Vehicle counting device and vehicle counting method
View Patent ↗A vehicle counting device including: a frequency analysis unit that analyzes a frequency of a surrounding sound detected by a vehicle sound detection microphone; a vehicle sound candidate selection unit that selects, as one or more vehicle sound candidates, one or more sounds included in the surrounding sound, based on the analysis by the frequency analysis unit, each of the one or more sounds being in a frequency band where a sound pressure is greater than or equal to a predetermined threshold value; a phase curve calculation unit that calculates, for each of the one or more vehicle sound candidates, a phase curve; and a vehicle count determination unit that classifies the one or more phase curves into at least one group, based on shapes of the one or more phase curves, and determines a total number of the at least one group as the number of the nearby vehicles.
1. A vehicle navigation system for use in a first vehicle, said vehicle navigation system comprising:
a processor; and
a memory storing instructions that, when executed by the processor, cause the navigation system to:
analyze a frequency of a surrounding sound that includes one or more vehicle sounds and is detected by a vehicle sound detection microphone;
select, as one or more vehicle sound candidates, one or more sounds included in the surrounding sound, based on a result of the analysis of the surrounding sound, each of the one or more sounds being in a frequency band where a sound pressure is greater than or equal to a predetermined threshold value;
calculate, for each of the selected one or more vehicle sound candidates, a phase curve indicating a time dependency of a phase;
classify the calculated one or more phase curves into at least one group, based on shapes of the calculated one or more phase curves, and determine a total number of the at least one group as the number of the vehicles approaching the first vehicle; and
notify a driver of the first vehicle of the determined number of the vehicles approaching the first vehicle.
2. The vehicle navigation system according to claim 1 ,
wherein, for each of the selected one or more vehicle sound candidates, a quadratic approximate curve is calculated as the phase curve, based on a phase of a signal in each of time periods, the signal indicating the vehicle sound candidate.
3. The vehicle navigation system according to claim 2 ,
wherein the calculated one or more phase curves are classified into the at least one group, based on a degree of similarity among quadratic coefficients of the one or more calculated quadratic approximate curves.
4. The vehicle navigation system according to claim 1 , wherein the instructions, when executed by the processor, further cause the navigation system to:
calculate an error between a phase resulting from the analysis of the frequency of the surrounding sound and a phase on the calculated phase curve, and extract, from regions resulting from the analysis of the frequency of the surrounding sound, a region corresponding to a vehicle sound, based on the calculated error, and
determine the number of the vehicles approaching the first vehicle, using a phase curve in the extracted region corresponding to the vehicle sound.
5. The vehicle navigation system according to claim 1 ,
wherein the driver of the first vehicle is notified of the determined number of the vehicles approaching the first vehicle in different modes depending on whether the determined number of the vehicles approaching the first vehicle is one or plural.
6. The vehicle navigation system according to claim 1 ,
wherein the driver of the first vehicle is notified of the determined number of the vehicles approaching the first vehicle by sound.
7. A computer-implemented approaching vehicle detection method for use by a vehicle navigation system, the approaching vehicle detecting method determining the number of vehicles approaching a first vehicle, using one or more vehicle sounds, the approaching vehicle detection method comprising:
analyzing, using a processor of the vehicle navigation system, a frequency of a surrounding sound including the one or more vehicle sounds, the surrounding sound being detected by a vehicle sound detection microphone;
selecting, using the processor of the vehicle navigation system, as one or more vehicle sound candidates, one or more sounds included in the surrounding sound, based on a result of the analysis in the analyzing, each of the one or more sounds being in a frequency band where a sound pressure is greater than or equal to a predetermined threshold value;
calculating, using the processor of the vehicle navigation system, for each of the selected one or more vehicle sound candidates, a phase curve indicating a time dependency of a phase;
classifying, using the processor of the vehicle navigation system, the calculated one or more phase curves into at least one group based on shapes of the calculated one or more phase curves, and determining a total number of the at least one group as the number of the vehicles approaching the first vehicle; and
notifying, using the processor of the vehicle navigation system, a driver of the first vehicle of the determined number of the vehicles approaching the first vehicle.
8. A non-transitory computer-readable recording medium for use in a computer, the recording medium having a computer program recorded thereon for causing the computer to execute the approaching vehicle detection method according to claim 7 .