Method and device for determining obstacles in parking path and surrounding environment using ultrasonic waves

Abstract

A method for determining an obstacle includes: determining whether ultrasonic noise exists within the time-of-flight (TOF) of a received ultrasonic wave reflected by an object; generating a virtual object on the outline of a parking path on which a vehicle is to travel based on the received ultrasonic wave TOF; generating a virtual indirect wave TOF using the virtual object; and determining whether the object is located inside or outside the outline of the parking path by comparing a real indirect wave TOF, which is an indirect wave TOF in the received ultrasonic wave TOF, with the virtual indirect wave TOF.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority from Korean Patent Application No. 10-2021-0170128, filed on December 1, 2021, which is hereby incorporated by reference herein. Technical Field

[0003] The present invention relates to a technology for determining whether obstacles on and around a parking path are located in the parking path of a vehicle using ultrasonic waves. Background Art

[0004] A plurality of ultrasonic sensors are installed in a vehicle to detect objects approaching the vehicle in situations such as parking.

[0005] For example, a plurality of ultrasonic sensors are mounted on a front bumper, a rear bumper, etc. of a vehicle to be horizontally spaced apart from each other.

[0006] An ultrasonic sensor detects an object by transmitting ultrasonic waves and then receiving the ultrasonic waves reflected by the object.

[0007] The matters described above as technical background are only intended to better understand the background of the present invention and should not be regarded as an admission that they belong to conventional technologies known to those skilled in the art. Summary of the Invention

[0008] An object of the present invention is to provide a method and apparatus for determining obstacles on and around a parking path on which a vehicle is to travel for parking, using ultrasonic waves, for determining whether obstacles on and around the parking path exist inside or outside the parking path of the vehicle using an ultrasonic sensor installed in the vehicle, thereby allowing smoother and safer parking to be performed.

[0009] To achieve the above-mentioned objectives, a method for determining obstacles on and around a parking path using ultrasonic waves according to the present invention includes: determining whether ultrasonic noise exists within the time of flight (TOF) of a received ultrasonic wave reflected by an object; when ultrasonic noise does not exist, generating a virtual object on the outline of a parking path on which a vehicle is to travel based on the received ultrasonic wave TOF; generating a virtual indirect wave TOF using the virtual object; and determining whether the object is located inside or outside the outline of the parking path by comparing a real indirect wave TOF, which is an indirect wave TOF in the received ultrasonic wave TOF, with the virtual indirect wave TOF.

[0010] In determining whether ultrasonic noise exists, when both direct wave TOF and indirect wave TOF exist and neither dynamic noise nor static noise exists in the received ultrasonic wave TOF, it can be determined that ultrasonic noise does not exist.

[0011] Dynamic noise can be identified in the following situations:

[0012] d (direct wave hTOF) > Vdt

[0013] in

[0014] Direct wave hTOF = Direct wave TOF / 2,

[0015] d (direct wave hTOF) = direct wave hTOF t=n – Direct wave hTOF t=n-1 [m],

[0016] V: vehicle speed, and

[0017] dt: Ultrasonic update period [ms].

[0018] Static noise can be detected in the following situations:

[0019] |Direct hTOF – Indirect hTOF| > Distance between sensors / 2

[0020] in

[0021] hTOF = TOF / 2; and

[0022] The “distance between sensors” refers to the distance between the sensor that transmits and receives the direct wave and the sensor that receives the indirect wave.

[0023] A virtual object may be generated at an intersection where a circle, centered at the position of the sensor that transmits and receives the direct wave and having a direct wave hToF as a radius, intersects the outline of the parking path.

[0024] The virtual indirect wave TOF may be calculated as the sum of a straight line connecting the position of the sensor that transmits and receives the direct wave and the virtual object and a straight line connecting the virtual object and the position of the sensor that receives the indirect wave.

[0025] In determining whether an object is located inside or outside the outline of the parking path, when the sensor that transmits and receives the direct wave is located outside the parking path compared to the sensor that receives the indirect wave, if the real indirect wave TOF is greater than the virtual indirect wave TOF, it can be determined that the object is located outside the outline of the parking path, while if the real indirect wave TOF is equal to or less than the virtual indirect wave TOF, it can be determined that the object is located inside the outline of the parking path.

[0026] A plurality of sensors installed in the vehicle may transmit ultrasonic waves in sequence, and each time ultrasonic waves are transmitted from each sensor, the above steps may be repeatedly performed for two adjacent sensors.

[0027] Furthermore, to achieve the above-mentioned object, the obstacle determination device for a parking path and its surroundings using ultrasonic waves according to the present invention may include: a noise determination unit that determines whether ultrasonic noise exists within the TOF of a received ultrasonic wave reflected by an object; a virtual object generation unit that generates a virtual object on the outline of the parking path on which the vehicle is to travel based on the received ultrasonic wave TOF when the noise determination unit determines that the ultrasonic noise does not exist; a virtual indirect wave generation unit that generates a virtual indirect wave TOF using the virtual object generated by the virtual object generation unit; and an object position determination unit that determines whether the object exists inside or outside the outline of the parking path by comparing a real indirect wave TOF, which is an indirect wave TOF in the received ultrasonic wave TOF, with the virtual indirect wave TOF generated by the virtual indirect wave generation unit.

[0028] The noise determination unit may be configured to include a dynamic noise determination unit and a static noise determination unit, and determine that there is no ultrasonic noise when both direct wave TOF and indirect wave TOF exist and neither dynamic noise nor static noise exists within the received ultrasonic wave TOF.

[0029] The dynamic noise determination unit may be configured to determine that the dynamic noise is generated in the following cases:

[0030] d (direct wave hTOF) > Vdt

[0031] in

[0032] Direct wave hTOF=direct wave TOF / 2,

[0033] d(direct wave hTOF) = direct wave hTOF t=n -Direct wave hTOF t=n-1 [m],

[0034] V: vehicle speed, and

[0035] dt: Ultrasonic update period [ms].

[0036] The static noise determination unit may be configured to determine that the static noise is generated in the following cases:

[0037] |Direct wave hTOF – Indirect wave hTOF|> Distance between sensors / 2

[0038] in

[0039] hTOF = TOF / 2; and

[0040] The “distance between sensors” refers to the distance between the sensor that transmits and receives the direct wave and the sensor that receives the indirect wave.

[0041] The virtual object generation unit may be configured to generate a virtual object at an intersection point where a circle having a position of a sensor that transmits and receives a direct wave as a center and a direct wave hToF as a radius intersects the outline of the parking path.

[0042] The virtual indirect wave generating unit may be configured to calculate the virtual indirect wave TOF as the sum of a straight line connecting the position of the sensor transmitting and receiving the direct wave and the virtual object and a straight line connecting the virtual object and the position of the sensor receiving the indirect wave.

[0043] When the sensor that transmits and receives the direct wave is located outside the parking path compared to the sensor that receives the indirect wave, the object position determination unit can be configured to: determine that the object is located outside the outline of the parking path if the real indirect wave TOF is greater than the virtual indirect wave TOF, and determine that the object is located inside the outline of the parking path if the real indirect wave TOF is equal to or less than the virtual indirect wave TOF.

[0044] The present invention allows the use of ultrasonic sensors installed in a vehicle to determine whether an obstacle located on or around a parking path on which the vehicle is to travel for parking is inside or outside the parking path of the vehicle, thereby allowing smoother and safer parking to be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 FIG. 1 is a diagram showing a sensor installation state of a vehicle to which the present invention can be applied.

[0046] Figures 2A to 2C is a flow chart illustrating a noise filtering method for a vehicle ultrasonic sensor signal according to the present invention.

[0047] Figure 3 It is a diagram showing the relationship between vehicle speed and direct wave TOF.

[0048] Figure 4 : are graphs showing changes in the indirect wave TOF according to the position of an arbitrary object P in three cases.

[0049] Figure 5 It is a graph of the indirect wave hTOF according to the change of θ.

[0050] Figure 61 is a flowchart showing a first embodiment of a method for determining obstacles on and around a parking path using ultrasonic waves.

[0051] Figure 7 It is a diagram describing the virtual indirect wave TOF.

[0052] Figure 8 1 is a flowchart illustrating a second embodiment of a method for identifying obstacles on and around a parking path using ultrasonic waves.

[0053] Figure 9 is a diagram showing reflections of direct and indirect waves by an object having a volume.

[0054] Figure 10 is a diagram showing that an object having a volume is modeled as a virtual circle having a radius F.

[0055] Figure 11 It describes the points N located in various locations. Figure 10 A plot of the probability on the circle in .

[0056] Figure 12 is a graph describing the probability density function of ultrasound.

[0057] Figure 13 is shown in Figure 12 A graph showing the value of the ultrasonic probability density function according to the change of α in the same case.

[0058] Figure 14 is a graph showing changes in P_m according to changes in α.

[0059] Figure 15 is a graph showing changes in P_n according to changes in α.

[0060] Figure 16 is shown in Figure 12 A graph of the portion where the true indirect wave hTOF is greater than the ideal indirect wave hTOF, the portion where the true indirect wave hTOF is less than the ideal indirect wave hTOF, and the portion where the value of the ultrasonic wave probability density function is greater than zero on a circle drawn under the same conditions.

[0061] Figure 17 and Figure 18 are graphs showing how the difference between the real indirect wave hTOF and the ideal indirect wave hTOF changes as α increases.

[0062] Figure 19 : is a table showing the minimum and maximum values ​​of the difference between the real indirect wave hTOF and the ideal indirect wave hTOF as α increases, and P_max.

[0063] Figure 20 Is a description for export Figure 19 View of the experimental conditions for the results.

[0064] Figure 21 1 is a flowchart showing a third embodiment of a method for determining obstacles on and around a parking path using ultrasonic waves.

[0065] Figure 22 is a flow chart showing a first embodiment of a method for filtering obstacles on and around a parking path using ultrasonic waves.

[0066] Figure 23 is a view showing that ghost coordinates are generated inside the parking path when real objects exist outside the parking path on each side.

[0067] Figure 24 is a flow chart showing a second embodiment of a method for filtering obstacles on and around a parking path using ultrasonic waves.

[0068] Figure 25 is a flowchart showing a third embodiment of a method for filtering obstacles on and around a parking path using ultrasonic waves.

[0069] Figure 26 is a diagram showing a case where a real object exists outside the parking path and ghost coordinates are located inside the parking path.

[0070] Figure 27 is a diagram showing a case where a real object exists inside a parking path and ghost coordinates are located outside the parking path.

[0071] Figure 28 is a diagram showing an embodiment of a noise filtering device for a vehicle ultrasonic sensor signal, the device being configured to implement the following Figures 2A to 2C The noise filtering method for the vehicle ultrasonic sensor signal is shown.

[0072] Figure 29 A device for determining obstacles on and around a parking path using ultrasonic waves is shown.

[0073] Figure 30 is a diagram showing an embodiment of a device for determining obstacles on and around a parking path using ultrasonic waves, the device being configured to achieve the following Figure 8 A second embodiment of a method for determining obstacles on and around a parking path using ultrasonic waves is shown.

[0074] Figure 31 is a diagram showing an embodiment of a device for determining obstacles on and around a parking path using ultrasonic waves, the device being configured to achieve the following Figure 21 A third embodiment of a method for determining obstacles on and around a parking path using ultrasonic waves is shown.

[0075] Figure 32 is a diagram showing an embodiment of a device for determining obstacles on and around a parking path using ultrasonic waves, the device being configured to achieve the following Figure 22 A first embodiment of a method for filtering obstacles on and around a parking path using ultrasonic waves is shown.

[0076] Figure 33 is a diagram showing an embodiment of a device for determining obstacles on and around a parking path using ultrasonic waves, the device being configured to achieve the following Figure 24 A second embodiment of a method for filtering obstacles on and around a parking path using ultrasonic waves is shown.

[0077] Figure 34 is a diagram showing an embodiment of a device for determining obstacles on and around a parking path using ultrasonic waves, the device being configured to achieve the following Figure 25 A third embodiment of a method for filtering obstacles on and around a parking path using ultrasonic waves is shown. Specific embodiments

[0078] The specific structural or functional descriptions of the embodiments of the present invention disclosed in this specification or application exist only for the purpose of describing the embodiments according to the present invention, and the embodiments according to the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described in this specification or application.

[0079] Since the embodiments of the present invention can be modified in various ways and have various forms, specific embodiments will be shown in the drawings and described in this specification or application. However, this is not intended to limit the embodiments according to the concept of the present invention to specific forms, but should be interpreted as including all modifications, equivalents and substitutes included in the spirit and technical scope of the present invention.

[0080] Terms such as first and / or second can be used to describe various components, but the components are not limited by these terms. These terms are only used to distinguish one component from other components. For example, a first component can be referred to as a second component, and similarly, a second component can also be referred to as a first component without departing from the scope of the invention.

[0081] When a component is referred to as being “connected” or “coupled” to another component, it may be directly connected or coupled to the other component, but it should be understood that other components may exist between them. On the other hand, when a component is referred to as being “directly connected” or “directly coupled” to another component, it should be understood that there are no intervening components. Other expressions describing the relationship between components, such as “between” and “directly between,” or “adjacent to” and “directly adjacent to,” should be interpreted in the same manner.

[0082] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. Unless the context clearly indicates otherwise, singular expressions include plural expressions. In this specification, terms such as "including" or "having" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof of an implementation, and should not be understood to exclude the presence or additional possibility of one or more of other features, numbers, steps, operations, components, parts, or combinations thereof.

[0083] Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should also be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with that in the context of the present invention and should not be interpreted as having an idealized or overly formal meaning unless expressly defined as such herein.

[0084] Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings. The same reference numerals in the various figures indicate the same components.

[0085] Information of the object can be obtained from a time of flight (TOF) of an ultrasonic signal that is emitted by an ultrasonic sensor (hereinafter simply referred to as a “sensor”), reflected by the object, and then received by the sensor.

[0086] That is, the distance from the sensor to the object can be calculated based on TOF, which is the time interval from the time point when the sensor transmits ultrasonic waves to the time point when the ultrasonic waves are reflected by the object and received by the sensor, and when multiple sensors installed in the vehicle are used, the position of the object relative to the vehicle can be calculated.

[0087] The ultrasonic waves reflected by the object may be received by the sensor that transmits the ultrasonic waves, or may be received by other adjacent sensors.

[0088] Here, when the sensor that transmits ultrasonic waves and the sensor that receives ultrasonic waves are the same as described above, the TOF of the ultrasonic waves received by the sensor will be referred to as "direct wave TOF", and when the sensor that transmits ultrasonic waves and the sensor that receives ultrasonic waves are different, the TOF of the ultrasonic waves received by the sensor will be referred to as "indirect wave TOF".

[0089] Information about objects around the vehicle can be obtained by repeatedly measuring the ultrasonic TOF using the vehicle sensor as described above. When the ultrasonic wave is not reflected by the same object and the ultrasonic TOF is not continuously updated, the accuracy of the information about the object's location may decrease, indicating that noise is generated in the ultrasonic sensor signal.

[0090] It should be noted that the distance from the sensor to the object is calculated according to the following formula:

[0091] (Ultrasonic TOF / 2)×C,

[0092] in

[0093] C = ultrasonic velocity.

[0094] In the following, for simplicity, the shorthand notation for "ultrasonic TOF" is "ultrasonic TOF × C," which is the round-trip distance from the sensor to the object, and "ultrasonic TOF / 2" is represented by "hTOF." That is, hTOF is the one-way distance between the sensor and the object.

[0095] Figure 1 This figure shows the sensor installation state of a vehicle to which the present invention can be applied. Four sensors A, B, C, and D are installed at the rear of a vehicle V. The parking path on which the vehicle is to travel is represented by two contour lines LN indicating the outer edges of the parking path. An object X located outside the parking path and an object Y located inside the parking path are also shown.

[0096] It should be noted that the parking path can be changed according to the speed, steering angle, etc. of the vehicle, and can be set by a device installed in the vehicle and configured to use known technology, and the sensor can be configured to sequentially transmit ultrasonic waves at predetermined intervals and receive ultrasonic waves reflected by the object, thereby allowing the sensor that transmits the ultrasonic wave to be distinguished.

[0097] Assume that among two sensors adjacent to each other, one receives direct waves and the other receives indirect waves, e.g. Figures 2A to 2CAs shown, the noise filtering method of the vehicle ultrasonic sensor signal is configured to include determining the number of direct wave TOFs and indirect wave TOFs in TOFs of ultrasonic waves received by two vehicle sensors adjacent to each other (S10); when the received ultrasonic TOF includes one direct wave TOF, if there is a previously valid direct wave TOF, determining whether dynamic noise is detected (S20); generating a virtual direct wave TOF when dynamic noise is detected, and setting the virtual direct wave TOF instead of the received real direct wave TOF as a normal ultrasonic TOF to be used for determining the position of an object (S30); when a direct wave TOF exists in the received ultrasonic TOF, a previously valid direct wave TOF exists, and an indirect wave TOF exists in the received ultrasonic TOF, determining whether static noise is detected (S40); and when static noise is detected, determining the normal ultrasonic TOF to be used for determining the position of the object to be one direct wave TOF and zero indirect wave TOFs, and when static noise is not detected, determining the normal ultrasonic TOF to be used for determining the position of the object to be one direct wave TOF and one indirect wave TOF (S50).

[0098] That is, depending on the number of direct wave TOF and indirect wave TOF, the method of filtering the noise of the sensor signal is configured differently, and when there is a direct wave TOF, the normal ultrasonic TOF to be used for determining the position of the object is determined differently depending on whether dynamic noise and static noise are detected as described above.

[0099] It should be noted that when a virtual direct wave TOF is generated as described above, the generated virtual direct wave TOF is set as the normal ultrasonic TOF to be used to subsequently determine the position of the object as described above, and when the virtual direct wave TOF is not generated, the received real direct wave TOF is used as the normal ultrasonic TOF.

[0100] Dynamic noise can be identified in the following situations:

[0101] d (direct wave hTOF)>Vdt,

[0102] in

[0103] Direct wave hTOF=direct wave TOF / 2,

[0104] dhTOF = hTOF t=n – hTOF t=n-1 [m],

[0105] V: vehicle speed, and

[0106] dt: Ultrasonic update period [ms].

[0107] Figure 3 From such as Figure 1 The diagram shows the relationship between vehicle speed and direct wave TOF at the angle of any sensor A among the sensors shown. It is expected that when the vehicle moves by Vdt, the maximum value of the change in direct wave hTOF reflected by the same object is equal to or less than Vdt. Therefore, if d (direct wave hTOF) is determined to be greater than Vdt, it cannot be assumed that the direct wave TOF is continuously reflected and updated by the same object, and dynamic noise is determined to be generated.

[0108] Static noise can be detected in the following situations:

[0109] |Direct wave hTOF – Indirect wave hTOF|> Distance between sensors / 2

[0110] in

[0111] hTOF = TOF / 2; and

[0112] The “distance between sensors” refers to the distance between the sensor that transmits and receives the direct wave and the sensor that receives the indirect wave.

[0113] Figure 4 This is a diagram showing changes in indirect wave TOF depending on the position of any object P. The case where the indirect wave TOF reaches a maximum value, the case where the indirect wave TOF = the direct wave TOF, and the case where the indirect wave TOF reaches a minimum value are compared side by side.

[0114] exist Figure 4 , sensor A is a sensor that transmits and receives direct waves, sensor B is a sensor that receives indirect waves, DIR represents the distance between sensor A and object P, IND represents the distance between object P and sensor B, E represents the distance between sensor A and sensor B, and θ represents the angle formed by the straight line connecting sensor A and sensor B with respect to the straight line represented by DIR.

[0115] Here, the direct wave hTOF is DIR, and the indirect wave hTOF can be calculated by (DIR+IND) / 2. Figure 4 The states of maximum and minimum values ​​in show that: the maximum value of the indirect wave hTOF is calculated by (DIR+DIR+E) / 2=DIR+E / 2, the minimum value of the indirect wave hTOF is calculated by (DIR+DIR–E) / 2=DIR–E / 2, and the indirect wave hTOF tends to decrease from the maximum value to the minimum value as θ increases, as shown in Figure 5 shown.

[0116] That is, the indirect wave hTOF varies within the range of DIR + E / 2 to DIR – E / 2, where DIR is the direct wave hTOF according to θ, so that the difference between the direct wave hTOF and the indirect wave hTOF is within E / 2 for all θ. If the difference between the direct wave hTOF and the indirect wave hTOF exceeds E / 2, it cannot be considered that the indirect wave TOF is continuously reflected and updated by the same object, and it is determined that static noise is generated.

[0117] In addition, when a direct wave TOF is received four times in one row, it is determined that there is a previous valid direct wave TOF, and

[0118] d[(direct wave hTOF) t=n-1 ≤V t=n-1 dt] and [(direct wave hTOF) t=n-2 ≤v t=n-2 dt]

[0119] in:

[0120] Direct wave hTOF=direct wave TOF / 2,

[0121] d (direct wave hTOF) t=n-1 = Direct wave hTOF t=n-1 - Direct wave hTOF) t=n-2 ,

[0122] d (direct wave hTOF) t=n-2 = Direct wave hTOF t=n-2 - Direct wave hTOF) t=n-3 ,

[0123] V: vehicle speed, and

[0124] dt: Ultrasonic update period [ms].

[0125] It should be noted that the cycle time of the controller implementing the present invention may be understood such that t=n may be understood as the current cycle time and t=n-1 may be understood as the previous cycle time.

[0126] That is, when it is checked that the direct wave TOF is received four times in one row and no dynamic noise is generated in the previous three direct wave hTOFs, it is determined that there is a previous valid direct wave TOF.

[0127] Therefore, even if it is determined that dynamic noise has occurred at t=n, if no dynamic noise has occurred at t=n-1 and t=n-2, it is determined that there is a previously valid direct wave TOF as described above, so that a virtual direct wave TOF is generated. This virtual direct wave TOF is set as the normal ultrasonic wave TOF to be used for determining the position of the object.

[0128] At t=n, where n is the current time, the virtual direct wave TOF is calculated as follows:

[0129] Direct wave TOF t=n-1 + k (direct wave TOF t=n-1 - Direct wave TOF t=n-2 )

[0130] Where k is the gain.

[0131] For example, k may be set to 1, and the value may vary depending on how much the direct wave TOF reflected in the virtual direct wave TOF varies.

[0132] On the other hand, when a virtual direct wave TOF is set as the normal ultrasonic wave TOF for determining the position of an object instead of the received direct wave TOF at least at one time point among t=n-1, t=n-2, and t=n-3, it is determined that there is no previously valid direct wave TOF.

[0133] In the noise filtering method of the ultrasonic sensor signal, when a direct wave TOF exists in the received ultrasonic TOF, a previously valid direct wave TOF exists, and an indirect wave TOF does not exist, the following determination (S60) may be performed: a normal ultrasonic TOF to be used for determining the position of an object is one direct wave TOF and zero indirect wave TOF.

[0134] In addition, when there is a direct wave TOF in the received ultrasonic wave TOF, there is no previously valid direct wave TOF, there is an indirect wave TOF, and static noise is not detected, the following determination may be performed ( S70 ): a normal ultrasonic wave TOF to be used for determining the position of the object is one direct wave TOF and one indirect wave TOF.

[0135] When there is a direct wave TOF, there is no previously valid direct wave TOF, there is an indirect wave TOF, and static noise is not detected, or when there is a direct wave TOF, there is no previously valid direct wave TOF, and there is no indirect wave TOF in the received ultrasonic TOF, the following determination may be performed (S80): a normal ultrasonic TOF to be used for determining the position of an object is one direct wave TOF and zero indirect wave TOF.

[0136] That is, when it is determined that one direct wave is received when determining the number of direct wave TOFs and indirect wave TOFs (S10), filtering is performed through S20 to S80 so that the received direct wave TOF is replaced with a virtual direct wave TOF or is set as a normal ultrasonic wave TOF to be used for determining the position of the object according to the presence or absence of dynamic noise, and the received indirect wave TOF is used or not used for determining the position of the object according to the presence or absence of static noise.

[0137] On the other hand, the noise filtering method for ultrasonic sensor signals also includes generating a virtual direct wave TOF and setting the virtual direct wave TOF as a normal ultrasonic wave TOF for determining the position of an object when no direct wave TOF exists in the received ultrasonic wave TOF, an indirect wave TOF exists, and a previously valid direct wave TOF exists (S90). After setting the virtual direct wave TOF as the normal ultrasonic wave TOF for determining the position of an object when no direct wave TOF exists in the received ultrasonic wave TOF, an indirect wave TOF exists, and a previously valid direct wave TOF exists, determining whether static noise is detected. The noise filtering method may further include setting the normal ultrasonic wave TOF for determining the position of the object to one direct wave TOF and one indirect wave TOF if static noise is not detected, and determining the normal ultrasonic wave TOF for determining the position of the object to one direct wave TOF and zero indirect wave TOFs if static noise is detected (S100).

[0138] Here, when there is no direct wave TOF, there is an indirect wave TOF, and there is no previously valid direct wave TOF in the received ultrasonic wave TOF, the virtual direct wave TOF as described above may not be generated as described above, so that the normal ultrasonic wave TOF to be used for determining the position of the object is set to zero direct wave TOF and one indirect wave TOF (S110).

[0139] In addition, the noise filtering method of the ultrasonic sensor signal may further include: when neither the direct wave TOF nor the indirect wave TOF exists in the received ultrasonic TOF and there is no previously valid direct wave TOF, setting the normal ultrasonic TOF to be used for determining the position of the object to zero direct wave TOF and zero indirect wave TOF (S120); and when neither the direct wave TOF nor the indirect wave TOF exists in the received ultrasonic TOF and there is a previously valid direct wave TOF, generating a virtual direct wave TOF, setting the virtual direct wave TOF to the normal ultrasonic TOF to be used for determining the position of the object, and setting the normal ultrasonic TOF to be used for determining the position of the object to one direct wave TOF and zero indirect wave TOF (S130).

[0140] In the noise filtering method of the vehicle ultrasonic sensor signal as described above, depending on whether there is dynamic noise and static noise in the received ultrasonic TOF, only the reliable ultrasonic TOF is set as the normal ultrasonic TOF and the less reliable ultrasonic TOF is excluded from the received ultrasonic TOF, so that when the sensor receives the ultrasonic wave reflected by the object and detects the object, the position of the object is determined more accurately.

[0141] Figure 28The noise filtering device for a vehicle ultrasonic sensor signal is shown to be configured to implement the noise filtering method for a vehicle ultrasonic sensor signal as described above, and may be configured to include: a TOF counter 100, which determines the number of direct wave TOFs and indirect wave TOFs in the TOFs of ultrasonic waves received by two vehicle sensors SR adjacent to each other; a dynamic noise determination unit 101, which determines whether dynamic noise is detected when the TOF counter 100 determines that one direct wave TOF is included in the received ultrasonic wave TOF and there is a previously valid direct wave TOF; a TOF setting unit 102, which generates a virtual direct wave TOF when the dynamic noise determination unit 101 detects dynamic noise, and sets the virtual direct wave TOF instead of the received direct wave TOF as a normal ultrasonic wave TOF to be used for determining the position of an object; and a static noise determination unit 103, which determines whether static noise is detected when a direct wave TOF, a previously valid direct wave TOF, and an indirect wave TOF are present in the received ultrasonic wave TOF.

[0142] In addition, the TOF setting unit 102 can be configured to: when the static noise determination unit 103 detects static noise, determine the normal ultrasonic TOF to be used for determining the position of the object as one direct wave TOF and zero indirect wave TOF, and when no static noise is detected, determine the normal ultrasonic TOF to be used for determining the position of the object as one direct wave TOF and one indirect wave TOF.

[0143] The TOF setting unit 102 may be configured to determine a normal ultrasonic wave TOF to be used for determining the position of the object as one direct wave TOF and zero indirect wave TOF when a direct wave TOF exists, a previously valid direct wave TOF exists, and no indirect wave TOF exists in the received ultrasonic wave TOF.

[0144] The TOF setting unit 102 may be configured to determine a normal ultrasonic TOF to be used for determining the position of an object as one direct wave TOF and one indirect wave TOF when a direct wave TOF exists in the received ultrasonic TOF, there is no previously valid direct wave TOF, and there is an indirect wave TOF, and at the same time, no static noise is detected.

[0145] The TOF setting unit 102 may be configured to determine a normal ultrasonic TOF to be used for determining the position of an object as one direct wave TOF and zero indirect wave TOF when a direct wave TOF exists in the received ultrasonic TOF, there is no previously valid direct wave TOF, there is an indirect wave TOF, and static noise is detected, or when a direct wave TOF exists in the received ultrasonic TOF, there is no indirect wave TOF, and there is no previously valid direct wave TOF.

[0146] In addition, the TOF setting unit 102 can be configured to: when there is no direct wave TOF in the received ultrasonic TOF, there is an indirect wave TOF, and there is a previously valid direct wave TOF, generate a virtual direct wave TOF, and set the virtual direct wave TOF as the normal ultrasonic TOF to be used to determine the position of the object.

[0147] After the TOF setting unit 102 sets the virtual direct wave TOF as the normal ultrasonic wave TOF for determining the position of the object when there is no direct wave TOF, an indirect wave TOF, or a previously valid direct wave TOF in the received ultrasonic wave TOF, the static noise determination unit 103 determines whether static noise is detected. The TOF setting unit 102 may be configured to set the normal ultrasonic wave TOF to be used for determining the position of the object to one direct wave TOF and one indirect wave TOF if no static noise is detected, and to determine the normal ultrasonic wave TOF to be used for determining the position of the object to one direct wave TOF and zero indirect wave TOF if static noise is detected.

[0148] The TOF setting unit 102 can be configured to: when neither the direct wave TOF nor the indirect wave TOF exists in the received ultrasonic TOF and there is no previously valid direct wave TOF, set the normal ultrasonic TOF to be used to determine the position of the object to zero direct wave TOF and zero indirect wave TOF; and when neither the direct wave TOF nor the indirect wave TOF exists in the received ultrasonic TOF and there is a previously valid direct wave TOF, generate a virtual direct wave TOF, set the virtual indirect wave TOF to the normal ultrasonic TOF to be used to determine the position of the object, and set the normal ultrasonic TOF to be used to determine the position of the object to one direct wave TOF and zero indirect wave TOF.

[0149] The dynamic noise determination unit 101 may be configured to determine that dynamic noise is generated in the following circumstances:

[0150] d (direct wave hTOF)>Vdt,

[0151] in

[0152] Direct wave hTOF=direct wave TOF / 2,

[0153] d(direct wave hTOF) = direct wave hTOF t=n -Direct wave hTOF t=n-1 [m],

[0154] V: vehicle speed, and

[0155] dt: Ultrasonic update period [ms].

[0156] The static noise determination unit 103 may be configured to determine that static noise is generated in the following cases:

[0157] |Direct wave hTOF – Indirect wave hTOF|> Distance between sensors / 2

[0158] in

[0159] hTOF = TOF / 2; and

[0160] The “distance between sensors” refers to the distance between the sensor that transmits and receives the direct wave and the sensor that receives the indirect wave.

[0161] The dynamic noise determination unit 101 and the static noise determination unit 103 are respectively configured to determine whether there is a previously valid direct wave TOF, and determine that there is a previously valid direct wave TOF when a direct wave TOF is received four times in a row, and

[0162] [d (direct wave hTOF) t=n-1 ≤V t=n-1 dt] and [d (direct wave hTOF) t=n-2 ≤V t=n-2 dt]

[0163] in

[0164] Direct wave hTOF=direct wave TOF / 2,

[0165] d (direct wave hTOF) t=n-1 = Direct wave hTOF t=n-1 -Direct wave hTOF t=n-1 ,

[0166] d (direct wave hTOF) t=n-2 = Direct wave hTOF t=n-2 -Direct wave hTOF t=n-3 ,

[0167] V: vehicle speed, and

[0168] dt: Ultrasonic update period [ms].

[0169] When a virtual direct wave TOF instead of the received direct wave TOF is set as a normal ultrasonic wave TOF to be used for determining the position of the object at least at one time point of t=n-1, t=n-2, and t=n-3, it is determined that there is no previously valid direct wave TOF.

[0170] At t=n, where n is the current time, the virtual direct wave TOF is calculated as follows:

[0171] Direct wave TOF t=n-1+k (direct wave TOF) t=n-1 -Direct wave TOF t=n-2 )

[0172] Where k is the gain.

[0173] Figure 6 A first embodiment of a method for determining obstacles on and around a parking path using ultrasonic waves is shown, including determining whether ultrasonic noise exists within the time of flight (TOF) of received ultrasonic waves reflected by an object (S210); when ultrasonic noise does not exist, generating a virtual object on the outline of a parking path on which a vehicle is to travel based on the received ultrasonic TOF (S220); generating a virtual indirect wave TOF using the virtual object (S230); and determining whether the object is located inside or outside the outline of the parking path by comparing a real indirect wave TOF, which is an indirect wave TOF in the received ultrasonic TOF, with the virtual indirect wave TOF (S240).

[0174] In determining whether ultrasonic noise exists ( S210 ), when both direct wave TOF and indirect wave TOF exist in the received ultrasonic wave TOF and neither dynamic noise nor static noise exists, it is determined that ultrasonic noise does not exist.

[0175] That is, when it is checked that both the direct wave TOF and the indirect wave TOF exist and there is neither dynamic noise nor static noise so that the direct wave TOF and the indirect wave TOF are continuously reflected by the same object and updated, the received direct wave TOF and the received indirect wave TOF are determined to be normal ultrasonic wave TOF to be used for determining the position of the object, thereby determining that there is no ultrasonic noise.

[0176] like Figure 7 As shown, a virtual object can be generated at an intersection point P_virtual where a circle intersects the outline of the parking path, where the circle has the position of the sensor that transmits and receives the direct wave as the center and the direct wave hToF as the radius.

[0177] The virtual indirect wave TOF is calculated as the sum of a straight line connecting the position of the sensor that transmits and receives the direct wave and the virtual object and a straight line connecting the virtual object and the position of the sensor that receives the indirect wave.

[0178] That is, in Figure 7 In this case, the virtual indirect wave TOF is calculated as the sum of the distance between P_virtual and sensor A and the distance between P_virtual and sensor B.

[0179] It should be noted that the real direct wave TOF is the one generated by Figure 7 The TOF of the direct wave received by the sensor in .

[0180] In determining whether the object is located inside or outside the outline of the parking path (S240), when the sensor that transmits and receives the direct wave is located outside the parking path compared to the sensor that receives the indirect wave, if the real indirect wave TOF is greater than the virtual indirect wave TOF, it is determined that the object is located outside the outline of the parking path, and if the real indirect wave TOF is equal to or less than the virtual indirect wave TOF, it is determined that the object is located inside the outline of the parking path.

[0181] examine Figure 7 It will help to understand its effectiveness.

[0182] Right now, Figure 7 It shows that when the ultrasonic wave emitted by sensor A is reflected at P_out located outside the outline of the parking path and received by sensor B, the indirect wave TOF will be greater than the virtual indirect wave TOF; and when the ultrasonic wave emitted by sensor A is reflected at P_in located inside the outline of the parking path and received by sensor B, the indirect wave TOF will be less than the virtual indirect wave TOF.

[0183] Therefore, whether the object reflecting the ultrasonic wave TOF is located inside the parking path can be determined according to whether the real indirect wave TOF measured by the sensor is larger or smaller than the virtual TOF calculated as described above.

[0184] It should be noted that “real indirect wave TOF” is an expression for clearly distinguishing from “virtual indirect wave TOF” and actually refers to the TOF of the indirect wave received and calculated by the sensor.

[0185] Of course, due to Figure 7 As shown, multiple sensors are installed in the vehicle, so the multiple sensors installed in the vehicle transmit ultrasonic waves in sequence, and each time each sensor transmits ultrasonic waves, the above steps are repeated by two adjacent sensors, so that it is more accurately determined whether obstacles on and around the parking path are located inside the parking path.

[0186] Figure 29A device for determining obstacles on and around a parking path using ultrasonic waves is shown. The device is configured to implement a first embodiment of a method for determining obstacles on and around a parking path using ultrasonic waves, and may be configured to include: a noise determination unit 200 that determines whether ultrasonic noise exists within the time of flight (TOF) of a received ultrasonic wave reflected by an object; a virtual object generation unit 201 that, when the noise determination unit 200 determines that ultrasonic noise does not exist, generates a virtual object on the outline of the parking path on which the vehicle is to travel based on the received ultrasonic TOF; a virtual indirect wave generation unit 202 that generates a virtual indirect wave TOF using the virtual object generated by the virtual object generation unit 201; and an object position determination unit 203 that determines whether the object is located inside or outside the outline of the parking path by comparing a real indirect wave TOF, which is an indirect wave TOF in the received ultrasonic TOF, with the indirect wave TOF generated by the virtual indirect wave generation unit 202.

[0187] The noise determination unit 200 may be configured to include a dynamic noise determination unit 200-1 and a static noise determination unit 200-2, and determine that there is no ultrasonic noise when both direct wave TOF and indirect wave TOF exist and neither dynamic noise nor static noise exists within the received ultrasonic wave TOF.

[0188] The dynamic noise determination unit 200 - 1 may be configured to determine that dynamic noise is generated in the following cases:

[0189] d (direct wave hTOF)>Vdt,

[0190] in

[0191] Direct wave hTOF=direct wave TOF / 2,

[0192] d(direct wave hTOF) = direct wave hTOF t=n -Direct wave hTOF t=n-1 [m],

[0193] V: vehicle speed, and

[0194] dt: Ultrasonic update period [ms].

[0195] The static noise determination unit 200-2 may be configured to determine that static noise is generated in the following cases:

[0196] |Direct wave hTOF – Indirect wave hTOF|> Distance between sensors / 2

[0197] in

[0198] hTOF = TOF / 2; and

[0199] The “distance between sensors” refers to the distance between the sensor that transmits and receives the direct wave and the sensor that receives the indirect wave.

[0200] The virtual object generation unit 201 may be configured to generate a virtual object at an intersection of a circle with the outline of the parking path, wherein the circle has the position of the sensor that transmits and receives the direct wave as the center and the direct wave hToF as the radius.

[0201] The virtual indirect wave generating unit 202 may be configured to generate the virtual indirect wave TOF as the sum of a straight line connecting the position of the sensor transmitting and receiving the direct wave and the virtual object and a straight line connecting the virtual object and the position of the sensor receiving the indirect wave.

[0202] When the sensor that transmits and receives the direct wave is located outside the parking path compared to the sensor that receives the indirect wave, the object position determination unit 203 may be configured to determine that the object is located outside the outline of the parking path if the real indirect wave TOF is greater than the virtual indirect wave TOF, and to determine that the object is located inside the outline of the parking path if the real indirect wave TOF is equal to or less than the virtual indirect wave TOF.

[0203] Figure 8 A second embodiment of a method for determining obstacles on and around a parking path using ultrasonic waves includes determining whether ultrasonic noise exists within the time of flight (TOF) of received ultrasonic waves reflected by an object (S310); generating a virtual object on the outline of a parking path on which a vehicle is to travel based on the received ultrasonic TOF when ultrasonic noise does not exist (S320); generating a virtual indirect wave TOF using the virtual object (S330); and determining whether the object is located inside or outside the outline of the parking path by comparing a real indirect wave TOF, which is an indirect wave TOF in the received ultrasonic TOF, with a sum of the virtual indirect wave TOF and a predetermined indirect wave offset (S340).

[0204] That is, the second embodiment of the method for determining obstacles on and around a parking path using ultrasonic waves differs from the first embodiment in that indirect wave deviation is also considered when determining whether an object is inside or outside the outline of the parking path.

[0205] Therefore, when determining whether ultrasonic noise exists (S310), when both direct wave TOF and indirect wave TOF exist and neither dynamic noise nor static noise exists in the received ultrasonic TOF, it is determined that ultrasonic noise does not exist, as in the first embodiment of the determination method for obstacles on and around a parking path using ultrasonic waves.

[0206] Furthermore, a virtual object may be generated at an intersection where a circle having the position of the sensor that transmits and receives the direct wave as its center and the direct wave hToF as its radius intersects the outline of the parking path.

[0207] Furthermore, the virtual indirect wave TOF is generated as the sum of a straight line connecting the position of the sensor that transmits and receives the direct wave and the virtual object and a line connecting the virtual object and the position of the sensor that receives the indirect wave.

[0208] It should be noted that the second embodiment of the method for determining obstacles on and around a parking path using ultrasonic waves adopts indirect wave migration in order to take into account the following real situation: Figure 9 As shown, the object detected by the sensor is an object OBJ that actually has a volume, and when ultrasonic waves emitted by the same sensor are received as direct waves and indirect waves after being reflected by the object, the direct waves and indirect waves may be reflected at different points of the object.

[0209] That is, in the first embodiment of the method for determining obstacles on and around a parking path using ultrasonic waves, an object that reflects both direct and indirect waves is treated as a single point, so that whether the object is located inside the parking path is determined based on the assumption that the direct and indirect waves are reflected at the same point on the object; whereas the second embodiment adopts indirect wave offset in order to take into account the fact that when ultrasonic waves are reflected by an object that actually has a volume, the reflection point of the direct wave and the reflection point of the indirect wave may be different even for the same object.

[0210] Assume that the direct wave and the indirect wave are reflected at two different points M and N of the same object, and calculate the ultrasonic probability density function of point N, as Figure 10 As shown, point N is assumed to be the reflection point of the indirect wave and is located on a circle with a radius of F and a center at point M. Point M is assumed to be the reflection point of the direct wave, and the radius F is the distance between the two points. It is then assumed that the indirect wave is reflected at the point where the probability of point N being at that location based on the ultrasonic probability density function is highest, and the indirect wave offset is set using the difference between the actual indirect wave hTOF and the ideal indirect wave hTOF.

[0211] Here, the ideal indirect wave hTOF is conceptually different from the virtual indirect wave hTOF.

[0212] Specifically, the virtual indirect wave hTOF is calculated by dividing the sum of a straight line connecting the position of the sensor that transmits and receives the direct wave (the indirect wave receiving sensor) to a virtual object and a straight line connecting the virtual object to the position of the indirect wave receiving sensor by two. The virtual object is generated at the intersection of a circle centered at the sensor that transmits and receives the direct wave and with the direct wave hTOF as its radius, and the parking path outline. The ideal indirect wave hTOF is calculated by dividing the sum of a straight line connecting the position of the sensor that transmits and receives the direct wave (the indirect wave receiving sensor) to the point with the highest probability of point N being at that position based on the ultrasonic wave probability density function, and a straight line connecting the point with the highest probability of point N being at that position to the position of the indirect wave receiving sensor by two.

[0213] It should be noted that Figure 11 Points N1 to N4 are shown, and the point N can be located differently as shown in FIG. Figure 10 On the circle shown.

[0214] Furthermore, it is assumed that the plane formed by the circle formed by the two points M and N is parallel to the plane formed by the sensor.

[0215] That is, the sensor can be regarded as being provided at the same height along the edge of the vehicle in the vehicle to form a plane, and the circle formed by the two points M and N of the object can be regarded as being formed on a plane parallel to the plane formed by the sensor, so that it is assumed that the sensor and the two points M and N can be regarded as Figure 9 The state shown is located on the same plane.

[0216] Figure 12 The value of the ultrasonic probability density function is obtained by the following formula

[0217] P_m*P_n

[0218] Among them, P_m is the probability that M' is consistent with M, P_n is the probability that N' is consistent with N, and on the infinite line L connecting two points M and N, M' is the point where the direct wave TOF is minimized and N' is the point where the indirect wave TOF is minimized, and the infinite line rotates around point M. The probability P_m is:

[0219] When M' is between M and N, (the distance between M' and N) / (the distance between N and M),

[0220] 1 when M' lies outside the interval between M and N on one side of M, or

[0221] When M' is outside the interval between M and N on one side of N, it is 0.

[0222] The probability P_n is:

[0223] When N' is between M and N, (the distance between N' and M) / (the distance between N and M),

[0224] 1 when N' lies outside the interval between M and N on one side of N, or

[0225] When N' is outside the interval between M and N on one side of M, it is 0.

[0226] Here, the point M' that minimizes the direct wave TOF on the infinite straight line connecting the two points M and N can be obtained by the intersection of the infinite straight line and the line perpendicular to the infinite straight line drawn from the sensor that transmits and receives the direct wave, and the point N' that minimizes the indirect wave TOF on the infinite straight line can be obtained by the intersection of the infinite straight line and the straight line connecting the point symmetrical to the position axis of the sensor that receives the indirect wave to the sensor that transmits and receives the direct wave.

[0227] The above determination of M' and N' is based on the following reasonable inference: among the reflection points of the object, the point where the ultrasonic wave moves the shortest distance has the highest probability of becoming the actual reflection point of the direct wave and the indirect wave.

[0228] As mentioned above, when the infinite line rotates around point M, the probability P_m that M' is consistent with M at each position is:

[0229] When M' is between M and N, (the distance between M' and N) / (the distance between N and M);

[0230] 1 when M' is outside the interval between M and N on one side of M; or

[0231] When M' is outside the interval between M and N on one side of N, it is 0.

[0232] The probability P_n that N' is consistent with N is:

[0233] When N' is between M and N, (the distance between N' and M) / (the distance between N and M);

[0234] 1 when N' lies outside the interval between M and N on one side of N; or

[0235] When N' is outside the interval between M and N on one side of M, it is 0.

[0236] The value of the ultrasonic probability density function is obtained from P_m*P_n using the value of P_m*P_n.

[0237] exist Figure 12, the ultrasonic probability density function can be viewed as a function having α as an independent variable and P_m*P_n as a dependent variable, where α is the angle between the line segment GM and MN, where point G is the point where the straight line through the sensor A that transmits and receives the direct wave and point M intersects the circle formed by rotating point N around point M.

[0238] Since the line segment MN is a line segment on the infinite line L, α changes as the infinite line is rotated, and the value of the ultrasonic probability density function also changes. Figure 13 As shown in Figure 2, when α takes a specific value, the probability density is higher.

[0239] In fact, Figure 13 is by Figure 14 Multiply the value in Figure 15 The value in is obtained. Figure 14 is a graph showing the variation of P_m with the variation of α, P_m is the probability that M' coincides with M, M being the reflection point of the true direct wave, where M' is closer to M than to N, and Figure 15 is a graph showing the variation of P_n as α varies, P_n being the probability that N' coincides with N, the reflection point of the true indirect wave, where N' is closer to N than to M.

[0240] therefore, Figure 13 The ultrasonic probability density function in has a peak value greater than zero in the interval of α, where the probability that N' is consistent with N is actually the highest while fully ensuring the probability that M' is consistent with M, and the probability that the indirect wave is actually reflected is the highest in these intervals.

[0241] Figure 16 is shown in Figure 12 A diagram of a circle drawn under the same conditions, with the solid line marking the portion where the true indirect wave hTOF is greater than the ideal indirect wave hTOF, the dashed line marking the portion where the true indirect wave hTOF is less than the ideal indirect wave hTOF, and the thick solid line marking the portion where only the ultrasonic wave probability density function value is greater than zero. Within the interval marked by the thick solid line, the probability of the indirect wave actually being reflected is higher. In other words, the probability that N actually lies within the interval marked by the thick solid line is higher. Naturally, the probability that the true direct wave is reflected at point M is higher.

[0242] Figure 17 : is a diagram showing how the difference between the real indirect wave hTOF and the ideal indirect wave hTOF changes as α increases. The portion marked by the solid line is a portion where P_m>0 and P_n>0, and therefore, the value of the ultrasonic wave probability density function is greater than zero.

[0243] Depend on Figure 17It can be seen that in the interval of P_m>0 and P_n>0, the difference between the real indirect wave hTOF and the ideal indirect wave hTOF is in the range of -1 cm to 5 cm.

[0244] Figure 18 is a diagram showing how the difference between the real indirect wave hTOF and the ideal indirect wave hTOF changes as α increases, as shown in FIG. Figure 17 The portion marked by the solid line is the portion that satisfies the conditions P_m>0.5 and P_n>0.5.

[0245] Right now, Figure 18 shows the expected point N at which the probability is higher than Figure 17 The difference between the true indirect wave hTOF and the ideal indirect wave hTOF may fall within the range of the probability interval described in . As a result, the difference between the true indirect wave hTOF and the ideal indirect wave hTOF is in the range of 1 cm to 3 cm.

[0246] Therefore, as a result, the range of the difference between the real indirect wave hTOF and the ideal indirect wave hTOF obtained in the interval where the expected point N exists with high probability and in which the probability of the indirect wave being reflected is high can be used as a basis for correctly setting the indirect wave offset.

[0247] Figure 19 is shown in Figure 20 A table showing the minimum and maximum values ​​of the difference between the true indirect wave hTOF and the ideal indirect wave hTOF as α increases within the interval that satisfies the conditions P_m>0.5 and P_n>0.5 in multiple experiments under the same conditions, and the value of P_max, where P_max is the difference between the true indirect wave hTOF and the ideal indirect wave hTOF at the point where the value of the ultrasonic probability density function is maximized.

[0248] exist Figure 20 , A and B represent sensors installed in the vehicle, and it is assumed that: an object including two points M and N is assumed to be a circle with a center at M and a radius F; point M is spaced apart from the vehicle by a predetermined distance in the parking path direction and the object is detectable by ultrasonic waves within the predetermined distance; and the circle is spaced apart from the outline of the parking path by a predetermined reference offset.

[0249] Figure 19The table in summarizes the results of the experiment, where the distance F between point M and point N is varied between 20 cm, 30 cm, and 50 cm to account for objects of various sizes that may exist in and around the parking path, the reference distance to the object is varied between 1.8 m and 1.2 m to account for various sensing ranges of the sensor, and the reference offset is varied between 0 cm and 10 cm to account for the case where the real object touches the contour of the parking path and the case where the real object is spaced apart from the contour by the reference offset.

[0250] That is, experiments are conducted under various conditions to fully reflect real situations that may occur in the process of determining the positions of objects that may exist in and around the parking path on which the vehicle is to travel for parking through sensors, and the indirect wave offset is calculated based on this.

[0251] Here, the indirect wave offset can be determined by considering the minimum value of P_max, which is the value in Figure 19 The difference between the true indirect wave hTOF and the ideal indirect wave hTOF at the point where the value of the ultrasonic probability density function is maximized.

[0252] Assuming that the indirect wave is reflected at a point where the probability of point N being located there is based on the highest value of the ultrasonic wave probability density function, P_max corresponds to the difference between the real indirect wave hTOF and the ideal indirect wave hTOF.

[0253] Figure 19 It is shown that when F=20 cm, the reference distance is 1.8 m, and the reference offset is 0 cm, the minimum value of P_max is 0.011, so that, based on this value, the indirect wave offset is set to 0.01.

[0254] That is, in Figure 19 In the data in , F is small, which means that the volume of the object is relatively small, and the reference offset is zero, so that the indirect wave offset is determined based on the object contacting the parking path.

[0255] Of course, when the F of the object is small and thus the volume is relatively small, the value of P_max may become smaller, but P_max of the object with the most appropriate F value may be calculated and used in actual consideration of various aspects such as the vehicle, sensor, etc.

[0256] In determining whether the object is located inside or outside the outline of the parking path (S340), when the sensor that transmits and receives the direct wave is located outside the parking path compared to the sensor that receives the indirect wave, if the real indirect wave hTOF is greater than the sum of the virtual indirect wave hTOF and the indirect wave offset, it is determined that the object is located outside the outline of the parking path, and if the real indirect wave hTOF is equal to or less than the sum of the virtual indirect wave hTOF and the indirect wave offset, it is determined that the object is located inside the outline of the parking path.

[0257] That is, compared with the first embodiment of the method for determining obstacles on and around the parking path using ultrasonic waves, the real indirect wave hTOF is not simply compared with the virtual indirect wave hTOF, but is compared with the sum of the virtual indirect wave hTOF and the indirect wave offset, so that if the real indirect wave hTOF is larger, it is determined that the object is outside the outline of the parking path.

[0258] Therefore, compared with the first embodiment, it is possible to more conservatively check that an object actually having a volume does not exist inside the contour of the parking path.

[0259] In addition, as described above, P_max when the reference offset is 0 cm is used as the indirect wave offset, and Figure 19 It is shown that P_max when the reference offset is 0 cm tends to be smaller than P_max when the reference offset is 10 cm, so that when determining that an object is outside the parking path based on the comparison between the real indirect wave hTOF and the sum of the indirect wave offset and the virtual indirect wave hTOF, it is naturally determined that the object with a reference offset of 10 cm is outside the parking path. Therefore, when using Figure 19 When setting the indirect wave offset with minimum P_max in , it is possible to reliably check that an object is not within the parking path.

[0260] Of course, also in the second embodiment, multiple sensors installed in the vehicle transmit ultrasonic waves in sequence, and the above steps are repeated by two adjacent sensors each time each sensor receives the ultrasonic wave, so that it is more accurately determined whether obstacles on and around the parking path are located inside the parking path.

[0261] Figure 30A device for determining obstacles on and around a parking path using ultrasonic waves is shown. The device is configured to implement a second embodiment of a method for determining obstacles on and around a parking path using ultrasonic waves, and may be configured to include: a noise determination unit 300 that determines whether ultrasonic noise exists within the time of flight (TOF) of a received ultrasonic wave reflected by an object; a virtual object generation unit 301 that, when the noise determination unit 300 determines that ultrasonic noise does not exist, generates a virtual object on the outline of the parking path on which the vehicle is to travel based on the received ultrasonic TOF; a virtual indirect wave generation unit 302 that generates a virtual indirect wave TOF using the virtual object generated by the virtual object generation unit 301; and an object position determination unit 304 that determines whether the object is located inside or outside the outline of the parking path by comparing a real indirect wave TOF, which is an indirect wave TOF within the received ultrasonic TOF, with a sum of a virtual indirect wave TOF and a predetermined indirect wave offset generated by the indirect wave offset generation unit 303.

[0262] The noise determination unit 300 may be configured to include a dynamic noise determination unit 300-1 and a static noise determination unit 300-2, and determine that there is no ultrasonic noise when both direct wave TOF and indirect wave TOF exist and neither dynamic noise nor static noise exists within the received ultrasonic wave TOF.

[0263] The dynamic noise determination unit 300 - 1 may be configured to determine that dynamic noise is generated in the following cases:

[0264] d (direct wave hTOF)>Vdt,

[0265] in

[0266] Direct wave hTOF=direct wave TOF / 2,

[0267] d(direct wave hTOF) = direct wave hTOF t=n -Direct wave hTOF t=n-1 [m],

[0268] V: vehicle speed, and

[0269] dt: Ultrasonic update period [ms].

[0270] The static noise determination unit 300-2 may be configured to determine that static noise is generated in the following cases:

[0271] |Direct wave hTOF – Indirect wave hTOF|> Distance between sensors / 2

[0272] in

[0273] hTOF = TOF / 2; and

[0274] The “distance between sensors” refers to the distance between the sensor that transmits and receives the direct wave and the sensor that receives the indirect wave.

[0275] The virtual object generation unit 301 may be configured to generate a virtual object at an intersection of a circle with the outline of the parking path, wherein the circle has the position of the sensor that transmits and receives the direct wave as the center and the direct wave hToF as the radius.

[0276] The virtual indirect wave generating unit 302 may be configured to generate the virtual indirect wave TOF as the sum of a straight line connecting the position of the sensor transmitting and receiving the direct wave to the virtual object and a straight line connecting the virtual object to the position of the sensor receiving the indirect wave.

[0277] Assuming that the direct wave and the indirect wave are reflected at two different points M and N of the same object, the indirect wave offset generating unit 303 can be configured to calculate the ultrasonic probability density function of point N, where point N is assumed to be the reflection point of the indirect wave and point N is located on a circle with a radius F between the two points and a center at point M, where point M is assumed to be the reflection point of the direct wave; and the direct wave offset can be set using the difference between the real indirect wave hTOF and the ideal indirect wave hTOF, assuming that the indirect wave is reflected at a point where the probability of point N being located here is based on the maximum value of the ultrasonic probability density function.

[0278] Assuming that the indirect wave is reflected at a point where the probability of point N being located there is based on the highest value of the ultrasonic probability density function, the indirect wave offset can be set using the difference between the real indirect wave hTOF and the ideal indirect wave hTOF.

[0279] The ideal indirect wave hTOF can be calculated by dividing the sum of the following terms by two: a straight line connecting the position of the sensor that transmits and receives the direct wave (sensor that receives the indirect wave) to the point at which the probability of point N being at that position is highest based on the ultrasonic probability density function; and a straight line connecting the point at which the probability of point N being at that position is highest to the position of the sensor that receives the indirect wave.

[0280] Assume that the plane formed by the circle formed by the two points M and N is parallel to the plane formed by the sensor.

[0281] The value of the ultrasonic probability density function is obtained by the following formula

[0282] P_m*P_n

[0283] Among them, P_m is the probability that M' is consistent with M, P_n is the probability that N' is consistent with N, and on the infinite line connecting two points M and N, M' is the point where the direct wave TOF is minimized and N' is the point where the indirect wave TOF is minimized, and the infinite line rotates around M. The probability P_m is:

[0284] When M' is between M and N, (the distance between M' and N) / (the distance between N and M);

[0285] 1 when M' is outside the interval between M and N on one side of M; or

[0286] When M' is outside the interval between M and N on one side of N, it is 0.

[0287] The probability P_n is:

[0288] When N' is between M and N, (the distance between N' and M) / (the distance between N and M);

[0289] 1 when N' lies outside the interval between M and N on one side of N; or

[0290] When N' is outside the interval between M and N on one side of M, it is 0.

[0291] Furthermore, the value of the probability density function is obtained as follows:

[0292] P_m*P_n

[0293] Where P_m is the probability that M' coincides with M, P_n is the probability that N' coincides with N, M' is the intersection point of the infinite straight line connecting points M and N and the line drawn perpendicular to the infinite straight line from the sensor that transmits and receives the direct wave, N' is the intersection point of the infinite straight line and the line connecting the sensor that transmits and receives the direct wave to a point axially symmetrical with respect to the position of the infinite straight line and the sensor that receives the indirect wave, and the infinite straight line rotates. The probability of P_m is:

[0294] When M' is between M and N, (the distance between M' and N) / (the distance between N and M);

[0295] 1 when M' is outside the interval between M and N on one side of M; or

[0296] When M' is outside the interval between M and N on one side of N, it is 0.

[0297] The probability P_n is:

[0298] When N' is between M and N, (the distance between N' and M) / (the distance between N and M);

[0299] 1 when N' lies outside the interval between M and N on one side of N; or

[0300] When N' is outside the interval between M and N on one side of M, it is 0.

[0301] exist Figure 20 In the embodiment, it is assumed that: the object including two points M and N is a circle with a center at M and a radius F; point M is spaced apart from the vehicle by a predetermined distance in the parking path direction and the object is detectable by ultrasonic waves within the predetermined distance; and the circle is spaced apart from the outline of the parking path by a predetermined reference offset.

[0302] When the sensor that transmits and receives the direct wave is located outside the parking path compared to the sensor that receives the indirect wave, the object position determination unit 304 can be configured to: if the real indirect wave hTOF is greater than the sum of the virtual indirect wave hTOF and the indirect wave offset, determine that the object is located outside the outline of the parking path; if the real indirect wave hTOF is equal to or less than the sum of the virtual indirect wave hTOF and the indirect wave offset, determine that the object is located inside the outline of the parking path.

[0303] Figure 21 A third embodiment of a method for determining obstacles on and around a parking path using ultrasonic waves includes obtaining a final path offset on a parking path on which a vehicle is to travel (S410); determining whether ultrasonic noise exists within the time of flight (TOF) of received ultrasonic waves reflected by an object (S420); adjusting a contour of the parking path on which the vehicle is to travel by adding the final path offset when noise does not exist, and generating a virtual object on the adjusted contour based on the received ultrasonic TOF (S430); generating an indirect wave TOF using the virtual object (S440); and determining whether the object is located inside or outside the contour of the parking path by comparing a real indirect wave TOF, which is an indirect wave TOF in the received ultrasonic TOF, with the virtual indirect wave TOF (S450).

[0304] That is, the third embodiment differs from the first embodiment only in that, when determining whether the object is inside or outside the outline of the parking path, the position of the object is determined based on the outline of the parking path to which the final path offset is added.

[0305] Therefore, in determining whether ultrasonic noise exists ( S420 ), when both direct wave TOF and indirect wave TOF exist and neither dynamic noise nor static noise exists in the received ultrasonic wave TOF, it is determined that ultrasonic noise does not exist.

[0306] Furthermore, a virtual object may be generated at an intersection where a circle having the position of the sensor emitting and receiving the direct wave as its center and the direct wave hToF as its radius intersects the outline of the parking path adjusted by adding the final path offset.

[0307] Furthermore, the virtual indirect wave TOF is generated as the sum of a straight line connecting the position of the sensor that transmits and receives the direct wave and the virtual object and a line connecting the virtual object and the position of the sensor that receives the indirect wave.

[0308] Of course, in determining whether the object is located inside or outside the outline of the parking path (S450), when the sensor that transmits and receives the direct wave is located outside the parking path compared to the sensor that receives the indirect wave, if the real indirect wave hTOF is greater than the virtual indirect wave hTOF, it is determined that the object is located outside the outline of the parking path, and if the real indirect wave hTOF is equal to or less than the virtual indirect wave hTOF, it is determined that the object is located inside the outline of the parking path.

[0309] In addition, multiple sensors installed in the vehicle transmit ultrasonic waves in sequence, and the above steps are repeated by two adjacent sensors each time each sensor transmits ultrasonic waves, so that it is more accurately determined whether obstacles on and around the parking path are located inside the parking path.

[0310] As the path offset added to the outline of the parking path so as to move the outline outward from the vehicle changes, the final path offset is determined as the path offset obtained when the value of the path probability density function is maximized, wherein the path probability density function is defined as P_in*P_out, where P_in is a probability of determining that the obstacle is inside the outline of the parking path when the vehicle moves along the parking path multiple times in a state where the obstacle is installed inside the outline of the parking path on which the vehicle is to travel, and P_out is a probability of determining that the obstacle is outside the outline of the parking path when the vehicle moves along the parking path multiple times in a state where the obstacle is installed outside the outline of the parking path on which the vehicle is to travel.

[0311] Right now,

[0312]

[0313] where i is the number of times the vehicle moves along the vehicle's parking path (i=1, 2, 3...n) and

[0314] P_in = [(number of times the obstacle is determined to be inside the contour in the i-th move) / (number of times the obstacle is determined to be inside or outside the contour in the i-th move)] * 100, and

[0315]

[0316] where i is the number of times the vehicle moves along the vehicle's parking path (i=1, 2, 3...n) and

[0317] P_out = [(number of times the obstacle is determined to be outside the contour in the i-th move) / (number of times the obstacle is determined to be inside or outside the contour in the i-th move)] * 100.

[0318] In practice, in a state where an obstacle is installed inside the outline of the parking path on which the vehicle is to travel, the probability P_in can be calculated by simulation while changing the path offset using the acquired ultrasonic TOF data as the vehicle moves multiple times along the parking path.

[0319] Similarly, in a state where an obstacle is set outside the outline of the parking path on which the vehicle is to travel, the probability P_out can be calculated by simulation while changing the path offset using the acquired ultrasonic TOF data as the vehicle moves multiple times along the parking path.

[0320] Of course, it is preferable to sequentially install multiple types of obstacles on the parking path, and acquire ultrasonic TOF data for each type of obstacle while moving the vehicle multiple times along the parking path.

[0321] Adjusting the contour of the parking path by adding the final path offset obtained by the above method allows for more accurate determination of whether an object is inside or outside the parking path than in the first embodiment, while fully accounting for errors in the parking path itself caused by vehicle speed, wheel slip, etc., as well as objects having real volumes.

[0322] Figure 31A device for determining obstacles on and around a parking path using ultrasonic waves is shown. The device is configured to implement a third embodiment of a method for determining obstacles on and around a parking path using ultrasonic waves, and may be configured to include: a final path offset generating unit 400 for generating a final path offset relative to a parking path on which a vehicle is to travel; a noise determining unit 401 for determining whether ultrasonic noise exists within the TOF of a received ultrasonic wave reflected by an object; and a virtual object generating unit 402 for adding a virtual object generated by the final path offset generating unit 400 when the noise determining unit 401 determines that ultrasonic noise does not exist. a virtual indirect wave generating unit 403 for generating a virtual indirect wave TOF using the virtual object generated by the virtual object generating unit 402; and an object position determining unit 404 for determining whether the object is located inside or outside the outline of the parking path by comparing a real indirect wave TOF, which is an indirect wave TOF in the received ultrasonic wave TOF, with the virtual indirect wave TOF generated by the virtual indirect wave generating unit.

[0323] The noise determination unit 401 may be configured to include a dynamic noise determination unit 401-1 and a static noise determination unit 401-2, and determine that there is no ultrasonic noise when both direct wave TOF and indirect wave TOF exist and neither dynamic noise nor static noise exists within the received ultrasonic wave TOF.

[0324] The dynamic noise determination unit 401-1 may be configured to determine that dynamic noise is generated in the following circumstances:

[0325] d (direct wave hTOF) > Vdt

[0326] in

[0327] Direct wave hTOF=direct wave TOF / 2,

[0328] dhTOF = hTOF t=n – hTOF t=n-1 [m],

[0329] V: vehicle speed, and

[0330] dt: Ultrasonic update period [ms].

[0331] The static noise determination unit 401-2 may be configured to determine that static noise is generated in the following cases:

[0332] |Direct wave hTOF – Indirect wave hTOF|> Distance between sensors / 2

[0333] in

[0334] hTOF = TOF / 2; and

[0335] The “distance between sensors” refers to the distance between the sensor that transmits and receives the direct wave and the sensor that receives the indirect wave.

[0336] The virtual object generation unit 402 may be configured to generate a virtual object at an intersection where a circle intersects the outline of the parking path adjusted by adding the final path offset, wherein the circle has the position of the sensor that transmits and receives the direct wave as the center and the direct wave hToF as the radius.

[0337] The virtual indirect wave generating unit 403 may be configured to generate the virtual indirect wave TOF as the sum of a straight line connecting the position of the sensor transmitting and receiving the direct wave to the virtual object and a straight line connecting the virtual object to the position of the sensor receiving the indirect wave.

[0338] When the sensor that transmits and receives the direct wave is located outside the parking path compared to the sensor that receives the indirect wave, the object position determination unit 404 can be configured to: if the real indirect wave hTOF is greater than the virtual indirect wave hTOF, determine that the object is located outside the outline of the parking path; if the real indirect wave hTOF is equal to or less than the virtual indirect wave hTOF, determine that the object is located inside the outline of the parking path.

[0339] As the path offset added to the outline of the parking path to move the outline outward from the vehicle changes, the final path offset generating unit 400 may be configured to determine the final path offset as a path offset obtained when maximizing a value of a path probability function, wherein the path probability density function is defined as P_in*P_out, wherein P_in is a probability of determining that an obstacle is inside the outline of the parking path when the vehicle moves along the parking path multiple times in a state where the obstacle is installed inside the outline of the parking path on which the vehicle is to travel, and P_out is a probability of determining that an obstacle is outside the outline of the parking path when the vehicle moves along the parking path multiple times in a state where the obstacle is installed outside the outline of the parking path on which the vehicle is to travel.

[0340] Right now,

[0341] where i is the number of times the vehicle moves along the vehicle's parking path (i=1, 2, 3...n) and

[0342] P_in=[(number of times the obstacle is determined to be inside the contour in the i-th move) / (number of times the obstacle is determined to be inside or outside the contour in the i-th move)]*100.

[0343] ,

[0344] where i is the number of times the vehicle moves along the vehicle's parking path (i=1, 2, 3...n) and

[0345] P_out = [(number of times the obstacle is determined to be outside the contour in the i-th move) / (number of times the obstacle is determined to be inside or outside the contour in the i-th move)] * 100.

[0346] In a state where an obstacle is installed inside the outline of the parking path on which the vehicle is to travel, the probability P_in can be calculated by simulation while using the acquired ultrasonic TOF data to change the path offset when the vehicle moves multiple times along the parking path; and in a state where the obstacle is set outside the outline of the parking path on which the vehicle is to travel, the probability P_out can be calculated by simulation while using the acquired ultrasonic TOF data to change the path offset when the vehicle moves multiple times along the parking path.

[0347] Figure 22 A first embodiment of an obstacle filtering method for and around a parking path using ultrasonic waves includes receiving input of coordinates of an object on and around a parking path on which a vehicle is to travel (S510); determining whether the object exists outside the parking path on either side based on the received object coordinates (S520); if the object exists outside the parking path on either side, determining whether there are object coordinates inside the parking path among the received object coordinates (S530); if there are object coordinates inside the parking path, calculating virtual indirect wave TOFs of two sensors located at the center of the vehicle among a plurality of sensors arranged along a vehicle width direction (S540); determining whether the object coordinates inside the parking path are phantom coordinates based on a comparison between the virtual indirect wave TOF and a real indirect wave TOF (S550); and if the object coordinates inside the parking path are phantom coordinates, removing the object coordinates inside the parking path (S560).

[0348] When receiving the coordinates of objects on and around a parking path on which the vehicle is to travel ( S510 ), the coordinates of the objects on and around the parking path may be received from a conventional parking assistance apparatus such as a parking collision avoidance assist (PCA) apparatus.

[0349] Ghost coordinates may be included in the above-mentioned input object coordinates, and when the input object coordinates include Figure 23 When ghost coordinates are shown, this embodiment is used to remove the ghost coordinates by filtering.

[0350] In conventional parking assistance devices such as PCA, when the Figure 23 When there are sensors such as A, B, C, D in the image, two sensors form a combination such as AB, BC, CD, and the ultrasonic TOF is combined to determine the position of the object. Figure 23 As shown, when a real object RM exists outside the parking path on either side, causing sensor B, the vehicle's left inner sensor, to detect the left object, while sensor C, the vehicle's right inner sensor, detects the right object, even if no real object exists in the parking path, the combined ultrasonic TOF signals of sensors B and C can generate object coordinates as shown in the figure. This embodiment is intended to eliminate ghost coordinates, which are object coordinates where no object exists, thereby preventing unnecessary warnings or braking during parking when ghost coordinates are generated within the parking path.

[0351] In determining whether the object exists outside the parking path on either side based on the input object coordinates (S520), when it is determined that the received object coordinates exist on either side of the vehicle, a distance between two object coordinates existing on either side of the vehicle exceeds the vehicle width, and the two object coordinates existing on either side of the vehicle exist outside the parking path, it is determined that the object exists outside the parking path on either side.

[0352] Here, based on a comparison between the virtual indirect wave TOF and the real indirect wave TOF of two sensors located on one side of the vehicle (for example, sensors AB and CD) among a plurality of sensors arranged along the vehicle width direction, if the real indirect wave TOF is greater than the virtual indirect wave TOF, it is determined that the object coordinates exist outside the parking path.

[0353] The direct wave TOF of the two sensors located on one side of the vehicle is calculated by adding the indirect wave hTOF and the straight line connecting the position of the sensor receiving the indirect wave to the following intersection point, where at the intersection point, a circle with the position of the sensor that transmits and receives the direct wave among the two sensors as the center and the direct wave hTOF as the radius intersects the contour of the parking path.

[0354] On the other hand, based on the comparison between the virtual indirect wave TOF of two sensors located at the center of the vehicle (e.g., sensor BC) and the real indirect wave TOF, when the real indirect wave TOF is greater than the virtual indirect wave TOF, it is determined that the coordinates of the object inside the parking path are phantom coordinates.

[0355] The virtual indirect wave TOF of the two sensors located at the center of the vehicle is calculated by adding the direct wave hTOF and the straight line connecting the position of the sensor receiving the indirect wave to the following intersection point, where at the intersection point, a circle with the position of the sensor that transmits and receives the direct wave among the two sensors as the center and the direct wave hTOF as the radius intersects the contour of the parking path.

[0356] Figure 23 A device for determining obstacles on and around a parking path using ultrasonic waves is shown. The device is configured to implement a first embodiment of a method for filtering obstacles on and around a parking path using ultrasonic waves, and may be configured to include: a data input unit 501 that receives input of coordinates of objects on and around a parking path on which a vehicle is to travel; a either-side object determination unit 502 that determines whether an object exists outside the parking path on either side based on the object coordinates input through the data input unit 501; and an internal object coordinate determination unit 503 that determines whether the received object coordinates are inside the parking path on either side when the either-side object determination unit 502 determines that the object exists outside the parking path on either side. whether there are object coordinates located inside the parking path; a virtual indirect wave generating unit 504, when the internal object coordinate determining unit 503 determines that there are object coordinates located inside the parking path, the virtual indirect wave generating unit 504 calculates the virtual indirect wave TOF by using two sensors located at the center of the vehicle among the multiple sensors arranged along the vehicle width direction; a phantom coordinate determining unit 505, based on a comparison between the virtual indirect wave TOF generated by the virtual indirect wave generating unit 504 and the real indirect wave TOF, determines whether the object coordinates inside the parking path are phantom coordinates; and a coordinate filtering unit 506, when the phantom coordinate determining unit 505 determines that the object coordinates inside the parking path are phantom coordinates, removes the object coordinates inside the parking path.

[0357] The either side object determination unit 502 may be configured to determine that an object exists outside the parking path on either side when it is determined that the object coordinates input through the data input unit 501 exist on either side of the vehicle, the distance between two object coordinates existing on either side of the vehicle exceeds the vehicle width, and the two object coordinates existing on either side of the vehicle exist outside the parking path.

[0358] The either side object determination unit 502 can be configured to: based on a comparison between the virtual indirect wave TOF and the real indirect wave TOF of two sensors located on one side of the vehicle among a plurality of sensors arranged along the vehicle width direction, determine that the object coordinates exist outside the parking path when the real indirect wave TOF is greater than the virtual indirect wave TOF.

[0359] The virtual indirect wave TOF of the two sensors located on one side of the vehicle can be calculated by adding the direct wave hTOF and the straight line connecting the position of the sensor receiving the indirect wave to the following intersection point, where at the intersection point, a circle with the position of the sensor that transmits and receives the direct wave among the two sensors as the center and the direct wave hTOF as the radius intersects the contour of the parking path.

[0360] The ghost coordinate determining unit 505 may be configured to determine that the object coordinates inside the parking path are ghost coordinates when the real indirect wave TOF is greater than the virtual indirect wave TOF based on a comparison between the virtual indirect wave TOF and the real indirect wave TOF of the two sensors located at the center of the vehicle.

[0361] The virtual indirect wave TOF of the two sensors located at the center of the vehicle can be calculated by adding the direct wave hTOF and the straight line connecting the position of the sensor receiving the indirect wave to the following intersection point, where at the intersection point, a circle with the position of the sensor that transmits and receives the direct wave among the two sensors as the center and the direct wave hTOF as the radius intersects the contour of the parking path.

[0362] Figure 24 A second embodiment of an obstacle filtering method for and around a parking path using ultrasonic waves includes receiving input of coordinates of an object on and around a parking path on which a vehicle is to travel (S610); determining whether the object exists outside the parking path on either side based on the input object coordinates (S620); when the object exists outside the parking path on either side, determining whether the object coordinates among the input object coordinates exist inside the parking path (S630); when the object coordinates exist inside the parking path, determining whether the object coordinates inside the parking path are ghost coordinates based on a comparison between a coordinate direct wave hTOF defined as a distance between coordinates of two sensors located at the center of the vehicle among a plurality of sensors arranged along a vehicle width direction that transmit and receive a direct wave and the received object coordinates and a true direct wave hTOF (S640); and when the object coordinates inside the parking path are ghost coordinates, removing the object coordinates inside the parking path (S650).

[0363] That is, like the first embodiment of the method for filtering obstacles on and around a parking path using ultrasonic waves, this embodiment proposes another technique that allows for the removal of obstacles in the parking path. Figure 23 The ghost coordinates generated in the case shown are removed and can be used separately from or in combination with the first embodiment, thereby allowing ghost coordinates formed in the parking path to be removed more reliably.

[0364] When the difference between the direct wave hTOF on the coordinates and the real direct wave hTOF exceeds a predetermined direct wave difference tolerance, it is determined that the coordinates of the object inside the parking path are ghost coordinates.

[0365] exist Figure 23 In the case shown, since the difference between the direct wave hTOF actually reflected by the object outside the parking path and the direct wave hTOF at the coordinates calculated relative to the object coordinates inside the parking path (phantom coordinates) is expected, it is possible to check whether the coordinates of the object inside the parking path are phantom coordinates by setting a direct wave difference tolerance for checking such a difference.

[0366] Therefore, the direct wave difference value tolerance can be designed through multiple experiments and interpretation according to the above intentions.

[0367] In addition, the present embodiment can be configured to further include: when it is determined that the coordinates of the object inside the parking path are not phantom coordinates based on the comparison between the coordinate direct wave hTOF and the real direct wave hTOF, calculating the coordinate indirect wave TOF by adding the coordinate direct wave hTOF to the following distance (S660), wherein the distance is the distance between the coordinates of the sensor receiving the indirect wave among the two sensors located at the center of the vehicle and the received object coordinates; and further determining whether the coordinate object inside the parking path is a phantom coordinate based on the comparison between the coordinate indirect wave TOF and the real indirect wave TOF (S670).

[0368] That is, even if it is determined that the coordinates of the object inside the parking path are not phantom coordinates based on the comparison between the coordinate direct wave hTOF and the real direct wave hTOF, it is further determined whether the coordinate object inside the parking path is a phantom coordinate based on the comparison between the coordinate indirect wave TOF and the real indirect wave TOF obtained as described above.

[0369] Of course, when the difference between the indirect wave TOF on the coordinates and the real indirect wave TOF exceeds the indirect wave difference tolerance, it is determined that the coordinates of the object inside the parking path are phantom coordinates.

[0370] The indirect wave difference tolerance can be designed through multiple experiments and interpretations to a degree that can distinguish the true indirect wave TOF from the indirect wave TOF on the coordinates for the ghost coordinates according to the above intention.

[0371] In this embodiment, when it is determined that the object coordinates inside the parking path are ghost coordinates, removal of the object coordinates inside the parking path is performed (S650), and when it is determined that the object coordinates inside the parking path are not ghost coordinates, the existing coordinates input from the parking assistance device such as PCA are output as they are, so that a warning device, a braking device, etc. can be actuated.

[0372] Figure 33 A device for determining obstacles on and around a parking path using ultrasonic waves is shown. The device is configured to implement a second embodiment of a method for filtering obstacles on and around a parking path using ultrasonic waves, and may be configured to include: a data input unit 601 that receives input of coordinates of objects on and around the parking path on which a vehicle is to travel; a either-side object determination unit 602 that determines whether an object exists outside the parking path on either side based on the object coordinates input through the data input unit 601; and an internal object coordinate determination unit 603 that, when the either-side object determination unit 602 determines that an object exists outside the parking path on either side, determines whether the input object coordinates exist. an object coordinate located inside the parking path; a phantom coordinate determining unit 604, which, when the internal object coordinate determining unit 603 determines that there are object coordinates located inside the parking path, determines whether the object coordinates inside the parking path are phantom coordinates based on a comparison between the on-coordinate direct wave hTOF and the real direct wave hTOF, where the on-coordinate direct wave hTOF is defined as a distance between the coordinates of a sensor that transmits and receives a direct wave and two sensors located at the center of the vehicle among a plurality of sensors arranged along the vehicle width direction and the received object coordinates; and a coordinate filtering unit 605, which, when the phantom coordinate determining unit 604 determines that the object coordinates inside the parking path are phantom coordinates, removes the object coordinates inside the parking path.

[0373] The ghost coordinate determining unit 604 may be configured to determine that the coordinates of the object inside the parking path are ghost coordinates when the difference between the direct wave hTOF on the coordinates and the real direct wave hTOF exceeds a predetermined direct wave difference tolerance.

[0374] In addition, the phantom coordinate determination unit 604 can be configured to: when it is determined that the coordinates of the object inside the parking path are not phantom coordinates based on the comparison between the coordinate direct wave hTOF and the real direct wave hTOF, calculate the coordinate indirect wave TOF by adding the coordinate direct wave hTOF to the following distance, where the distance is the distance between the coordinates of the sensor receiving the indirect wave among the two sensors located at the center of the vehicle and the received object coordinates; and further determine whether the coordinate object inside the parking path is a phantom coordinate based on the comparison between the coordinate indirect wave TOF and the real indirect wave TOF.

[0375] Furthermore, the ghost coordinate determining unit 604 may be configured to determine that the coordinates of the object inside the parking path are ghost coordinates when the difference between the indirect wave TOF on the coordinates and the real indirect wave TOF exceeds the indirect wave difference tolerance.

[0376] Figure 25A third embodiment of a method for filtering obstacles on and around a parking path using ultrasonic waves is shown, including receiving input of coordinates of an object on and around a parking path on which a vehicle is to travel (S710); determining whether the input object coordinates are coordinates inside the parking path (S720); when the input object coordinates are coordinates inside the parking path, calculating virtual indirect wave TOFs of two sensors on one side of the vehicle (S730); and based on a comparison between the virtual indirect wave TOF and a real indirect wave TOF, when it is determined that a source object of the input object coordinates is an object inside the parking path, outputting the input object coordinates as valid coordinates, and when it is determined that the source object is an object outside the parking path, removing the input object coordinates (S740).

[0377] That is, when it is determined that the input object coordinates are located inside the parking path due to errors, noise, etc. of the parking assistance device, even if the source object RM of the input object coordinates is actually located outside the parking path, whether the source object is located inside the parking path is determined based on the comparison between the virtual indirect wave TOF and the real indirect wave TOF calculated as described above, and the position of the source object is finally determined based on the comparison result between the virtual indirect wave TOF and the real indirect wave TOF.

[0378] In addition, the present embodiment further includes: when the input object coordinates are not coordinates inside the parking path, calculating a virtual indirect wave TOF by two sensors on one side of the vehicle (S750), and based on a comparison between the virtual indirect wave TOF and the real indirect wave TOF, when it is determined that the source object of the input object coordinates is an object outside the parking path, outputting the input object coordinates as valid coordinates; and when it is determined that the source object is an object inside the parking path, removing the input object coordinates and determining that the source object is an object inside the parking path (S760).

[0379] That is, with Figure 26 In contrast to the case in , when the input object coordinates are located outside the parking path due to various reasons such as noise, even if the source object RM of the input object coordinates is as in Figure 27 In the example, if the source object is actually located inside the parking path, it is finally determined whether the source object is actually located inside the parking path based on the comparison between the virtual indirect wave TOF calculated as described above and the real indirect wave TOF.

[0380] Therefore, in a parking assistance device such as PCA, even if erroneous object coordinates are input due to various reasons, error-free correction can be performed by the above-mentioned obstacle filtering method.

[0381] That is, when it is determined based on the comparison between the virtual indirect wave TOF and the real indirect wave TOF that the source object of the input object coordinates is an object outside the parking path, even when the input object coordinates are coordinates inside the parking path, the input object coordinates are excluded from the coordinates used to drive the parking distance warning (PDW) device or the braking device.

[0382] Of course, when it is determined based on the comparison between the virtual indirect wave TOF and the real indirect wave TOF that the source object of the input object coordinates is an object inside the parking path, even when the input object coordinates are not coordinates inside the parking path, the input object coordinates are included in the coordinates used to drive the parking distance warning (PDW) device or the braking device.

[0383] Therefore, proper operational reliability of the stopping distance device or brake device of the vehicle is ensured, and undesirable malfunctions can be effectively prevented.

[0384] Figure 34 A device for determining obstacles on and around a parking path using ultrasonic waves is shown. The device is configured to implement a third embodiment of a method for filtering obstacles on and around a parking path using ultrasonic waves, and may be configured to include: a data input unit 701 that receives input of coordinates of an object on and around a parking path on which a vehicle is to travel; an in-path coordinate determination unit 702 that determines whether the object coordinates input through the data input unit 701 are coordinates within the parking path; a virtual indirect wave generation unit 703 that calculates virtual indirect wave time of flight (TOF) from two sensors on one side of the vehicle when the in-path coordinate determination unit 702 determines that the object coordinates input through the data input unit 701 are coordinates within the parking path; and a coordinate filtering unit 704 that, based on a comparison between the virtual indirect wave TOF generated by the virtual indirect wave generation unit 703 and a real indirect wave TOF, outputs the input object coordinates as valid coordinates when a source object of the input object coordinates is determined to be an object within the parking path, and removes the input object coordinates when the source object is determined to be an object outside the parking path (S740).

[0385] The virtual indirect wave generating unit 703 may be configured to calculate the virtual indirect wave TOF by the two sensors on one side of the vehicle when the in-path coordinate determining unit 702 determines that the object coordinates input through the data input unit 701 are not coordinates within the parking path; and the coordinate filtering unit 704, based on a comparison between the virtual indirect wave TOF and the real indirect wave TOF, outputs the input object coordinates as valid coordinates when it is determined that the source object of the input object coordinates is an object outside the parking path, and removes the input object coordinates and determines that the source object is an object within the parking path when it is determined that the source object is an object within the parking path.

[0386] In addition, the coordinate filtering unit 704 can be configured to: when it is determined based on the comparison between the virtual indirect wave TOF and the real indirect wave TOF that the source object of the input object coordinates is an object outside the parking path, even if the input object coordinates are coordinates inside the parking path, exclude the input object coordinates from the coordinates used to drive the parking distance warning (PDW) device or the braking device.

[0387] In addition, the coordinate filtering unit 704 can be configured to: when it is determined based on the comparison between the virtual indirect wave TOF and the real indirect wave TOF that the source object of the input object coordinates is an object inside the parking path, even if the input object coordinates are not coordinates inside the parking path, include the input object coordinates in the coordinates used to drive the parking distance warning (PDW) device or the parking device.

[0388] While specific embodiments of the present invention have been shown and described, it will be self-evident to those skilled in the art that the present invention may be improved and modified in various ways without departing from the scope of the technical spirit of the invention provided by the following patent claims.

Claims

1. A method for determining obstacles on and around a parking path, wherein a vehicle is to move along the parking path, the method comprising: determining whether ultrasonic noise exists within a time of flight (TOF) of an ultrasonic wave received and reflected by an object; When there is no ultrasonic noise, generating a virtual object on the outline of the parking path based on the received ultrasonic time-of-flight TOF; generating a virtual indirect wave TOF using the virtual object, wherein the virtual indirect wave TOF refers to an indirect wave TOF for the virtual object, and the indirect wave TOF refers to a TOF of an ultrasonic wave received by a receiving sensor when a transmitting sensor that transmits the ultrasonic wave and a receiving sensor that receives the ultrasonic wave are different; as well as By comparing a real indirect wave TOF, which is an indirect wave TOF among the received ultrasonic wave TOFs for the object, with the virtual indirect wave TOF, it is determined whether the object is located inside or outside the outline of the parking path.

2. The determination method according to claim 1, wherein: When determining whether ultrasonic noise exists, it is determined that ultrasonic noise does not exist when both direct wave TOF and indirect wave TOF exist and neither dynamic noise nor static noise exists within the received ultrasonic TOF, wherein the direct wave TOF refers to the TOF of the ultrasonic wave received by the receiving sensor when the transmitting sensor and the receiving sensor are the same.

3. The determination method according to claim 2, wherein: The dynamic noise is determined to be generated in the following cases: d (direct wave hTOF distance)>Vdt, in: Direct wave hTOF distance=direct wave TOF distance / 2, wherein “direct wave hTOF distance” refers to the one-way distance between the object and the receiving sensor that receives the direct wave, and “direct wave TOF distance” refers to the round-trip distance between the object and the receiving sensor that receives the direct wave, d (direct wave hTOF distance) = direct wave hTOF distance t=n - Direct wave hTOF distance t=n-1 , where "direct wave hTOF distance t=n " refers to the direct wave hTOF distance at time t=n, "direct wave hTOF distance t=n-1 " refers to the direct wave hTOF distance at time t=n-1, in meters, V: vehicle speed, and dt: Ultrasonic update period, in ms.

4. The determination method according to claim 2, wherein: The static noise is determined to be generated in the following cases: |Direct wave hTOF distance – Indirect wave hTOF distance|> Distance between sensors / 2 in: Direct wave hTOF distance = direct wave TOF distance / 2, and indirect wave hTOF distance = indirect wave TOF distance / 2, Wherein, "direct wave hTOF distance" refers to the one-way distance between the object and the receiving sensor receiving the direct wave, and "direct wave TOF distance" refers to the round-trip distance between the object and the receiving sensor receiving the direct wave; Wherein, "indirect wave hTOF distance" refers to the one-way distance between the object and the receiving sensor receiving the indirect wave, and "indirect wave TOF distance" refers to the round-trip distance between the object and the receiving sensor receiving the indirect wave, and Here, "the distance between sensors" refers to the distance between the sensor that transmits and receives the direct wave and the sensor that receives the indirect wave.

5. The determination method according to claim 1, wherein: The virtual object is generated at an intersection point where a circle intersects the outline of the parking path, wherein the circle has the position of the sensor that transmits and receives the direct wave as a center and has the direct wave hToF distance as a radius. The determination method according to claim 5 , wherein: The virtual indirect wave TOF is calculated as the sum of a straight line connecting the position of a sensor that transmits and receives a direct wave and the virtual object and a straight line connecting the virtual object and the position of a sensor that receives an indirect wave.

7. The determination method according to claim 6, wherein: In determining whether the object is located inside or outside the outline of the parking path, when the sensor that transmits and receives the direct wave is located outside the parking path, if the real indirect wave TOF is greater than the virtual indirect wave TOF, then the object is determined to be located outside the outline of the parking path, and if the real indirect wave TOF is equal to or less than the virtual indirect wave TOF, then the object is determined to be located inside the outline of the parking path.

8. The determination method according to claim 1, wherein: A plurality of sensors installed in the vehicle sequentially transmit ultrasonic waves, and each time each sensor transmits the ultrasonic wave, the steps of determining whether ultrasonic noise exists to determining whether the object is located inside or outside the outline of the parking path are repeatedly performed by two adjacent sensors.

9. A device for determining obstacles on and around a parking path, wherein a vehicle is to move along the parking path, the device comprising: a noise determination unit that determines whether ultrasonic noise exists within a time of flight (TOF) of the received ultrasonic wave reflected by the object; a virtual object generating unit, which generates a virtual object on the outline of the parking path based on the received ultrasonic wave time-of-flight (TOF) when the noise determining unit determines that there is no ultrasonic wave noise; a virtual indirect wave generating unit that generates a virtual indirect wave TOF using the virtual object generated by the virtual object generating unit, wherein the virtual indirect wave TOF refers to an indirect wave TOF for the virtual object, and the indirect wave TOF refers to a TOF of an ultrasonic wave received by a receiving sensor when a transmitting sensor that transmits the ultrasonic wave and a receiving sensor that receives the ultrasonic wave are different; and an object position determining unit that determines whether the object is located inside or outside the outline of the parking path by comparing a real indirect wave TOF, which is an indirect wave TOF in the received ultrasonic wave TOF for the object, with a virtual indirect wave TOF generated by the virtual indirect wave generating unit.

10. The determination device according to claim 9, wherein: The noise determination unit includes a dynamic noise determination unit and a static noise determination unit, and determines that there is no ultrasonic noise when both a direct wave TOF and an indirect wave TOF exist and neither dynamic noise nor static noise exists within the received ultrasonic wave TOF, wherein the direct wave TOF refers to the TOF of the ultrasonic wave received by the receiving sensor when the transmitting sensor and the receiving sensor are the same.

11. The determination device according to claim 10, wherein: The dynamic noise determination unit is configured to determine that the dynamic noise is generated in the following circumstances: d (direct wave hTOF distance) > Vdt in: Direct wave hTOF distance=direct wave TOF distance / 2, wherein “direct wave hTOF distance” refers to the one-way distance between the object and the receiving sensor that receives the direct wave, and “direct wave TOF distance” refers to the round-trip distance between the object and the receiving sensor that receives the direct wave, d (direct wave hTOF distance) = direct wave hTOF distance t=n - Direct wave hTOF distance t=n-1 , where "direct wave hTOF distance t=n " refers to the direct wave hTOF distance at time t=n, "direct wave hTOF distance t=n-1 " refers to the direct wave hTOF distance at time t=n-1, in meters, V: vehicle speed, and dt: Ultrasonic update period, in ms.

12. The determination device according to claim 10, wherein: The static noise determination unit is configured to determine that the static noise is generated in the following circumstances: |Direct wave hTOF distance – Indirect wave hTOF distance|> Distance between sensors / 2 in: Direct wave hTOF distance = direct wave TOF distance / 2, and indirect wave hTOF distance = indirect wave TOF distance / 2, Wherein, "direct wave hTOF distance" refers to the one-way distance between the object and the receiving sensor that receives the direct wave, and "direct wave TOF distance" refers to the round-trip distance between the object and the receiving sensor that receives the direct wave; wherein, "indirect wave hTOF distance" refers to the one-way distance between the object and the receiving sensor that receives the indirect wave, and "indirect wave TOF distance" refers to the round-trip distance between the object and the receiving sensor that receives the indirect wave, and Here, "the distance between sensors" refers to the distance between the sensor that transmits and receives the direct wave and the sensor that receives the indirect wave.

13. The determination device according to claim 9, wherein: The virtual object generation unit generates the virtual object at an intersection point where a circle intersects the outline of the parking path, wherein the circle has a position of a sensor that transmits and receives a direct wave as a center and a direct wave hToF distance as a radius.

14. The determination device according to claim 13, wherein: The virtual indirect wave generating unit calculates the indirect wave TOF as the sum of a straight line connecting the position of the sensor transmitting and receiving the direct wave and the virtual object and a straight line connecting the virtual object and the position of the sensor receiving the indirect wave.

15. The determination device according to claim 14, wherein: When a sensor that transmits and receives direct waves is located outside the parking path, the object position determining unit determines that the object is located outside the outline of the parking path if the indirect wave TOF is greater than the virtual indirect wave TOF, and determines that the object is located inside the outline of the parking path if the real indirect wave TOF is equal to or less than the virtual indirect wave TOF.

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