JP2002008312A - Data memory device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow long-term saving of digital data, such as videos or speech. SOLUTION: Input digital data, such as videos or speech, are successively stored in a memory section 3 and are accumulated. A control section 7 monitors the memory section 3 and when the free capacity of the memory section 3 attains a predetermined capacity or when a timer section 5 clocking the lapse time after the memory section 3 starts storage, the data are read out successively in the order in which the data are stored from the memory section 3 and the processing to decrease the data quantity is performed in a data processing means 4. Which of the free capacity or the lapse time is to be used as a reference is preferably set by a processing reference setting means 6a. There is a mode shown in Figure in addition to a data compression processing mode 4a as the modes of the processing of the processing means 4 described above and these modes are previously set by a video processing setting section 6b and a speech processing setting section 6c. The data processed in the processing means 4 are converted to the data prior to the processing and are restored in the memory section 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a data storage device, and more particularly, to an arrangement for enabling long-term storage of digital data such as video or audio.

[0002]

2. Description of the Related Art Conventionally, for example, in a surveillance camera system or the like, data such as surveillance video or audio is stored and stored in a memory unit or the like for later confirmation. However, the memory part used also has a memory capacity,
At some point, the memory capacity is full. Conventionally, when this state is reached, new data is overwritten in order from oldest data and data is stored. Therefore, old data is sequentially erased from the time when the memory capacity is full.

[0003]

However, there is a case where old data is desired to be stored as long as possible. For example, it can be said that the demand is strong in the surveillance camera system. In this case, if the memory capacity is increased, long-term storage is possible, but on the other hand, the cost is increased and the adoption is not easy. Therefore, it would be advantageous if data could be stored for a long period of time without increasing the memory capacity. In this case, a slight reduction in data quality for old data is often permitted. The present invention has been made from such a viewpoint, and an object of the present invention is to provide a data storage device capable of storing data for a long period of time while permitting deterioration in quality of old stored data.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a memory section for sequentially storing and accumulating digital data such as video or audio data and a data read from the memory section are reduced in data amount of the data. Data processing means for processing the data, and a control part for controlling the memory part and the data processing means, wherein the data processed by the data processing means is replaced with the data before the processing and the data is stored again in the memory part. A storage device is provided.

Further, reading from the memory section is performed in order from the oldest data before the data processing.

[0006] Further, the reading of data from the memory section and the processing by the data processing means are performed by the control section monitoring the free space of the memory section, based on when the free space becomes a predetermined capacity. Start.

Alternatively, a timer unit is provided under the control unit for measuring an elapsed time after the start of storage of the data reading from the memory unit and the processing by the data processing unit. The unit may start on the basis of a predetermined elapsed time measurement.

Further, a processing reference setting unit is provided under the control unit, and the processing reference setting unit selects a reference for starting processing by the data processing means and enables setting.

The processing by the data processing means may be
This is frame rate change processing for video data.

Alternatively, the process by the data processing means is a process of changing a data compression ratio of video data.

Alternatively, the processing by the data processing means is a screen size reduction processing for video data.

Alternatively, the processing by the data processing means is a key area extraction processing in the video data.

An image processing setting section is provided under the control section, and the image processing setting section controls the frame rate change processing, the data compression rate change processing, the screen size reduction processing, and the important area extraction processing. One or an arbitrary plurality can be set.

The processing by the data processing means may be
Sampling data reduction processing for audio data is performed.

Alternatively, the processing by the data processing means is a quantization bit number conversion processing in audio data.

Alternatively, an audio decompression processor is provided in the data processing means, and the audio decompression processor once decompresses the data to be subjected to the quantization bit number conversion processing, and the data after the decompression processing has the quantized bit. Performs number conversion processing.

Alternatively, the process by the data processing means is a process of changing a data compression ratio of audio data.

An audio processing setting unit is provided under the control unit, and the audio processing setting unit performs one of the sampling data reduction processing, the quantization bit number conversion processing, and the data compression rate changing processing. Allows setting for any multiple.

Further, the frame rate change processing, the screen size reduction processing or the sampling data reduction processing is performed on data after a predetermined time from the start of each data.

[0020]

Embodiments of the present invention will be described below with reference to the drawings based on embodiments. FIG. 1 is a block diagram of a main part showing an embodiment of a data storage device according to the present invention, and FIG. 2 is an explanatory diagram relating to FIG. In FIG. 1, S1 is input analog video data, S2 is input digital video data, S3 is input analog audio data, and S4 is input digital audio data. 1 is the input analog video data
An A / D converter for video, which converts S1 into digital video data, and an A / D converter 2 for audio, which converts input analog audio data S3 into digital audio data. A memory unit 3 stores and stores the input new video and audio data, and rewrites old data into data processed by the data processing unit 4 described below. Numeral 4 denotes data processing means for performing processing for reducing the data amount of old data stored in the memory unit 3 according to the set processing mode.

As the processing mode, for video data, a data compression processing mode for further compressing the video data
4a, a frame rate change processing mode 4b for changing the frame rate of the video, a screen size reduction processing mode 4c for reducing the screen size, and a priority area extraction processing mode 4d for extracting the priority area. Data compression processing mode 4e for further compression, sampling data reduction processing mode 4f for reducing the sampling data, quantization bit number conversion processing mode for converting the quantization bit number
4g. Reference numeral 4h denotes an audio decompression processor for temporarily decompressing audio data. Reference numeral 5 denotes a timer section, which counts an elapsed time after the memory section 3 starts storing data. Reference numeral 6 denotes a setting unit for setting a reference or a processing mode for starting processing in the data processing means 4, and more specifically, a processing reference setting unit 6 for setting a reference for starting processing.
a, a video processing setting unit 6b for setting a processing mode for video data, and an audio processing setting unit 6c for setting a processing mode for audio data. A control unit 7 controls the memory unit 3, the data processing unit 4, the timer unit 5, the setting unit 6, and the like. Reference numeral 8 denotes a bus line that connects the above functional blocks.

Next, the operation of the present invention will be described. Each of the analog video or audio data (S1, S3) is converted into digital data by a video A / D conversion unit 1 or an audio A / D conversion unit 2, and the converted data is sent to a control unit. Under the control of 7, data compression processing is performed by the data compression processing mode 4a for video and the data compression processing mode 4e for audio of the data processing means 4, respectively.
The data after the compression processing is stored in the memory unit 3. In addition, digital video or audio data (S2, S
4) is stored in the memory unit 3 after the same data compression processing as described above. In this manner, every time data is input, the data is stored in the memory unit 3, and the data is accumulated, so that the memory data amount increases. Therefore, the memory capacity becomes full at some point. Therefore, a certain criterion is set, and when the criterion is reached, data is read from the memory unit 3 and the data processing unit 4 starts a process of reducing the data amount.

As a criterion, the control unit 7 monitors the free space of the memory unit 3 and when the free space reaches a predetermined capacity, or when the memory unit 3 starts storing data. Is reached when a predetermined time has elapsed. The latter elapsed time follows the time measurement by the timer unit 5. The above criteria can be set to any one. This is the processing reference setting unit 6a of the setting unit 6, and the setting unit 6a sets the above reference to either the free space of the memory unit 3 or the elapsed time. Note that a configuration in which the setting function is not provided and one of the above-described standards is fixed may be employed. When the reference according to the setting of the processing reference setting unit 6a is reached, the control unit 7 reads data from the memory unit 3 and causes the data processing unit 4 to start processing for reducing the data amount. In this case, the data reading from the memory unit 3 is performed in the order from the old data which has not been processed yet to reduce the data amount. Further, the data processing means 4
The processing modes described above include the modes described above and those shown in the drawing. One or more of these modes are set in advance by the video processing setting unit 6b for video data and by the audio processing setting unit 6c for audio data. Keep it.

Hereinafter, each processing mode will be described. In the video data, the data compression processing mode 4a is a mode (method) for further compressing read data (processing target data) from the memory unit 3 that has already been compressed. The frame rate change processing mode 4b holds the data state (frame rate) of data from the start of video data to be processed to a predetermined time and changes the frame rate of data after the same time. Mode. For example, as shown in FIG. 2A, the video data to be processed is “30 frames (F) / 1
In the case of data having 10 minutes in "second (S)", the data state "30 frames / 1 second" is held until a certain time (for example, 5 minutes) after the start of data, and " Reduce the number of frames per second, such as "15 frames per second". Alternatively, a mode in which the frame rate is changed immediately after the start of the data may be adopted.

The screen size reduction processing mode 4c is a mode for performing processing such as data thinning so as to reduce the size (horizontal direction and vertical direction) of a display image. For example, the number of pixels and the number of lines are thinned out so that the image size before processing is reduced to three quarters in both the horizontal and vertical directions. Regarding this size reduction process,
As in the case of the frame rate change processing mode 4b,
Any processing may be performed immediately after the start of data or from data after a predetermined time after the start of data. The priority area extraction processing mode 4d is a mode for extracting (cutting out) only a part of a particularly important area from areas of video data to be processed. In this case, the region to be extracted is set in advance. For example, as shown in FIG. 2B, only video data of a preset central region (b) is extracted from the video data region (a). On the other hand, in the audio data, the data compression processing mode 4e is a mode in which, similarly to the case of the video data, the data read from the memory unit 3 that has been subjected to the compression processing is further compressed.

Also, a sampling data reduction processing mode
4f holds the data state of the data from the start of the audio data to be processed to a predetermined time,
In this mode, data after the same time (= sampling data) is thinned out. The thinning process is set in advance, and for example, one data is thinned out for two data. In this processing mode, the processing may be performed immediately after the start of the data. The quantization bit number conversion processing mode 4g is a mode for performing conversion so as to reduce the number of bits (quantization bit number) forming each piece of audio data to be processed. For example, when each data before processing is composed of 8 bits, it is converted into data of 4 bits. Since the process of reducing the number of bits to half as in this example is relatively easy, the data read from the memory unit 3 may be directly processed. In the case of conversion, the data read from the memory unit 3 is subjected to data decompression processing by the audio decompression processing unit 4h to return to the original data, and the decompressed data is subjected to quantization bit number conversion processing. Conversion processing may be performed in mode 4g.

The above is a description of each mode. When a plurality of these modes are selected, the processing in each mode is performed repeatedly. Each data processed in such a manner as to reduce the data amount is re-stored (stored) in the memory unit 3 under the control of the control unit 7. The state of the memory unit 3 after the re-storage becomes a state in which the free space is increased as compared with before the processing, and new data can be stored. When the memory unit 3 again reaches the above-mentioned standard, the memory unit 3
More unprocessed data is read out, and the data processing unit 4 performs processing to reduce the data amount. It should be noted that although the data of the re-storage is reduced in data quality due to the reduced data amount, it is considered that the data is old and has no practical effect in many cases.

[0028]

As described above, according to the present invention, of the stored data of video or audio, the amount of old data can be reduced in various modes and stored again. This allows long-term storage without erasing old data even with limited memory capacity. In addition, the total memory data amount increases.

[Brief description of the drawings]

FIG. 1 is a main block diagram showing an embodiment of a data storage device according to the present invention.

FIG. 2 is a diagram for explaining FIG. 1;

[Explanation of symbols]

 1, 2 A / D conversion unit 3 Memory unit 4 Data processing means 4a Data compression processing mode 4b Frame rate change processing mode 4c Screen size reduction processing mode 4d Focused area extraction processing mode 4e Data compression processing mode 4f Sampling data reduction processing mode 4g Quantization bit number conversion processing mode 4h Audio expansion processing section 5 Timer section 6 Setting section 6a Processing reference setting section 6b Video processing setting section 6c Audio processing setting section 7 Control section 8 Bus line

Claims (16)

[Claims] 1. A memory unit for sequentially storing and accumulating digital data such as video or audio, and data processing means for processing data read from the memory unit so as to reduce the data amount of the data. A data storage device, comprising: a control unit that controls the memory unit and the data processing unit, wherein data processed by the data processing unit is replaced with data before the processing and stored again in the memory unit. 2. The data storage device according to claim 1, wherein the data read from the memory unit is sequentially read from the oldest data before the data processing. 3. The data reading from the memory unit and the processing by the data processing means are performed by the control unit monitoring the free space of the memory unit, based on when the free space becomes a predetermined capacity. The data storage device according to claim 1, wherein the data storage is started. 4. A timer unit for measuring an elapsed time after starting to store data in said memory unit under the control unit for reading data from said memory unit and processing by said data processing means, 2. The data storage device according to claim 1, wherein the unit starts on the basis of a predetermined elapsed time. 5. A processing reference setting unit provided under the control unit, wherein the processing reference setting unit selects and sets a reference for starting processing by the data processing means. The data storage device according to claim 4. 6. The data storage device according to claim 1, wherein the processing by said data processing means is a frame rate change processing for video data. 7. The data storage device according to claim 1, wherein the processing by said data processing means is a processing of changing a data compression ratio of video data. 8. The data storage device according to claim 1, wherein the processing by said data processing means is a screen size reduction processing on video data. 9. The data storage device according to claim 1, wherein the processing by said data processing means is a key area extraction processing in video data. 10. A video processing setting unit is provided under the control unit, and the video processing setting unit performs one of the frame rate changing process, the data compression ratio changing process, the screen size reducing process, and the important region extracting process. The data storage device according to claim 6, wherein one or an arbitrary plurality of data are set. 11. The data storage device according to claim 1, wherein the processing by said data processing means is a sampling data reduction processing on audio data. 12. The data storage device according to claim 1, wherein the processing by said data processing means is a quantization bit number conversion processing in audio data. 13. An audio decompression processing unit is provided in said data processing means, said audio decompression processing unit temporarily decompresses the data to be subjected to said quantization bit number conversion processing, and said data after said decompression processing is subjected to said quantization bit processing. 13. The data storage device according to claim 12, wherein a number conversion process is performed. 14. The data storage device according to claim 1, wherein the processing by said data processing means is a change processing of a data compression ratio in audio data. 15. An audio processing setting unit is provided under the control unit, and one of the sampling data reduction processing, the quantization bit number conversion processing, and the data compression rate changing processing is provided by the audio processing setting unit. 15. The data storage device according to claim 11, wherein an arbitrary plurality is set. 16. The data processing method according to claim 6, wherein the frame rate change processing, the screen size reduction processing, or the sampling data reduction processing is performed on data after a predetermined time from the start of each data. The data storage device according to claim 11.