CN104166424A - Data recording device and correction method - Google Patents

Abstract

The data recording device (1) of the present invention has: a storage part (20), which stores the time when the time is changed; The number of recorded data until the previous time change, divide the number of recorded data by the time from the current time change to the previous time change to calculate the data rate, and determine whether the data rate is within the specified range and the recording time correction part (16), the recording time correction part (16) performs any one time correction in the first time correction and the second time correction according to the judgment result of the judging part (13), at the first time correction In the period from the previous time change to the current time change, linear interpolation is performed on the period corrected at the time of the current time change, thereby calculating the correction time at the time of recording data, and recording The time of the data is corrected, and in the second time correction, the time of the past recorded data is corrected according to the time corrected at the time of the current time change. Thus, the time is corrected so that the time-series data can be reproduced.

Description

Data recording device and time correction method

technical field

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

Background technique

The data recording device for recording data such as the state of the monitoring object has a clock, and records the collected data together with the time. However, the clock may deviate from the true time (actual time) little by little due to temperature changes and the like. Therefore, the time of the clock needs to be corrected at a certain point in time.

After time adjustment, the following problems arise when reading recorded data from a data recording device or reproducing recorded data from a data recording device. The first case is that the clock is adjusted forward when the time is corrected. At this time, the recorded data at the same time will exist repeatedly. The second case is that the clock is corrected backward during the time correction, at this time, there will be blank time periods in the time series data.

As a prior art, Patent Document 1 discloses a technique for overwriting the data recorded before the time change with the data recorded after the time change in order to cope with the above-mentioned first case, and in order to cope with the above-mentioned second case In this case, the blank time period is treated as an undetected time period. In addition, Patent Document 1 also discloses a technology for performing time correction, which linearly interpolates the period 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. , so as to calculate the correction time of the time when the data is recorded, and perform time correction.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2002-258942

Contents of the invention

However, in the technique of performing time correction by linear interpolation disclosed in Patent Document 1, when the time set at the time of the current time change is changed to a time earlier than the time set at the time of the previous time change, There is a problem of going back to the past when the data is recorded. Also, in the technique disclosed in Patent Document 1, since the correction time of the recording data is obtained by linear interpolation, the time interval between sequential data may become larger or narrower than the allowable range. Here, the allowable range refers to the time interval during which the data recording device can perform recording and/or reproduction. For example, when the recorded data is a monitor image, if the allowable range is not met, the image may not be recorded or reproduced.

Therefore, an object of the present invention is to provide a technique for correcting time so that data can be reproduced in the order in which they were recorded.

solution

In order to solve the above-mentioned problems, the data recording device of the present invention is characterized in that it has: a storage part that stores the time when the time is changed; The number of pieces of recorded data up to the time, divide the number of pieces of recorded data by the time from the time of the current time change to the time of the previous time change to calculate the data rate, and determine whether the data rate is within within a specified range; and a recording time correction section, the recording time correction section performs any one of the first time correction and the second time correction according to the judgment result of the judgment part, and in the first time correction , during the period from the previous time change to the current time change, perform linear interpolation on the period corrected at the time of the current time change, thereby calculating the correcting the time, and correcting the time of the recorded data, in the second time correction, correcting the past time of the recorded data according to the corrected time when the current time is changed.

Invention effect

According to the present invention, the time of data can be corrected so that the data can be reproduced in the order in which they were recorded.

Description of drawings

FIG. 1 is an exemplary diagram showing functions of a data recording device.

FIG. 2 is an explanatory diagram showing an example of a processing flow of time correction.

FIG. 3 is an explanatory diagram showing an example of a time correction table.

FIG. 4 is a diagram illustrating a first time correction method.

FIG. 5 is a diagram showing a second time correction method.

FIG. 6 is a diagram showing an example of time correction.

Detailed ways

Hereinafter, a mode for implementing the present invention (hereinafter referred to as "the present embodiment") will be described in detail with reference to the drawings as appropriate.

First, a functional example of a data recording device capable of time correction will be described with reference to FIG. 1 . The data recording device 1 has a function of recording and reproducing (reading) a predetermined amount of data per unit time. In the data recording device 1 , when the monitoring target is, for example, a monitoring image (data) of a predetermined frame rate, an allowable range is set in advance for the frame rate (data rate). When the data recording device 1 records the data (temperature or the state of the monitoring target device, etc.) measured in accordance with a predetermined cycle, in this embodiment, the allowable range of the data rate is adjusted according to the constraints of the communication protocol and the communication interface. stipulated. In this embodiment, an example of the functions of the data recording device 1 will be described by taking the case where the recorded data is a monitor image as an example.

As shown in FIG. 1 , the data recording device 1 has a processing section 10 , a storage section 20 and a communication section 30 .

The communication unit 30 is a communication interface and has a function of receiving monitoring images (data) from the monitoring target device 2 via the network 3 .

The storage section 20 is a memory, a hard disk, etc., and stores processing results of the processing section 10, recorded data, application programs, and the like. In addition, the storage unit 20 also stores a time correction table 21, and the time correction table 21 stores information on the changed time and the method of correcting the time. Details of the time correction table 21 will be described later.

The processing section 10 has a clock correction section 11 , a clock section 12 , a judgment section 13 , a data collection section 14 , a time correction management section 15 , and a recording time correction section 16 . Processing part 10 is made up of unillustrated CPU (Central Processing Unit, central processing unit) and main memory, and the function of each part 11～16 in processing part 10 reads out the application program that is stored in storage part 20 to main memory. implemented in memory.

The clock correction unit 11 has a function of receiving a time change request input through an input device not shown and sending a time change command to the clock unit 12 . The time change request input by the input device may be, for example, any one of the set time, the amount of backward correction of the clock, or the amount of forward correction of the clock.

The clock section 12 has a function of outputting the time and changing the time according to a time change request received from the clock correction section 11 .

The judging part 13 has the information when reading this time change and the previous time change from the storage part 20, obtains the number of image frames (data quantity) recorded between the two time change times, and the image frame number (data quantity) Amount) divided by the elapsed time between two time change times to calculate the frame rate (data rate), and determine whether the frame rate (data rate) is within the specified range. In addition, the judging section 13 also has a function of selecting a time correction method from two predetermined time correction methods based on the judgment result.

The data collection part 14 has to receive the image frame (data) from the monitoring target device 2, and the item number (specifically, the time correction table 21 shown in FIG. item number) is stored in the storage section 20 in association with the function.

The time correction management section 15 has a function of selecting a correction method. In addition, the time correction management part 15 also has the time corresponding to the time change request received by the clock correction part 11 (time after change), the time of the clock part 12 at the time of the time change (time before change), and the judgment part. 13 The selected correction method is stored in association with the function in the storage section 20.

The recording time correction section 16 has a function of correcting the time of the image frame (data) using the correction method selected by the judgment section 13 .

Next, the flow of information among the respective sections 11 to 16 will be specifically described with reference to FIG. 1 .

The clock correction unit 11 receives, for example, the time Tnew at the time of the current time change as a time change request from an input device not shown. For example, the input device outputs the time Tnew to the clock correction section 11 when the time Tnew is set and the setting button is pressed. Next, the clock correcting section 11 transmits a time change request to the clock section 12, and obtains the time T0 of the clock section 12 at the time of the change request as the pre-change time T0. The clock section 12 sets a clock with the time Tnew as the post-change time Tnew. Thereafter, the clock correction section 11 sends the post-change time Tnew and the pre-change time T0 to the judging section 13 .

The determination unit 13 receives the pre-change time T0 and the post-change time Tnew of the current time change from the clock correction unit 11 , and acquires the time Told of the previous time change from the storage unit 20 via the time correction management unit 15 . The determination unit 13 acquires the number of image frames Pnum from the previous time change to the current time change from the storage unit 20 via the data collection unit 14 . The determination process is executed by the time correction process flow shown in FIG. 2 . The judgment part 13 selects any one of the first time correction method and the second time correction method according to the judgment process, and sends the pre-change time T0 and the post-change time Tnew together with the selected time correction processing method to the time correction management Part 15.

The time correction management part 15 receives the pre-change time T0 and the post-change time Tnew and the time correction processing method of this time change, and stores them in the time correction table 21 of the storage part 20 after assigning an item number, and the item number Sent to the data collection section 14.

The data collecting part 14 obtains the image frame (data) from the monitoring object device 2, obtains the current time from the clock part 12, obtains the item number from the time correction management part 15, and compares the obtained image frame (data) with the time and the item number stored in the storage section 20 in association.

After receiving the playback request (readout request) of the image frame (data), the recording time correction section 16 acquires the time correction processing method from the storage section 20 via the time correction management section 15 using the item number associated with the image frame, And correct the time of the image frame (data).

An example of the processing flow of the time correction in the judging section 13 will be described below with reference to FIG. 2 . Here, the judging unit 13 is in a state where the pre-change time T0 and the post-change time Tnew of the current time change have been acquired from the clock correction unit 11 , that is, the time change has already occurred.

In step S201, the judging section 13 refers to the storage section 20 to judge whether or not there is past recording data.

When it is determined that there is past recorded data (Yes in step S201), the process proceeds to step S202, and when it is determined that there is no past recorded data (No in step S201), the process proceeds to step S206.

In step S202, the judgment section 13 refers to the time correction table 21 of the storage section 20 to judge whether or not the time has been changed in the past. Here, when it is determined that the time has been changed in the past, the information at the time of the time change is already stored in the time correction table 21 together with the item number.

When it is determined that the time has been changed in the past (Yes in step S202), the process proceeds to step S203, and when 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 judging part 13 divides the number of image frames (data quantity) Pnum between the time Tnew when this time is changed and the time Told when the previous time is changed by the time Tnew when this time is changed. The frame rate (data rate) F is calculated for the time from the time Told at the time of the previous time change. Specifically, the determination unit 13 receives the time Tnew at the time of the current time change from the clock 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 . Then, the determination unit 13 acquires the number of image frames (number of data) Pnum from the previous time change to the current time change from the storage unit 20 via the data collection unit 14 . The calculation of Pnum/(Tnew-Told) is performed in the judging section 13, and the result is taken as the frame rate (data rate) F.

In step S204, the judging section 13 judges whether or not the frame rate (data rate) F satisfies the condition of being greater than or equal to Fmin and less than or equal to Fmax. That is, the judging section 13 judges whether or not the frame rate (data rate) F satisfies a prescribed range. Here, Fmin represents, for example, the minimum frame rate (data rate) at which the data recording device 1 can record or reproduce, and Fmax represents, for example, the maximum frame rate (data rate) at which the data recording device 1 can record or reproduce.

When it is judged that the frame rate (data rate) F satisfies the condition of more than Fmin and less than Fmax (Yes in step S204), the process proceeds to step S205, and when it is judged that the frame rate (data rate) F does not satisfy the condition of more than Fmin and When the condition is equal to or less than Fmax (No in step S204), the process proceeds to step S206.

In step S205, the judgment section 13 selects the first time correction method.

In step S206, the judgment section 13 selects the second time correction method.

The details of the first time correction method and the second time correction method will be described later.

An example of the time correction table 21 will be described below with reference to FIG. 3 .

As shown in FIG. 3 , in the time correction table 21 , an item number, a time before change, a time after change, and a correction method are stored in association with each other.

In the item number column, identification information issued by the clock correction management section 15 when the time is changed is stored.

The time T0 obtained from the clock section 12 at the time of the time change is stored in the column of the time before change.

The time Tnew received as a time change request from an input device (not shown) at the time of time change is stored in the post-change time column.

Either one of the first time correction method and the second time correction method selected by the judging section 13 is stored in the correction method column.

"1" in the item number column of the time correction table 21 shown in Figure 3 indicates that the time was changed for the first time, and the time was changed from 12 o'clock on January 22, 2013 (time before the change) to 12 o'clock 5 minutes ( time after the change). The "2" in the item number column indicates the second time change, and the time has been changed from 13:05 on January 22, 2013 (time before the change) to 13:00 (time after the change). The "3" in the item number column indicates the third time change, and the time has been changed from 14:00 on January 22, 2013 to 12:30. In addition, "first" and "second" in the correction method column represent the time correction method selected by the processing flow shown in FIG. 2, "first" represents the first time correction method, and "second" represents the second time correction method. Always correct the method.

FIG. 4 is an explanatory diagram of a first time correction method. The horizontal axis represents the actual time, and the vertical axis represents the time of the clock section 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 at the current time change, the time from the time Told at the previous time change to the pre-change time T0 The corrected time is calculated by adding the time added to the recording data recorded during the period to the time correction amount calculated from the ratio of the time change amount (Tnew-T0) (the length of the hollow arrow) to the recording period (T0-Told). In other words, the time period (time change amount (Tnew-T0) (length of the hollow arrow) corrected at the time of the current time change is calculated from the period from the time of the previous time change to the time of the current time change. ) to perform linear interpolation to calculate the correction time (the correction value indicated by the solid arrow in FIG. 4 ) at the time of recording data. As an example, the corrected time Tb can be calculated by the following equation (1).

Tb=(Tnew-T0)(Ta-Told)/(T0-Told)+Ta...Formula (1)

FIG. 5 is an explanatory diagram of a second time correction method. The horizontal axis represents the actual time, and the vertical axis represents the time of the clock section 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 at the current time change, the time of all recorded data before the pre-change time T0 is added to the time change amount (Tnew-T0) (the length of the hollow arrow), from which the corrected time is calculated.

As an example, the corrected time Tb can be calculated by the following equation (2).

Tb=(Tnew-T0)+Ta...Formula (2)

FIG. 6 shows an example in which the information recorded in the time correction table 21 shown in FIG. 3 is marked on the coordinates indicated by the actual time and the time of the data recording device (see FIG. 3 as appropriate).

In the time change of "1" in the item number column, since the second time correction method is used, all the recorded data before 12 o'clock on January 22, 2013 are added with a time change amount (5 minutes). The value obtained by adding this amount of time change (5 minutes) is indicated by a dotted line 61 .

In addition, in the time change of "2" in the item number column, since the first time correction method is used, with respect to the recorded data between 12:05 and 13:05, the corrected time is calculated using formula (1). Time Tb. The calculated value is indicated by a dotted line 62 .

In the time change of "3" in the item number column, since the second time correction method is used, all the recorded data before 14:00 are subtracted by the time change amount (90 minutes). The calculated value is indicated by a dotted line 63 .

As described above, the data recording device 1 of the present invention has: the storage part 20, which stores the time when the time is changed; The number of recorded data until now, divide the number of recorded data by the time from the current time change to the previous time change to calculate the data rate, and determine whether the data rate is within the specified range; and record time correction Part 16, when the judging part 13 judges that the data rate is within the specified range, the recording time correction part 16 executes the first time correction, and during the period from the previous time change to the current time change, The time period corrected at the time of this time change is linearly interpolated, thereby calculating the corrected time of the recorded data time, and correcting the recorded data time, and the judging section 13 judges that the data rate is outside the prescribed range. , the recording time correction section 16 executes the second time correction, and corrects the time of the past record data according to the time corrected when the current time is changed. Therefore, the data recording device 1 can correct the data time so that the recorded time-series data can be reproduced in the recording order.

The present invention is not limited to the above-described embodiments, and various modifications may be included. For example, the above-mentioned embodiments are used to explain the present invention in detail in an easy-to-understand manner, but it does not mean that the present invention must have all the explained structures. In addition, a part of the structure of one embodiment may be substituted with the structure of another embodiment, and the structure of another embodiment may be added to the structure of one embodiment. In addition, it is possible to add, delete, or replace a part of the configurations of the embodiments with other configurations.

Some or all of the various functions of the data recording device 1 can be realized by hardware by designing an integrated circuit or the like, for example. In addition, various functions and the like of the processing section 10 can also be realized by software by interpreting and executing programs for realizing various functions by a processor. Information such as programs, charts, and files used to realize various functions can be stored in recording devices such as memory, hard disk, SSD (Solid State Drive, Solid State Drive), or IC card, SD card, and DVD (Digital Versatile Disc, Digital Versatile Disc) and other recording media.

In addition, the control lines and information lines only show the parts that need to be shown for explanation, and do not mean to show all the control lines and information lines of the product. It can be considered that practically all components are related and connected to each other.

Symbol Description

1 data recording device

2 Monitoring target device

3 network

10 processing part

11 Clock correction part

12 clock section

13 Judgment part

14 Data Collection Section

15 time correction management part

16 Recording time correction part

20 Storage section

21 Time correction table

30 Communication section

Claims (4)

1. A data recording device, characterized in that it has: a storage part that stores the time when the time is changed; a judging part, the judging part acquires the number of pieces of recorded data from the time of the current time change to the time of the previous time change, and divides the number of pieces of recorded data by Calculate the data rate from the time until a time change, and determine whether the data rate is within a specified range; and A recording time correction section that executes any one of a first time correction and a second time correction based on the judgment result of the judgment section, in the first time correction, after the previous performing linear interpolation on the period of time corrected at the time of the current time change in the period from the time of the first time change to the time of the current time change, thereby calculating the correction time of the time of the recorded data, and The time of the recorded data is corrected, and in the second time correction, the past time of the recorded data is corrected according to the time corrected at the time of the current time change. 2. The data recording device according to claim 1, wherein: When the judging section judges that the data rate is within the prescribed range, the recording time correcting section executes the first time correction, and when the judging section judges that the data rate is within the prescribed When it is out of the range, the recording time correction unit executes the second time correction. 3. A time correction method, which is a time correction method of a data recording device that records recorded data together with time, characterized in that, The data recording device has a storage unit for storing the time when the time is changed, The time correction method includes a judging step and a recording time correction step, In the judging step, the number of pieces of recorded data from the current time change to the previous time change is obtained, and the number of recorded data is divided by the number of records from the current time change to the previous time. the time until the time of a time change to calculate the data rate and determine whether the data rate is within the specified range, and In the record time correction step, any one of the first time correction and the second time correction is executed according to the judgment result of the judgment step, and in the first time correction, when the time is changed from the previous time During the period from when the current time is changed, linear interpolation is performed on the time period corrected when the current time is changed, thereby calculating the corrected time of the time of the recorded data, and the recorded data In the second time correction, the past time of the recorded data is corrected according to the time corrected when the current time is changed. 4. The time correction method according to claim 3, wherein: In the recording time correcting step, when it is determined in the determining step that the data rate is within the predetermined range, the first time correction is performed, and in the determining step it is determined that the When the data rate is out of the predetermined range, the second time correction is performed.