US-12622639-B2 - Measurement system, measurement method, measurement device, and program

US12622639B2US 12622639 B2US12622639 B2US 12622639B2US-12622639-B2

Abstract

A measurement system includes a measurement unit configured to perform measurement a plurality of times on the basis of a first clock signal having a first clock period to obtain a plurality of measurement results, a time stamp provision unit configured to provide a time stamp indicating a measurement time to each measurement result obtained in the second period among the plurality of measurement results obtained using the measurement unit the basis of a second clock signal having a second clock period longer than the first clock period and having better period accuracy than the first clock signal, and a measurement time correction unit configured to correct a measurement time of a measurement result in accordance with a period specified using two time stamps and the number of measurement results obtained during the period.

Inventors

Kei KUWABARA
Kenichi Matsunaga
Takayuki Ogasawara

Assignees

NTT, INC.

Dates

Publication Date: 20260512
Application Date: 20201208

Claims (11)

1 . A measurement system, comprising: one or more processors; one or more storage devices storing one or more programs for execution by the one or more processors; a first oscillator configured to oscillate a first clock signal having a first clock period; a second oscillator configured to oscillate a second clock signal having a second clock period longer than the first clock period and with higher period accuracy than the first clock period; a measurement device executing on at least one of the one or more processors and configured to perform measurement a plurality of times to obtain a plurality of measurement results, the measurement device configured to operate on a first basis of the first clock signal having the first clock period; a time stamp provision circuit executing on at least one of the one or more processors and configured to provide a time stamp indicating a measurement time to each of two or more of the plurality of measurement results obtained through the measurement device, the time stamp provision circuit configured to provide the time stamp to each of two or more of the plurality of measurement results on a second basis of the second clock signal having the second clock period; and a measurement time correction circuit executing on at least one of the one or more processors and configured to correct a measurement time of a measurement result other than the measurement result to which the time stamp is provided to obtain a corrected measurement result, the corrected measurement result being among the measurement results obtained during a period specified using two time stamps of the time stamps provided to each of the two or more of the plurality of measurement results.
2 . The measurement system according to claim 1 , wherein: the plurality of measurement results obtained using the measurement device includes a plurality of measurement result sequences, one measurement result sequence being N measurement results obtained through consecutive N measurements, the time stamp provision circuit is further configured to add the time stamp to a first measurement result of each of the plurality of measurement result sequences, and the measurement time correction circuit is further configured to: specify a measurement period in which the N measurement results of the measurement result sequence are obtained using a difference between the two time stamps; delete a measurement result from or add a new measurement result to a measurement result sequence in accordance with a length of the specified measurement period; and bring a first number of measurement results of the measurement result sequence closer to a second number of measurement results obtained in the measurement period when the first clock signal does not have a periodic error to correct the measurement time.
3 . The measurement system according to claim 2 , wherein each of the plurality of measurement results includes a first type of measurement result and a second type of measurement result different from the first type, and the measurement time correction circuit is configured so that the result of the first type of measurement is not deleted when deleting the measurement result.
4 . The measurement system according to claim 2 , wherein the measurement time correction circuit is configured to, when a period of the measurement based on the first clock signal when there is no periodic error is T cycle and the measurement period is T term , delete |M| measurement results from the measurement result sequence when M obtained by the following Expression (A) is negative and add M new measurement results to the measurement result sequence when the M is positive: M =int( T term /T cycle )− N ( A ) where, int(T term /T cycle ) is an integer conversion operation of a value obtained through T term /T cycle .
5 . The measurement system according to claim 2 , wherein the measurement result includes a time interval measured on the first basis of the first clock signal, and the measurement system further includes a measurement result correction circuit executing on at least one of the one or more processors and configured to correct the time interval by multiplying the time interval by a correction coefficient C calculated by the following Expression (B): C=T term /( T cycle ×N ) ( B ) when T cycle is a cycle of the measurement based on the first clock signal when there is no periodic error, and T term is the measurement period in the measurement system.
6 . A measurement method, comprising: performing measurement a plurality of times on a first basis of a first clock signal having a first clock period to obtain a plurality of measurement results, wherein the first clock signal having the first clock period is oscillated by a first oscillator; providing a time stamp indicating a measurement time to each of two or more of the plurality of measurement results obtained through performing the measurement on a second basis of a second clock signal having a second clock period, wherein: the second clock signal having the second clock period is oscillated by a second oscillator, and the second clock period is longer than the first clock period and has higher accuracy than the first clock period; and correcting a measurement time of a measurement result other than the measurement result to which the time stamp is provided among the measurement results obtained during a period specified using two time stamps of the time stamps provided to each of the two or more of the plurality of measurement results.
7 . The measurement method of claim 6 , wherein: the plurality of measurement results are obtained using a measurement device, the plurality of measurement results obtained using the measurement device includes a plurality of measurement result sequences, one measurement result sequence being N measurement results obtained through consecutive N measurements, and the measurement method further comprises: adding the time stamp to a first measurement result of each of the plurality of measurement result sequences, specifying a measurement period in which the N measurement results of the measurement result sequence are obtained using a difference between the two time stamps, deleting a measurement result from or add a new measurement result to a measurement result sequence in accordance with a length of the specified measurement period, and bringing a first number of measurement results of the measurement result sequence closer to a second number of measurement results obtained in the measurement period when the first clock signal does not have a periodic error to correct the measurement time.
8 . The measurement method of claim 7 , wherein each of the plurality of measurement results includes a first type of measurement result and a second type of measurement result different from the first type, and wherein the result of the first type of measurement is not deleted when deleting the measurement result.
9 . The measurement method of claim 7 , further comprising: when a period of the measurement based on the first clock signal when there is no periodic error is T cycle and the measurement period is T term , deleting |M| measurement results from the measurement result sequence when M obtained by the following Expression (A) is negative and adding M new measurement results to the measurement result sequence when the M is positive: M =int( T term /T cycle )− N ( A ) where, int (T term /T cycle ) is an integer conversion operation of a value obtained through T term /T cycle .
10 . The measurement method of claim 7 , wherein the measurement result includes a time interval measured on the first basis of the first clock signal, and the method further comprises: correcting the time interval by multiplying the time interval by a correction coefficient C calculated by the following Expression (B): C=T term /( T cycle ×N ) ( B ) when T cycle is a cycle of the measurement based on the first clock signal when there is no periodic error, and T term is the measurement period in a measurement system.
11 . A non-transitory computer readable storage medium storing a program causing a computer which acquires a plurality of measurement results obtained by performing measurement a plurality of times on a first basis of a first clock signal having a first clock period and a time stamp indicating a measurement time provided to each of two or more of the plurality of measurement results on a second basis of a second clock signal having a second clock period, to function as: a measurement time correction circuit configured to correct a measurement time of a measurement result other than the measurement result to which the time stamp is provided among the measurement results obtained during a period specified using two time stamps of the time stamps provided to each of the two or more of the plurality of measurement results, in accordance with the period and a number of measurement results obtained during the period among the plurality of measurement results, wherein: the first clock signal having the first clock period is oscillated by a first oscillator, the second clock signal having the second clock period is oscillated by a second oscillator, the second clock period is longer than the first clock period, and the second clock period has higher accuracy than the first clock period.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a national phase entry of PCT Application No. PCT/JP2020/045633 filed on Dec. 8, 2020, which application is hereby incorporated herein by reference. TECHNICAL FIELD Embodiments of the present invention relates to a measurement system, a measurement method, a measurement device, and a program for obtaining a measurement result together with a measurement time. BACKGROUND In recent years, services have been used in which a small wearable sensor is used for continuously measuring a user's biological information or environmental information for a long period of time and the measurement results obtained through the measurement are used for health management and the like. As a technique used for such services, PLT 1 discloses a technique of measuring a heart rate and the like from an electrocardiographic potential which is an action potential of the heart using a wearable device and transmitting the measurement results obtained through the measurement to a smartphone or the like in real time or recording the measurement results in a memory. CITATION LIST Patent Literature [PTL 1] PCT International Publication No. 2016/24495 SUMMARY Technical Problem Wearable sensors which are worn on a daily basis are required to be small and light, which limits battery capacity. Therefore, measurement with low power consumption is required for performing the measurement over a long period of time. Incidentally, there is a case in which it is desired to link and manage the measurement result and the user's activity at that time, and then analyze the measurement result while considering the user's activity. In this case, the correspondence relation between each of the measurement results and the user's activity is managed by the time. For this management, it is desirable that the measurement result is managed together with an accurate measurement time. Here, the measurement timing is generally controlled using a clock signal. If a highly accurate clock signal is used for measurement to accurately manage the measurement time as described above, power consumption will increase. On the other hand, if an oscillation circuit operating with low power consumption is used, the precision of the clock signal is reduced, and thus the accuracy of the measurement time is also reduced. Thus, there is a trade-off relationship between the power consumption and the accuracy of the measurement time. Note that such a trade-off occurs not only in wearable sensors but also in general measurement. An object of embodiments of the present invention is to obtain, with low power consumption, a measurement result to which a measurement time having a small time lag with respect to a real time is provided. Solution to Problem In order to solve the problems described above, a measurement system includes: a measurement unit configured to perform measurement a plurality of times on the basis of a first clock signal having a first clock period to obtain a plurality of measurement results; a time stamp provision unit configured to provide a time stamp indicating a measurement time to each of two or more of the plurality of measurement results obtained through the measurement unit, the two or more of the plurality of measurement results being a part of the plurality of measurement results, on the basis of a second clock signal having a second clock period longer than the first clock period and having better period accuracy than the first clock signal; and a measurement time correction unit configured to correct a measurement time of a measurement result other than the measurement results to which the time stamp has been provided among the measurement results obtained during a period in accordance with a period specified using two time stamps of the time stamps provided to each of the two or more of the plurality of measurement results, which is a part of the plurality of measurement results, and the number of measurement results obtained during the period among the plurality of measurement results. A measurement method includes: a measurement step of performing measurement a plurality of times on the basis of a first clock signal having a first clock period to obtain a plurality of measurement results; a time stamping providing step of providing a time stamp indicating a measurement time to each of two or more of the plurality of measurement results obtained through the measurement step, the two or more of the plurality of measurement results being a part of the plurality of measurement results, on the basis of a second clock signal having a second clock period longer than the first clock period and having better period accuracy than the first clock signal; and a measurement time correction step of correcting a measurement time of a measurement result other than the measurement result to which the time stamp is provided among the measurement results obtained during the period in accordance with a period sp