JP5474414B2 - Data recording device - Google Patents

Description

  The present invention is a data recording apparatus for constantly recording a series of data that is continuously input in time series for subsequent verification on a recording medium of a certain capacity, and in particular, image data used for monitoring purposes is always recorded. The present invention relates to a data recording apparatus that devises a recording method to an external recording medium in a recording camera system.

  In recent years, security cameras and the like are increasing in the world. However, it is not realistic for the observer to constantly monitor the state of the camera as in the past due to the increase in the number of cameras and the associated increase in labor costs. In view of this, there is already known a system in which video captured by a camera is always recorded as still image data on a recording medium, and when an event occurs, the recording medium is taken out and viewed for subsequent verification.

  Here, since the capacity of the recording medium is finite, only data for a fixed time determined by the frame rate (image acquisition interval) and the image size can be recorded. Therefore, when the capacity of the recording medium is full, it is necessary to stop the subsequent data recording or to erase the data recorded on the recording medium in the oldest order and overwrite the new data for recording. .

As a result, there has been a problem that if a past image is desired rather than expected, there is a high possibility that the image has been deleted if the time has passed.
In addition, for example, there is a problem that it is difficult to respond to a request to record the situation at the time of the accident finely and leave an image for a long time.

  As a conventional technique that can solve such a problem, for example, as disclosed in Patent Document 1, relatively new data is stored while maintaining high quality, and the quality is lowered and stored as it gets older. A data recording device is already known. This is because, when there is no more free space in the storage area, the oldest image data frame stored in the storage area is thinned out at a thinning rate of 1/2 and moved to another storage area. The newly received image data is overwritten at the full rate in the empty area generated in the area.

JP 2008-193715 A

  However, in the conventional technique described in Patent Document 1 described above, the writing process to the recording medium is necessary to determine most of the processing performance of the entire system. Performing a complicated process of thinning and moving to another storage area has a problem that the recording rate becomes slow. There is also a problem that the write processing program becomes complicated and the burden on the capacity of the program increases.

  The present invention has been made paying attention to the problems of the prior art as described above, and the data recording rate becomes higher as the time is the latest without performing complicated processing when recording data. An object of the present invention is to provide a data recording apparatus that can record an image for a long period of time and can reduce the capacity of a program although the data recording rate is low when a certain time has passed.

The gist of the present invention for achieving the object described above resides in the inventions of the following items.
[1] In a data recording device (10) for constantly recording a series of data continuously input in time series for post-verification on a recording medium (13) having a fixed capacity,
A unit for dividing the memory area of the recording medium (13) into a plurality of continuous groups, and sequentially allocating and recording the series of data in groups of two or more and a certain number of adjacent arrays less than the total number of groups. Select as the recording target group,
In the process of allocating and recording a group of data in the recording target group, a certain group in the array constituting the recording target group is the target of transition determination, and the capacity of the group that is the target of transition determination is full of data In this case, the array constituting the recording target group is moved one group at a time in a certain direction, and selected as a new recording target group,
A data recording apparatus (10), wherein a group on one end side in the arrangement of all groups is set as a group logically adjacent to the other end side, and the transition of the recording target group is repeated cyclically.

[ 2 ] When any of the recording target groups including the group to be transferred is filled with data, newly recorded data in the group is overwritten in a ring buffer format. The data recording device (10) according to [1 ], wherein

Next, the operation based on the above solution will be described.
According to the data recording apparatus (10) of the present invention, the memory area of the recording medium (13) is divided into a plurality of continuous groups, and two or more of them and a group of a fixed number of adjacent arrays less than the total number of groups. Is selected as a recording target group which is a unit for sequentially allocating and recording a series of data .

  Here, the recording target group is used for recording new data, and groups other than the recording target group are used for recording old data. File fragmentation is suppressed by sequentially recording a series of data input in time series in consecutive sectors in the recording target group. This can be expected to increase the speed of access to the recording medium (13).

  In the process of allocating and recording a group of data within a recording target group, one group in the array that constitutes the recording target group is the target of transition determination, and the capacity of the group that is the target of transition determination becomes full of data. In this case, the array constituting the recording target group is shifted one group at a time in a fixed direction and selected as a new recording target group.

  A group on one end side in the arrangement of all groups is set as a group logically adjacent to the other end side, and the transition of the recording target group is repeated cyclically. Thereby, the number of times of recording for each group of the recording medium (13) is kept uniform, and concentration of recording to a specific group can be prevented. Therefore, it is possible to suppress the occurrence of defective sectors in the recording medium (13).

  In this way, the arrangement of recording target groups is shifted one by one and circulated, and each time a series of data need only be recorded in units of recording target groups, specific data can be thinned out, deleted, moved or freed No complicated processing such as formation is required. Regardless of such simple and high-speed recording processing, the data retention time within the fixed capacity of the recording medium (13) is 2 for short-term recording in the recording target group and long-term recording in other groups. Tiered into stages.

  As a result, the rate of new data can be recorded in detail, and the old data can be stored for a long period of time at a reduced rate. Therefore, in the ex-post verification when an unexpected event occurs, it is possible to perform detailed verification using close-rate data for upcoming verification, while when it is necessary to verify old data It will also be possible to verify long-term stored data at a reduced rate.

  In addition, if any of the plurality of groups including the group to be determined for migration is filled with data, newly recorded data in the group is overwritten in a ring buffer format. good. As a result, the latest data can be stored at a high speed without deleting or moving the data.

  According to the data recording apparatus of the present invention, the data recording rate is higher as the time is the latest without performing complicated processing at the time of data recording. Although lower, images can be recorded for a long time. In addition, the capacity of the control program related to the recording process can be reduced. In addition, by recording data on each group of the recording medium in a sequential order, it is possible to suppress file fragmentation and to speed up access to the recording medium. Furthermore, it is possible to suppress the occurrence of defective sectors by equalizing the number of recordings to each group of recording media.

1 is a block diagram schematically showing a data recording apparatus according to an embodiment of the present invention. FIG. 3 is an explanatory diagram showing a concept of transferring a recording target group by dividing a memory area of a recording medium into a plurality of groups in the data recording apparatus according to the embodiment of the present invention. It is explanatory drawing which shows in detail the concept which transfers a recording object group with the data recording device which concerns on embodiment of this invention. It is explanatory drawing of a continuation of FIG. It is a flowchart which shows the process at the time of the recording of the image data with the data recording device which concerns on embodiment of this invention. It is explanatory drawing which represented the image which distributes and records image data to a recording object group in the data recording device which concerns on embodiment of this invention. It is explanatory drawing of a continuation of FIG. It is explanatory drawing of a continuation of FIG. It is explanatory drawing of a continuation of FIG. It is a table | surface which shows the frequency | count of transfer of the recording object group in the data recording device which concerns on embodiment of this invention, and the frequency | count of overwriting of each group.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments representing the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram schematically showing a data recording apparatus 10 according to the present embodiment. Hereinafter, a case where the data recording apparatus 10 is applied to a camera system that constantly records image data used for monitoring purposes will be described as an example.

  As shown in FIG. 1, the data recording apparatus 10 according to the present embodiment includes a camera 11 on the camera system side, an image storage substrate 12, a recording medium 13 as a recording medium, and a power supply substrate 14. . The power supply board 14 is supplied with a power supply voltage necessary for system operation from the outside.

  Further, a drawing side device 20 for browsing the image data recorded on the recording medium 13 is connected to the image storage substrate 12 via a communication network. Here, the drawing-side device 20 includes a monitor 21 that outputs image data, and an input device that performs a predetermined operation (not shown).

  As for the performance of the camera 11 on the camera system side, for example, JPEG is used as the image compression method, and the image size is set to 640 × 480, 320 × 240, or the like. It is preferable that two channels can be input, the recording frame rate is set to 5 frames / second for each channel, and the image data input along the time series can be always recorded.

  As the recording medium 13, for example, a small flash memory (CF card) having a capacity of several tens of gigabytes has appeared, and these may be used. As a design policy for the recording medium 13, a continuous sector can be secured when writing image data. Further, the processing speed at the time of writing is given priority over the time of reading, and the reading operation during the system operation is not assumed, and the drawing-side device 20 reads after the stop.

  The image storage substrate 12 forms the basis of the data recording apparatus 10 according to the present invention, and records a CPU that performs a central function of image data recording control, a program executed by the CPU, and various fixed data. It is composed of a ROM and a substrate whose main parts are a RAM and the like for recording data temporarily necessary for executing the program. In addition to the power supply substrate 14 to which a power supply voltage is supplied from the outside, the image storage substrate 12 is connected to the camera 11 and the recording medium 13, and the drawing side device 20 as described above.

Next, the operation of the data recording apparatus 10 according to the present embodiment will be described.
As shown in FIG. 2A, the data recording apparatus 10 divides a physically continuous memory area of the recording medium 13 into, for example, eight groups as shown in FIG. 2B. . Here, each group is recorded separately into a header portion containing management information and actual image data.

  Among a plurality of (eight) divided groups, two or more adjacent groups of less than the total number of groups (eight) are arranged as recording targets. As shown in FIG. 2 (b), if the predetermined number is, for example, 5, a unit for sequentially allocating and recording a series of image data sequentially input from the camera 11 in time series. It is used as a “recording target group”.

  The total number of groups and a certain number of recording target groups are appropriately determined according to an arbitrary ratio of the recording target group to the capacity of the recording medium 13, the use of image data, recording conditions, and the like. Each group records image data in a ring buffer format.

  The five adjacent groups constituting the recording target group are used for recording new data, and the remaining three groups other than the recording target group are used for recording old data. By sequentially recording a series of data input from the camera 11 in time series in consecutive sectors in the recording target group, file fragmentation is suppressed. This can be expected to increase the access speed to the recording medium 13.

  As shown in FIG. 2C, the five adjacent groups forming the recording target group are sequentially shifted one by one in a certain direction. 3 and 4 are explanatory diagrams showing in detail the migration of recording target groups. 3 and 4, the memory area of the recording medium 13 is divided into ten, and five groups in an adjacent array are selected as recording target groups.

  Then, a certain group in the array constituting the recording target group is set as a migration determination target. Specifically, for example, it may be determined as the first group among the groups constituting the recording target group. In the process of allocating and recording a series of data within the recording target group, if the capacity of the group that is the target of migration is full of data, the array that constitutes the recording target group and the transition judgment target within it A group is moved one group at a time in a certain direction and selected as a new recording target group.

  As shown in FIG. 4, one end side (end) group in the arrangement of all groups is set as a group logically adjacent to the other end side (start), and the transition of the recording target group is repeated cyclically. Thereby, the number of times of recording for each group of the recording medium 13 is kept uniform, and concentration of recording to a specific group can be prevented. Accordingly, it is possible to suppress the occurrence of defective sectors in the recording medium 13.

FIG. 5 is a flowchart showing processing at the time of recording image data.
In the data recording apparatus 10, the task that executes the recording process waits until a recording command is received (step S101). When a recording command is received, first, a recording target group to which a series of data is distributed is determined (step S102).

  Next, the required number of sectors is calculated from the data length to be recorded, and the free area in the recording target group is confirmed (step S103). If there is sufficient free space (step S103; yes), a series of data is distributed and recorded in each group constituting the recording target group (step S107). On the other hand, if there are not enough free areas (step S103; no), it is confirmed whether or not a group having no free areas is the target of migration determination (step S104).

  If it is not a group to be transferred (step S104; no), a series of data is distributed and recorded for each group constituting the recording target group (step S106) as it is (step S107). On the other hand, if it is a group to be transferred (step S104; yes), the array forming the recording target group and the group to be transferred are transferred one by one in a certain direction (step S105). A series of data is distributed and recorded in a new recording target group (step S107).

  Thereafter, the next writing position is determined (step S108). If any of the recording target groups including the group to be transferred is filled with data, newly recorded data in the group is overwritten in a ring buffer format. As a result, the latest data can be stored at a high speed without deleting or moving the data. The above processing is executed by the image storage substrate 12.

  Further, the selection pattern of the present embodiment will be described schematically. 6 to 10 are explanatory diagrams schematically illustrating an image of recording five pieces of image data on the recording medium 13 per second based on the group transfer process in FIGS. 3 and 4 described above. The recording process here follows the flowchart shown in FIG. For simplification, it is assumed that the file size of each group is constant, and 12 pieces of image data are included in one group.

  As shown in FIG. 6, one second after the recording process is started, five groups # 0, # 1, # 2, # 3, and # 4 are recorded from one end (end) in the arrangement of all groups. The target group is selected, and one piece of image data is allocated and stored in each group. As shown in FIG. 7, when 12 seconds have elapsed, the five groups # 0, # 1, # 2, # 3, and # 4 that have been recording target groups so far have full capacity.

  At this time, since the capacity of the group # 0, which is the target of the migration determination among the recording target groups, is filled with data, the groups # 0 to # 4 in the array constituting the recording target group and the target of the migration determination among them. A certain group # 0 is moved one group at a time in a certain direction. As a result, as shown in FIG. 8, five groups of arrays # 1 to # 5 are selected as new recording target groups, and the image data is assigned to each group # 1 to # 5, one per second. It is allocated and saved one by one.

  Such migration of the recording target group is executed when the capacity of the group subject to the determination of the first transition among the recording target groups at that time becomes full including the overwriting. Then, as shown in FIG. 9, in the transition of the recording target group, one end (end) group # 9 in the arrangement of all groups is set as a group logically adjacent to the other end (start) # 0. The transition of the recording target group is repeated cyclically.

  FIG. 10 is a table showing the number of times the recording target group has been transferred and the number of times each group has been overwritten. In the figure, the vertical represents a group, and the horizontal represents the number of transitions. As described above, with the shift of the recording target group, there is a difference in the number of overwriting for each group in the short term, but it becomes almost uniform in the long term. Therefore, as described above, the number of times of recording for each group of the recording media 13 is kept uniform, and concentration of recording in a specific group can be prevented.

  In this way, in the data recording apparatus 10, it is only necessary to move and circulate the array of recording target groups one by one, and each time a series of data is recorded in units of recording target groups. There is no need for complicated processing such as movement or formation of an empty area. Regardless of such simple and high-speed recording processing, the data retention time within a fixed capacity of the recording medium 13 is divided into two stages: short-term recording in the recording target group and long-term recording in other groups. Layered.

  That is, new image data can be recorded with a fine rate, and old image data can be stored for a long period of time although the rate is low. Therefore, in the post-verification when an unexpected event occurs, it is possible to perform detailed verification using image data with a fine rate for upcoming verification, while it is necessary to verify old image data In this case, the image data stored for a long time can be verified though the rate is lowered. The image data recorded on the recording medium 13 can be read on the monitor 21 by the drawing side device 20 and viewed at any time.

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to the above-described embodiments, and there are changes and additions within the scope not departing from the gist of the present invention. Are also included in the present invention. For example, the image data is not limited to still image data, and may be configured to always record moving image data or high bit rate audio.

  The data recording apparatus according to the present invention can be applied to a one-man vehicle door, a luggage storage area, a guest room, a driver's cab, a railroad crossing, and other monitoring applications in the railway field, and other fields where images are used.

DESCRIPTION OF SYMBOLS 10 ... Data recording device 11 ... Camera 12 ... Image storage board 13 ... Recording medium 14 ... Power supply board 20 ... Drawing side apparatus 21 ... Monitor

Claims (2)

In a data recording apparatus for constantly recording a series of data input continuously in time series for subsequent verification, on a recording medium of a certain capacity,
Recording the memory area of the recording medium into a plurality of continuous groups, among which a group of two or more and a certain number of adjacent arrays less than the total number of groups is a unit for sequentially allocating and recording the series of data. Select as target group,
In the process of allocating and recording a group of data in the recording target group, a certain group in the array constituting the recording target group is the target of transition determination, and the capacity of the group that is the target of transition determination is full of data In this case, the array constituting the recording target group is moved one group at a time in a certain direction, and selected as a new recording target group,
A data recording apparatus, wherein a group on one end side in the array of all groups is set as a group logically adjacent to the other end side, and the transition of the recording target group is repeated cyclically. When any capacity of the recording target group including the group that is the target of the migration determination is filled with data, newly recorded data in the group is overwritten in a ring buffer format. The data recording apparatus according to claim 1.

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