JP2014225107A - Data recording device and time correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a time correction in a manner capable of reproducing time-series data.SOLUTION: A data recording device 1 according to the present invention comprises: a storage part 20 in which time at a time when changing time is stored; a determination part 13 that acquires the number of pieces of record data during a time from when changing current time to when changing previous time, divides the number of pieces of record data by time taken from when changing the current time to when changing the previous time, and calculates a data rate; a determination part 13 that determines whether or not the data rate falls with a prescribed range; and a record time modification part 16 that performs a linear interpolation of a modified time portion when changing the current time during a period from when changing the previous time to when changing the current time on the basis of the determination result of the determination part 13, and thereby calculates a correction time when recording data, and executes any of a first time correction correcting the time when the data is recorded and a second time correction correcting time of past record data by a time modified when changing the current time.

Description

  The present invention relates to a technique for correcting the time of data recorded in a data recording apparatus.

  A data recording device that records data such as the status of a monitoring target includes a clock and records the collected data together with the time. However, the timepiece may gradually shift from the true time (actual time) due to a temperature change or the like. Therefore, the clock is set at a certain time.

  The following problems occur when the recorded data is read or reproduced from the data recording device after the time is set. In the first case, when the clock is returned with the time adjustment, the recorded data at the same time is duplicated. In the second case, when the clock is advanced by adjusting the time, there is a blank time zone in the time series data.

  In Patent Document 1, as a prior art, in order to deal with the case of the first case, the data recorded before the time change is overwritten with the data recorded after the time change, and the case of the second case is dealt with. In order to do this, it is described that the blank time zone is treated as missing. Further, in Patent Document 1, the correction time at the time of the recording data is calculated by linearly interpolating the time corrected at the time of the current time change from the time of the previous time change to the time of the current time change. Thus, a technique for performing time correction is disclosed.

JP 2002-258942 A

However, in the technique described in Patent Document 1 that corrects the time by linear interpolation, when the time set at the time change of the current time is returned from the time set at the time of the previous time change, the time of the recording data is the past. There is a problem of going backwards. In the technique described in Patent Document 1, since the correction time of the recording data is obtained by linear interpolation, there is a possibility that the time interval between the time series data becomes wider than the allowable range or becomes narrower than the allowable range. . Here, the allowable range means a time interval in which the data recording apparatus can record and / or reproduce. For example, when the recording data is a monitoring video, there is a possibility that the video cannot be recorded or reproduced if the allowable range is not satisfied.
Accordingly, an object of the present invention is to provide a technique for performing time correction so that data can be reproduced in the order of recording.

  In order to solve the above-mentioned problem, the data recording apparatus of the present invention obtains the number of recorded data from the time of the current time change to the time of the previous time change, and a storage unit that stores the time of the time change. A determination unit that calculates the data rate by dividing the number of the recording data by the time from the current time change to the previous time change, and determines whether the data rate is within a predetermined range And based on the determination result of the determination unit, linearly interpolates the time corrected at the time of the current time change from the time of the previous time change to the time of the current time change. The first time correction for correcting the time of the recording data by calculating the correction time at the time of the second time, or the second time for correcting the time of the past recording data with the time corrected when the current time is changed correction Characterized in that it comprises a recording time correction unit that performs either.

  According to the present invention, it is possible to perform time correction so that data can be reproduced in the order of recording.

It is a figure which shows the function example of a data recording device. It is a figure which shows the example of a processing flow of time correction. It is a figure which shows an example of a time correction table. It is a figure which shows the 1st time correction method. It is a figure which shows the 2nd time correction method. It is a figure which shows an example of time correction.

  Here, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings as appropriate.

  First, an example of functions of a data recording apparatus capable of time correction will be described with reference to FIG. It is assumed that the data recording apparatus 1 has a function of recording and reproducing (reading) a predetermined number of data per unit time. For example, when the monitoring target is monitoring video (data) having a predetermined frame rate, the data recording apparatus 1 determines an allowable range of the frame rate (data rate). Further, when the data recording device 1 records data measured at a predetermined cycle (temperature, state of a device to be monitored, etc.), in this embodiment, the data is restricted by a communication protocol, a communication interface, etc. An acceptable range of rates is determined. In the present embodiment, an example of functions of the data recording apparatus 1 will be described below, taking as an example the case where the recording data is a monitoring video.

As shown in FIG. 1, the data recording apparatus 1 includes a processing unit 10, a storage unit 20, and a communication unit 30.
The communication unit 30 is a communication interface and has a function of receiving monitoring video (data) from the monitoring target device 2 via the network 3.
The storage unit 20 is a memory, a hard disk, or the like, and stores processing results of the processing unit 10, recording data, and application programs. In addition, the storage unit 20 stores a time correction table 21 in which information regarding the changed time and the time correction method is stored. Details of the time correction table 21 will be described later.

  The processing unit 10 includes a clock correction unit 11, a clock unit 12, a determination unit 13, a data collection unit 14, a time correction management unit 15, and a recording time correction unit 16. The processing unit 10 includes a CPU (Central Processing Unit) and a main memory (not shown), and the functions of the units 11 to 16 in the processing unit 10 are realized by developing an application program stored in the storage unit 20 in the main memory. It becomes.

The clock correction unit 11 has a function of receiving a time change request input via an input device (not shown) and transmitting a time change instruction to the clock unit 12. Note that the input time change request may be any of the set time, the amount by which the clock is advanced, and the amount by which the clock is returned.
The clock unit 12 has a function of outputting the time and changing the time based on the time change request received from the clock correction unit 11.

  The determination unit 13 reads information on the current time change and the previous time change from the storage unit 20, acquires the number of video frames (data number) recorded during both time changes, and the number of video frames ( The frame rate (data rate) is calculated by dividing the number of data) by the time between the time changes of both times, and has a function of determining whether or not the frame rate (data rate) is within a predetermined range. The determination unit 13 has a function of selecting one of the two correction methods determined in advance based on the determination result.

The data collection unit 14 receives the video frame (data) from the monitoring target device 2 and the item number issued by the time correction management unit 15 (specifically, the item number of the time correction table 21 shown in FIG. 3). It has a function of storing in association with the storage unit 20.
The time correction management unit 15 has a function of selecting a correction method. Further, the time correction management unit 15 uses the time corresponding to the time change request received by the clock correction unit 11 (time after change), the time of the clock unit 12 at the time change (pre-change time), and the determination unit 13. A function of storing the selected correction method in association with the storage unit 20 is provided.
The recording time correction unit 16 has a function of correcting the time of the video frame (data) using the correction method selected by the determination unit 13.

Next, the flow of information between the units 11 to 16 will be specifically described with reference to FIG.
The clock correction unit 11 receives, for example, a time Tnew at the time of this time change as a time change request from an input device (not shown). For example, the input device outputs the time Tnew to the time correction unit 11 when the time Tnew is set and the set button is pressed. Next, the clock correction unit 11 transmits a time change request to the clock unit 12, and acquires the time T0 of the clock unit 12 at the time of the change request as the pre-change time T0. The clock unit 12 sets the clock with the time Tnew as the changed time Tnew. Then, the clock correction unit 11 transmits the post-change time Tnew and the pre-change time T0 to the determination unit 13.

  The determination unit 13 receives the pre-change time T0 and the post-change time Tnew at the time of the current time change from the clock correction unit 11, and the time Told at the previous time change from the storage unit 20 via the time correction management unit 15. get. The determination unit 13 acquires the number of video frames Pnum from the storage unit 20 from the previous time change to the current time change via the data collection unit 14, and performs the determination process according to the time correction processing flow shown in FIG. Run. The determination unit 13 selects either the first time correction method or the second time correction method based on the determination processing, and corrects the time correction processing method selected together with the pre-change time T0 and the post-change time Tnew. It transmits to the management unit 15.

The time correction management unit 15 receives the pre-change time T0, the post-change time Tnew, and the time correction processing method at the time of the current time change, stores the item numbers in the time correction table 21 of the storage unit 20, and stores them. The item number is transmitted to the data collection unit 14.
The data collection unit 14 acquires a video frame (data) from the monitoring target device 2, acquires the current time from the clock unit 12, acquires an item number from the time correction management unit 15, and acquires the acquired video frame (data). The time and the item number are associated with each other and stored in the storage unit 20.
When the recording time correction unit 16 receives a playback request (reading request) for a video frame (data), the recording time correction unit 16 uses the item number associated with the video frame to store the time from the storage unit 20 via the time correction management unit 15. A correction processing method is acquired, and the time of the video frame (data) is corrected.

  Here, an example of a processing flow of time correction in the determination unit 13 will be described with reference to FIG. Note that the determination unit 13 is in a state where the pre-change time T0 and the post-change time Tnew at the time of the current time change are received from the time correction unit 11, that is, a time change has occurred.

In step S <b> 201, the determination unit 13 refers to the storage unit 20 and determines whether there is past recording data.
If it is determined that there is past recording data (Yes in step S201), the process proceeds to step S202. If it is determined that there is no past recording data (No in step S201), the process proceeds to step S206.

In step S202, the determination unit 13 refers to the time correction table 21 in the storage unit 20 and determines whether the time has been changed in the past. The case where it is determined that the time has been changed in the past is a case where the time correction information is already stored in the time correction table 21 together with the item number.
If it is determined that the time has been changed in the past (Yes in step S202), the process proceeds to step S203. If it is determined that the time has not been changed in the past (No in step S202), the process proceeds to step S206.

  In step S203, the determination unit 13 sets the number of video frames (number of data) Pnum between the time Tnew when the current time is changed and the time Told when the previous time is changed to the time Tnew when the current time is changed and the previous time. The frame rate (data rate) F is calculated by dividing by the time between the time Told and the time Told when the time is changed. Specifically, the determination unit 13 receives the time Tnew at the time of the current time change from the time correction unit 11 and acquires the time Told at the time of the previous time change from the storage unit 20 via the time correction management unit 15. . In addition, the determination unit 13 acquires the number of video frames (data number) Pnum from the storage unit 20 from the previous time change to the current time change via the data collection unit 14. Then, the determination unit 13 calculates Pnum / (Tnew−Told) and sets the result as a frame rate (data rate) F.

In step S204, the determination unit 13 determines whether or not the frame rate (data rate) F satisfies Fmin or more and Fmax or less. In other words, the determination unit 13 determines whether or not the frame rate (data rate) F satisfies a predetermined range. Here, Fmin represents the minimum frame rate (data rate) that the data recording apparatus 1 can record or reproduce, for example. Fmax represents the maximum frame rate (data rate) that can be recorded or reproduced by the data recording apparatus 1, for example.
If it is determined that F is greater than or equal to Fmin and less than or equal to Fmax (Yes in step S204), the process proceeds to step S205, and if it is determined that F is not greater than or equal to Fmin and less than or equal to Fmax (No in step S204), the process is performed. Proceed to step S206.

In step S205, the determination unit 13 selects the first time correction method.
In step S206, the determination unit 13 selects the second time correction method.
Details of the first time correction method and the second time correction method will be described later.

Next, an example of the time correction table 21 will be described with reference to FIG.
As shown in FIG. 3, the time correction table 21 stores an item number, a time before change, a time after change, and a correction method in association with each other.
In the item number column, identification information issued by the time correction management unit 15 when the time is changed is stored.
The time T0 acquired from the clock unit 12 when the time is changed is stored in the “before change” column.
The time after change field stores the time Tnew received as a time change request from an input device (not shown) when the time is changed.
In the correction method column, either the first time correction method or the second time correction method selected by the determination unit 13 is stored.

  The item number “1” of the time correction table 21 shown in FIG. 3 represents the first time change, and from 12 o'clock on January 22, 2013 (pre-change time) to 12:05 (post-change time). The time is moving forward. The item number “2” represents the second time change, and the time is returned from 13:05 (pre-change time) on January 22, 2013 to 13:00 (post-change time). The item number “3” represents the third time change, and the time is returned from 14:00 on January 22, 2013 to 12:30. In the correction method, the time correction method selected by the processing flow shown in FIG. 2 is expressed as “first” and “second”. “First” represents the first time correction method, and “second” represents the second time correction method.

FIG. 4 is a diagram for explaining the first time correction method. The horizontal axis represents the actual time, and the vertical axis represents the time of the clock unit 12 of the data recording device 1.
In the first time correction method, when the time is changed from the pre-change time T0 to the post-change time Tnew due to the current time change, the time was recorded between the previous time change time Tod and the pre-change time T0. By adding the time correction amount calculated from the ratio of the time change amount (Tnew-T0) (the length of the white arrow) and the recording period (T0-Told) to the time attached to the recording data. Then, the corrected time is calculated. That is, the amount of time (time change amount (Tnew−T0) (length of white arrow)) corrected at the time of the current time change is linearly interpolated between the previous time change and the current time change. Thus, the correction time (the correction value indicated by the solid line in FIG. 4) at the time of the recording data is calculated. As an example, the corrected time Tb is calculated by the following equation (1).
Tb = (Tnew-T0) (Ta-Told) / (T0-Told) + Ta (1)

FIG. 5 is a diagram for explaining the second time correction method. The horizontal axis represents the actual time, and the vertical axis represents the time of the clock unit 12 of the data recording device 1.
In the second time correction method, when the time is changed from the pre-change time T0 to the post-change time Tnew due to the current time change, the time change amount (with respect to the time of all recorded data before the pre-change time T0 ( The corrected time is calculated by adding (Tnew−T0) (the length of the white arrow). As an example, the corrected time Tb is calculated by the following equation (2).
Tb = (Tnew−T0) + Ta (2)

FIG. 6 shows the information described in the time correction table 21 shown in FIG. 3 written in the coordinates represented by the actual time and the time of the data recording device (see FIG. 3 as appropriate).
When the item number “1” is changed, the second time correction method is used. Therefore, a time change amount of 5 minutes is added to all the recorded data before 12:00 on January 22, 2013. The added value is represented by a broken line 61.
Next, since the first time correction method is used in the time change of the item number “2”, the recording data from 12: 5 to 13: 5 is corrected by the equation (1). Time Tb is calculated. The calculated value is represented by a broken line 62.
Next, in the time change of item number “3”, since the second time correction method is used, the time change amount of 90 minutes is subtracted from all the recorded data before 14:00. The calculated value is represented by a broken line 63.

  As described above, the data recording apparatus 1 of the present invention acquires the storage unit 20 in which the time at the time change is stored, and the number of recorded data from the time change at this time to the time at the previous time change, A determination unit 13 for calculating the data rate by dividing the number of recording data by the time from the current time change to the previous time change, and determining whether the data rate is within a predetermined range; When it is determined that the rate is within a predetermined range, the time corrected at the time change of the current time is linearly interpolated between the time of the previous time change and the time of the current time change. When the correction time is calculated and the first time correction for correcting the time of the recording data is executed and it is determined that the data rate is out of the predetermined range, the past recording is performed at the time corrected when the time is changed this time. Data Comprising a recording time correction unit 16 that executes the second time correction for correcting the time, the. Therefore, the data recording apparatus 1 can perform time correction so that the recorded time series data can be reproduced in the order of recording.

In addition, this invention is not limited to above-described embodiment, Various modifications are included. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of the embodiment.
Further, each function or the like of the data recording apparatus 1 may be realized by hardware by designing a part or all of them, for example, by an integrated circuit. Each function of the processing unit 10 may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function is stored in a memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD (Digital Versatile Disc). be able to.
In addition, the control lines and information lines are those that are considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. In practice, it may be considered that almost all configurations are connected to each other.

DESCRIPTION OF SYMBOLS 1 Data recording apparatus 2 Monitoring object apparatus 3 Network 10 Processing part 11 Clock correction part 12 Clock part 13 Judgment part 14 Data collection part 15 Time correction management part 16 Recording time correction part 20 Storage part 21 Time correction table 30 Communication part

Claims (4)

A storage unit for storing the time when the time is changed;
The number of recorded data from the current time change to the previous time change is obtained, and the data rate is divided by the time from the current time change to the previous time change. A determination unit that calculates and determines whether or not the data rate is within a predetermined range;
Based on the determination result of the determination unit, the time of the recording data is obtained by linearly interpolating the time corrected at the time of the current time change from the time of the previous time change to the time of the current time change. The first time correction for correcting the time of the recording data by calculating the correction time at the time or the second time correction for correcting the time of the past recording data with the time corrected at the time of the current time change. A recording time correction unit for executing one of the following:
A data recording apparatus comprising: The recording time correction unit
When the determination unit determines that the data rate is within the predetermined range, the first time correction is performed, and the determination unit determines that the data rate is outside the predetermined range The data recording apparatus according to claim 1, wherein the second time correction is performed. A time correction method for a data recording apparatus for recording recorded data together with time,
The data recording device comprises:
A storage unit for storing the time when the time is changed,
The number of recorded data from the current time change to the previous time change is obtained, and the data rate is divided by the time from the current time change to the previous time change. A determination step of calculating and determining whether the data rate is within a predetermined range;
Based on the determination result in the determination step, the time of the recording data is obtained by linearly interpolating the time corrected at the time of the current time change from the time of the previous time change to the time of the current time change. The first time correction for correcting the time of the recording data by calculating the correction time at the time or the second time correction for correcting the time of the past recording data with the time corrected at the time of the current time change. A recording time correction step for performing one of the following:
The time correction method characterized by performing. In the recording time correction step,
When it is determined in the determination step that the data rate is within the predetermined range, the first time correction is performed, and when the data rate is determined to be outside the predetermined range in the determination step The time correction method according to claim 3, wherein the second time correction is executed.

Images