Step width measurement device, measurement system, step width measurement method, and program

Abstract

A step width measurement device includes a distance calculation unit that calculates a distance between both feet of a user by using propagation data related to transmission/reception times of ultrasonic waves transmitted/received by ultrasonic transmission/reception devices mounted on each of the both feet of the user, a height calculation unit that calculates a height of a sensor by using sensor data including a spatial acceleration and a spatial angular velocity measured by sensors mounted on each of the both feet of the user, and a step width calculation unit that calculates a step width of the user by using the distance between the both feet measured at the same timing and the height of the sensor.

1 . A step width measurement device, comprising:
 at least one memory storing instructions; and   at least one processor connected to the at least one memory and configured to execute the instructions to:   calculate a distance between both feet of a user by using propagation data related to transmission/reception times of ultrasonic waves transmitted/received by ultrasonic transmission/reception devices mounted on each of the both feet of the user;   calculate a height of a sensor by using sensor data including a spatial acceleration and a spatial angular velocity measured by sensors mounted on each of the both feet of the user; and   calculate a step width of the user by using the distance between the both feet measured at the same timing and the height of the sensor.   
     
     
         2 . The step width measurement device according to  claim 1 , wherein
 the at least one processor is configured to execute the instructions to   calculate the distance between the both feet associated with a transmission time by using the transmission time of the ultrasonic wave transmitted from the ultrasonic transmitter included in the ultrasonic transmission/reception device mounted on a first foot and a reception time of a reflected wave of the transmitted ultrasonic wave received by an ultrasonic receiver included in the ultrasonic transmission/reception device mounted on the first foot, and   calculate the step width of the user by using the distance between the both feet associated with the transmission time and the height of the sensor calculated based on the sensor data measured at the transmission time by the sensor mounted on a second foot.   
     
     
         3 . The step width measurement device according to  claim 1 , wherein
 the at least one processor is configured to execute the instructions to   calculate the distance between the both feet associated with a reception time by using the transmission time of the ultrasonic wave transmitted from the ultrasonic transmitter included in the ultrasonic transmission/reception device mounted on a first foot and a reception time of a reflected wave of the transmitted ultrasonic wave received by an ultrasonic receiver included in the ultrasonic transmission/reception device mounted on a second foot, and   calculate the step width of the user by using the distance between the both feet associated with the reception time and the height of the sensor calculated based on the sensor data measured at the reception time by the sensor mounted on the second foot.   
     
     
         4 . A measurement system, comprising:
 the step width measurement device according to  claim 1 ; and   data acquisition devices configured to be arranged at each of both feet of a user, measure a spatial acceleration and a spatial angular velocity according to walking of the user, generate sensor data based on the measured spatial acceleration and the spatial angular velocity, control ultrasonic transmission/reception devices mounted on each of the both feet of the user, generate propagation data related to a transmission/reception time of an ultrasonic wave transmitted/received by the ultrasonic transmission/reception device, and transmit the generated sensor data and the propagation data to the step width measurement device.   
     
     
         5 . The measurement system according to  claim 4 , wherein
 the step width measurement device includes   at least one memory storing instructions, and   at least one processor connected to the at least one memory and configured to execute the instructions to   detect a gait parameter in walking of the user based on the sensor data and control the data acquisition device according to a timing at which the gait parameter is detected.   
     
     
         6 . The measurement system according to  claim 5 , wherein
 the at least one processor is configured to execute the instructions to   detect a midstance stage based on time series data of a parameter related to the spatial acceleration or the spatial angular velocity included in the sensor data generated by the data acquisition device, and   control the data acquisition device to transmit the ultrasonic wave from the ultrasonic transmission/reception device mounted on a foot in which the midstance stage is detected.   
     
     
         7 . The measurement system according to  claim 5 , wherein
 the at least one processor is configured to execute the instructions to   transmit the ultrasonic waves from the ultrasonic transmission/reception devices mounted on the both feet of the user, and   control the data acquisition device in such a way that a timing at which the ultrasonic wave is transmitted from the ultrasonic transmission/reception device mounted on one foot approaches a timing at which the ultrasonic wave is transmitted from the ultrasonic transmission/reception device mounted on the other foot, to thereby synchronize the times of the data acquisition devices mounted on the both feet of the user.   
     
     
         8 . The measurement system according to  claim 4 , further comprising ultrasonic transmission/reception devices configured to be mounted on each of the both feet of the user and arranged in such a way that a transmission/reception direction of the ultrasonic wave faces an inside of the foot. 
     
     
         9 . A step width measurement method executed by a computer, the method comprising:
 calculating a distance between both feet of a user by using propagation data related to transmission/reception times of ultrasonic waves transmitted/received by ultrasonic transmission/reception devices mounted on each of the both feet of the user;   calculating a height of a sensor by using sensor data including a spatial acceleration and a spatial angular velocity measured by sensors mounted on each of the both feet of the user; and   calculating a step width of the user by using the distance between the both feet measured at the same timing and the height of the sensor.   
     
     
         10 . A non-transitory recording medium recorded with a program causing a computer to perform the following processes:
 calculating a distance between both feet of a user by using propagation data related to transmission/reception times of ultrasonic waves transmitted/received by ultrasonic transmission/reception devices mounted on each of the both feet of the user;   calculating a height of a sensor by using sensor data including a spatial acceleration and a spatial angular velocity measured by sensors mounted on each of the both feet of the user; and   calculating a step width of the user by using the distance between the both feet measured at the same timing and the height of the sensor.