Signal processing device

Abstract

The signal processing apparatus includes a setting unit (S103-S107, S205-S209), an extraction unit (S108, S210), and a storage processing unit (S109, S211). The extraction unit is configured to extract at least one target peak value from an intensity distribution, where the target peak value is a peak value larger than an intensity threshold, using a pre-set upper limit number as the upper limit. The setting unit sets an intensity threshold based on the number of extracted peak values ​​stored in the storage unit for previous intensity distributions to suppress situations where the number of at least one target peak value for a new intensity distribution exceeds the upper limit number.

Description

Technical Field

[0001] This invention relates to a signal processing apparatus. Background Technology

[0002] Patent Document 1 describes a radar signal detection device that uses CFAR processing on signals obtained from a radar device and sets a threshold to keep the false detection rate of the signal constant. CFAR is an abbreviation for Constant False Alarm Rate. Generally, when using CFAR processing and setting a threshold, peak values ​​exceeding the threshold are extracted from the signal from the radar device, and objects are identified based on these extracted peak values.

[0003] Patent Document 1: Patent No. 3420177

[0004] However, the inventors' detailed research revealed the following issue: when the signal from the radar device contains many peaks exceeding a threshold, the processing load increases when identifying objects based on these peaks. On the other hand, setting an upper limit on the number of extracted peaks may prevent the extraction of peaks indicating the presence of important objects. Summary of the Invention

[0005] One preferred embodiment of the present invention provides an unextracted signal processing device capable of suppressing peak values.

[0006] One aspect of the present invention provides a signal processing apparatus mounted on a moving body, which uses an observation signal to perform processing for determining objects present in the vicinity of the moving body, the observation signal being an observation signal based on the reflected wave of an irradiated transmitted wave. The signal processing apparatus includes a setting unit, an extraction unit, and a storage processing unit. 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 at least one object peak, i.e., a peak value larger than the intensity threshold, from the intensity distribution, using a pre-set upper limit number as an upper limit. The storage processing unit is configured to store the number of at least one object peak value extracted by the extraction unit, i.e., the number of extracted peak values, in a storage unit. The setting unit sets an intensity threshold based on the number of extracted peak values ​​stored in the storage unit for a previous intensity distribution to suppress the situation where the number of at least one object peak value for a new intensity distribution exceeds the upper limit number.

[0007] Based on the above structure, it is possible to suppress the situation where the number of extracted at least one object peaks reaches the upper limit before extracting at least one object peak from the entire region of the intensity distribution, thus causing the extraction of at least one object peak to be interrupted midway. Therefore, it is possible to suppress the failure to extract peaks. Attached Figure Description

[0008] Figure 1 It is a block diagram representing the structure of a signal processing device.

[0009] Figure 2 This diagram illustrates an example of a detection area when a radar device is mounted at the front of a vehicle.

[0010] Figure 3 This diagram illustrates an example of a detection area where the radar device is mounted outside the front of the vehicle.

[0011] Figure 4 This is an explanatory diagram showing an overview of two-dimensional FFT processing.

[0012] Figure 5 This is a flowchart of the peak extraction process in the first embodiment.

[0013] Figure 6 This is a flowchart of the peak extraction process in the second embodiment.

[0014] Figure 7 This is an illustrative diagram showing an example of setting a first threshold in the distance spectrum.

[0015] Figure 8 This is an illustrative diagram showing an example of setting a second threshold in the distance spectrum. Detailed Implementation

[0016] The following is a reference to the appendix. Figure 1 The exemplary embodiments of the present invention will be described below.

[0017] [1. First Implementation Method]

[0018] [1-1. Structure]

[0019] Figure 1 The signal processing device 1 shown is mounted on a moving body. The signal processing device 1 is a device that uses at least one observation signal (described later) to process objects present in the vicinity of the moving body. The moving body may be, for example, a vehicle, an aircraft, or a ship. In addition to the signal processing device 1, a radar device 2 is also mounted on the moving body. In this embodiment, the signal processing device 1 and the radar device 2 are mounted on a vehicle 10.

[0020] like Figure 2 As shown, the radar device 2 is mounted at the front center of the vehicle 10 (e.g., the center of the front bumper). The area at the front center of the vehicle 10 can also be used as the detection area Rd. Additionally, as... Figure 3As shown, radar device 2 is mounted in five positions on the front center, left front side, right front side, left rear side, and right rear side of vehicle 10. Alternatively, the area in front center, left front, right front, left rear, and right rear of vehicle 10 can be designated as the detection area Rd. The number and mounting positions of radar devices 2 mounted on vehicle 10 can be appropriately selected.

[0021] Radar device 2 is a millimeter-wave radar. Radar device 2 includes a transmitting array antenna and a receiving array antenna. More specifically, as an example, radar device 2 is configured as a millimeter-wave radar using FCM (Fast Chirp Modulation). Furthermore, FCM is an abbreviation for Fast Chirp Modulation.

[0022] In each processing cycle, which occurs at a predetermined period Tcy, radar device 2 illuminates the detection area Rd with a transmitted wave as a linear frequency modulated (LFM) signal. In each processing cycle, radar device 2 transmits the LFM signal N times at a predetermined period T. Furthermore, radar device 2 receives the reflected waves generated by the reflection of each LFM signal at the reflection point of the object.

[0023] Furthermore, radar device 2 generates a beat signal by mixing the transmitted linear frequency modulated signal with the reflected signal of the reflected wave based on the linear frequency modulated signal. Radar device 2 outputs the observation signal generated by sampling the beat signal to signal processing device 1.

[0024] like Figure 1 As shown, the signal processing apparatus 1 is configured around a known microcomputer having a CPU 11, ROM 12, RAM 13, flash memory 14, etc. The CPU 11 executes a program stored in a non-transferable physical recording medium, i.e., ROM 12. By executing the program, the method corresponding to the program is executed. The signal processing apparatus 1 may also include a coprocessor that performs high-speed Fourier transform (hereinafter, FFT) processing, etc.

[0025] [1-2. Summary of the Process]

[0026] The signal processing device 1 performs processing to determine the object present in the detection area Rd based on the N beat signals (hereinafter referred to as observation signals) generated in each processing cycle.

[0027] That is, such as Figure 4As shown, CPU 11 performs FFT processing on each of the N observation signals generated in each processing cycle, generating N distance spectra. The distance spectrum is a spectrum representing power relative to distance. The distance spectrum has frequency components corresponding to the distance between the moving body and the object (in other words, the reflection point), therefore the frequency BIN of the generated distance spectrum is equivalent to the distance BIN. Furthermore, 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 representing the power of distance and the relative velocity of the object relative to the moving body. CPU 11 uses the distance-velocity spectrum as an intensity distribution and extracts peak values ​​from the intensity distribution. The peak values ​​of the intensity distribution represent the object, and based on the velocity BIN and distance BIN corresponding to the extracted peak values, the relative velocity and distance of the object are determined.

[0028] CPU 11 uses a pre-set upper limit as the upper limit, extracts at least one object peak from the intensity distribution, where the object peak is a peak larger than the intensity threshold, and stores the number of extracted object peaks, i.e., the total number of extracted peaks, in RAM 13. The intensity threshold is set when extracting at least one new object peak. That is, CPU 11 sets the intensity threshold based on the number of extracted peaks for the previous intensity distribution to prevent the number of at least one object peak for the new intensity distribution from exceeding the upper limit.

[0029] [1-3. Details of the handling]

[0030] use Figure 5 The flowchart shown illustrates the peak extraction process performed by the CPU 11 of the signal processing device 1. Furthermore, this process is repeatedly initiated for each processing cycle.

[0031] First, in S101, CPU11 acquires N observation signals output from radar device 2.

[0032] Next, in S102, CPU11 generates the range-velocity spectrum as the intensity distribution of N observed signals.

[0033] Next, CPU11 extracts at least one object peak that is greater than the intensity threshold from the newly generated intensity distribution in this processing cycle (hereinafter referred to as the current intensity distribution). Subsequently, the number of at least one object peak extracted from the intensity distribution generated in the preceding processing cycle is recorded as the number of peaks extracted in the preceding cycle.

[0034] That is, in S103, CPU11 determines whether the number of extracted peaks immediately preceding the current peaks is above the upper threshold. The upper threshold is a value smaller than the upper limit. Then, if the CPU11 receives a positive determination (S103: Yes), it proceeds to S106; if the CPU11 receives a negative determination (S103: No), it proceeds to S104.

[0035] In S104, CPU11 determines whether the number of preceding extracted peaks is below the lower threshold. The lower threshold is a value smaller than the upper threshold. Then, if the CPU11 receives a positive determination (S104: Yes), it proceeds to S105; if the CPU11 receives a negative determination (S104: No), it proceeds to S107.

[0036] In S105, CPU11 sets the first threshold as an intensity threshold. In this embodiment, the first threshold is calculated using CFAR processing. Alternatively, a pre-defined threshold may be used as the first threshold.

[0037] In S106, CPU11 sets the second threshold as the intensity threshold. In this embodiment, the second threshold is a value obtained by adding a predetermined additive value to the first threshold calculated using the same CFAR processing as in S105. That is, the second threshold is larger than the first threshold.

[0038] In S107, CPU 11 sets the intensity threshold in the same way as the preceding processing cycle. In this embodiment, if a first threshold is set as the intensity threshold in the preceding processing cycle, the first threshold is also calculated in this processing cycle and set as the intensity threshold. On the other hand, if a second threshold is set as the intensity threshold in the preceding processing cycle, the second threshold is also calculated in this processing cycle and set as the intensity threshold.

[0039] Next, in S108, the CPU 11 extracts at least one object peak from the intensity distribution. In this embodiment, the CPU 11 sequentially determines whether an intensity threshold is exceeded, starting from the peak of the velocity BIN corresponding to the smaller relative velocity, and extracts the peaks exceeding the intensity threshold as at least one object peak. Furthermore, if multiple peaks with the same velocity BIN exist, the CPU 11 sequentially determines whether an intensity threshold is exceeded, starting from the peak of the distance BIN corresponding to the shorter distance, and extracts the peaks exceeding the intensity threshold as at least one object peak.

[0040] Furthermore, the CPU 11 can also sequentially determine whether an intensity threshold is exceeded in the distance-velocity spectrum, starting from the peak of the distance BIN corresponding to a shorter distance, and extract the peaks exceeding the intensity threshold as at least one object peak. Moreover, when multiple peaks with the same distance BIN exist, the CPU 11 can also sequentially determine whether an intensity threshold is exceeded for each of these multiple peaks, starting from the peak of the velocity BIN corresponding to a smaller relative velocity, and extract the peaks exceeding the intensity threshold as at least one object peak.

[0041] Next, in S109, the CPU11 stores the number of at least one object peak extracted in S108, i.e., the number of extracted peaks, in the storage unit.

[0042] Furthermore, based on at least one extracted object peak, the distance to the object and the relative velocity with respect to the object are calculated.

[0043] [1-3. Variations]

[0044] The range-velocity spectrum, as an intensity distribution, can also have two or one of multiple ranges of distance and multiple ranges of relative velocity. Furthermore, multiple ranges of distance are formed by dividing the distance bins (BINs) in the range-velocity spectrum into multiple ranges. That is, the distance bin corresponding to the peak is contained within any one of the ranges. Similarly, multiple ranges of relative velocity are formed by dividing the velocity bins (BINs) in the range-velocity spectrum into multiple ranges. That is, the velocity bin corresponding to the peak is contained within any one of the ranges of relative velocity.

[0045] Furthermore, each intensity threshold can be inherently set by setting an intensity threshold corresponding to each distance range and / or each relative velocity range. That is, for example, an inherent intensity threshold can be set corresponding to each distance range, or an inherent intensity threshold can be set corresponding to each relative velocity range. Alternatively, for example, a region on the distance-velocity spectrum determined by the combination of each distance range and each relative velocity range can be used as a combination range, and an inherent intensity threshold can be set corresponding to each combination range.

[0046] In other words, in peak extraction processing steps S103 and S104, CPU 11 compares the number of immediately preceding extracted peaks for each distance range, relative velocity range, or combined range with the upper and lower thresholds for each distance range, relative velocity range, or combined range. Furthermore, in peak extraction processing steps S105 to S107, CPU 11 calculates a first threshold or a second threshold corresponding to each distance range, relative velocity range, or combined range using CFAR processing. Then, CPU 11 sets each first threshold or second threshold to the intensity threshold corresponding to the same distance range, relative velocity range, or combined range as the first threshold or second threshold.

[0047] Then, in S108, if an inherent intensity threshold is set corresponding to each distance range, the CPU 11 extracts at least one target peak from the peaks corresponding to each distance range whose intensity exceeds the intensity threshold set for that distance range, using a pre-set upper limit number as the upper limit. Here, the peak corresponding to a distance range refers to the peak whose corresponding distance BIN is included within that distance range. Furthermore, if an inherent intensity threshold is set corresponding to each relative velocity range, the CPU 11 extracts at least one target peak from the peaks corresponding to each relative velocity range whose intensity exceeds the intensity threshold set for that relative velocity range, using a pre-set upper limit number as the upper limit. Here, the peak corresponding to a relative velocity range refers to the peak whose corresponding velocity BIN is included within that relative velocity range. Additionally, if an inherent intensity threshold is set corresponding to each combined range, the CPU 11 extracts at least one target peak from the peaks corresponding to each combined range whose intensity exceeds the intensity threshold set for that combined range, using a pre-set upper limit number as the upper limit. The peak value corresponding to the combination range refers to the peak value of the corresponding distance BIN and velocity BIN that are included in the combination range.

[0048] [1-4. Effects]

[0049] According to the first embodiment described in detail above, the following effects are obtained.

[0050] (1a) The signal processing device 1 sets an intensity threshold based on the number of peaks extracted for the previous intensity distribution to suppress the situation where the number of peaks of at least one object exceeds the upper limit.

[0051] Here, when signal processing device 1 extracts at least one object peak, it searches for at least one object peak in the intensity distribution until the number exceeds an upper limit, but if the upper limit is exceeded, no further searching is performed. That is, if the number of at least one object peak exceeds the upper limit, a range is generated in the intensity distribution that is not searched. This range may, for example, include peaks representing important objects such as leading vehicles. Therefore, if an intensity threshold is set to suppress the situation where the number of at least one object peak exceeds the upper limit, the number of at least one object peak can be reduced, and a wider range can be searched in the intensity distribution. Thus, it is possible to extract at least one object peak that was not extracted when the number of at least one object peak exceeds the upper limit. Therefore, according to the above structure, compared to the case where no intensity threshold is set to suppress the situation where the number of at least one object peak exceeds the upper limit, it is possible to suppress the non-extraction of peaks representing important objects.

[0052] (1b) When the number of extracted peaks immediately preceding the signal is above the upper threshold, the signal processing device 1 sets the intensity threshold high in comparison with the case where the number of extracted peaks immediately preceding the signal is less than the upper threshold.

[0053] Here, for example, the number of peaks tends to depend on the surrounding environment of the moving object, such that in an environment with many stationary objects around the moving object, the number of peaks tends to increase. Furthermore, as the surrounding environment of the moving object changes gradually, the number of peaks does not change drastically instantaneously.

[0054] That is, "the number of extracted peaks in the preceding processing cycle is above the upper threshold" means that the number of peaks extracted in the preceding processing cycle may have already approached the upper limit. Therefore, in this processing cycle, it is preferable that the number of extracted peaks does not approach the upper limit. Therefore, the signal processing device 1 sets the intensity threshold high to reduce the number of at least one object peak in this processing cycle. As a result, it is possible to suppress the situation where the number of at least one object peak exceeds the upper limit, and thus it is possible to suppress the failure to extract peaks representing important objects.

[0055] (1c) The signal processing device 1 extracts signals sequentially from the intensity distribution from the peak values ​​corresponding to objects at shorter distances. With this structure, the signal processing device 1 can preferentially extract signals from peak values ​​that are highly likely to be close to a moving object.

[0056] (1d) The signal processing device 1 extracts sequentially from the object peaks corresponding to smaller relative velocities in the intensity distribution. With this structure, the signal processing device 1 can preferentially extract from peaks that are highly likely to be close to the moving object.

[0057] (1e) For example, in an intensity distribution, the intensity may vary depending on the distance BIN and / or relative velocity BIN, as the intensity of the peak corresponding to a shorter distance tends to be stronger. Therefore, if an intensity threshold is uniformly determined across the entire range, it is possible to extract at least one object peak biased towards the distance BIN and / or relative velocity BIN within a defined range.

[0058] In contrast, in a variation of the first embodiment, intensity thresholds corresponding to each distance range and / or each relative velocity range are set, and the values ​​of each intensity threshold are inherently set. This allows it to suppress situations where at least one object peak is concentrated within a defined distance range or relative velocity range.

[0059] Therefore, it is possible to appropriately extract at least one object peak from the entire region of the intensity distribution.

[0060] Furthermore, in the first embodiment, S103 to S107 correspond to the processing of the setting unit, S108 corresponds to the processing of the extraction unit, S109 corresponds to the processing of the storage processing unit, and the upper threshold corresponds to the peak number threshold.

[0061] [2. Second Implementation]

[0062] [2-1. Differences from the first embodiment]

[0063] The basic structure of the second embodiment is the same as that of the first embodiment, so the description of the same structure is omitted and the description focuses on the differences.

[0064] In the first embodiment described above, during peak extraction processing, the CPU 11 sets an intensity threshold based on the number of preceding extracted peaks. Conversely, in the second embodiment, during peak extraction processing, the CPU 11 sets the intensity threshold based on a prediction number, which is a value obtained by predicting the number of extracted peaks in the current intensity distribution.

[0065] [2-2. Processing]

[0066] Reference Figure 6 The flowchart illustrates how the peak extraction process performed by the signal processing apparatus 1 of the second embodiment replaces the peak extraction process of the first embodiment.

[0067] S201 and S202 are related to Figure 5 The same processing applies to S101 and S102.

[0068] Next, in S203, CPU 11 calculates the change in speed of the moving body within a specified time. Alternatively, CPU 11 can also calculate the change in speed of vehicle 10 based on the speed of vehicle 10 obtained from a speed sensor (not shown).

[0069] Next, in S204, CPU 11 calculates the predicted number. In this embodiment, CPU 11 calculates the predicted number based on the number of extracted peaks within a certain period including the preceding processing cycle, which is stored in the memory. That is, the number of extracted peaks in the past multiple processing cycles including the preceding processing cycle. For example, if the number of extracted peaks in the past multiple processing cycles shows an increasing trend, it is considered that the number of extracted peaks in the current processing cycle is higher than the number of extracted peaks in the previous processing cycle. Therefore, CPU 11 calculates the predicted number based on the proportion of increase or decrease in the number of extracted peaks in the past multiple processing cycles.

[0070] At this point, CPU 11 also considers the velocity change of the moving body calculated in S203 and calculates the number of predictions. That is, for example, even under the same environmental conditions surrounding the moving body, there is a trend that the faster the moving body's velocity, the greater the peak value. Therefore, the greater the velocity change of the moving body, the more predictions CPU 11 calculates. Alternatively, CPU 11 may calculate the number of predictions without considering the velocity change. In this case, CPU 11 may not need to perform the processing in S203.

[0071] Next, in S205, CPU11 determines whether the number of predictions is above the upper prediction threshold. Furthermore, the upper prediction threshold is set to a value smaller than the upper limit. Moreover, if CPU11 receives a positive determination (S205: Yes), it proceeds to S208; if it receives a negative determination (S205: No), it proceeds to S206.

[0072] In S206, CPU11 determines whether the number of predictions is below the lower prediction threshold. Furthermore, the lower prediction threshold is set to a value smaller than the upper prediction threshold. Moreover, if CPU11 receives a positive determination (S206: Yes), it proceeds to S207; if it receives a negative determination (S206: No), it proceeds to S209.

[0073] In S207, with Figure 5 Similarly, in S105, CPU11 sets the first threshold as the intensity threshold.

[0074] In S208, with Figure 5 Similarly, in S106, CPU11 sets the second threshold as the intensity threshold.

[0075] In S209, with Figure 5 Similarly, in S107, CPU11 sets the intensity threshold in the same way as the preceding processing cycle.

[0076] Next, in S210, with Figure 5 Similarly, in S108, CPU11 extracts at least one object peak from the intensity distribution.

[0077] Next, in S211, with Figure 5 Similarly to S109, CPU11 stores the number of at least one object peak extracted in S210, i.e., the number of extracted peaks, in the storage unit.

[0078] [2-3. Variations]

[0079] Similar to the first embodiment, the distance-velocity spectrum as the intensity distribution may also have two or one of multiple distance ranges and multiple relative velocity ranges.

[0080] Furthermore, intensity thresholds corresponding to each distance range and / or each relative velocity range can be set, thus inherently setting each intensity threshold.

[0081] That is, in peak extraction processing S205 and S206, CPU 11 compares the predicted number of each distance range, each relative velocity range, or each combined range with the upper and lower prediction thresholds of each distance range, each relative velocity range, or each combined range. Furthermore, in peak extraction processing S207 to S209, CPU 11 calculates a first threshold or a second threshold corresponding to each distance range, each relative velocity range, or each combined range through CFAR processing. Moreover, CPU 11 sets each first threshold or second threshold to the intensity threshold corresponding to the same distance range, relative velocity range, or combined range as the first threshold or second threshold.

[0082] Then, in S210, if an inherent intensity threshold is set corresponding to each distance range, the CPU 11 uses a pre-set upper limit number for each distance range as an upper limit, and extracts the peak value whose intensity exceeds the intensity threshold set for that distance range as at least one target peak value. Alternatively, if an inherent intensity threshold is set corresponding to each relative velocity range, the CPU 11 uses a pre-set upper limit number for each relative velocity range as an upper limit, and extracts the peak value whose intensity exceeds the intensity threshold set for that relative velocity range as at least one target peak value. Furthermore, if an inherent intensity threshold is set corresponding to each combined range, the CPU 11 uses a pre-set upper limit number for each combined range as an upper limit, and extracts the peak value whose intensity exceeds the intensity threshold set for that combined range as at least one target peak value.

[0083] [2-4. Effects]

[0084] According to the second embodiment detailed above, in addition to the effects of the first embodiment described above, the following effects are also obtained.

[0085] (2a) When the number of predictions is above the upper prediction threshold, the signal processing device 1 sets the intensity threshold higher compared to the case where the number of predictions is less than the upper prediction threshold.

[0086] Here, given that the number of peaks does not change dramatically instantaneously, the number of at least one object peak in this processing cycle can be predicted based on the trend of increase or decrease in the number of extracted peaks over the past multiple processing cycles.

[0087] Furthermore, a prediction number exceeding the upper prediction threshold means that the prediction number is likely to approach the upper limit. Therefore, in this processing cycle, it is preferable to adjust the number of at least one object peak to not approach the upper limit. Thus, the signal processing device 1 sets the intensity threshold high to reduce the number of at least one object peak in this processing cycle. This suppresses the number of at least one object peak from exceeding the upper limit, thereby suppressing the failure to extract peaks representing important objects.

[0088] (2b) The signal processing device 1 calculates the number of predictions based on the velocity change of the moving body. According to this structure, compared with the structure that calculates the number of predictions without considering the velocity change of the moving body, the signal processing device 1 is able to predict the number of at least one object peak in this processing cycle with higher accuracy.

[0089] Furthermore, 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.

[0090] [3. Other implementation methods]

[0091] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments and various methods can also be used.

[0092] (3a) In the above embodiment, the range-velocity spectrum is used as the intensity distribution. However, the type of intensity distribution is not limited to this, and the range spectrum may also be used as the intensity distribution.

[0093] That is, CPU11 can also generate the distance spectrum of the observed signal as the current intensity distribution in S102 of the peak extraction process in the first embodiment, and extract at least one object peak exceeding the intensity threshold from the current intensity distribution in S103 to S108. For example, it can also be as follows Figure 7As shown, in S105, CPU11 sets the first threshold 71 as the intensity threshold. Alternatively, for example, it can be done as follows: Figure 8 As shown, in S106, CPU11 sets a second threshold 72, which is higher than the first threshold 71, as the intensity threshold. Alternatively, in S108, it can sequentially determine whether the intensity threshold is exceeded, starting from the peak value of the distance BIN corresponding to the shorter distance, and extract the peak values ​​exceeding the intensity threshold as at least one object peak value. Furthermore, the distance to the object can be calculated based on the extracted at least one object peak value.

[0094] Furthermore, in the peak extraction process of the second embodiment, the CPU 11 can similarly generate the distance spectrum of the observed signal as the current intensity distribution in S202, and extract at least one object peak exceeding the intensity threshold from the current intensity distribution in S203 to S210. Alternatively, in S210, the CPU 11 can sequentially determine whether the intensity threshold is exceeded, starting from the peak of the distance BIN corresponding to a shorter distance, and extract the peaks exceeding the intensity threshold as at least one object peak. Moreover, the distance to the object can be calculated based on the extracted at least one object peak.

[0095] (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 an intensity threshold may be set based on the upper threshold. That is, if the number of immediately preceding extracted peaks is less than the upper threshold, a first threshold may be set as the intensity threshold.

[0096] Alternatively, in the second embodiment, S206 and S209 can be omitted, and when the number of predictions is less than the upper prediction threshold, the first threshold is set as the intensity threshold.

[0097] (3c) In the above embodiment, a millimeter-wave radar using the FCM method is used as radar device 2. However, the type of radar device 2 is not limited to this. For example, millimeter-wave radars using the FMCW method or the multi-frequency CW method can also be used.

[0098] (3d) Alternatively, the function of one component in the above embodiments can be distributed among multiple components, or the functions of multiple components can be integrated into one component. Furthermore, a portion of the structure in the above embodiments can be omitted. Additionally, at least a portion of the structure in the above embodiments can be added to, replaced, or otherwise modified relative to the structures of other above embodiments.

Claims

1. A signal processing apparatus mounted on a moving body, using at least one observation signal to perform processing for determining objects present in the vicinity of the moving body, said observation signal being an observation signal based on a reflected wave of an irradiated transmitted wave, wherein, The signal processing device has the following features: The setting unit is configured to set an intensity threshold corresponding to the intensity distribution of the at least one periodically generated observation signal; The extraction unit is configured to extract at least one object peak from the intensity distribution, using a pre-set upper limit number as the upper limit, wherein the object peak is a peak larger than the intensity threshold. as well as The storage processing unit is configured to store the number of at least one object peak extracted by the extraction unit, i.e., the number of extracted peaks, in the storage unit. The setting unit sets the intensity threshold based on the number of extracted peaks for the previous intensity distribution stored in the storage unit, in order to suppress the situation where the number of peaks of at least one object for the new intensity distribution exceeds the upper limit. The signal processing device further includes a prediction unit that calculates a prediction number, which is a value obtained by predicting the number of extracted peaks in the intensity distribution (i.e., the current intensity distribution) for which the setting unit will set the intensity threshold. The prediction unit calculates the predicted number based on the number of extracted peaks in the intensity distribution generated before the current intensity distribution, which is stored in the storage unit. When the number of predictions calculated by the prediction unit is above a predetermined peak prediction threshold, compared with the case where the number of predictions is less than the peak prediction threshold, the setting unit sets the intensity threshold higher. The intensity distribution is the intensity distribution corresponding to the distance between the object and the moving body and the relative velocity between the object and the moving body. The prediction unit calculates the number of predictions based on the velocity change of the moving body.

2. The signal processing apparatus according to claim 1, wherein, The extraction unit sequentially extracts from the intensity distribution at least one object peak corresponding to a smaller relative velocity.

3. A signal processing apparatus mounted on a moving body, using at least one observation signal to perform processing for determining objects present in the vicinity of the moving body, said observation signal being an observation signal based on a reflected wave of an irradiated transmitted wave, wherein, The signal processing device has the following features: The setting unit is configured to set an intensity threshold corresponding to the intensity distribution of the at least one periodically generated observation signal; The extraction unit is configured to extract at least one object peak from the intensity distribution, using a pre-set upper limit number as the upper limit, wherein the object peak is a peak larger than the intensity threshold. as well as The storage processing unit is configured to store the number of at least one object peak extracted by the extraction unit, i.e., the number of extracted peaks, in the storage unit. The setting unit sets the intensity threshold based on the number of extracted peaks for the previous intensity distribution stored in the storage unit, in order to suppress the situation where the number of peaks of at least one object for the new intensity distribution exceeds the upper limit. The intensity distribution is the intensity distribution corresponding to the distance between the object and the moving body and the relative velocity between the object and the moving body. The extraction unit sequentially extracts from the intensity distribution at least one object peak corresponding to a smaller relative velocity.

4. The signal processing apparatus according to claim 3, wherein, The setting unit sets the intensity threshold based on the number of extracted peaks in the intensity distribution immediately preceding the current intensity distribution, which is stored in the storage unit. The current intensity distribution is the intensity distribution for which the intensity threshold is to be set. When the number of extracted peaks immediately preceding a given peak count is above a predetermined peak count threshold, the intensity threshold is set higher when compared to the case where the number of extracted peaks immediately preceding a given peak count is below the peak count threshold.

5. The signal processing apparatus according to claim 3, wherein, The signal processing device further includes a prediction unit that calculates a prediction number, which is a value obtained by predicting the number of extracted peaks in the intensity distribution (i.e., the current intensity distribution) for which the setting unit will set the intensity threshold. The prediction unit calculates the predicted number based on the number of extracted peaks in the intensity distribution generated before the current intensity distribution, which is stored in the storage unit. When the number of predictions calculated by the prediction unit is above a predetermined peak prediction threshold, the setting unit sets the intensity threshold higher compared to the case where the number of predictions is less than the peak prediction threshold.

6. The signal processing apparatus according to any one of claims 1 to 5, wherein, The intensity distribution is the intensity distribution corresponding to the relative velocity between the object and the moving body. The intensity distribution has multiple relative velocity ranges, and the relative velocity corresponding to the peak value is included in any of the relative velocity ranges. The setting unit sets the intensity threshold corresponding to each of the relative velocity ranges in the intensity distribution. The extraction unit uses a pre-set upper limit for the number of peaks in each relative speed range as the upper limit, and extracts the peak values ​​in each relative speed range that are larger than the intensity threshold corresponding to that relative speed range as the at least one object peak value. The setting unit sets the intensity threshold to suppress the situation where the number of at least one object peaks extracted by the extraction unit for each of the relative speed ranges exceeds the upper limit number.

7. A signal processing apparatus mounted on a moving body, using at least one observation signal to perform processing for determining objects present in the vicinity of the moving body, said observation signal being an observation signal based on a reflected wave of an irradiated transmitted wave, wherein, The signal processing device has the following features: The setting unit is configured to set an intensity threshold corresponding to the intensity distribution of the at least one periodically generated observation signal; The extraction unit is configured to extract at least one object peak from the intensity distribution, using a pre-set upper limit number as the upper limit, wherein the object peak is a peak larger than the intensity threshold. as well as The storage processing unit is configured to store the number of at least one object peak extracted by the extraction unit, i.e., the number of extracted peaks, in the storage unit. The setting unit sets the intensity threshold based on the number of extracted peaks for the previous intensity distribution stored in the storage unit, in order to suppress the situation where the number of peaks of at least one object for the new intensity distribution exceeds the upper limit. The intensity distribution is the intensity distribution corresponding to the distance between the object and the moving body. The intensity distribution has multiple distance ranges, and the distance corresponding to the peak value is included in any of the distance ranges. The setting unit sets the intensity threshold corresponding to each of the distance ranges in the intensity distribution. The extraction unit will use a pre-set upper limit for the number of peaks in each distance range as the upper limit, and extract at least one object peak from the peaks contained in each distance range that are larger than the intensity threshold corresponding to that distance range. The setting unit sets the intensity threshold to suppress the situation where the number of at least one object peaks extracted by the extraction unit for each distance range exceeds the upper limit number.

8. The signal processing apparatus according to claim 7, wherein, The extraction unit sequentially extracts from the intensity distribution at least one object peak corresponding to the shorter distance.

9. A signal processing apparatus mounted on a moving body, using at least one observation signal to perform processing for determining objects present in the vicinity of the moving body, the observation signal being an observation signal based on a reflected wave of an irradiated transmitted wave, wherein, The signal processing device has the following features: The setting unit is configured to set an intensity threshold corresponding to the intensity distribution of the at least one periodically generated observation signal; The extraction unit is configured to extract at least one object peak from the intensity distribution, using a pre-set upper limit number as the upper limit, wherein the object peak is a peak larger than the intensity threshold. as well as The storage processing unit is configured to store the number of at least one object peak extracted by the extraction unit, i.e., the number of extracted peaks, in the storage unit. The setting unit sets the intensity threshold based on the number of extracted peaks for the previous intensity distribution stored in the storage unit, in order to suppress the situation where the number of peaks of at least one object for the new intensity distribution exceeds the upper limit. The intensity distribution is the intensity distribution corresponding to the distance between the object and the moving body and the relative velocity between the object and the moving body. The intensity distribution has multiple relative velocity ranges, and the relative velocity corresponding to the peak value is included in any of the relative velocity ranges. The setting unit sets the intensity threshold corresponding to each of the relative velocity ranges in the intensity distribution. The extraction unit uses a pre-set upper limit for the number of peaks in each relative speed range as the upper limit, and extracts the peak values ​​in each relative speed range that are larger than the intensity threshold corresponding to that relative speed range as the at least one object peak value. The setting unit sets the intensity threshold to suppress the situation where the number of at least one object peaks extracted by the extraction unit for each of the relative speed ranges exceeds the upper limit number.

10. The signal processing apparatus according to any one of claims 7 to 9, wherein, The setting unit sets the intensity threshold based on the number of extracted peaks in the intensity distribution immediately preceding the current intensity distribution, which is stored in the storage unit. The current intensity distribution is the intensity distribution for which the intensity threshold is to be set. When the number of extracted peaks immediately preceding a given peak count is above a predetermined peak count threshold, the intensity threshold is set higher when compared to the case where the number of extracted peaks immediately preceding a given peak count is below the peak count threshold.

11. The signal processing apparatus according to any one of claims 7 to 9, wherein, The signal processing device further includes a prediction unit that calculates a prediction number, which is a value obtained by predicting the number of extracted peaks in the intensity distribution (i.e., the current intensity distribution) for which the setting unit will set the intensity threshold. The prediction unit calculates the predicted number based on the number of extracted peaks in the intensity distribution generated before the current intensity distribution, which is stored in the storage unit. When the number of predictions calculated by the prediction unit is above a predetermined peak prediction threshold, the setting unit sets the intensity threshold higher compared to the case where the number of predictions is less than the peak prediction threshold.

12. A signal processing apparatus mounted on a moving body, using at least one observation signal to perform processing for determining objects present in the vicinity of the moving body, the observation signal being an observation signal based on a reflected wave of an irradiated transmitted wave, wherein, The signal processing device has the following features: The setting unit is configured to set an intensity threshold corresponding to the intensity distribution of the at least one periodically generated observation signal; The extraction unit is configured to extract at least one object peak from the intensity distribution, using a pre-set upper limit number as the upper limit, wherein the object peak is a peak larger than the intensity threshold. as well as The storage processing unit is configured to store the number of at least one object peak extracted by the extraction unit, i.e., the number of extracted peaks, in the storage unit. The setting unit sets the intensity threshold based on the number of extracted peaks for the previous intensity distribution stored in the storage unit, in order to suppress the situation where the number of peaks of at least one object for the new intensity distribution exceeds the upper limit. The setting unit sets the intensity threshold based on the number of extracted peaks in the intensity distribution immediately preceding the current intensity distribution, which is stored in the storage unit. The current intensity distribution is the intensity distribution for which the intensity threshold is to be set. If the number of preceding extracted peaks is above a predetermined peak count threshold, the intensity threshold is set higher if the number of preceding extracted peaks is less than the threshold. The threshold for the number of peaks is a value smaller than the upper limit.

13. A signal processing apparatus mounted on a moving body, using at least one observation signal to perform processing for determining objects present in the vicinity of the moving body, the observation signal being an observation signal based on a reflected wave of an irradiated transmitted wave, wherein, The signal processing device has the following features: The setting unit is configured to set an intensity threshold corresponding to the intensity distribution of the at least one periodically generated observation signal; The extraction unit is configured to extract at least one object peak from the intensity distribution, using a pre-set upper limit number as the upper limit, wherein the object peak is a peak larger than the intensity threshold. as well as The storage processing unit is configured to store the number of at least one object peak extracted by the extraction unit, i.e., the number of extracted peaks, in the storage unit. The setting unit sets the intensity threshold based on the number of extracted peaks for the previous intensity distribution stored in the storage unit, in order to suppress the situation where the number of peaks of at least one object for the new intensity distribution exceeds the upper limit. The signal processing device further includes a prediction unit that calculates a prediction number, which is a value obtained by predicting the number of extracted peaks in the intensity distribution (i.e., the current intensity distribution) for which the setting unit will set the intensity threshold. The prediction unit calculates the predicted number based on the number of extracted peaks in the intensity distribution generated before the current intensity distribution, which is stored in the storage unit. When the number of predictions calculated by the prediction unit is above a predetermined peak prediction threshold, compared with the case where the number of predictions is less than the peak prediction threshold, the setting unit sets the intensity threshold higher. The peak prediction threshold is a value smaller than the upper limit number.

Images