JP7426717B2 - Finder - Google Patents

Description

The present invention relates to a detector capable of receiving laser light emitted by a laser speed measuring device.

When a vehicle approaches a speed measuring device or receives radar waves from a speed measuring device, the detector notifies the vehicle of information directly or indirectly encouraging speed compliance. This detector uses an antenna to receive radar waves transmitted from a speed measuring device. The detector also has a function of detecting when the own vehicle position specified by GPS approaches a predetermined distance from the pre-registered position of the speed measuring device, and notifying information as a warning.

In recent years, speed measuring devices are increasingly non-radar, such as loop coil types and phototube types. In this trend toward non-radar technology, laser light-based speed measuring devices have been developed. Laser light speed measuring devices detect speed by scanning a predetermined range with laser light, irradiating a moving vehicle with laser light, and detecting the reflected laser light. There are fixed types that have a fixed installation location, and mobile types that are easy to install and remove. The laser beam is emitted continuously for a predetermined emission time at predetermined emission intervals.

Patent No. 6161429

Conventional detectors do not have the ability to detect laser light, so they cannot detect laser light-based speed measuring devices unless the installation location is known. Therefore, the development of detectors that can detect laser light is progressing, but since laser light has a characteristic of high directivity that radar waves do not have, there is a risk that the timing of notifying that it has received laser light may be delayed. was there.

That is, since radar waves are highly diffusive, the sensor can receive the radar waves even if the sensor of the detector is not located on the radiation axis of the radar waves. On the other hand, since laser light is highly directional, the sensor of the detector must be located on the optical axis of the laser light emitted by the speed measuring device, reducing the chances of receiving the laser light.

Therefore, if the vehicle is far from the speed measuring device, a situation occurs in which the first laser beam is successfully received, but the next laser beam is unsuccessfully received. Further, due to the presence of a shield between the vehicle and the speed measuring device, a situation occurs in which the first laser beam is successfully received, but the next laser beam is unsuccessfully received. There is an idea to issue a notification to encourage speed compliance when the first laser beam is received, but this would increase the number of false alarms.

The present invention was proposed in order to solve the problems of the prior art as described above, and its purpose is to quickly notify the reception of laser light emitted by a speed measuring device and to suppress false alarms. The purpose is to provide a detector.

In order to achieve the above object, the detector according to the present invention is a detector installed in a vehicle, which receives light in a wavelength band including the wavelength of laser light emitted by a speed measuring device, and an optical sensor that outputs a detection signal based on a light reception time and a light reception interval; a determination unit that determines whether a determination condition matches the detection signal based on the detection signal output by the optical sensor; a notification unit that notifies predetermined information when it is determined that the detection signal satisfies the determination condition, and the determination condition includes that the pulse interval of the detection signal is one times the transmission interval of the laser beam. A pulse interval condition that is an integral multiple of the pulse interval condition is included, and the determination unit determines the pulse interval condition.

The determination condition includes a first NOT condition in which the pulse interval of the detection signal is also an integral multiple including one time of a predetermined pulse interval different from the transmission interval of the laser beam, and the determination unit In addition to the conditions, the first NOT condition may be determined.

The determination condition includes a second NOT condition in which the pulse interval of the detection signal is an interval between the reception of the laser beam and the noise that appears immediately after the reception of the laser beam, and the determination unit is configured to determine the pulse interval of the detection signal. In addition to the conditions, the second NOT condition may be determined.

The determination condition includes an AND condition in which the pulse width of the detection signal falls within a predetermined range including the emission time of the laser beam, and the determination unit determines the AND condition in addition to the pulse interval condition. It's okay.

The determination unit includes a distance calculation unit that calculates a distance between the vehicle and the speed measurement device, and the determination unit changes the determination condition based on the distance calculated by the distance calculation unit, and the determination unit changes the determination condition based on the distance calculated by the distance calculation unit. is within a predetermined distance, the determination condition is that the pulse width of the detection signal falls within a predetermined range including the emission time of the laser beam, and the distance calculated by the distance calculation unit is a predetermined distance. If not, the determination condition may include an AND condition of the pulse interval condition and the pulse width condition.

The determination unit may include a condition fulfillment counter and determine whether the determination condition is satisfied two or more predetermined times.

The determination condition includes one or more AND conditions including the pulse width condition and a predetermined NOT condition, and the determination unit includes a condition fulfillment counter and determines whether the determination condition is satisfied two or more predetermined consecutive times. , when the light satisfies the predetermined NOT condition, the value of the condition fulfillment counter may be maintained.

The determination condition includes a first NOT condition that the pulse interval of the detection signal is also an integral multiple including one time of a predetermined pulse interval different from the transmission interval of the laser beam, and the pulse interval of the detection signal is The determination unit further includes a second NOT condition that is an interval between the reception of the laser beam and the noise that appears immediately after the reception of the laser beam, and the determination unit has a condition fulfillment counter, and the determination unit sets the determination condition to two or more predetermined conditions. It may be determined whether the condition is satisfied a consecutive number of times, and when the light corresponds to the first NOT condition or the second NOT condition, the value of the condition fulfillment counter may be maintained.

The optical sensor has an optical filter that limits the wavelength of light to a predetermined wavelength band, and the predetermined wavelength band includes the wavelength of light emitted on the road and along the road in addition to the laser light of the speed measuring device. It may be possible to do so.

According to the present invention, even if not all the laser beams can be continuously received, it is possible to issue a notification to encourage speed compliance, and since the notification is issued by receiving the laser beam two or more times, false alarms can also be suppressed.

FIG. 3 is a perspective view showing a surface of the detector facing outside the vehicle. FIG. 3 is a perspective view showing the surface of the detector facing into the vehicle interior. FIG. 2 is a block diagram showing the internal configuration of the detector. FIG. 2 is a block diagram showing the configuration of a control section of the detector. 3 is a flowchart showing a first example of operation of the optical signal determination section. FIG. 3 is a schematic diagram showing an effect based on a first operation example. It is a flowchart which shows the 2nd example of operation of an optical signal determination part. FIG. 7 is a schematic diagram showing an effect based on a second operation example. It is a flowchart which shows the 3rd example of operation of an optical signal determination part. FIG. 7 is a schematic diagram showing an effect based on a third example of operation. 3 is a first flowchart showing an example of a comprehensive operation of an optical signal determination section. 12 is a second flowchart illustrating a comprehensive operation example of the optical signal determining section. 12 is a third flowchart illustrating a comprehensive operation example of the optical signal determining section.

(composition)
A detector according to an embodiment of the present invention will be described in detail with reference to the drawings. The detector 1 is installed in vehicles such as automobiles, motorcycles, trucks, and buses. This detector 1 notifies the user of information that encourages speed compliance through direct or indirect content, triggered by an event that should encourage speed compliance. The detector 1 is typically installed on a dashboard, and is powered from the vehicle side via an OBD-II connector, cigarette lighter socket, or the like. The dashboard is an example of a place where radar waves and laser light emitted by the speed measuring device can be easily received and where information can be reported to the driver. Radar waves and laser light are collectively called electromagnetic waves.

Speed measuring devices include a radar type that emits radar waves, a non-radar type that has a loop coil or phototube, and a laser beam type that emits laser light.The radar type and laser beam type include fixed types and mobile types. There is. Events that should encourage speed compliance are when the vehicle arrives within a predetermined distance from a speed measuring device whose installation location is known, and when electromagnetic waves emitted by the speed measuring device are received. The information to be notified includes, for example, the presence of the speed measuring device, the type of the speed measuring device, the reception and type of electromagnetic waves emitted by the speed measuring device, a warning to comply with the speed, or a plurality of these.

As shown in FIGS. 1 and 2, the detector 1 includes a screen 14, a speaker 15, and a lamp 16 on the outer surface of a housing 10. The screen 14 is a liquid crystal display, an organic EL display, or the like, and is arranged on the front surface 12 of the detector 1, and displays notification information in a visually appealing format such as letters, pictures, and symbols. The speaker 15 outputs the notification information as voice. The lamp 16 notifies the notification information by emitting light in a regular manner such as color, blinking, lighting interval, etc. The front surface 12 is a surface that faces inside the vehicle and is visible to the driver, while the rear surface 11 is a surface that faces outside the vehicle through the windshield.

The back surface 11 of the detector 1 is a reception area 13. That is, as shown in FIG. 3, a radio wave sensor 2, a positioning signal receiving section 3, and an optical sensor 4 are housed inside the housing 10 and arranged on the back surface 11. The radio wave sensor 2 has an antenna and a demodulator of a superheterodyne type, etc., and receives and detects radar waves in the X-band and K-band wavelength bands irradiated by a radar-type speed measuring device. This radio wave sensor 2 outputs a detection signal when receiving radar waves from a speed measuring device. The positioning signal receiving unit 3 has an antenna, a demodulator, and a processor capable of receiving radio signals from positioning satellites, receives and demodulates positioning signals from GNSS (Global Navigation Satellite System), and determines the positioning signal based on the latitude and longitude of the current position. Calculate the own vehicle position.

The optical sensor 4 includes an optical filter 41, a light receiving element 42, and a converter 43, and outputs a detection signal when receiving light. The detection signal is a voltage signal having a pulse width that matches the light reception time, and is output at pulse intervals that match the light reception interval.

This optical filter 41 is desirably made of a material that allows light to easily pass through even from an angle, and is made of, for example, acrylic resin. As a result, by installing the speed measuring device along the road, even if the filter surface of the optical filter 41 is oblique to the optical axis of the laser beam emitted by the speed measuring device, reception leakage can be prevented. It can be suppressed. However, the optical filter 41 is not limited to acrylic resin, and a wide variety of known materials can be used.

Moreover, this optical filter 41 is a filter that transmits a wavelength band including the wavelength of the laser light irradiated by the speed measuring device. This wavelength band may include, for example, the wavelength of light emitted by VICS (registered trademark), the N system, an on-vehicle distance measurement sensor, and other facilities on the road or a running vehicle. For example, the wavelength band transmitted by the optical filter 41 may include light emitted by an electronic bulletin board mounted on a vehicle.

The light-receiving element 42 is a detector that responds by including a wavelength band that is transmitted by the optical filter 41, and passes current by receiving light. This light receiving element 42 is installed behind the optical filter 41 and receives the light transmitted through the optical filter 41. The light receiving element 42 is, for example, a phototransistor or a photodiode.

The converter 43 converts the current signal output by the light receiving element 42 into a voltage signal and outputs the voltage signal as a detection signal. This conversion unit 43 is configured to include, for example, an operational amplifier, and when it receives a current signal from the light receiving element 42, it falls from the reference voltage and outputs a Lo signal, and when the current signal from the light receiving element 42 is interrupted, it rises to the reference voltage. Return to That is, the optical sensor 4 lowers the voltage to the Lo level at a timing that coincides with the start of light reception, and maintains the voltage at the Lo level at a timing that coincides with the light reception time. The period during which this voltage is at Lo level is called a detection signal. However, the logic of the voltage levels including the reference voltage may be reversed.

As shown in FIG. 3, the detector 1 further includes a control section 5 and a notification section 6. The radio wave sensor 2, the positioning signal receiving section 3, and the optical sensor 4 input signals to the control section 5. The control unit 5 is a so-called computer that includes a processor such as a CPU, an FPGA, or a microcomputer, a storage for storing programs and data, and a work memory.

The control unit 5 determines whether the radio wave sensor 2 and the optical sensor 4 have received electromagnetic waves from the speed measuring device. In addition, the control unit 5 outputs a speed measuring device whose own vehicle position and installation location are known, which is output by the positioning signal receiving unit 3, and a position where a speed measuring device has been installed in the past (hereinafter collectively referred to as a registered speed measuring device). ) to determine the distance. Then, the control unit 5 causes the notification unit 6 to notify information according to the determination result. The notification unit 6 is a screen 14, a speaker 15, a lamp 16, or a plurality of these arranged on the outer surface of the housing 10.

As shown in FIG. 4, the control section 5 includes a radar wave processing section 51, a distance calculation section 52, a storage section 53, and a laser beam determination section 54, which are processed by a processor or the like. When the detection signal of the radio wave sensor 2 is input to the control unit 5, the radar wave processing unit 51 performs an interrupt process and causes the notification unit 6 to notify information encouraging speed compliance. In particular, it is desirable that the radar wave processing section 51 causes the notification section 6 to notify information that notifies the existence of a radar-type speed measuring device and the reception of radar waves emitted by the speed measuring device.

The storage unit 53 is configured by a storage included in the detector 1 or a portable storage medium such as an SD card, and stores the latitude and longitude of the registered speed measuring device. The distance calculation unit 52 calculates the distance between the own vehicle position output by the positioning signal reception unit 3 and the registered speed measuring device stored in the storage unit 53.

Furthermore, the distance calculation unit 52 has a threshold value in advance, and compares the calculation result with the threshold value. If the calculation result is less than or equal to the threshold value, that is, if the vehicle position is within a predetermined distance from the registered speed measuring device, the distance calculation unit 52 controls the notification unit 6 to notify information. In particular, it is desirable that the distance calculation unit 52 causes the notification unit 6 to notify information that notifies the existence and type of the registered speed measurement device, as well as the distance between the registered speed measurement device and the vehicle position.

When the detection signal of the optical sensor 4 is input to the control unit 5, the laser beam determination unit 54 performs an interrupt process and determines whether the optical sensor 4 has received the laser beam from the speed measuring device. The laser light determination unit 54 has a determination condition, determines whether the detection signal output by the optical sensor 4 matches the determination condition, and as a result determines whether laser light has been received.

When the detection signal output by the optical sensor 4 matches the determination condition, the laser light determination unit 54 controls the notification unit 6 to notify information. In particular, it is desirable that the laser light determination unit 54 causes the notification unit 6 to notify information that reports the presence of a laser-type speed measuring device and the reception of the laser beam irradiated by the speed measuring device.

(Example 1 of judgment of received light wave)
A first example of determination processing by the laser beam determination section 54 will be described based on FIG. 5. FIG. 5 is a flowchart showing a first example of operation of the laser light determining section 54. The laser light determination unit 54 changes the determination conditions according to the situation and suppresses the delay associated with the determination process, thereby quickly notifying that the laser light from the speed measuring device has been received.

That is, the laser light determination unit 54 determines whether the pulse width of the detection signal output by the optical sensor 4 is equal to or less than a predetermined pulse width A (step S01). The pulse width is obtained by sampling the voltage at a sampling rate based on, for example, a clock frequency, and obtaining the number of sampled Lo level voltages, or by converting the number into time. The predetermined pulse width A is stored in advance by the laser light determination section 54, and the laser light determination section 54 compares the obtained pulse width with the predetermined pulse width A.

This predetermined pulse width A is a threshold value for separating light from several other known light sources from the laser light from the speed measuring device. This predetermined pulse width A has a value that is greater than or equal to the transmission time during which the speed measuring device emits laser light at one time, and is less than the transmission time at which other light transmission sources such as the N system transmit light at one time. has the value of The range below the predetermined pulse width A includes the emission time of the laser beam of the speed measuring device. However, below the predetermined pulse width A, since the emission time is similar to that of the speed measuring device, the emission time of an unknown or known optical source that cannot be distinguished by the predetermined pulse width A is included.

If the pulse width of the detection signal is not less than the predetermined pulse width A (step S01, No), it is unlikely that the optical sensor 4 has received the laser beam from the speed measuring device, and the interrupt process ends. That is, the notification process (step S09) is not executed.

If the pulse width of the detection signal is equal to or less than the predetermined pulse width A (step S01, Yes), the laser light determination unit 54 determines whether the vehicle position is within distance B from the registered speed measuring device (step S02). The distance B is stored in advance by the laser beam determination section 54. The distance between the own vehicle position and the registered speed measuring device is calculated by the distance calculating section 52 upon receiving an interrupt from the positioning signal receiving section 3 or periodically, and the laser beam determining section 54 calculates the distance between the own vehicle position and the registered speed measuring device. , the calculation result of the distance calculation unit 52 and the distance B are compared in magnitude.

This distance B is the distance at which highly directional laser light can reach the vehicle. That is, if the optical sensor 4 is located within the distance B and outputs a detection signal with a predetermined pulse width A or less, the optical sensor 4 detects light from an unknown light source or laser light from a speed measuring device. It is more likely that the laser light from the speed measuring device was received, rather than the light from a known light source that emits light with a transmission time similar to .

Therefore, if the own vehicle position is within the distance B from the registered speed measuring device (Step S02, Yes), the laser beam determination section 54 controls the notification section 6 to notify information such as the reception of the laser beam ( Step S09).

In this manner, the laser light determination unit 54 performs notification processing using only the pulse width of the detection signal when the vehicle position is located at a known location where there is a high possibility of receiving the laser light from the speed measuring device. As a result, this detector 1 can make a notification at a quick timing by receiving only one pulse of light.

In addition, although a mode has been described in which it is determined whether the own vehicle position exists within distance B after receiving light having a pulse width that is less than or equal to a predetermined pulse width A, the laser beam determination unit 54 does not determine whether the distance calculation unit 52 Each time the calculation result is calculated, the calculation result is compared with the distance B, and if the optical sensor 4 receives light and the detection signal is equal to or less than the pulse width A, the notification process may be performed immediately. In this case, since distance determination after receiving light is omitted, notification can be made at a more rapid timing.

Here, if the own vehicle position is not within the distance B from the registered speed measuring device (step S02, No), high reliability cannot be obtained with only the pulse width A, so the laser beam determination unit 54 determines other conditions. Based on the added determination condition, it is determined whether the laser light is from a speed measuring device (step S03~). That is, the determination condition is changed depending on whether the vehicle position is within distance B from the registered speed measuring device.

If the own vehicle position is not within distance B from the registered speed measuring device (step S02, No), the laser beam determination unit 54 determines whether the condition fulfillment counter is zero (step S03). Furthermore, even if the condition fulfillment counter is not zero (step S03, No), it is determined whether the pulse interval of the detection signal is equal to or greater than a predetermined pulse interval C (step S04). The condition fulfillment counter is stored in the laser beam determining section 54 as a changeable variable, and the predetermined pulse interval C is stored in advance in the laser beam determining section 54.

The pulse interval is the time from the end of the previous detection signal, that is, the timing when the voltage rises to Hi level, to the end of the latest detection signal. The pulse interval is obtained by sampling the voltage at a sampling rate based on, for example, a clock frequency, and obtaining the number of sampled Hi-level voltages, or by converting the number into time.

The condition fulfillment counter is the number of consecutive times of light reception that satisfies the determination condition. When the condition fulfillment counter is zero, it means that light having a pulse width equal to or less than the predetermined pulse width A is received for the first time. That is, it means that the first pulse satisfying the conditions of the laser light of the speed measuring device has been received. In addition, the predetermined pulse interval C is too long compared to the interval at which the laser beam of the speed measuring device can be received, even if failure to receive the highly directional laser beam is taken into consideration. This is an interval that can be regarded as the reception of the first pulse that satisfies the requirement.

If the condition fulfillment counter is zero (Step S03, Yes), and if the pulse interval is equal to or greater than the predetermined pulse interval C (Step S04, Yes), as the first light reception which may be the laser light of the speed measuring device, The laser beam determination unit 54 sets the condition fulfillment counter to "1" (step S05). Note that the initial value of the condition fulfillment counter is zero.

If the condition fulfillment counter is not zero (step S03, No) and the pulse interval is not equal to or greater than the predetermined pulse interval C (step S04, NO), it means that the first time that the laser light from the speed measuring device may have been received has been received. Show that. At this time, the laser beam determination unit 54 determines whether the pulse interval is an integral multiple of the predetermined pulse interval D (step S06). The predetermined pulse interval D is stored in advance by the laser light determining section 54.

The predetermined pulse interval D is the emission interval of the laser beam of the speed measuring device. Here, due to the high directivity of the laser beam, the optical sensor 4 may not be able to receive all of the laser beam, or the optical sensor 4 may not be able to receive all of the laser beam due to the fact that there is a blocking object such as a truck in front of the vehicle. 4 may not be able to receive all of the laser light. In particular, since the speed measuring device scans a predetermined range on the road, if the vehicle is far away from the speed measuring device, the timing at which the optical sensor 4 is present on the optical path of the laser beam will be reduced, and the light Timings at which the sensor 4 cannot receive light are likely to occur.

If there is a timing in which the optical sensor 4 cannot receive the light, and if it is determined that it is not a laser beam because it does not match the predetermined pulse interval D, the vehicle must approach the speed measuring device to a position where the laser beam can be reliably received. Otherwise, the notification will be delayed. However, the laser light determining unit 54 takes into account the existence of timings at which light cannot be received by comparing it with an integral multiple of the predetermined pulse interval D, thereby increasing the promptness of notification.

If the pulse interval is an integral multiple of the predetermined pulse interval D (step S06, Yes), the condition fulfillment counter is incremented by 1 (step S07). Note that the integral multiple of the predetermined pulse interval D includes one time. On the other hand, if the pulse interval is not an integral multiple of the predetermined pulse interval D (step S06, No), the possibility that the laser beam of the speed measuring device was received becomes low, and the condition fulfillment counter is initialized to zero (step S10). , the determination process ends. In this way, the increased condition fulfillment counter indicates the number of consecutive times that light that is likely to be the laser light of the speed measuring device has been received.

When the condition fulfillment counter is incremented by 1 (step S07), the laser light determination unit 54 determines whether the condition fulfillment counter has reached the threshold value N (step S08). The threshold value N is stored in advance by the laser light determination unit 54. The laser beam determination unit 54 compares the condition fulfillment counter with the threshold value N.

If the condition fulfillment counter has reached the threshold value N (step S08, Yes), the laser light determination unit 54 performs a notification process (step S09), and returns the condition fulfillment counter to the initial value of zero (step 10). ), the determination process ends. If the condition fulfillment counter has not reached the threshold value N (step S08, No), the determination process ends with the value of the condition fulfillment counter left as is.

FIG. 6 is a schematic diagram showing the operation of the laser beam determination section 54 based on the first operation example. It is assumed that the threshold value N of the condition fulfillment counter is 3. At this time, in the first light reception, if the pulse width is less than the predetermined pulse width A and the own vehicle position is within the distance B from the registered speed measuring device, the notification is quickly performed in the first light reception.

When the own vehicle position is not within distance B from the registered speed measuring device, the second light reception is less than the predetermined pulse width A and is 1 times the predetermined pulse interval D, so the condition fulfillment counter is set to 2. Make it. Even if the third light reception fails, the fourth light reception is less than the predetermined pulse width A, and the pulse interval is twice the predetermined pulse interval D based on the second light reception. , the condition fulfillment counter can be set to 3 on the fourth light reception. Then, since the condition fulfillment counter has reached 3, notification is performed.

Note that since the optical filter 41 easily transmits oblique light, the possibility of failure in receiving light is suppressed. Therefore, the comparison with an integer multiple of the predetermined pulse interval D, together with this optical filter 41, increases the possibility that even a highly directional laser beam can be notified more quickly.

Here, the condition fulfillment counter only needs to be 2 or more, and if the condition fulfillment counter is 2, notification can be made at the second light reception. In order to ensure high reliability, when the condition fulfillment counter is set to 2, another AND condition that can be determined for the second light reception may be added.

Further, even after the second light reception, only the condition of the predetermined pulse width A or less may be determined. However, by including the pulse interval, which is different from the pulse width, in the conditions, it is possible to further reduce the possibility of false alarms caused by other optical sources with similar pulse widths.

In this way, if the vehicle position is not within the distance B from the registered speed measuring device, the laser light determination unit 54 changes the determination condition so that the detection signal with a predetermined pulse width A or less is an integral multiple of the predetermined pulse interval D. By obtaining the laser beam N times in succession at intervals of Furthermore, by comparing an integral multiple of the predetermined pulse interval D with the pulse interval of the detection signal output by the optical sensor 4, the laser light determination unit 54 can detect the laser beam without approaching the speed measuring device to a distance where the light can be reliably received. Furthermore, even if a blocking object is temporarily present, the reception of the laser beam from the speed measuring device is notified.

(Example 2 of judgment of received light wave)
A second example of the determination process of the laser beam determination section 54 will be described based on FIG. 7. FIG. 7 is a flowchart showing a second example of the operation of the laser light determination section 54. For example, in order to more quickly notify the laser beam irradiation from the speed measuring device by comparing it with an integral multiple of the predetermined pulse width D, the laser beam determination unit 54 incorporates measures against false alarms. However, this laser beam determination unit 54 does not initialize the value of the condition fulfillment counter to zero for a predetermined condition, but maintains the value, thereby achieving both countermeasures against false alarms and promptness of notification. I'm trying.

That is, the laser light determination unit 54 determines whether the pulse width of the detection signal output by the optical sensor 4 is equal to or less than the predetermined pulse width A (step S21). The predetermined pulse width A has a value greater than or equal to the pulse width of the laser beam of the speed measuring device, and has a value less than the pulse width of the light emitted by another light source such as the N system. If the pulse width of the detection signal is not less than the predetermined pulse width A (step S21, No), the interrupt process ends. That is, the notification process (step S31) is not executed.

If the pulse width of the detection signal is equal to or less than the predetermined pulse width A (Step S21, Yes), the laser light determining unit 54 determines whether the vehicle position is within distance B from the registered speed measuring device (Step S22). The distance B is the distance at which highly directional laser light can reach the vehicle. If the own vehicle position is within the distance B from the registered speed measuring device (Step S22, Yes), the laser light determination unit 54 controls the notification unit 6 to notify information such as the reception of laser light (Step S31). ).

If the own vehicle position is not within the distance B from the registered speed measuring device (step S22, No), the laser light determination unit 54 determines whether the condition fulfillment counter is zero (step S23). If the condition fulfillment counter is not zero (step S23, No), it is determined whether the pulse interval of the detection signal is equal to or greater than a predetermined pulse interval C (step S24). The condition fulfillment counter is the number of consecutive times the laser beam of the speed measuring device receives light that satisfies the conditions. The predetermined pulse interval C is too long compared to the interval at which the laser beam of the speed measuring device can be received, and is therefore an interval that can be regarded as the reception of the first pulse that satisfies the conditions for the laser beam of the speed measuring device.

If the condition fulfillment counter is zero (step S23, Yes), or if the pulse interval is equal to or greater than the predetermined pulse interval C (step S24, Yes), the laser beam determination unit 54 sets the condition fulfillment counter to "1" ( Step S25).

If the condition fulfillment counter is not zero (step S23, No) and the pulse interval is not equal to or greater than the predetermined pulse interval C (step S24, NO), the laser beam determination unit 54 determines that the pulse interval is less than the predetermined pulse interval E. (Step S26). The predetermined pulse interval E is stored in advance by the laser light determination section 54. The laser light determination unit 54 compares the obtained pulse interval with the predetermined pulse interval E.

If the pulse interval of the detection signal is less than the predetermined pulse interval E (step S26, Yes), the process ends while maintaining the value of the condition fulfillment counter. That is, detection signals less than the predetermined pulse interval E are ignored.

Regarding pulse intervals less than the predetermined pulse interval E, it has been found that when a vehicle approaches the speed measuring device, noise may be introduced at intervals very close to the reception of laser light. Less than the predetermined pulse interval E is a threshold value for separating this noise, and is a NOT condition for determining whether the interval is between the reception of the laser beam and the noise. However, if the condition fulfillment counter is initialized to zero (step S32) due to the presence of noise, the notification will be delayed. Therefore, if the detection signals are very close, it is noise, and the laser light determination unit 54 does not increase the condition fulfillment counter as a countermeasure against false alarms, nor initializes it to zero, thereby reducing the speed of notification. The value of the condition fulfillment counter is maintained from the viewpoint.

If the pulse interval of the detection signal is not less than the predetermined pulse interval E (step S26, No), the laser beam determination unit 54 determines whether the pulse interval is an integral multiple of the predetermined pulse interval D (step S27). The predetermined pulse interval D is the pulse interval of the laser beam of the speed measuring device.

If the pulse interval is not an integral multiple of the predetermined pulse interval D (step S27, No), the condition fulfillment counter is initialized to zero (step S32), and the determination process ends. On the other hand, if the pulse interval is an integer multiple of the predetermined pulse interval D (step S27, Yes), the laser beam determination unit 54 further determines whether the pulse interval is an integer multiple of the predetermined pulse interval F (step S28). The predetermined pulse interval F is stored in advance by the laser light determination unit 54.

If the pulse interval of the detection signal is not an integral multiple of the predetermined pulse interval F (step S28, No), the condition fulfillment counter is incremented by 1 (step S29). On the other hand, if the pulse interval of the detection signal is an integral multiple of the predetermined pulse interval F (step S28, Yes), the process ends while maintaining the value of the condition fulfillment counter. That is, the detection signal is ignored if either the condition that the pulse interval is less than the predetermined pulse interval E or the condition that the pulse interval is an integer multiple of the predetermined pulse interval D or the predetermined pulse interval F is satisfied.

The integral multiple of the predetermined pulse interval F is the transmission interval of a light source different from the speed measuring device, such as the light emitted by the N system. Therefore, a pulse interval that is an integral multiple of the predetermined pulse interval D and an integral multiple of the predetermined pulse interval F raises doubts about the possibility of the laser beam of the speed measuring device. On the other hand, there is also a possibility that it is a laser beam from a speed measuring device. Therefore, the laser beam determination unit 54 prevents false alarms by not increasing the value of the condition fulfillment counter, and maintains the value of the condition fulfillment counter without initializing it to zero, thereby ensuring promptness of notification. There is.

When the condition fulfillment counter is incremented by 1 (step S29), the laser beam determination unit 54 determines whether the condition fulfillment counter has reached the threshold value N (step S30). If the condition fulfillment counter has reached the threshold value N (step S30, Yes), the laser light determination unit 54 performs a notification process (step S31), and returns the condition fulfillment counter to the initial value of zero (step S32). ), the determination process ends. When the condition fulfillment counter has not reached the threshold value N (step S30, No), the value of the condition fulfillment counter is left as is and the determination process is ended.

FIG. 8 is a schematic diagram showing the effect of the laser beam determining section 54 based on the second example of operation. It is assumed that the threshold value N of the condition fulfillment counter is 3. After the speed measuring device receives the first laser beam irradiated, a detection signal generated at less than the predetermined pulse interval E is noise. Therefore, the laser light determination section 54 ignores this detection signal. That is, the condition fulfillment counter is maintained at "1".

Since it is not an integral multiple of the predetermined pulse interval D, if the condition fulfillment counter is set to zero in response to this noise detection signal, the notification will be delayed by at least the predetermined pulse interval D. However, since a condition fulfillment counter is maintained for this noise detection signal, false alarms are suppressed and the promptness of alarms is maintained.

It is assumed that the third and fourth laser beams emitted by the speed measuring device cannot be received, but the fifth laser beam can be received. At this time, a detection signal is generated at a pulse interval three times the predetermined pulse interval D. However, the pulse interval that is three times the predetermined pulse interval D is equal to one time the predetermined pulse interval F. Then, there is a possibility that the second and fifth detection signals are based on light emitted by a light source other than the speed measuring device. Therefore, the laser light determination unit 54 ignores the detection signal based on the fifth laser light emitted by the speed measuring device. That is, the condition fulfillment counter is maintained at "2". Then, in the sixth time, the condition fulfillment counter can be set to 3, and since the condition fulfillment counter has reached 3, notification is performed.

In reality, there is no mistake in the fifth laser beam from the speed measuring device, and the notification is delayed by one tempo, but it is possible to prevent the notification from being sent to a light source other than the speed measuring device, and the condition fulfillment counter is As a result, false alarms are suppressed and a certain level of promptness of notifications is maintained.

In this way, if the pulse interval is an integral multiple of the predetermined pulse interval F and the pulse interval is less than the predetermined pulse interval E, the laser beam determination unit 54 determines whether the laser beam is from a speed measuring device or not. It does not determine that it is not light and ignores the detection signal. This achieves both countermeasures against false alarms and speedy notification.

(Example 3 of judgment of received light wave)
A third example of the determination process of the laser beam determination section 54 will be described based on FIG. 9. FIG. 9 is a flowchart showing a third example of the operation of the laser light determination section 54. Note that in this operational example, the determination as to whether or not the own vehicle position is within distance B from the registered speed measuring device is omitted, but this determination may be added or excluded.

For example, if the laser beam determining unit 54 cannot determine whether the laser beam is from a speed measuring device or not, the laser beam from the speed measuring device is being received, but the laser beam from another light source is also being received. If it is suspected that there is a noise or if it is noise, the value of the condition fulfillment counter is maintained, thereby achieving both false alarm suppression and promptness of notification. On the other hand, there are cases where there is a high possibility that the light is not the laser light of the speed measuring device. If there is a high possibility that the laser light is not from the speed measuring device, the laser light determination unit 54 prevents the condition fulfillment counter from increasing even if there is a received light that may be the laser light from the speed measuring device, and notifies the user. We are increasing the level of countermeasures against false alarms to the extent that they do not cause delays.

That is, the laser light determination unit 54 determines whether the detection signal outputted by the optical sensor 4 matches the condition that the detection signal is the laser light of the speed measuring device (step S41). These conditions include, for example, that the pulse width is less than or equal to the predetermined pulse width A, that the pulse interval is an integral multiple of the predetermined pulse interval D, that the pulse interval is greater than or equal to the predetermined pulse interval E, and that the pulse interval is the predetermined pulse interval F. is not an integral multiple of , or a combination of these.

The detection signal output by the optical sensor 4 does not match the laser beam conditions of the speed measuring device (step S41, No), and the reason for the mismatch is that the pulse interval is less than the predetermined pulse interval E (step S42, Yes); Or, if the reason for the discrepancy is that the pulse interval is an integral multiple of the predetermined pulse interval D, but also an integral multiple of the predetermined pulse interval E (step S43, Yes), the detection signal is ignored and the determination process ends. do. On the other hand, the conditions that are inconsistent are that the pulse interval is other than less than the predetermined pulse interval E (step S42, No), and that the pulse interval is an integral multiple of the predetermined pulse interval D, but at the same time is an integral multiple of the predetermined pulse interval E. If not (Step S43, No), the laser beam determination unit 54 sets an invalid period (Step S44) and resets a false alarm prevention counter (Step S45).

That is, for example, if the pulse width is not less than the predetermined pulse width A, or if the pulse interval is not an integral multiple of the predetermined pulse interval D, the laser beam determination unit 54 sets an invalid period (step S44) to prevent false alarms. The counter is reset (step S45), and the condition fulfillment counter is also reset to zero (step S46).

The invalid period is set when there is a possibility that light other than the speed measuring device's laser light may have been received, and the condition fulfillment counter will be increased with exceptions even if light that may be the speed measuring device's laser light is received. This is a period in which they are not allowed to do so. That is, the laser light determination unit 54 increases the level of false alarm suppression when there is a possibility that the vehicle has received light that is not a laser light from the speed measuring device. The false alarm prevention counter is counted up when receiving light that may be a laser beam from the speed measuring device during the invalid period, and adjusts the false alarm suppression level during the invalid period.

Then, if the detection signal outputted by the optical sensor 4 matches the laser beam conditions of the speed measuring device (Step S41, Yes), the laser light determination unit 54 determines whether it is an invalid period (Step S47). . If it is not an invalid period (step S47, No), the condition fulfillment counter is increased (step S50), and if the condition fulfillment counter has reached the threshold value N (step S51, Yes), a notification process is performed (step S52), The condition fulfillment counter is reset to zero (step S46), and the determination process is ended.

If it is the invalid period (Step S47, Yes), the laser light determination unit 54 increases the false alarm prevention counter by 1 (Step S48). The false alarm prevention counter is stored in the laser light determination unit 54 as a variable that can be changed. Note that, if the detection signal output by the optical sensor 4 does not match the laser beam conditions of the speed measuring device, the laser light determination unit 54 resets the false alarm prevention counter to zero.

After increasing the false alarm prevention counter, the laser light determination unit 54 determines whether the false alarm prevention counter has reached the threshold value M (step S49). The threshold value M is stored in advance by the laser light determination unit 54. The laser light determination unit 54 compares the false alarm prevention counter with the threshold value M.

If the false alarm prevention counter has reached the threshold M (step S49, Yes), the laser light determination unit 54 increases the condition fulfillment counter by 1 (step S50). However, if the false alarm prevention counter has not reached the threshold M (step S49, No), even if the detection signal output by the optical sensor 4 matches the laser beam conditions of the speed measuring device (step S41, Yes). , the determination process ends without changing the value of the condition fulfillment counter.

That is, during the invalid period, the laser beam determination unit 54 determines whether the detection signal output by the optical sensor 4 matches the condition of the laser beam of the speed measuring device or is invalid for the number of consecutive times the false alarm prevention counter reaches the threshold value M. The condition fulfillment counter is not counted up until the period ends. As a result, if there is a possibility that the vehicle may have received light other than the laser light from the speed measuring device, the level of false alarm suppression is increased.

FIG. 10 is a schematic diagram showing the effect of the laser beam determining section 54 based on the third example of operation. It is assumed that the threshold value N of the condition fulfillment counter is 3, and the threshold value M of the false alarm prevention counter is 2.

Since the first detection signal has a pulse width less than or equal to the predetermined pulse width A, the condition fulfillment counter increases to "1", and the second detection signal has a pulse width less than or equal to the predetermined pulse width A. Since the pulse interval is reached at one time the pulse interval D, the condition fulfillment counter increases to "2". However, since the third detection signal has a pulse width exceeding the predetermined pulse width A, the condition fulfillment counter is reset to zero. Further, since a third detection signal that does not match the conditions is generated, an invalid period is set and the false alarm prevention counter is reset to zero.

The fourth detection signal has a pulse width less than or equal to the predetermined pulse width A, and arrives at a pulse interval that is one time the predetermined pulse interval D. However, since it is in the invalid period, the condition fulfillment counter maintains its value and the false alarm prevention counter increases to "1". The fifth detection signal has a pulse width less than or equal to the predetermined pulse width A, but arrives at a pulse interval less than the predetermined pulse interval E. Therefore, the fifth detection signal is ignored, and neither the condition fulfillment counter nor the false alarm prevention counter changes. Note that even if the pulse interval is reached at an integral multiple of the predetermined pulse interval D, the detection signal is ignored, and neither the condition fulfillment counter nor the false alarm prevention counter changes.

The sixth detection signal has a pulse width less than or equal to the predetermined pulse width A, but arrives at a pulse interval that is not an integral multiple of the predetermined pulse interval D. Therefore, both the condition fulfillment counter and the false alarm prevention counter are reset to zero, and the invalid period is reset. The next seventh detection signal has a pulse width that is less than or equal to the predetermined pulse width A, and arrives at a pulse interval that is one time the predetermined pulse interval D. However, since it is in the invalid period, the condition fulfillment counter maintains its value and the false alarm prevention counter increases to "1".

The eighth detection signal has a pulse width that is less than or equal to the predetermined pulse width A, and arrives at a pulse interval that is one time the predetermined pulse interval D. Therefore, since it is in the invalid period, the false alarm prevention counter increases to "2". Here, since the false alarm prevention counter reached "2" during the invalid period, the condition fulfillment counter increases by 1 and the value becomes "1" in response to the 8th detection signal. Furthermore, the ninth detection signal has a pulse width that is less than or equal to the predetermined pulse width A, and arrives at a pulse interval that is one time the predetermined pulse interval D. Even if the false alarm prevention counter is increased, it is still greater than "2", so the condition fulfillment counter is increased by 1 and the value becomes "2".

The tenth detection signal has a pulse width that is less than or equal to the predetermined pulse width A, and arrives at a pulse interval that is one time the predetermined pulse interval D. Moreover, since the invalid period has ended, the condition fulfillment counter increases by 1 and becomes "3" regardless of the value of the false alarm prevention counter. Since the condition fulfillment counter has reached "3", the laser determination section 54 controls the notification section 6 and causes the notification section 6 to notify information that directly or indirectly urges compliance with the speed.

In this way, the laser light determination unit 54 sets an invalid period when there is a high possibility that the laser light is not the laser light of the speed measuring device. During the invalidation period, the laser light determination unit 54 does not increase the condition fulfillment counter unless it receives a predetermined number of consecutive lights that may be laser light from the speed measuring device. That is, when the laser light determination unit 54 receives light that is highly likely not to be the laser light of the speed measuring device, it increases the level of false alarm suppression.

(Example 4 of judgment of received light wave)
A typical example of operation that integrates the various determination processes described above will be explained based on FIGS. 11 to 13. 11 to 13 are flowcharts showing typical operation examples of the laser light determining section 54.

The laser light determination unit 54 determines whether the pulse width of the detection signal output by the optical sensor 4 is less than or equal to the predetermined pulse width A (FIG. 11: Step S61, Yes) and the own vehicle position is within distance B from the registered speed measuring device. (FIG. 11: Step S62, Yes), the notification unit 6 is controlled to notify information such as the reception of laser light (FIG. 12: Step S63). Further, the laser beam determination unit 54 initializes the invalid period to zero (FIG. 12: Step S64), initializes the condition fulfillment counter to "1" (Step S65), and ends the determination process.

If the pulse width of the detection signal is not equal to or less than the predetermined pulse width A (FIG. 11: Step S61, No), the laser beam determination unit 54 resets the false alarm prevention counter to zero (FIG. 13: Step S70) and sets the invalid period. settings (FIG. 13: Step S71).

The laser light determination unit 54 determines that although the pulse width of the detection signal output by the optical sensor 4 is less than or equal to the predetermined pulse width A (FIG. 11: Step S61, Yes), the vehicle position is not within distance B from the registered speed measuring device. (FIG. 11: Step S62, No), it is determined whether the pulse interval of the detection signal is equal to or greater than a predetermined pulse interval C (FIG. 11: Step S66). This includes the case where no detection signal is received beyond the predetermined pulse interval C and therefore the pulse interval cannot be calculated.

If the pulse interval of the detection signal is equal to or greater than the predetermined pulse interval C (FIG. 11: Step S66, Yes), the laser light determination unit 54 resets the false alarm prevention counter to zero (FIG. 12: Step S67), and sets the invalid period. The counter is initialized to zero (FIG. 12: Step S64), the condition fulfillment counter is initialized to "1" (Step S65), and the determination process ends.

If the pulse interval of the detection signal is not equal to or greater than the predetermined pulse interval C (FIG. 11: Step S66, No), the laser beam determination unit 54 determines whether the pulse interval of the detection signal is less than the predetermined pulse interval E (FIG. 11). : step S68). If the pulse interval of the detection signal is less than the predetermined pulse interval E (FIG. 11: Step S68, Yes), the laser light determination unit 54 ignores the detection signal and ends the determination (FIG. 12).

If the pulse interval of the detection signal is not less than the predetermined pulse interval E (FIG. 11: Step S68, No), the laser beam determination unit 54 determines whether the pulse interval of the detection signal is an integral multiple of D (FIG. 11: Step S69). If the pulse interval of the detection signal is not an integral multiple of D (FIG. 11: Step S69, No), the laser beam determination unit 54 resets the false alarm prevention counter to zero (FIG. 13: Step S70) and sets an invalid period. (FIG. 13: Step S71).

On the other hand, if the pulse interval of the detection signal is an integral multiple of D (FIG. 11: Step S69, Yes), the laser beam determination unit 54 determines whether the false alarm prevention counter is equal to or greater than the threshold M (FIG. 11: Step S72). ). If the false alarm prevention counter is not equal to or greater than the threshold value M (FIG. 11: Step S72, No), the laser light determination unit 54 determines whether the pulse interval of the detection signal is an integral multiple of the predetermined pulse interval F (FIG. 11: Step S72, No). S73).

If it is not an integer multiple of the predetermined pulse interval F (FIG. 11: Step S73, No), the laser light determination unit 54 increases the false alarm prevention counter by 1 (FIG. 11: Step S74), and sets the false alarm prevention counter and the threshold M again. Compare. If the false alarm prevention counter is equal to or greater than the threshold value M (FIG. 11: Step S75, Yes), the laser beam determination unit 54 increases the condition fulfillment counter by 1 (FIG. 11: Step S77).

On the other hand, even if the false alarm prevention counter is not equal to or greater than M (FIG. 11: Step S75, No), if it is not an invalid period (FIG. 11: Step S76, No), the laser beam determination unit 54 increases the condition fulfillment counter by 1. (FIG. 11: Step S77). However, if it is an invalid period (FIG. 11: Step S76, Yes), the invalid period is reset (FIG. 13: Step S71) and the condition fulfillment counter is set to "1" (FIG. 12: Step S65).

After incrementing the condition fulfillment counter by 1 (FIG. 11: Step S77), the laser beam determination unit 54 determines whether the condition fulfillment counter has reached the threshold value N (FIG. 12: Step S78), and the condition fulfillment counter reaches the threshold value N. If N has not been reached (FIG. 12: Step S78, No), the determination process ends. If the condition fulfillment counter has reached the threshold value N (FIG. 12: Step S78, Yes), the notification unit 6 is controlled to notify information such as the reception of laser light (FIG. 12: Step S63). Further, the laser beam determination unit 54 initializes the invalid period to zero (FIG. 12: Step S64), initializes the condition fulfillment counter to "1" (Step S65), and ends the determination process.

(effect)
As described above, the detector 1 includes the optical sensor 4, the laser light determination section 54, and the notification section 6. The optical sensor 4 receives light in a wavelength band including the wavelength of the laser light emitted by the speed measuring device, and outputs a detection signal based on the light reception time and light reception interval of the light. The laser light determination unit 54 determines whether the determination condition and the detection signal match based on the detection signal output by the optical sensor 4. The notification unit 6 notifies predetermined information when the laser light determination unit 54 determines that the detection signal satisfies the determination condition. Then, by comparing the pulse interval of the detection signal with an integer multiple of the predetermined pulse interval D, the laser beam determination unit 54 determines that the pulse interval of the detection signal is an integer including one times the transmission interval of the laser beam. The pulse interval condition is now included.

This increases the speed of notification even if not all laser beams can be received continuously due to failures in receiving light due to the highly directional nature of the laser beam or failures in receiving light due to obstructing objects. be able to. On the other hand, since notification is performed by receiving the laser beam twice or more, false notifications can also be suppressed.

Incidentally, the laser beam determination section 54 uses a predetermined pulse width A that defines a threshold value in a predetermined range including the emission time of the laser beam, regardless of whether the distance calculated by the distance calculation section 52 is within the predetermined distance B or not. The comparison between the pulse width of the detection signal and the pulse width of the detection signal may be omitted, and even in this case, there may be a failure in light reception due to the high directivity of the laser beam or a failure in light reception due to the presence of a blocking object. It is also possible to increase the speed of notification even in the case of failure.

However, in this detector 1, if the distance calculated by the distance calculation section 52 is within the predetermined distance B, the laser light determination section 54 compares the pulse width of the detection signal with the predetermined pulse width A. That is, if the distance calculated by the distance calculation unit 52 is within the predetermined distance B, the pulse width condition that the pulse width of the detection signal falls within a predetermined range including the emission time of the laser beam is determined as the determination condition.

Then, if the distance calculated by the distance calculating section 52 is not within the predetermined distance B, the laser light determining section 54 compares the pulse width and pulse interval of the detection signal with respect to the predetermined pulse width A and the predetermined pulse interval D. I made it. That is, if the distance calculated by the distance calculation unit 52 is not within the predetermined distance B, the determination conditions are that the pulse width of the detection signal is the emission time of the laser beam, and the pulse interval of the detection signal is the pulse width condition of the laser beam. The AND condition includes a pulse interval condition that is an integral multiple of the transmission interval. As a result, when the vehicle position is located at a known location where there is a high possibility of receiving the laser beam from the speed measuring device, the notification can be made quickly by receiving the laser beam only once.

Further, the determination condition includes a NOT condition in which the pulse interval of the detection signal is an integer multiple including one time of a predetermined pulse interval F that is different from the transmission interval of the laser beam, and the laser beam determination unit 54 This NOT condition is determined in addition to the pulse interval condition in which the interval is an integral multiple of the laser beam transmission interval. Thereby, it is possible to ensure promptness of notification regarding the laser beam speed measuring device and to suppress false alarms due to the presence of a light source different from the speed measuring device.

Further, the determination conditions include a NOT condition that the pulse interval of the detection signal is less than a predetermined pulse interval E, that is, a NOT condition that the pulse interval of the detection signal is the interval between the reception of the laser beam and the noise that appears immediately after the laser beam, and the laser beam determination unit 54, this NOT condition is also determined. Thereby, it is possible to suppress false alarms due to noise mixed in the detection signal while ensuring promptness of notification regarding the laser light type speed measuring device.

The laser light determination unit 54 has a condition fulfillment counter and determines whether the determination condition is satisfied two or more predetermined times. Thereby, it is possible to further suppress false alarms while ensuring promptness of alarms regarding the laser light type speed measuring device.

Further, the determination conditions include one or more AND conditions including a pulse interval condition in which the pulse interval of the detection signal is an integral multiple including one time the emission interval D of the laser beam, and a predetermined NOT condition, and the laser beam determination unit 54 has a condition fulfillment counter to determine whether the determination condition is satisfied two or more predetermined consecutive times. Then, when the detection signal output from the optical sensor 4 satisfies a predetermined NOT condition, the laser beam determination unit 54 maintains the value of the condition fulfillment counter. The predetermined NOT condition is a case where there is a doubt that the laser beam is being received, but there is still a good possibility that the laser beam is being received. It is possible to simultaneously suppress false alarms.

For example, one of the predetermined NOT conditions is that the pulse interval of the detection signal is an integral multiple of the predetermined pulse interval F, which is different from the emission interval of the laser beam, and includes one time. is the interval between the reception of the laser beam and the noise that appears immediately after the laser beam, which is another predetermined NOT condition.

As described above, the laser light determination unit 54 compares various pulse intervals such as the predetermined pulse intervals C, D, E, and F, but the detection signal output from the optical sensor 4 is strictly the comparison target. The pulse interval does not have to match the pulse interval of . That is, typically, the laser light determining unit 54 determines whether the detection signal output by the optical sensor 4 is within a predetermined pulse interval before or after various pulse intervals, or is above or beyond the range. Or, it may be determined whether it is below or below the range. That is, the fact that the pulse interval of the detection signal is an integral multiple including one time the pulse interval of the laser beam allows a predetermined error. The fact that the pulse interval of the detection signal is also an integral multiple including one time of a predetermined pulse interval different from the emission interval of the laser beam allows a predetermined error.

Further, the predetermined pulse interval E due to noise is a short pulse interval. Therefore, when a predetermined error is allowed in the comparison of pulse intervals, the pulse interval for the next light reception may be set at the end of the noise, or may be set at the end of the detection signal immediately before the noise. If the pulse interval of the detection signal is an integral multiple of a predetermined pulse interval F that is different from the emission interval of the laser beam, the end of the detection signal that meets this condition may be used as the starting point, or the end of the immediately preceding detection signal may be used as the starting point. It can also be used as a starting point.

Such a detector 1 is particularly useful when using an optical filter 41 that also transmits wavelengths of light emitted on the road. Generally, the narrower the wavelength band that can be transmitted by the optical filter 41, the more difficult it becomes to reduce the reflectance of obliquely incident light. However, since the optical filter 41 transmits a wide wavelength band, it is easy to reduce the reflectance from an oblique direction, and the probability that the light receiving element 42 receives the laser beam increases. Therefore, the promptness of notification is further improved. On the other hand, various countermeasures against false alarms by the laser light determining section 54 achieve both speedy notification and suppression of false alarms.

(Other embodiments)
Although the embodiments of the present invention have been described above, various omissions, substitutions, and changes can be made without departing from the gist of the invention. This embodiment and its modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

For example, the information to be notified may include information indicating how many times the pulse interval of the detection signal is compared to the transmission interval of the laser beam. That is, the pulse interval of the detection signal may be divided by the predetermined pulse interval D, and the integer part of the quotient may be reported. Considering that the farther the distance between your vehicle and the speed measuring device is, the more difficult it is to receive the laser beam, the distance between your vehicle and the speed measuring device and the integer part of this quotient are roughly proportional to each other. be. Therefore, this detector 1 can notify the approximate distance between the speed measuring device and the own vehicle. Note that the detector 1 may classify the integer part of the quotient into categories such as "laser strong" or "laser weak" and notify the classification.

1 Detector 10 Housing 11 Back side 12 Front side 13 Receiving area 14 Screen 15 Speaker 16 Lamp 2 Radio wave sensor 3 Positioning signal receiving section 4 Optical sensor 41 Optical filter 42 Light receiving element 43 Conversion section 5 Control section 51 Radar wave processing section 52 Distance calculation Section 53 Storage section 54 Laser light determination section 6 Notification section

Claims (2)

A detector installed in a vehicle,
A detection signal having a pulse width and a pulse interval based on the time when the speed measuring device can receive the light and the interval at which the light can be received for light in a wavelength band that includes the wavelength of the laser light irradiated by the speed measuring device at a predetermined transmission time and transmission interval. an optical sensor that outputs
a determination unit that determines whether the detection signal satisfies a determination condition based on the detection signal output by the optical sensor;
When the determination unit determines that the detection signal satisfies the determination condition, a notification unit that reports information according to a multiplier of the pulse interval of the detection signal with respect to the emission interval of the laser beam ;
to have
A detector featuring: The notification unit divides the magnification into categories and notifies information according to the category to which the magnification belongs;
The detector according to claim 1, characterized in that:

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