA'' of surface 2 having the third roughness R2''. The third calibration data CD'' also shows the amount of the third calibration offset CO'' of surface 2 having the third roughness R2'' with the third structure K2'' within the range of 500 μm to a maximum of 1000 μm. The third calibration amplitude CA'' and the third calibration offset O2'' give the third calibration intensity CI''. Thus, the third calibration amplitude CA'' corresponds to the third amplitude A2'' according to Figure 11, and the third calibration offset O2'' corresponds to the third offset O2'' according to Figure 11. - The fourth calibration data CD'''' shows the size of the fourth structure K2'''' according to Figure 2 in the range of 1000 μm to a maximum of 2000 μm for the fourth roughness R2'''' according to Figure 2. Furthermore, the fourth calibration data CD'''' shows the amount and shape of the fourth calibration amplitude CA'''' of surface 2 having the fourth roughness R2''''. The fourth calibration data CD'''' also shows the amount of the fourth calibration offset CO'''' of surface 2 having the fourth roughness R2'''' with the fourth structure K2'''' in the range of 1000 μm to a maximum of 2000 μm. The fourth calibration amplitude CA'''' and the fourth calibration offset O2'''' give the fourth calibration intensity CI''''. The fourth calibration amplitude CA'''' therefore corresponds to the fourth amplitude A2'''' according to Figure 12, and the fourth calibration offset O2'''' therefore corresponds to the fourth offset O2'''' according to Figure 12.
[0042] Figure 13 shows a flowchart including steps S1-S5 of a first modified version of a method for determining the roughness R of surface 2 using a sensor device 10. In the first modified version of the method, the roughness R of surface 2 is determined solely from the amplitude A of the measurement data D14 and D15 of surface 2. To achieve this objective, the relative change in the amount of amplitude A of the measurement data D14 and D15 of surface 2 is used to estimate the change in the roughness R of surface 2. Steps S1-S5 of the first modified version of the method include the first step S1, the second step S2, the third step S3, the fourth step S4, and the fifth step S5. - In the first step S1, measurement data D14 and D15 of surface 2 are provided. For this purpose, the evaluation program CP loaded into the data processor 26 is configured to load the measurement data D14 and D15 of surface 2 into the data processor 26. The measurement data D14 and D15 of surface 2 are obtained at different points in time t * , t ** It was obtained in [location]. - In the second step S2, the first time point t * Surface roughness R * It is determined whether the first time point t is higher or lower than the lattice constants G14 and G15 of the photodetectors 14 and 15. Preferably, the first time point t * Surface roughness R * This is determined visually or tactilely. In this way, the human operator of the sensor device 10 determines the first time point t by visual assessment or tactile assessment. * Surface roughness R * The operator can determine the first time point t * Surface roughness R * It can be assessed whether it contains a coarse structure and whether it is greater than the lattice constants G14, G15, or whether it contains a smooth structure and is less than the lattice constants G14, G15. * The surface roughness R of surface 2 determined in * This is provided to the evaluation program CP. Preferably, at the first time point t * The surface roughness R of surface 2 determined in *This is input to the evaluation unit 20 via input device 28. Input device 20 may be a keyboard or touch screen for this purpose. A first time point t characterized by a rough structure * Surface roughness R * In this case, the operator can input the value "coarse", which is the first time point t * Surface roughness R * This means that the lattice constants G14 and G15 are greater than the first point t which is characterized by a smooth structure. * Surface roughness R * In this case, the operator can input the value "smooth", which is the first time point t * Surface roughness R * This means that the first time point t input via input device 28 is smaller than the lattice constants G14 and G15. * Surface roughness R * The first time point t input via input device 28 can be stored in data memory 27 by the evaluation program CP. * Surface roughness R * This can be loaded into the data processor 26 by the evaluation program CP. - In the third step S3, the first time point t * Amplitude A of measurement data D14 and D15 on surface 2. * and further point t ** Further amplitude A of measurement data D14 and D15 on surface 2. ** However, it is extracted from the intensity I of the measurement data D14 and D15 of surface 2 by the evaluation program CP. - In the fourth step S4, normalized data ND, including the maximum amplitude MA, is provided. To achieve this objective, the evaluation program CP loads the normalized data ND into the data processor 26. - In the fifth step S5, the evaluation program CP uses normalized data ND and time point t * , t ** The amplitude A extracted in * , A **Compare them. In this method, the evaluation program CP checks whether the extracted amplitude A * , A ** decreases over time points t * , t ** , or whether the extracted amplitude A * , A ** remains constant over time points t * , t ** , or whether the extracted amplitude A * , A ** increases over time points t * , t ** . * If the roughness R of surface 2 at the first time point t * is higher than the lattice constants G14, G15, the evaluation program CP concludes from the decrease in the extracted amplitude A * that the roughness R of surface 2 at time point t * , A, A ** is higher, while on the other hand, the evaluation program CP concludes from the increase in the extracted amplitude A ** that the roughness R of surface 2 at time point t ** is smaller. * , A ** ** ** * When the extracted amplitudes A * , A, A ** remain constant over time points t * , t ** , the evaluation program CP concludes that the roughness R of surface 2 at time point t[[ID=S7]] ** has not changed compared to the roughness R of surface 2 at time point t ** * * . * If the roughness R of surface 2 at the first time t * is smaller than the lattice constants G14, G15, the evaluation program CP concludes from the decrease in the extracted amplitude A * that the roughness R of surface 2 * , A, A ** is smaller at time point t ** , while on the other hand, the evaluation program CP concludes from the increase in the extracted amplitude A ** * and ** from the increase of A, it is concluded that the roughness R of surface 2 ** is higher at time point t ** . The evaluation program CP can store in the data memory 27 the estimated changes in the roughness R at time points t * , t ** . The evaluation program CP can output on the output device 29 the estimated changes in the roughness R at time points t * , R ** . * , t ** . The evaluation program CP can output on the output device 29 the estimated changes in the roughness R at time points t * , R ** .
[0043] FIG. 14 shows steps SS1 to SS8 of a second variant of a method for determining the roughness R of surface 2 using the sensor device 10. In the second variant of the method, the roughness R is no longer estimated, but is determined by excluding the information on the light intensity L of surface 2 within the intensities I of the first and second measurement data D14, D15 of surface 2. Thereby, the second variant of the method is more accurate than the first variant of the method. The steps SS1 to SS7 of the second variant of the method include a first step SS1, a second step SS2, a third step SS3, a fourth step SS4, a fifth step SS5, an optional sixth step SS6, an optional seventh step, and an optional eighth step. - In the first step SS1, the measurement data D14, D15 of surface 2 and the light intensity data D17 for these first and second measurement data D14, D15 of surface 2 are provided. For this purpose, the evaluation program CP loaded in the data processor 26 is configured to load into the data processor 26 the measurement data D14, D15 of surface 2 and the light intensity data D17 for these first and second measurement data D14, D15 of surface 2. - In the second step SS2, the evaluation program CP subtracts the intensity I17 of the luminosity data D17 from the intensity I of the measurement data D14 and D15 of surface 2. As a result of this subtraction, the information of the luminosity L of surface 2 is excluded, and a corrected intensity VI of the measurement data D14 and D15 is obtained, which includes only the information of the roughness R of surface 2. - In the third step SS3, the calibration data CD~CD''' is provided. For this purpose, the evaluation program CP loads the calibration data CD~CD''' into the data processor 26. - In the fourth step SS4, the evaluation program CP compares the calibration data CD~CD''' with the corrected intensity VI. From the calibration data CD~CD''', the evaluation program CP determines the calibrated intensity CI~CI''' of the corrected intensity VI, and this determined calibrated intensity CI~CI''' represents the minimum deviation in quantity and shape from the corrected intensity VI. - In the fifth step, SS5, the evaluation program CP assigns the roughness R2 to R2'''' of the determined calibration intensity CI to the corrected intensity VI. The sixth step SS6, the seventh step SS7, and the eighth step SS8 are optional, meaning that these steps are not strictly required to determine the roughness R2~R2''. - In the sixth step SS6, the evaluation program CP extracts the offset O from the intensity I of the measurement data D14 and D15 of surface 2. - In the seventh step SS7, the evaluation program CP determines the calibration offset CO~CO''' of the calibration data CD~CD''' for the extracted offset O, and this determined calibration offset CO~CO''' represents the minimum deviation in terms of quantity and shape from the extracted offset O. - In the eighth step SS5, the evaluation program CP assigns the roughness R2~R2''' of the determined calibration offset CO~CO''' to the extracted offset O. For roughness R smaller than lattice constants G14 and G15, the offset O is small. For roughness R larger than lattice constants G14 and G15, the offset O increases with the size of the structure K of roughness R. The determination of roughness R is verified when the roughness R2~R2''' assigned to the calibration offset CO~CO''' determined in steps SS6~SS7 is equal to the roughness R2~R2''' assigned to the calibration intensity CI~CI''' determined in steps SS3 and SS4. The evaluation program CP can output the assigned roughness R2 to R2''' on the output device 29. [Explanation of Symbols]
[0044] 1 vehicle 2 surface 3 road 10 Sensors and Devices 11 light 12 Optical Lenses 13 Aperture 14. First photodetector 14i First photodiode 15. Second photodetector 15i Second photodiode 16 Axis of Symmetry 17, 17' photodiode 20 evaluation units 21 First Subtractor 22 Second Subtractor 23. First Analog-to-Digital Converter 24. Second Analog-to-Digital Converter 25. The third analog-to-digital converter 26 Data Processors 27 Data Memory 28 Input Devices 29 Output Devices α photodetector angle A, A2~A2''', A * , A ** amplitude CA~CA''' Calibration Amplitude CD~CD''' Calibration Data CO~CO''' Calibration Offset CP Evaluation Program D14 First measurement data D15 Second measurement data D17 Luminous Intensity Data G14 First lattice constant G15 Second lattice constant i index I, I2~I2''' Intensity I17 Luminosity K, K2~K2''' Roughness structure L luminous intensity M Image Scale MA maximum amplitude n Plurality ND Normalized Data O, O2~O2''' Offset Image of the P2 surface R, R2~R2''', R * , R ** Surface roughness S1-S5 Method Steps SS1~SS8 Method Steps S14i First measurement signal S14p First even measurement signal S14u First odd measurement signal S15i Second measurement signal S15p Second even measurement signal S15u Second odd measurement signal S17 Luminosity signal t time t * , t ** at that time T2~T2''' Period Length X14 First potential difference X15 Second potential difference V speed VI2~VI2''' Corrected Intensity
Claims
1. A method for determining the roughness (R) of a road surface (2) using a sensor device (10) attached to a vehicle (1), wherein the sensor device (10) comprises at least one photodetector (14, 15), the vehicle (1) is moved on the road (3), a portion of the surface (2) is imaged as an image (P2) on the photodetector (14, 15), and the photodetector (14, 15) measures the image (P2) to obtain measurement signals (S14i, S15i, i=1 ... n) in a method for generating the measurement signal (S14i, S15i, i=1 ... n) is provided as measurement data (D14, D15), the measurement data (D14, D15) includes intensity (I), the intensity (I) includes information relating to the roughness (R) of the surface (2) and information relating to the luminosity (L) of the surface (2), and the intensity (I) of the measurement data (D14, D15) is composed of amplitude (A) and offset (O), a method characterized in that
2. In the second step (S2), the first time point (t ＊ The roughness (R) of the surface (2) in ) ＊ The method according to claim 1, characterized in that it is determined whether the value of the photodetector (14, 15) is smaller than or larger than the lattice constants (G14, G15).
3. In the third step (S3), the amplitude (A ＊ ), is extracted from the intensity (I) of the measurement data (D14, D15) at the first point in time (t ＊ ), and a further amplitude (A ＊＊ ), is extracted from the intensity (I) of the measurement data (D14, D15) at a further point in time (t ＊＊ ). In the fourth step (S4), the maximum amplitude (MA) of the sensor device (10) is provided. In the fifth step (S5), it is determined whether the extracted amplitudes (A ＊ , A ＊＊ ) decrease over the points in time (t ＊ , t ＊＊ ), or whether the extracted amplitudes (A ＊ , A ＊＊ ) remain constant over the points in time (t ＊ , t ＊＊ ), or whether the extracted amplitudes (A ＊ , A ＊＊ ) increase over the points in time (t ＊ , t ＊＊ ). The method according to claim 2, characterized in that.
4. The first time point (t ＊ The roughness (R) of the surface (2) in ) ＊ If the extracted amplitude (A) is greater than the lattice constants (G14, G15), ＊ A ＊＊ From the decrease of ), the aforementioned time point (t ＊＊ ) the roughness of the surface (2) (R ＊＊ It was concluded that the extracted amplitude (A) was larger. ＊ A ＊＊ From the increase of ), the aforementioned time point (t ＊＊ ) the roughness of the surface (2) (R ＊＊ It was concluded that the aforementioned time (t ＊ ,t ＊＊ The amplitude (A) extracted in ) ＊ A ＊＊ When the time point (t) is constant, ＊＊ The roughness (R) of the surface (2) in ) ＊＊ ) is the aforementioned time (t ＊ The roughness (R) of the surface (2) in ) ＊ It was concluded that there was no change compared to the first time point (t ＊ The roughness (R) of the surface (2) in ) ＊ If the extracted amplitude (A) is smaller than the lattice constants (G14, G15), ＊ A ＊＊ From the decrease of ), the aforementioned time point (t ＊＊ ) the roughness of the surface (2) (R ＊＊ It was concluded that the extracted amplitude (A) is smaller, and the extracted amplitude (A) ＊ A ＊＊ From the increase of ), the aforementioned time point (t ＊＊ ) the roughness of the surface (2) (R ＊＊ The method according to claim 3, characterized in that it is concluded that ) is greater.
5. The method according to claim 1, characterized in that the sensor device (10) comprises at least a photometric photodiode (17, 17'), the photometric photodiode (17, 17') generates a photometric signal (S17, S17') for the photometric intensity (L) of the surface (2), the photometric signal (S17, S17') has an intensity (I17), the photometric signal (S17, S17') is converted into photometric data (D17), in the first step (SS1) the photometric data (D17) is provided, and in the second step (SS2) the intensity (I17) of the photometric data (D17) is subtracted from the intensity (I) of the measurement data (D14, D15) of the surface (2), and as a result of the subtraction, a corrected intensity (VI) of the measurement data (D14, D15) is obtained.
6. The method according to claim 5, characterized in that, in a third step (SS3), calibration data (CD to CD''') is provided, the calibration data (CD to CD''') includes calibration intensities (CI to CI''') for different roughnesses (R2 to R2''') of the surface (2), in a fourth step (SS4), the calibration intensities (CI to CI''') are determined for the corrected intensity (VI), the determined calibration intensities (CI to CI''') represent the minimum deviation in quantity and shape from the corrected intensity (VI), and in a fifth step (SS5), the roughness (R2 to R2''') of the determined calibration intensities (CI to CI''') is assigned to the corrected intensity (VI).
7. The method according to claim 6, characterized in that, in a sixth step (SS6), the offset (O) is extracted from the intensity (I) of the measurement data (D14, D15); in a seventh step (SS7), a calibration offset (CO to CO''') from the calibration data (CD to CD''') is determined for the extracted offset (O), wherein the determined calibration offset (CO to CO''') represents the minimum deviation in quantity and shape from the extracted offset (0); and in an eighth step (SS8), the roughness (R2 to R2''') of the determined calibration offset (CO to CO''') is assigned to the extracted offset (O).
8. A sensor device (10) for carrying out a method for determining the roughness (R) of the surface (3) of a road (3), wherein the sensor device (10) comprises at least one photodetector (14, 15), the sensor device (10) can be mounted on a vehicle (1), and when mounted on the vehicle (1), is moved by the vehicle (1) on the road (3), thereby capturing an image (P2) of a portion of the surface (2) on the photodetector (14, 15), and the photodetector (14, 15) collects measurement signals (S14i, S15i, i=1) from the image (P2). ...n) is generated, and the sensor device (10) comprises at least an evaluation unit (20), and the evaluation unit (20) generates the measurement signal (S14i, S15i, i=1 ... A sensor device (10) that converts n) into measurement data (D14, D15), wherein the evaluation unit (20) comprises at least an evaluation program (CP), the evaluation program (CP) is configured to load and evaluate the measurement data (D14, D15), the measurement data (D14, D15) includes intensity (I), the intensity (I) includes information relating to the roughness (R) of the surface (2) and information relating to the luminosity (L) of the surface (2), and the intensity (I) of the measurement data (D14, D15) is composed of amplitude (A) and offset (O).
9. First time point (t ＊ ) the roughness of the surface (2) (R ＊ ) is provided to the evaluation program (CP), and the roughness (R ＊ The sensor device (10) according to claim 8, characterized in that the ) is smaller than or larger than the lattice constants (G14, G15) of the photodetectors (14, 15).
10. The evaluation program (CP) is performed at the first time point (t ＊ From the intensity (I) to the amplitude (A) of the measurement data (D14, D15) in ) ＊ ) extract and further time points (t ＊＊ From the intensity (I) of the measurement data (D14, D15) in ), a further amplitude (A ＊＊ The sensor device (10) according to claim 9, characterized by extracting ).
11. The evaluation program (CP) loads the maximum amplitude (MA) of the sensor device (10), and the evaluation program then processes the extracted amplitude (A ＊ A ＊＊ ) is the aforementioned time (t ＊ ,t ＊＊ Whether it decreases over the range of the extracted amplitude (A ＊ A ＊＊ ) is the aforementioned time (t ＊ ,t ＊＊ Whether it remains constant over the specified period, or whether the extracted amplitude (A ＊ A ＊＊ ) is the aforementioned time (t ＊ ,t ＊＊ The sensor device (10) according to claim 10, characterized in that it determines whether it increases over a certain range.
12. At the time point (t ＊ ), when the roughness (R ＊ ) of the surface (2) is greater than the lattice constant (G14, G15), the evaluation program (CP) concludes from the decrease in the extracted amplitudes (A ＊ , A ＊＊ ) that the roughness (R ＊＊ ) of the surface (2) at the time point (t ＊＊ ) is greater, and concludes from the increase in the extracted amplitudes (A ＊ , A ＊＊ [[ID=X]]) that the roughness (R ＊＊ ) of the surface (2) at the time point (t ＊＊ ) is smaller. When the extracted amplitudes (A ＊ , A ＊＊ ) are constant over the time points (t ＊ , t ＊＊ ), the evaluation program (CP) concludes that the roughness (R ＊＊ ) of the surface (2) at the time point (t ＊＊ ) has not changed compared to the roughness (R ＊ ) of the surface (2) at the time point (t ＊ ). When the roughness (R ＊ ) of the surface (2) at the first time point (t ＊ ) is smaller than the lattice constant (G14, G15), the evaluation program (CP) concludes from the decrease in the extracted amplitudes (A ＊ , A ＊＊ ) that the roughness (R ＊＊ ) of the surface (2) at the time point (t ＊＊ ) is smaller, and concludes from the increase in the extracted amplitudes (A ＊ , A ＊＊ ) that the roughness (R ＊＊ ) of the surface (2) at the time point (t ＊＊ ) is higher. Sensor device (10) according to claim 11, characterized in that.
13. The sensor device (10) according to claim 8, wherein the sensor device (10) comprises at least a photometric photodiode (17, 17'), the photometric photodiode (17, 17') generates a photometric signal (S17, S17') for the photometric intensity (L) of the surface (2), the photometric signal (S17, S17') includes an intensity (I17), the evaluation unit (20) converts the photometric signal (S17, S17') into photometric data (D17), the evaluation program (CP) loads and evaluates the photometric data (D17), the evaluation program (CP) subtracts the intensity (I17) of the photometric data (D17) from the intensity (I) of the measurement data (D14, D15) of the surface (2), and as a result of the subtraction, a corrected intensity (VI) of the measurement data (D14, D15) is obtained.
14. The sensor device (10) according to claim 13, wherein the evaluation program (CP) loads calibration data (CD to CD'''), the calibration data (CD to CD''') includes calibration intensities (CI to CI''') for different surface roughnesses (R2 to R2''') of the surface (2), the evaluation program (CP) determines the calibration intensities (CI to CI''') for the corrected intensity (VI), and the determined calibration intensities (CI to CI''') represent the minimum deviation in quantity and shape from the corrected intensity (VI).
15. The sensor device (10) according to claim 14, characterized in that the evaluation program (CP) assigns the roughness (R2 to R2'') of the determined calibration intensity (CI to CI'') to the corrected intensity (VI).
16. The sensor device (10) according to claim 15, characterized in that the evaluation program (CP) extracts the offset (O) from the intensity (I) of the measurement data (D14, D15), the evaluation program (CP) determines the calibration offset (CO to CO''') of the calibration data (CD to CD''') with respect to the extracted offset (O), the determined calibration offset (CO to CO''') represents the minimum deviation in quantity and shape from the extracted offset (O), and the evaluation program (CP) assigns the roughness (R2 to R2''') of the determined calibration offset (CO to CO''') to the extracted offset (O).