Signal Processing Device

Abstract

To provide a signal processing apparatus that can suppress an un-extracted peak.SOLUTION: A signal processing apparatus sets an intensity threshold corresponding to intensity distribution based on an observation signal periodically generated at S103-S107 of peak extraction processing. The signal processing apparatus then extracts a target peak which is a peak being larger than the intensity threshold in the intensity distribution with an upper limit number as an upper limit at S108, and stores an extracted peak number which is the number of the extracted target peaks at S109. At S103-S107, the intensity threshold is set such that exceeding the upper limit number of a target peak number for new intensity distribution is suppressed on the basis of the extracted peak number for the prior intensity distribution.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a signal processing device. [Background technology]

[0002] Patent Document 1 describes a radar signal detection device that uses CFAR processing to set a threshold value for a signal acquired from a radar device so that the false detection rate of the signal is constant. Note that CFAR is an abbreviation for Constant False Alarm Rate. In general, when a threshold value is set using CFAR processing, peaks that exceed the threshold value are extracted from the signal from the radar device, and objects are recognized based on the extracted peaks. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3420177 Summary of the Invention [Problem to be solved by the invention]

[0004] However, as a result of detailed investigation by the inventors, the following problem was found: When there are many peaks exceeding a threshold in a signal from a radar device, the processing load increases when recognizing an object based on the peaks. However, on the other hand, if an upper limit is set on the number of peaks to be extracted, there is a risk that, for example, a peak indicating the presence of an important object cannot be extracted.

[0005] One aspect of the present disclosure provides a signal processing device capable of suppressing unextracted peaks. [Means for solving the problem]

[0006] One aspect of the present disclosure is a signal processing device that is mounted on a moving body (10) and performs processing for measuring objects present around the moving body using an observation signal based on a reflected wave of an irradiated transmission wave, and includes a setting unit (S103 to S107, S205 to S209), an extraction unit (S108, S210), and a storage processing unit (S109, S211). The setting unit is configured to set an intensity threshold corresponding to an intensity distribution based on a periodically generated observation signal. The extraction unit is configured to extract target peaks that are peaks greater than the intensity threshold in the intensity distribution, with a preset upper limit number as the upper limit. The storage processing unit is configured to store the number of extracted peaks, which is the number of target peaks extracted by the extraction unit, in a storage unit (13). The setting unit sets the intensity threshold based on the number of extracted peaks for the previous intensity distribution stored in the storage unit so as to prevent the number of target peaks for a new intensity distribution from exceeding the upper limit number.

[0007] According to the above configuration, it is possible to prevent the number of extracted target peaks from reaching the upper limit before the extraction of the target peaks from the entire region of the intensity distribution is completed, and to prevent the extraction of the target peaks from being terminated halfway. Therefore, it is possible to prevent the peaks from not being extracted. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a block diagram showing a configuration of a signal processing device. [Diagram 2] FIG. 2 is a diagram showing an example of a detection area when a radar device is mounted on the front of a vehicle. [Diagram 3] 10A and 10B are diagrams illustrating an example of a detection area when a radar device is mounted in a location other than the front of a vehicle. [Figure 4] FIG. 1 is an explanatory diagram showing an overview of two-dimensional FFT processing. [Diagram 5] 4 is a flowchart of a peak extraction process in the first embodiment. [Figure 6] 13 is a flowchart of a peak extraction process in the second embodiment. [Figure 7]FIG. 11 is an explanatory diagram showing an example in which a first threshold value is set in a distance spectrum. [Figure 8] FIG. 13 is an explanatory diagram showing an example in which a second threshold value is set in the distance spectrum. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. First embodiment] [1-1. Configuration] 1 is a device mounted on a moving body and performs processing to measure objects present around the moving body using observation signals described later. The moving body is, for example, a vehicle, an aircraft, a ship, etc. In addition to the signal processing device 1, a radar device 2 is mounted on the moving body. In this embodiment, the signal processing device 1 and the radar device 2 are mounted on a vehicle 10.

[0010] As shown in Fig. 2, the radar device 2 may be mounted in the front center of the vehicle 10 (for example, in the center of the front bumper), and the front center area of ​​the vehicle 10 may be set as the detection area Rd. Also, as shown in Fig. 3, the radar devices 2 may be mounted in five locations, namely, the front center, the left front side, the right front side, the left rear side, and the right rear side, and the front center, the left front, the right front, the left rear, and the right rear areas of the vehicle 10 may be set as the detection area Rd. The number and mounting positions of the radar devices 2 mounted on the vehicle 10 may be appropriately selected.

[0011] The radar device 2 is a millimeter wave radar and includes a transmitting array antenna and a receiving array antenna. More specifically, the radar device 2 is configured as an FCM type millimeter wave radar, for example. FCM is an abbreviation for Fast Chirp Modulation.

[0012] The radar device 2 irradiates a transmission wave, which is a chirp signal, to the detection area Rd in each processing cycle that arrives at a predetermined period Tcy. In each processing cycle, the radar device 2 transmits the chirp signal N times in a predetermined period T. Then, the radar device 2 receives reflected waves generated when each chirp signal is reflected at a reflecting point of an object.

[0013] Furthermore, the radar device 2 generates a beat signal by mixing the transmitted chirp signal with a reflected signal based on the reflected wave of the chirp signal, and outputs an observation signal generated by sampling the beat signal to the signal processing device 1.

[0014] As shown in Fig. 1, the signal processing device 1 is mainly configured with a well-known microcomputer having a CPU 11, a ROM 12, a RAM 13, a flash memory 14, etc. The CPU 11 executes a program stored in the ROM 12, which is a non-transient physical recording medium. By executing the program, a method corresponding to the program is performed. The signal processing device 1 may include a coprocessor that executes a fast Fourier transform (hereinafter, FFT) process, etc.

[0015] [1-2. Processing Overview] The signal processing device 1 performs processing for measuring an object present in the detection area Rd based on N beat signals (hereinafter, observed signals) generated in each processing cycle.

[0016] That is, as shown in FIG. 4, the CPU 11 performs FFT processing on each of the N observation signals generated in each processing cycle to generate N distance spectra. The distance spectrum is a spectrum that represents power relative to distance. Since the distance spectrum has frequency components according to the distance between the moving body and the object (in other words, the reflection point), the frequency BIN of the generated distance spectrum corresponds to the distance BIN. Furthermore, the CPU 11 performs FFT processing on each distance BIN of the generated N distance spectra to generate a distance-velocity spectrum. The distance-velocity spectrum is a two-dimensional spectrum that represents power relative to the distance and the relative velocity of the object relative to the moving body. The CPU 11 uses the distance-velocity spectrum as an intensity distribution and extracts a peak from the intensity distribution. The peak of the intensity distribution indicates an object, and the relative velocity and distance of the object are measured based on the velocity BIN and distance BIN corresponding to the extracted peak.

[0017] CPU 11 extracts target peaks, which are peaks larger than the intensity threshold, from the intensity distribution, with a preset upper limit as the upper limit, and stores the number of extracted peaks, which is the number of extracted target peaks, in RAM 13. The intensity threshold is set when extracting a new target peak. That is, CPU 11 sets the intensity threshold based on the number of extracted peaks in the previous intensity distribution so as to prevent the number of target peaks in the new intensity distribution from exceeding the upper limit.

[0018] [1-3. Processing details] The peak extraction process executed by the CPU 11 of the signal processing device 1 will be described with reference to the flowchart shown in Fig. 5. This process is repeatedly started for each processing cycle.

[0019] First, in S101, the CPU 11 acquires N observation signals output from the radar device 2. Next, in S102, the CPU 11 generates a distance-velocity spectrum as the intensity distribution of the N observed signals.

[0020] Next, the CPU 11 extracts target peaks larger than the intensity threshold from the intensity distribution newly generated in the current processing cycle (hereinafter, the current intensity distribution). Hereinafter, the number of target peaks extracted from the intensity distribution generated in the previous processing cycle will be referred to as the number of previously extracted peaks.

[0021] That is, in S103, the CPU 11 judges whether the number of immediately preceding extracted peaks is equal to or greater than an upper threshold. The upper threshold is a value smaller than the upper limit number. If the CPU 11 judges that the number of immediately preceding extracted peaks is equal to or greater than an upper threshold, the CPU 11 proceeds to S106 when the CPU 11 judges that the number of immediately preceding extracted peaks is equal to or greater than an upper limit number. If the CPU 11 judges that the number of immediately preceding extracted peaks is equal to or greater than an upper limit number ...4 when the CPU 11 judges that the number of immediately preceding extracted peaks is equal to or greater than an upper limit number.

[0022] In S104, the CPU 11 judges whether the number of immediately preceding extracted peaks is equal to or smaller than a lower threshold. The lower threshold is a value smaller than the upper threshold. If the CPU 11 judges that the number of immediately preceding extracted peaks is equal to or smaller than a lower threshold (S104: Yes), the CPU 11 proceeds to S105. If the CPU 11 judges that the number of immediately preceding extracted peaks is equal to or smaller than a lower threshold (S104: No), the CPU 11 proceeds to S107.

[0023] In S105, the CPU 11 sets the first threshold as the intensity threshold. In this embodiment, the first threshold is calculated using the CFAR process. Note that a predetermined threshold may be used as the first threshold.

[0024] In S106, the CPU 11 sets the second threshold as the intensity threshold. In this embodiment, the second threshold is a value obtained by adding a predetermined value to the first threshold calculated using the CFAR process in the same manner as in S105. In other words, the second threshold is greater than the first threshold.

[0025] In S107, the CPU 11 sets the intensity threshold in the same manner as in the immediately preceding process cycle. In this embodiment, if the first threshold was set as the intensity threshold in the immediately preceding process cycle, the first threshold is calculated and set as the intensity threshold in the current process cycle. On the other hand, if the second threshold was set as the intensity threshold in the immediately preceding process cycle, the second threshold is calculated and set as the intensity threshold in the current process cycle.

[0026] Next, in S108, the CPU 11 extracts a target peak from the intensity distribution. In this embodiment, the CPU 11 determines whether or not the intensity threshold is exceeded, starting from the peak of the speed BIN corresponding to the smaller relative speed, and extracts the peak that exceeds the intensity threshold as the target peak. Furthermore, when there are multiple peaks with the same speed BIN, the CPU 11 determines whether or not the intensity threshold is exceeded, starting from the peak of the distance BIN corresponding to the shorter distance, for the multiple peaks, and extracts the peak that exceeds the intensity threshold as the target peak.

[0027] Note that the CPU 11 may determine whether the peaks exceed the intensity threshold in the distance speed spectrum in ascending order of distance BINs corresponding to shorter distances, and extract the peaks that exceed the intensity threshold as the target peak. Furthermore, when there are multiple peaks with the same distance BIN, the CPU 11 may determine whether the peaks exceed the intensity threshold in the ascending order of speed BINs corresponding to smaller relative speeds, and extract the peaks that exceed the intensity threshold as the target peak.

[0028] Next, in S109, the CPU 11 stores the number of extracted peaks, which is the number of target peaks extracted in S108, in the storage unit. Based on the extracted target peak, the distance to the object and the relative speed with respect to the object are calculated.

[0029] [1-3. Modifications] The distance-velocity spectrum, which is an intensity distribution, may have both or either of a plurality of distance ranges and a plurality of relative velocity ranges. The plurality of distance ranges are formed by dividing a distance BIN in the distance-velocity spectrum into a plurality of ranges. In other words, a distance BIN corresponding to a peak is included in any one of the distance ranges. The plurality of relative velocity ranges are formed by dividing a velocity BIN in the distance-velocity spectrum into a plurality of ranges. In other words, a velocity BIN corresponding to a peak is included in any one of the relative velocity ranges.

[0030] Then, an intensity threshold corresponding to each distance range and / or each relative speed range may be provided, and each intensity threshold may be set uniquely. That is, for example, a unique intensity threshold may be provided corresponding to each distance range, or a unique intensity threshold may be provided corresponding to each relative speed range. Also, for example, a region on the distance-speed spectrum specified by a combination of each distance range and each relative speed range may be set as a combination range, and a unique intensity threshold may be provided corresponding to each combination range.

[0031] That is, in S103 and S104 of the peak extraction process, the CPU 11 compares the number of immediately preceding extracted peaks for each distance range, each relative velocity range, or each combination range with the upper threshold and the lower threshold for each distance range, each relative velocity range, or each combination range. In addition, in S105 to S107 of the peak extraction process, the CPU 11 calculates a first or second threshold corresponding to each distance range, each relative velocity range, or each combination range by CFAR processing. Then, the CPU 11 sets each first or second threshold to an intensity threshold corresponding to the same distance range, relative velocity range, or combination range as the first or second threshold.

[0032] Then, in S108, if the CPU 11 sets a unique intensity threshold corresponding to each distance range, the CPU 11 extracts, as the target peak, a peak whose intensity exceeds the intensity threshold set for each distance range, with the upper limit number set in advance for each distance range as the upper limit. Note that the peak corresponding to the distance range means a peak whose corresponding distance BIN is included in the distance range. If the CPU 11 sets a unique intensity threshold corresponding to each relative speed range, the CPU 11 extracts, as the target peak, a peak whose intensity exceeds the intensity threshold set for each relative speed range, with the upper limit number set in advance for each relative speed range as the upper limit. Note that the peak corresponding to the relative speed range means a peak whose corresponding speed BIN is included in the relative speed range. If the CPU 11 sets a unique intensity threshold corresponding to each combination range, the CPU 11 extracts, as the target peak, a peak whose intensity exceeds the intensity threshold set for each combination range, with the upper limit number set in advance for each combination range as the upper limit. Note that the peak corresponding to the combination range means a peak whose corresponding distance BIN and speed BIN are included in the combination range.

[0033] [1-4. Effects] According to the first embodiment described above in detail, the following effects can be obtained. (1a) The signal processing device 1 sets an intensity threshold based on the number of extracted peaks in the previous intensity distribution so as to prevent the number of target peaks from exceeding an upper limit number.

[0034] Here, when the signal processing device 1 extracts the target peak, the target peak is searched in the intensity distribution until the number of the target peaks exceeds the upper limit, but when the number of the target peaks exceeds the upper limit, the search is not performed any more. In other words, when the number of the target peaks exceeds the upper limit, a range that is not searched in the intensity distribution occurs, and this range may include a peak indicating an important object such as a preceding vehicle. Therefore, if an intensity threshold is set to suppress the number of the target peaks from exceeding the upper limit, the number of the target peaks can be reduced, and a wider range is searched in the intensity distribution. As a result, a target peak that is not extracted when the number of the target peaks exceeds the upper limit can be extracted. Therefore, according to the above-mentioned configuration, it is possible to suppress the non-extraction of a peak indicating an important object, compared to a case where an intensity threshold is not set to suppress the number of the target peaks from exceeding the upper limit.

[0035] (1b) When the number of immediately preceding extracted peaks is equal to or greater than the upper threshold, the signal processing device 1 sets the intensity threshold higher than when the number of immediately preceding extracted peaks is less than the upper threshold. Here, the number of peaks tends to depend on the environment around the moving object, for example, the number of peaks tends to be large in an environment with many stationary objects around the moving object. Also, the environment around the moving object changes gradually, and the number of peaks does not change significantly instantaneously.

[0036] That is, when the number of previous extracted peaks is equal to or greater than the upper threshold, it is possible that the number of extracted peaks in the previous processing cycle was already approaching the upper limit. Therefore, it is preferable to prevent the number of extracted peaks in the current processing cycle from approaching the upper limit. Therefore, the signal processing device 1 sets the intensity threshold high so as to reduce the number of target peaks in the current processing cycle. This makes it possible to prevent the number of target peaks from exceeding the upper limit, thereby making it possible to prevent peaks indicating important objects from not being extracted.

[0037] (1c) The signal processing device 1 extracts target peaks from the intensity distribution in order starting from the peaks corresponding to shorter distances. With this configuration, the signal processing device 1 can preferentially extract peaks that are more likely to approach a moving object.

[0038] (1d) The signal processing device 1 extracts target peaks from the intensity distribution in order starting from those corresponding to smaller relative velocities. With this configuration, the signal processing device 1 can preferentially extract peaks that are more likely to approach a moving object.

[0039] (1e) For example, in an intensity distribution, the intensity may vary depending on the distance BIN and / or the relative velocity BIN, such that the peaks of distance BINs corresponding to shorter distances tend to have stronger intensity. For this reason, if the intensity threshold is set uniformly over the entire range, there is a risk that target peaks will be extracted disproportionately from distance BINs and / or relative velocity BINs in a specific range.

[0040] In contrast, in the modified example of the first embodiment, an intensity threshold value corresponding to each distance range and / or each relative velocity range is provided, and the value of each intensity threshold value is set uniquely, which makes it possible to prevent target peaks from concentrating in a specific distance range or relative velocity range.

[0041] Therefore, the target peak can be suitably extracted from the entire range of the intensity distribution. In the first embodiment, S103 to S107 correspond to the processing performed by the setting unit, S108 corresponds to the processing performed by the extraction unit, S109 corresponds to the processing performed by the storage processing unit, and the upper threshold corresponds to the peak number threshold.

[0042] [2. Second embodiment] [2-1. Differences from the first embodiment] Since the second embodiment has a basic configuration similar to that of the first embodiment, a description of the common configuration will be omitted and the following description will focus on the differences.

[0043] In the first embodiment described above, in the peak extraction process, the CPU 11 sets the intensity threshold based on the number of previously extracted peaks. On the other hand, in the second embodiment, in the peak extraction process, the CPU 11 sets the intensity threshold based on a predicted number, which is a value obtained by predicting the number of extracted peaks in the current intensity distribution.

[0044] [2-2. Processing] The peak extraction process that the signal processing device 1 of the second embodiment executes in place of the peak extraction process of the first embodiment will be described with reference to the flowchart of FIG.

[0045] Steps S201 and S202 are similar to steps S101 and S102 in FIG. Next, in S203, the CPU 11 calculates the amount of change in speed of the moving object within a predetermined time. The CPU 11 may calculate the amount of change in speed of the vehicle 10 based on the speed of the vehicle 10 acquired by a speed sensor (not shown).

[0046] Next, in S204, the CPU 11 calculates the predicted number. In this embodiment, the CPU 11 calculates the predicted number based on the number of extracted peaks within a certain period including the immediately preceding processing cycle, that is, the number of extracted peaks in the past processing cycles including the immediately preceding processing cycle, among the numbers of extracted peaks stored in the storage unit. That is, for example, if the number of extracted peaks has tended to increase in the past processing cycles, it is considered that the number of extracted peaks in the current processing cycle will be greater than the number of extracted peaks in the immediately preceding processing cycle. Therefore, the CPU 11 calculates the predicted number according to the rate of increase or decrease in the number of extracted peaks in the past processing cycles.

[0047] At this time, CPU 11 calculates the predicted number taking into account the speed change of the moving object calculated in S203. That is, for example, even if the environment around the moving object is similar, the peak tends to increase as the speed of the moving object increases. Therefore, CPU 11 calculates a larger predicted number as the speed change of the moving object increases. Note that CPU 11 may calculate the predicted number without taking into account the speed change. In this case, CPU 11 does not need to perform the process of S203.

[0048] Next, in S205, the CPU 11 judges whether the predicted number is equal to or greater than the upper prediction threshold. The upper prediction threshold is set to a value smaller than the upper limit number. If the CPU 11 judges that the predicted number is equal to or greater than the upper prediction threshold (S205: Yes), the CPU 11 proceeds to S208. If the CPU 11 judges that the predicted number is equal to or greater than the upper prediction threshold (S205: No), the CPU 11 proceeds to S206.

[0049] In S206, the CPU 11 judges whether the predicted number is equal to or smaller than a lower prediction threshold. The lower prediction threshold is set to a value smaller than the upper prediction threshold. If a positive judgment is obtained (S206: Yes), the CPU 11 proceeds to S207, and if a negative judgment is obtained (S206: No), the CPU 11 proceeds to S209.

[0050] In S207, the CPU 11 sets the first threshold value as the intensity threshold value, similarly to S105 in FIG. In S208, the CPU 11 sets the second threshold value as the intensity threshold value, similarly to S106 in FIG.

[0051] In S209, the CPU 11 sets the intensity threshold in the same manner as in the immediately preceding processing cycle, similar to S107 in FIG. Next, in S210, the CPU 11 extracts a target peak from the intensity distribution, similarly to S108 in FIG.

[0052] Next, in S211, the CPU 11 stores the number of extracted peaks, which is the number of target peaks extracted in S210, in the storage unit, similarly to S109 in FIG. [2-3. Modifications] As in the first embodiment, the distance velocity spectrum, which is an intensity distribution, may have a plurality of distance ranges and / or a plurality of relative velocity ranges.

[0053] Then, an intensity threshold may be provided corresponding to each distance range and / or each relative speed range, and each intensity threshold may be uniquely set. That is, in S205 and S206 of the peak extraction process, the CPU 11 compares the predicted number for each distance range, each relative velocity range, or each combination range with the upper prediction threshold and the lower prediction threshold for each distance range, each relative velocity range, or each combination range. In addition, in S207 to S209 of the peak extraction process, the CPU 11 calculates a first or second threshold corresponding to each distance range, each relative velocity range, or each combination range by CFAR processing. Then, the CPU 11 sets each first or second threshold to an intensity threshold corresponding to the same distance range, relative velocity range, or combination range as the first or second threshold.

[0054] Then, in S210, if the CPU 11 sets a unique intensity threshold for each distance range, it extracts, as the target peak, a peak whose intensity exceeds the intensity threshold set for the distance range, with the upper limit number set for each distance range as the upper limit. If the CPU 11 sets a unique intensity threshold for each relative speed range, it extracts, as the target peak, a peak whose intensity exceeds the intensity threshold set for the relative speed range, with the upper limit number set for each relative speed range as the upper limit. If the CPU 11 sets a unique intensity threshold for each combination range, it extracts, as the target peak, a peak whose intensity exceeds the intensity threshold set for the combination range, with the upper limit number set for each combination range as the upper limit.

[0055] [2-4. Effects] According to the second embodiment described above in detail, in addition to the effects of the first embodiment described above, the following effects can be obtained.

[0056] (2a) When the predicted number is equal to or greater than the upper prediction threshold, the signal processing device 1 sets the intensity threshold higher than when the predicted number is less than the upper prediction threshold. Considering that the number of peaks does not change significantly instantaneously, it is possible to predict the number of target peaks in the current processing cycle from the trend of increase / decrease in the number of extracted peaks in past processing cycles.

[0057] And, when the predicted number is equal to or greater than the upper prediction threshold, it is possible that the predicted number is approaching the upper limit number. Therefore, it is preferable to adjust the number of target peaks in the current processing cycle so that the number does not approach the upper limit number. Therefore, the signal processing device 1 sets the intensity threshold high so as to reduce the number of target peaks in the current processing cycle. This makes it possible to prevent the number of target peaks from exceeding the upper limit number, and therefore to prevent peaks indicating important objects from not being extracted.

[0058] (2b) The signal processing device 1 calculates the predicted number based on the speed change amount of the moving object. With this configuration, the signal processing device 1 can predict the number of target peaks in the current processing cycle with higher accuracy than a configuration in which the predicted number is calculated without taking into account the speed change amount of the moving object.

[0059] In the second embodiment, S203 and S204 correspond to the processing of the prediction unit, S205 to S209 correspond to the processing of the setting unit, S210 corresponds to the processing of the extraction unit, S211 corresponds to the processing of the storage processing unit, and the upper prediction threshold corresponds to the peak prediction threshold.

[0060] 3. Other embodiments Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take various forms.

[0061] (3a) In the above embodiment, a distance-velocity spectrum is used as the intensity distribution. However, the type of intensity distribution is not limited to this, and a distance spectrum may be used as the intensity distribution.

[0062] That is, in S102 of the peak extraction process of the first embodiment, the distance spectrum of the observation signal may be generated as the current intensity portion, and in S103 to S108, a target peak exceeding an intensity threshold may be extracted from the current intensity distribution. For example, in S105, the CPU 11 may set a first threshold 71 as the intensity threshold as shown in FIG. 7. Also, in S106, the CPU 11 may set a second threshold 72 higher than the first threshold 71 as the intensity threshold as shown in FIG. 8. Also, in S108, it may be determined whether the intensity threshold is exceeded in order from the peak of the distance BIN corresponding to the shorter distance, and the peak exceeding the intensity threshold may be extracted as the target peak. Then, the distance to the object may be obtained based on the extracted target peak.

[0063] Similarly, in the peak extraction process of the second embodiment, the distance spectrum of the observed signal may be generated as the current intensity portion in S202, and a target peak exceeding an intensity threshold may be extracted from the current intensity distribution in S203 to S210. In addition, in S210, it may be determined whether or not the intensity threshold is exceeded in order of the peaks of the distance BINs corresponding to shorter distances, and the peaks exceeding the intensity threshold may be extracted as the target peaks. Then, the distance to the object may be calculated based on the extracted target peaks.

[0064] (3b) In the first embodiment, an upper threshold and a lower threshold are used as in S103 and S104. However, for example, S104 and S107 may be omitted, and the intensity threshold may be set based on the upper threshold. That is, when the number of immediately preceding extracted peaks is less than the upper threshold, the first threshold may be set as the intensity threshold.

[0065] Also in the second embodiment, S206 and S209 may be omitted, and when the predicted number is less than the upper prediction threshold, the first threshold may be set as the intensity threshold. (3c) In the above embodiment, an FCM millimeter wave radar was used as the radar device 2. However, the type of the radar device 2 is not limited to this. For example, a millimeter wave radar of an FMCW type or a multi-frequency CW type may be used.

[0066] (3d) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. [Explanation of symbols]

[0067] 1...signal processing device, 10...vehicle, 11...CPU, 13...RAM.

Claims

1. A signal processing device is mounted on a moving body (10) and performs processing for measuring objects present in the vicinity of the moving body using observation signals based on reflected waves of irradiated transmission waves, A setting unit (S103 to S107, S205 to S209) configured to set an intensity threshold corresponding to an intensity distribution based on the periodically generated observation signal; an extraction unit (S108, S210) configured to extract, from the intensity distribution, target peaks that are peaks greater than the intensity threshold, with a preset upper limit number as an upper limit; a storage processing unit (S109, S211) configured to store the number of extracted peaks, which is the number of the target peaks extracted by the extraction unit, in a storage unit (13); Equipped with the setting unit sets the intensity threshold value based on the number of extracted peaks for the previous intensity distribution stored in the storage unit so as to suppress the number of target peaks for the new intensity distribution from exceeding the upper limit number; a prediction unit (S203, 204) for calculating a predicted number of the extracted peaks in a current intensity distribution, which is the intensity distribution for which the setting unit is to set the intensity threshold value; the prediction unit calculates the predicted number based on the number of extracted peaks in the intensity distribution generated before the current intensity distribution, among the number of extracted peaks stored in the storage unit; the setting unit sets the intensity threshold higher when the predicted number calculated by the prediction unit is equal to or greater than a predetermined peak prediction threshold, compared to when the predicted number is less than the peak prediction threshold; the intensity distribution is an intensity distribution according to a distance between the object and the moving body and a relative speed between the object and the moving body, The prediction unit calculates the predicted number based on an amount of change in speed of the moving object.

2. 2. The signal processing device according to claim 1, The signal processing device, wherein the extraction unit extracts the target peaks from the intensity distribution in order starting from the target peaks corresponding to the smaller relative velocities.

3. A signal processing device is mounted on a moving body (10) and performs processing for measuring objects present in the vicinity of the moving body using observation signals based on reflected waves of irradiated transmission waves, A setting unit (S103 to S107, S205 to S209) configured to set an intensity threshold corresponding to an intensity distribution based on the periodically generated observation signal; an extraction unit (S108, S210) configured to extract, from the intensity distribution, target peaks that are peaks greater than the intensity threshold, with a preset upper limit number as an upper limit; a storage processing unit (S109, S211) configured to store the number of extracted peaks, which is the number of the target peaks extracted by the extraction unit, in a storage unit (13); Equipped with the setting unit sets the intensity threshold value based on the number of extracted peaks for the previous intensity distribution stored in the storage unit so as to suppress the number of target peaks for the new intensity distribution from exceeding the upper limit number; the intensity distribution is an intensity distribution according to a distance between the object and the moving body and a relative speed between the object and the moving body, The signal processing device, wherein the extraction unit extracts the target peaks from the intensity distribution in order starting from the target peaks corresponding to the smaller relative velocities.

4. 4. The signal processing device according to claim 3, The setting unit is setting the intensity threshold based on a previous extracted peak number, which is the number of extracted peaks in the intensity distribution generated immediately before a current intensity distribution, which is the intensity distribution for which the intensity threshold is to be set, among the extracted peak numbers stored in the storage unit; When the number of immediately preceding extracted peaks is equal to or greater than a predetermined peak number threshold, the intensity threshold is set higher than when the number of immediately preceding extracted peaks is less than the peak number threshold.

5. 4. The signal processing device according to claim 3, a prediction unit (S203, 204) for calculating a predicted number of the extracted peaks in a current intensity distribution, which is the intensity distribution for which the setting unit is to set the intensity threshold value; the prediction unit calculates the predicted number based on the number of extracted peaks in the intensity distribution generated before the current intensity distribution, among the number of extracted peaks stored in the storage unit; The signal processing device, wherein the setting unit sets the intensity threshold higher when the predicted number calculated by the prediction unit is equal to or greater than a predetermined peak prediction threshold compared to when the predicted number is less than the peak prediction threshold.

6. A signal processing device according to any one of claims 1 to 5, the intensity distribution has a plurality of relative velocity ranges, and the relative velocity corresponding to the peak is included in any one of the relative velocity ranges; the setting unit sets the intensity threshold value corresponding to each of the relative velocity ranges in the intensity distribution; the extraction unit extracts, for each of the relative velocity ranges, peaks that are greater than the intensity threshold value corresponding to the relative velocity range from among the peaks included in the respective relative velocity ranges, up to an upper limit number preset for each of the relative velocity ranges, as the target peaks; The setting unit sets the intensity threshold value so as to prevent the number of the target peaks for each of the relative velocity ranges extracted by the extraction unit from exceeding the upper limit number.

7. A signal processing device is mounted on a moving body (10) and performs processing for measuring objects present in the vicinity of the moving body using observation signals based on reflected waves of irradiated transmission waves, A setting unit (S103 to S107, S205 to S209) configured to set an intensity threshold corresponding to an intensity distribution based on the periodically generated observation signal; an extraction unit (S108, S210) configured to extract, from the intensity distribution, target peaks that are peaks greater than the intensity threshold, with a preset upper limit number as an upper limit; a storage processing unit (S109, S211) configured to store the number of extracted peaks, which is the number of the target peaks extracted by the extraction unit, in a storage unit (13); Equipped with the setting unit sets the intensity threshold value based on the number of extracted peaks for the previous intensity distribution stored in the storage unit so as to suppress the number of target peaks for the new intensity distribution from exceeding the upper limit number; the intensity distribution is an intensity distribution according to a distance between the object and the moving body, the intensity distribution has a plurality of distance ranges, and the distance corresponding to the peak is included in any one of the distance ranges; the setting unit sets the intensity threshold value corresponding to each of the distance ranges in the intensity distribution; the extraction unit extracts, for each distance range, peaks that are greater than the intensity threshold corresponding to the distance range from among peaks included in the respective distance ranges, up to an upper limit number preset for each distance range; and The setting unit sets the intensity threshold value so as to prevent the number of the target peaks for each distance range extracted by the extraction unit from exceeding the upper limit number.

8. 8. A signal processing device according to claim 7, The signal processing device, wherein the extraction unit extracts the target peaks from the intensity distribution in order starting from the target peaks corresponding to the shorter distances.

9. A signal processing device is mounted on a moving body (10) and performs processing for measuring objects present in the vicinity of the moving body using observation signals based on reflected waves of irradiated transmission waves, A setting unit (S103 to S107, S205 to S209) configured to set an intensity threshold corresponding to an intensity distribution based on the periodically generated observation signal; an extraction unit (S108, S210) configured to extract, from the intensity distribution, target peaks that are peaks greater than the intensity threshold, with a preset upper limit number as an upper limit; a storage processing unit (S109, S211) configured to store the number of extracted peaks, which is the number of the target peaks extracted by the extraction unit, in a storage unit (13); Equipped with the setting unit sets the intensity threshold value based on the number of extracted peaks for the previous intensity distribution stored in the storage unit so as to suppress the number of target peaks for the new intensity distribution from exceeding the upper limit number; the intensity distribution is an intensity distribution according to a distance between the object and the moving body and a relative speed between the object and the moving body, the intensity distribution has a plurality of relative velocity ranges, and the relative velocity corresponding to the peak is included in any one of the relative velocity ranges; the setting unit sets the intensity threshold value corresponding to each of the relative velocity ranges in the intensity distribution; the extraction unit extracts, for each of the relative velocity ranges, peaks that are greater than the intensity threshold value corresponding to the relative velocity range from among the peaks included in the respective relative velocity ranges, up to an upper limit number preset for each of the relative velocity ranges, as the target peaks; The setting unit sets the intensity threshold value so as to prevent the number of the target peaks for each of the relative velocity ranges extracted by the extraction unit from exceeding the upper limit number.

10. A signal processing device according to any one of claims 7 to 9, The setting unit is setting the intensity threshold based on a previous extracted peak number, which is the number of extracted peaks in the intensity distribution generated immediately before a current intensity distribution, which is the intensity distribution for which the intensity threshold is to be set, among the extracted peak numbers stored in the storage unit; When the number of immediately preceding extracted peaks is equal to or greater than a predetermined peak number threshold, the intensity threshold is set higher than when the number of immediately preceding extracted peaks is less than the peak number threshold.

11. A signal processing device according to any one of claims 7 to 9, a prediction unit (S203, 204) for calculating a predicted number of the extracted peaks in a current intensity distribution, which is the intensity distribution for which the setting unit is to set the intensity threshold value; the prediction unit calculates the predicted number based on the number of extracted peaks in the intensity distribution generated before the current intensity distribution, among the number of extracted peaks stored in the storage unit; The signal processing device, wherein the setting unit sets the intensity threshold higher when the predicted number calculated by the prediction unit is equal to or greater than a predetermined peak prediction threshold compared to when the predicted number is less than the peak prediction threshold.

12. A signal processing device is mounted on a moving body (10) and performs processing for measuring objects present in the vicinity of the moving body using observation signals based on reflected waves of irradiated transmission waves, A setting unit (S103 to S107, S205 to S209) configured to set an intensity threshold corresponding to an intensity distribution based on the periodically generated observation signal; an extraction unit (S108, S210) configured to extract, from the intensity distribution, target peaks that are peaks greater than the intensity threshold, with a preset upper limit number as an upper limit; a storage processing unit (S109, S211) configured to store the number of extracted peaks, which is the number of the target peaks extracted by the extraction unit, in a storage unit (13); Equipped with the setting unit sets the intensity threshold value based on the number of extracted peaks for the previous intensity distribution stored in the storage unit so as to suppress the number of target peaks for the new intensity distribution from exceeding the upper limit number; The setting unit is setting the intensity threshold based on a previous extracted peak number, which is the number of extracted peaks in the intensity distribution generated immediately before a current intensity distribution, which is the intensity distribution for which the intensity threshold is to be set, among the extracted peak numbers stored in the storage unit; When the number of immediately preceding extracted peaks is equal to or greater than a predetermined peak number threshold, the intensity threshold is set higher than when the number of immediately preceding extracted peaks is less than the peak number threshold; The peak number threshold is a value smaller than the upper limit number.

13. A signal processing device is mounted on a moving body (10) and performs processing for measuring objects present in the vicinity of the moving body using observation signals based on reflected waves of irradiated transmission waves, A setting unit (S103 to S107, S205 to S209) configured to set an intensity threshold corresponding to an intensity distribution based on the periodically generated observation signal; an extraction unit (S108, S210) configured to extract, from the intensity distribution, target peaks that are peaks greater than the intensity threshold, with a preset upper limit number as an upper limit; a storage processing unit (S109, S211) configured to store the number of extracted peaks, which is the number of the target peaks extracted by the extraction unit, in a storage unit (13); Equipped with the setting unit sets the intensity threshold value based on the number of extracted peaks for the previous intensity distribution stored in the storage unit so as to suppress the number of target peaks for the new intensity distribution from exceeding the upper limit number; a prediction unit (S203, 204) for calculating a predicted number of the extracted peaks in a current intensity distribution, which is the intensity distribution for which the setting unit is to set the intensity threshold value; the prediction unit calculates the predicted number based on the number of extracted peaks in the intensity distribution generated before the current intensity distribution, among the number of extracted peaks stored in the storage unit; the setting unit sets the intensity threshold higher when the predicted number calculated by the prediction unit is equal to or greater than a predetermined peak prediction threshold, compared to when the predicted number is less than the peak prediction threshold; The signal processing device, wherein the peak prediction threshold is a value smaller than the upper limit number.

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