WO2015132885A1

WO2015132885A1 - Moving image compression apparatus and moving image compression/decompression system

Info

Publication number: WO2015132885A1
Application number: PCT/JP2014/055481
Authority: WO
Inventors: 孝治久納; 聡大郷
Original assignee: エヌ・ティ・ティレゾナント・テクノロジー株式会社
Priority date: 2014-03-04
Filing date: 2014-03-04
Publication date: 2015-09-11
Also published as: JPWO2015132885A1; JP5739079B1

Abstract

Hash values are calculated from the respective frame images constituting moving image data. The hash values calculated for the respective frame images are then listed in order of the frame images, thereby generating a hash table, which is then stored. Those ones of the frame images the hash values of which are different from one another and those hash values are stored in correspondence with each other, while only one of those ones of the frame images the hash values of which are identical to one another is stored with the others deleted. In this way, the quantity of frame images to be stored can be reduced, thereby reducing the data amount of the moving images as a whole.

Description

Movie compression apparatus and movie compression / decompression system

The present invention relates to a moving image compression apparatus and a moving image compression / decompression system.

In recent years, usage scenes of moving image data such as moving image advertisements and web services on websites are rapidly increasing. Usually, since moving image data has a huge amount of data, data compression is performed so as to facilitate storage and communication (see, for example, Patent Document 1).
JP 2006-191534 A

The data processing apparatus described in Patent Document 1 generates compressed encoded data by compressing and encoding the supplied video signal, thereby reducing the amount of data to be communicated. Also, protected compressed encoded data is generated by replacing selected data bits of the compressed encoded data with data bits of a secure hash value.

By the way, data compression is roughly divided into lossless compression and lossy compression. Lossless compression is a method of reducing the number of bits by identifying and removing statistical redundancy, and information is not lost. On the other hand, lossy compression is a method of reducing the number of bits by identifying and removing unnecessary information, and some information is lost by compression. Therefore, in irreversible compression, it is necessary to reproduce the original image by complementing the information lost during the compression during the decompression.

Generally, moving image compression is performed by combining compression of still images (intraframe compression) and time-series compression (interframe compression) constituting each frame. The inter-frame compression is a method in which frame sequences are compared before and after and only a region having a change is stored as difference data. Most of the video compression algorithms using these mechanisms are lossy compression. Representative examples of this type of moving image compression algorithm include MPEG, Motion-JPEG, H.264, and H.264. H.264, VC-2, and the like are known.

However, in conventional video compression algorithms represented by MPEG and the like that employ an irreversible compression method, if the compression rate is too high, the reproducibility (image quality) of the original image deteriorates. The algorithm is designed with consideration. For this reason, there is a problem that it is difficult to increase the compression rate while maintaining good image quality, to reduce the storage capacity of the moving image data, and to increase the communication speed.

The present invention has been made to solve such a problem, and while maintaining the reproducibility (image quality) of the original image, the storage capacity of the moving image data is reduced and the communication speed is increased. The purpose is to be able to.

In order to solve the above-described problems, in the present invention, a hash value is calculated from each frame image constituting the moving image data, and a plurality of hash values calculated for each frame image are listed in the order of each frame image. A hash table is generated and stored. In addition, among each frame image, a plurality of frame images having different hash values are stored in association with each hash value, while for a plurality of frame images having the same hash value, only one of them is stored and the others are deleted. Like to do.

According to the present invention configured as described above, each frame image constituting the moving image data is replaced with a hash value having an extremely small data amount. The original frame image is saved because it is necessary for reproduction from the hash value, but only one of the frame images with the same hash value is stored and the others are deleted. The overall data volume is reduced. Also, since the replacement of the frame image with the hash value is lossless compression, the original frame image can be completely reproduced from the hash value. Thereby, the compression rate of the moving image data can be increased while maintaining the reproducibility (image quality) of the original image, and the storage capacity of the moving image data can be reduced or the communication speed can be increased.

It is a whole block diagram which shows the structural example of the moving image compression / decompression system provided with the moving image compression apparatus by 1st Embodiment. It is a block diagram which shows the function structural example of the client apparatus by 1st Embodiment. It is a block diagram which shows the function structural example of the image generation server by 1st Embodiment. It is an image figure showing typically an example of a hash table and a frame picture memorized by a compression data storage part in a 1st embodiment. It is a flowchart which shows the operation example of the moving image compression / decompression system by 1st Embodiment. It is a block diagram which shows the function structural example of the client apparatus by 2nd Embodiment. It is a block diagram which shows the function structural example of the image generation server by 2nd Embodiment. It is an image figure showing typically an example of a plurality of hash tables and a frame picture memorized by a compression data storage part in a 2nd embodiment. It is a flowchart which shows the operation example of the moving image compression / decompression system by 2nd Embodiment. It is a whole block diagram which shows the structural example of the moving image compression / decompression system provided with the moving image compression apparatus by 3rd Embodiment. It is a block diagram which shows the function structural example of the client apparatus by 3rd Embodiment. It is a block diagram which shows the function structural example of the image generation server by 3rd Embodiment. It is a block diagram which shows the function structural example of the image storage server by 3rd Embodiment.

(First embodiment)
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram illustrating a configuration example of a moving image compression / decompression system including a moving image compression device according to the first embodiment. As shown in FIG. 1, the moving image compression / decompression system according to the first embodiment includes a client device 100 and an image generation server 200, and is configured to be connectable via a communication network such as the Internet 500.

FIG. 2 is a block diagram illustrating a functional configuration example of the client device 100 according to the first embodiment. As shown in FIG. 2, the client device 100 according to the first embodiment includes a communication I / F unit 11, a request transmission unit 12, a compressed data reception unit 13, a compressed data storage unit 14, and a moving image expansion unit as its functional configuration. 15 and a second compressed data storage unit 110. The moving image decompression unit 15 includes a hash value reading unit 15a and a moving image reproduction unit 15b as specific functional configurations.

The above functional blocks 11 to 15 can be configured by any of hardware, DSP (Digital Signal Processor), and software. For example, when configured by software, each of the functional blocks 11 to 15 actually includes a CPU, RAM, ROM, etc. of a computer, and is stored in a recording medium such as a RAM, ROM, hard disk, or semiconductor memory. Is realized by operating.

FIG. 3 is a block diagram illustrating a functional configuration example of the image generation server 200 according to the first embodiment. As shown in FIG. 3, the image generation server 200 according to the first embodiment includes a communication I / F unit 21, a request reception unit 22, a moving image generation unit 23, a moving image compression unit 24, and a compressed data transmission unit as its functional configuration. 25 and a compressed data storage unit 210. As a specific functional configuration, the moving image compression unit 24 includes a hash calculation unit 24a, a hash table generation unit 24b, and an image thinning unit 24c.

The above functional blocks 21 to 25 can be configured by any of hardware, DSP, and software. For example, when configured by software, each of the functional blocks 21 to 25 is actually configured by including a CPU, RAM, ROM, etc. of a computer, and a program stored in a recording medium such as RAM, ROM, hard disk, or semiconductor memory. Is realized by operating.

The communication I / F unit 11 of the client apparatus 100 and the communication I / F unit 21 of the image generation server 200 communicate with each other via the Internet 500. The request transmission unit 12 of the client device 100 transmits an image acquisition request to the image generation server 200 via the Internet 500. This image acquisition request is generated, for example, when the user of the client device 100 operates an operation unit (not shown).

The request reception unit 22 of the image generation server 200 receives an image acquisition request sent from the client device 100 via the Internet 500. The moving image generating unit 23 generates moving image data in response to the image acquisition request received by the request receiving unit 22.

For example, the moving image generation unit 23 generates moving image data by performing camera shooting with a smartphone (not shown) connected to the image generation server 200 fixed. Alternatively, the screen of the smartphone is sequentially changed, and the moving image data is generated by performing capture processing of each changed screen.

Here, camera shooting and screen capture are continuously performed a plurality of times in response to a single image acquisition request output from the client device 100. In this case, the processing may be terminated when a predetermined time has elapsed after the generation of the moving image data is started, or the processing is continued until a processing stop command is output from the client device 100 next time. May be. Alternatively, the processing may be continued until the connection between the client device 100 and the image generation server 200 is disconnected.

In this way, video data is generated by camera shooting and screen capture with smartphones, whether camera shooting is performed without problems with smartphones of various models, whether screen transition is performed without problems, This is because the client apparatus 100 can access the image generation server 200 and verify remotely whether or not the application installed on the smartphone is operating normally.

The moving image compression unit 24 corresponds to a moving image compression device, and the moving image data generated by the moving image generation unit 23 is processed by the hash calculation unit 24a, the hash table generation unit 24b, and the image thinning unit 24c. Perform compression.

The hash calculation unit 24a performs a hash calculation on each frame image constituting the moving image data generated by the moving image generation unit 23, and calculates a hash value as a feature quantity that can identify the identity of the frame image. A known method can be applied to the hash calculation itself.

The hash table generation unit 24b generates a hash table formed by listing a plurality of hash values calculated for each frame image by the hash calculation unit 24a in the order of each frame image, and stores the hash table in the compressed data storage unit 210. Remember me.

The image thinning unit 24c, among the frame images constituting the moving image data generated by the moving image generation unit 23, each of a plurality of frame images having different hash values calculated by the hash calculation unit 24a in the hash table. The compressed data storage unit 210 stores the hash value in association with the hash value. On the other hand, among a plurality of frame images having the same hash value among the frame images constituting the moving image data, only one of them is stored in the compressed data storage unit 210 in association with the same hash value in the hash table. .

FIG. 4 is an image diagram schematically showing an example of a hash table and a frame image stored in the compressed data storage unit 210. FIG. 4A shows an example of a hash table stored by the hash table generation unit 24b. FIG. 4B shows an example of a frame image stored by the image thinning unit 24c. This set of hash tables and frame images is used as compressed data for moving images.

As shown in FIG. 4A, the hash table generation unit 24b sequentially stores a plurality of hash values calculated by the hash calculation unit 24a for each frame image constituting the moving image data in the order of the frame images. I will let you.

As described above, when the moving image generation unit 23 generates moving image data by camera shooting or screen capture, there may be many of the same frame images. However, the hash table generation unit 24b lists the hash values calculated by the hash calculation unit 24a for all the frame images in the order of the frame images regardless of whether or not they are the same frame image. Let me remember.

On the other hand, as shown in FIG. 4B, the image thinning unit 24c stores a plurality of frame images having different hash values in association with each hash value in the hash table. On the other hand, for a plurality of frame images having the same hash value, only one (for example, the frame image stored first) is stored in association with the same hash value in the hash table.

That is, every time a hash value is calculated by the hash calculation unit 24a, the image thinning unit 24c determines whether or not the hash value is already stored in the hash table of the compressed data storage unit 210. Only when it is determined that there is no frame image, the frame image corresponding to the hash value is added to the compressed data storage unit 210 and stored.

On the other hand, when it is determined that the hash value is already stored in the hash table of the compressed data storage unit 210, the image thinning unit 24c adds the frame image corresponding to the hash value to the compressed data storage unit 210 and stores it. Only the association between the already stored frame image and the hash value is performed. In this way, image compression is performed by thinning out frame images to be stored in the compressed data storage unit 210 to reduce the data capacity.

The compressed data transmission unit 25 generates compressed data generated by the moving image compression unit 24 and stored in the compressed data storage unit 210, that is, a hash table and a plurality of frame images associated with each hash value of the hash table on the Internet. The data is transmitted to the client apparatus 100 via 500.

The transmission of the compressed data is not necessarily performed after the hash table stored in the compressed data storage unit 210 is completed. That is, each time one hash value is added to the hash table of the compressed data storage unit 210, the compressed data may be transmitted sequentially. Further, the processing of the image thinning unit 24c may be performed, and the compressed data may be stored in the compressed data storage unit 210 asynchronously. In addition to the hash value and the frame image, the compressed data transmission unit 25 may transmit the metadata such as the relative time of the frame image together.

Here, when the set of the hash value and the frame image is stored in the compressed data storage unit 210 by the image thinning unit 24c, the compressed data transmission unit 25 converts the set of the hash value and the frame image into the compressed data. To the client device 100. On the other hand, when the frame image is thinned out and only the hash value is stored in the compressed data storage unit 210, only the hash value is transmitted to the client apparatus 100 as compressed data.

When the frame image is thinned out and only the hash value is stored in the compressed data storage unit 210, the same frame image has already been transmitted to the client apparatus 100 in the previous frame. In this case, the transmission data amount is reduced by transmitting only the hash value having a small data amount and omitting the transmission of the frame image.

The compressed data receiving unit 13 of the client device 100 receives the compressed data (a combination of a hash value and a frame image or only a hash value) transmitted by the compressed data transmitting unit 25 of the image generation server 200. The compressed data storage unit 14 stores the compressed data received by the compressed data receiving unit 13 in the second compressed data storage unit 110.

Here, when the compressed data receiving unit 13 receives a set of a hash value and a frame image as compressed data, the compressed data storage unit 14 adds the hash value to the hash table and stores it, and also stores the frame image in the hash image. Store in association with the hash value.

On the other hand, when the compressed data receiving unit 13 receives only the hash value as the compressed data, the compressed data storage unit 14 adds the hash value to the hash table and stores the hash value. The frame image already stored in association is associated with the hash value newly added to the hash table. Accordingly, the compressed data stored in the second compressed data storage unit 110 is also in the same state as shown in FIG.

The video decompression unit 15 corresponds to a video decompression device, and performs image decompression on the compressed data stored in the second compressed data storage unit 110 by processing of the hash value reading unit 15a and the video reproduction unit 15b. Do. The hash value reading unit 15a sequentially reads a plurality of hash values from the hash table stored in the second compressed data storage unit 110 based on the compressed data transmitted from the image generation server 200.

Note that reading of the hash value is not necessarily performed after the hash table stored in the second compressed data storage unit 110 is completed. That is, each time a hash value is added to the hash table of the second compressed data storage unit 110 by the compressed data storage unit 14, the hash value may be read sequentially. In this way, it is possible to shorten the time from when the client apparatus 100 transmits an image acquisition request to the image generation server 200 until the corresponding moving image starts to be played.

The moving image reproducing unit 15b sequentially reads a plurality of frame images corresponding to the plurality of hash values sequentially read by the hash value reading unit 15a from the second compressed data storage unit 110, and executes reproduction of the moving image. Since the hash table stored in the second compressed data storage unit 110 is a list of hash values in the order of the frame images constituting the moving image, the hash values are sequentially processed by the hash calculation unit 24a. The moving image reproduction unit 15b sequentially reproduces the frame images corresponding to the hash values, thereby reproducing the moving image.

FIG. 5 is a flowchart showing an operation example of the moving picture compression / decompression system according to the first embodiment configured as described above. First, the request transmission unit 12 of the client device 100 transmits an image acquisition request to the image generation server 200 via the Internet 500 (step S1). In the image generation server 200, when the request acquisition unit 22 receives this image acquisition request, the moving image generation unit 23 generates a frame image of the moving image data corresponding to the image acquisition request (step S2).

Next, the hash calculator 24a performs a hash calculation on the frame image of the moving image data generated by the moving image generator 23, and calculates a hash value as a feature quantity that can identify the identity of the frame image (step S3). ). Here, the hash table generation unit 24b determines whether or not the same hash value as the hash value calculated by the hash calculation unit 24a already exists in the hash table stored in the compressed data storage unit 210 for the current moving image generation. Is determined (step S4).

When the hash value calculated by the hash calculation unit 24a already exists in the hash table, the hash table generation unit 24b adds the hash value to the hash table and stores the hash value, and the hash value already existing in the hash table The newly added hash value is associated with the frame image already stored in the compressed data storage unit 210 in association with (step S5). Then, the compressed data transmission unit 25 reads only the hash value calculated by the hash calculation unit 24a in step S3 from the compressed data storage unit 210 and transmits it to the client device 100 (step S6).

On the other hand, when the hash value calculated by the hash calculation unit 24a does not exist in the hash table, the hash table generation unit 24b adds the hash value to the hash table and stores it. The image thinning unit 24c stores the frame image generated by the moving image generation unit 23 in step S2 in the compressed data storage unit 210 in association with the hash value newly added to the hash table (step S7). Then, the compressed data transmission unit 25 reads the set of the frame image generated by the moving image generation unit 23 in step S2 and the hash value calculated by the hash calculation unit 24a in step S3 from the compressed data storage unit 210 and reads the client. It transmits to the apparatus 100 (step S8).

Thereafter, the moving image generation unit 23 determines whether or not to end the generation of moving image data (step S9). That is, the moving image generation unit 23 disconnects the connection with the client device 100, whether a predetermined time has elapsed since the start of the generation of moving image data, whether a processing stop command has been sent from the client device 100, or not. It is determined whether or not. Here, when the generation of the moving image data is not yet finished, the process returns to step S2 to generate the next frame image. On the other hand, when the generation of moving image data ends, the processing in the image generation server 200 ends.

In the client device 100, after transmitting the image acquisition request to the image generation server 200 in step S <b> 1, the compressed data reception unit 13 transmits the compressed data (hash value and frame) transmitted by the compressed data transmission unit 25 of the image generation server 200. A pair with an image or only a hash value is received (step S10).

Here, the compressed data storage unit 14 determines whether or not the compressed data receiving unit 13 has received a set of a hash value and a frame image as compressed data (step S11). When the compressed data receiving unit 13 receives a set of a hash value and a frame image, the compressed data storage unit 14 causes the second compressed data storage unit 110 to store the hash value in addition to the hash table. The frame image is stored in association with the hash value (step S12).

On the other hand, when the compressed data receiving unit 13 receives only the hash value as the compressed data, the compressed data storage unit 14 causes the second compressed data storage unit 110 to store the hash value in addition to the hash table. Then, the frame image that is already stored in association with the same hash value as that hash value is associated with the hash value newly added to the hash table (step S13).

Next, the hash value reading unit 15a reads the hash value stored in addition to the hash table of the second compressed data storage unit 110 in step S12 or step S13 (step S14). Then, the moving image reproducing unit 15b reads out and reproduces the frame image corresponding to the hash value read by the hash value reading unit 15a from the second compressed data storage unit 110 (step S15).

Thereafter, the moving image reproducing unit 15b determines whether or not to end the reproduction of the moving image data (step S16). That is, the video playback unit 15b disconnects the connection with the image generation server 200, whether or not a predetermined time has elapsed since the start of video data generation, whether or not a processing stop command has been transmitted to the client device 100, and so on. It is determined whether or not. Here, when the reproduction of the moving image data is not yet finished, the process returns to step S10, and the compressed data relating to the next frame is received. On the other hand, when the reproduction of the moving image data is finished, the processing in the client device 100 is finished.

As described above in detail, in the moving image compression / decompression system according to the first embodiment, a hash value is calculated from each frame image constituting the moving image data, and a plurality of hash values calculated for each frame image are calculated for each frame image. A hash table formed by listing in order is generated and stored. In addition, among each frame image, a plurality of frame images having different hash values are stored in association with each hash value, while for a plurality of frame images having the same hash value, only one of them is stored and the others are deleted. Like to do.

According to the first embodiment configured as described above, each frame image constituting the moving image data is replaced with a hash value having an extremely small data amount. The original frame image is saved because it is necessary for reproduction from the hash value, but only one of the frame images with the same hash value is stored and the others are deleted. The overall data volume is reduced. Also, since the replacement of the frame image with the hash value is lossless compression, the original frame image can be completely reproduced from the hash value.

Accordingly, the compression rate of the moving image data can be increased while maintaining the reproducibility (image quality) of the original image, and the capacity of the moving image data stored in the second compressed

data storage units

110 and 210 can be reduced, The amount of frame images transmitted from the image generation server 200 to the client device 100 can be reduced to increase the communication speed.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. The configuration of the moving image compression / decompression system including the moving image compression apparatus according to the second embodiment is the same as that shown in FIG.

FIG. 6 is a block diagram illustrating a functional configuration example of the client apparatus 100 according to the second embodiment. In FIG. 6, those given the same reference numerals as those shown in FIG. 2 have the same functions, and therefore redundant description is omitted here. As shown in FIG. 6, the client device 100 according to the second embodiment further includes an inquiry response unit 16 as its functional configuration.

FIG. 7 is a block diagram illustrating a functional configuration example of the image generation server 200 according to the second embodiment. Note that in FIG. 7, those given the same reference numerals as those shown in FIG. 3 have the same functions, and thus redundant description is omitted here. As shown in FIG. 7, the image generation server 200 according to the second embodiment further includes a feature amount determination unit 26 as its functional configuration. Further, instead of the image thinning unit 24c and the compressed data transmitting unit 25, an image thinning unit 24c 'and a compressed data transmitting unit 25' are provided.

The image thinning unit 24c ′ is not limited to the hash table stored in the compressed data storage unit 210 for the current movie generation, but is also stored in the compressed data storage unit 210 including the hash table stored in the past movie generation. It is determined whether or not the same hash value as the hash value calculated this time has already been stored by the hash calculator 24a for a plurality of hash tables. If the same hash value is already stored, the storage of the frame image corresponding to the hash value in the compressed data storage unit 210 is thinned out.

That is, every time a hash value is calculated by the hash calculation unit 24a for certain moving image data, the image thinning unit 24c ′ has at least one of the hash tables generated for each of the plurality of moving image data. It is determined whether it is already stored in one. Only when it is determined that the hash value is not stored in any hash table, the frame image corresponding to the hash value is stored in the compressed data storage unit 210.

FIG. 8 is an image diagram schematically showing an example of a plurality of hash tables and frame images stored in the compressed data storage unit 210 in the second embodiment. As shown in FIG. 8A, the hash table generation unit 24b generates another hash table for each of a plurality of moving image data and stores the generated hash table in the compressed data storage unit 210.

Further, as shown in FIG. 8B, the image thinning unit 24c ′ associates all the frame images with each hash value in the hash table for the frame images having different hash values through all the hash tables. Remember me. On the other hand, for a plurality of frame images having the same hash value in the same hash table or in different hash tables, the image thinning unit 24c 'stores only one of them in association with the same hash value.

The feature amount determination unit 26 determines whether or not the hash value sequentially calculated for each frame image by the hash calculation unit 24a is stored in the client device 100. Specifically, the feature amount determination unit 26 transmits the hash value calculated by the hash calculation unit 24 a to the client device 100 via the communication I / F unit 21, and the same hash value is transmitted to the client device 100. 2 is inquired as to whether it is stored in the compressed data storage unit 110. As a result, based on the response content sent from the client apparatus 100, it is determined whether or not the hash value is stored in the client apparatus 100. Then, the determination result is notified to the compressed data transmission unit 25 ′.

The compressed data transmission unit 25 ′ transmits the hash value and the frame image associated therewith to the client device 100 only when the feature value determination unit 26 determines that the hash value is not stored in the client device 100. . On the other hand, when it is determined that the hash value is already stored in the client device 100, the compressed data transmission unit 25 'transmits only the hash value to the client device 100. Note that since the hash value has already been transmitted to the client device 100 at the time of the inquiry by the feature amount determination unit 26, it may be omitted to transmit the hash value again.

For example, the client device 100 transmits a plurality of image acquisition requests to the image generation server 200, acquires compressed data (hash table and frame image) regarding a plurality of moving image data, and stores them in the second compressed data storage unit 110. In this case, the hash value and the frame image to be transmitted from the image generation server 200 to the client device 100 this time may already be stored in the client device 100. In this case, the transmission data amount is reduced by transmitting only the hash value having a small data amount and omitting the transmission of the frame image.

The inquiry response unit 16 of the client device 100 performs a process of responding to the inquiry transmitted from the feature amount determination unit 26 of the image generation server 200. That is, the inquiry response unit 16 receives the hash value transmitted from the feature amount determination unit 26 and confirms whether this has already been stored in the second compressed data storage unit 110. Then, a confirmation result as to whether or not it is stored is returned to the feature amount determination unit 26 of the image generation server 200.

FIG. 9 is a flowchart showing an operation example of the moving image compression / decompression system according to the second embodiment configured as described above. First, the request transmission unit 12 of the client device 100 transmits an image acquisition request to the image generation server 200 via the Internet 500 (step S21). In the image generation server 200, when the request acquisition unit 22 receives this image acquisition request, the moving image generation unit 23 generates a frame image of the moving image data corresponding to the image acquisition request (step S22).

Next, the hash calculation unit 24a performs a hash calculation on the frame image of the moving image data generated by the moving image generation unit 23, and calculates a hash value as a feature quantity that can identify the identity of the frame image (step S23). ). Here, the hash table generation unit 24b determines whether the same hash value as the hash value calculated by the hash calculation unit 24a already exists in the plurality of hash tables stored in the compressed data storage unit 210. (Step S24).

If the hash value calculated by the hash calculation unit 24a already exists in any hash table, the hash table generation unit 24b adds the hash value to the hash table related to the current video generation and stores it. The newly added hash value is associated with the frame image already associated with the same hash value and stored in the compressed data storage unit 210 (step S25).

On the other hand, if the hash value calculated by the hash calculation unit 24a does not exist in any hash table, the hash table generation unit 24b adds the hash value to the hash table for the current moving image generation and stores it. In addition, the image thinning unit 24c ′ stores the frame image generated by the moving image generation unit 23 in step S22 in the compressed data storage unit 210 in association with the hash value newly added to the hash table (step S26). .

Here, the feature amount determination unit 26 transmits each hash value calculated by the hash calculation unit 24a to the client device 100, and inquires whether the same hash value is already stored in the client device 100 (step S27). The inquiry response unit 16 of the client device 100 confirms whether the hash value received from the image generation server 200 is already stored in the second compressed data storage unit 110 (step S28).

Here, when the hash value related to the inquiry is stored in the second compressed data storage unit 110, the inquiry response unit 16 generates an image as a confirmation result for the inquiry that the hash value is stored in the client device 100. It returns to the feature amount determination unit 26 of the server 200 (step S29).

On the other hand, when the hash value related to the inquiry is not stored in the second compressed data storage unit 110, the inquiry response unit 16 confirms that the hash value is not stored in the client device 100 as the confirmation result for the inquiry as an image generation server. 200 is returned to the feature amount determination unit 26 (step S30).

In the image generation server 200 that has received the response to the inquiry from the client device 100, the feature amount determination unit 26 determines whether or not the hash value is stored in the client device 100 based on the response content (step S31). .

Here, when the feature value determination unit 26 determines that the hash value is stored in the client device 100, the compressed data transmission unit 25 ′ uses only the hash value calculated by the hash calculation unit 24a in step S23. The data is read from the compressed data storage unit 210 and transmitted to the client device 100 (step S32). Note that, as described above, step S32 may be omitted, and the client device 100 may use the hash value transmitted at the time of the inquiry in step S27.

On the other hand, when the feature amount determination unit 26 determines that the hash value is not stored in the client device 100, the compressed data transmission unit 25 ′ determines the frame image generated by the moving image generation unit 23 in step 22 and step S23. Then, the pair with the hash value calculated by the hash calculation unit 24a is read from the compressed data storage unit 210 and transmitted to the client device 100 (step S33).

Thereafter, the moving image generating unit 23 determines whether or not to end the generation of moving image data (step S34). Here, when the generation of the moving image data is not finished yet, the process returns to step S22 to generate the next frame image. On the other hand, when the generation of moving image data ends, the processing in the image generation server 200 ends.

In the client device 100, after making a response in step S29 or step S30, the compressed data receiving unit 13 transmits the compressed data (the hash value and the frame image) transmitted by the compressed data transmitting unit 25 ′ of the image generation server 200. A pair or only a hash value is received (step S35).

Here, the compressed data storage unit 14 determines whether or not the compressed data receiving unit 13 has received a set of a hash value and a frame image as compressed data (step S36). When the compressed data receiving unit 13 receives a set of a hash value and a frame image, the compressed data storage unit 14 adds a hash value to the hash table relating to the current moving image reproduction to the second compressed data storage unit 110. And store the frame image in association with the hash value (step S37).

On the other hand, when the compressed data receiving unit 13 receives only the hash value as the compressed data, the compressed data storage unit 14 adds the hash value to the hash table relating to the current moving image reproduction to the second compressed data storage unit 110. And the frame image already associated with the same hash value as the hash value is stored in association with the newly added hash value in the hash table (step S38).

Next, the hash value reading unit 15a reads the hash value stored in addition to the hash table of the second compressed data storage unit 110 in step S37 or step S38 (step S39). Then, the moving image reproducing unit 15b reads out and reproduces the frame image corresponding to the hash value read by the hash value reading unit 15a from the second compressed data storage unit 110 (step S40).

Thereafter, the moving image playback unit 15b determines whether or not to end the playback of the moving image data (step S41). Here, when the reproduction of the moving image data is not yet finished, the process returns to step S35, and the compressed data relating to the next frame is received. On the other hand, when the reproduction of the moving image data is finished, the processing in the client device 100 is finished.

As described above in detail, in the moving image compression / decompression system according to the second embodiment, a plurality of hash values having the same value as the hash value calculated by the hash calculation unit 24a are stored in the compressed data storage unit 210. When it is included in at least one of the hash tables, the storage of the frame image corresponding to the hash value in the compressed data storage unit 210 is thinned out.

Further, in the second embodiment, the frame image of the moving image generated by the image generation server 200 has already been transmitted from the image generation server 200 to the client device 100 at a time before that, and the second compressed data storage unit 110, the frame image is not transmitted from the image generation server 200 to the client device 100 based on the result of the inquiry using the hash value.

According to the second embodiment configured as described above, it is possible to further reduce the capacity of moving image data by reducing the amount of frame images stored in the second compressed

data storage units

110 and 210. In addition, the amount of frame images transmitted from the image generation server 200 to the client device 100 can be reduced to further increase the communication speed.

It should be noted that the frame images corresponding to the same hash value can be stored in the compressed data storage unit 210 without being thinned out, and the transmission of the frame images can be thinned out.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. FIG. 10 is an overall configuration diagram illustrating a configuration example of a moving image compression / decompression system including a moving image compression device according to the third embodiment. Note that in FIG. 10, those given the same reference numerals as those shown in FIG. 1 have the same functions, and thus redundant description is omitted here.

As shown in FIG. 10, the moving image compression / decompression system according to the third embodiment includes a client device 100, an image generation server 200, and an image storage server 300. The client device 100, the image generation server 200, and the image storage server 300 are configured to be connected to each other via the Internet 500.

FIG. 11 is a block diagram illustrating a functional configuration example of the client device 100 according to the third embodiment. In FIG. 11, components having the same reference numerals as those shown in FIG. 6 have the same functions, and thus redundant description is omitted here.

As shown in FIG. 11, the client device 100 according to the third embodiment further includes a hash list acquisition unit 17, a hash value existence determination unit 18, and a frame image acquisition unit 19 as its functional configuration. Further, a moving image reproducing unit 15b ″ is provided instead of the moving image reproducing unit 15b. The first compressed data receiving unit 13 and the first compressed data storing unit 14 are the compressed data receiving unit 13 shown in FIG. The compressed data storage unit 14 has the same function.

FIG. 12 is a block diagram illustrating a functional configuration example of the image generation server 200 according to the third embodiment. In FIG. 12, components having the same reference numerals as those shown in FIG. 7 have the same functions, and therefore redundant description is omitted here.

As shown in FIG. 12, the image generation server 200 according to the third embodiment further includes a second compressed data transmission unit 27, a hash list transmission unit 28, and an inquiry response unit 29 as its functional configuration. The first compressed data transmitter 25 'has the same function as the compressed data transmitter 25' shown in FIG.

FIG. 13 is a block diagram illustrating a functional configuration example of the image storage server 300 according to the third embodiment. As shown in FIG. 13, the image storage server 300 according to the third embodiment includes a communication interface unit 31, a second compressed data receiving unit 32, a second compressed data storing unit 33, and a request receiving unit as functional configurations. 34, a frame image transmission unit 35, an inquiry response unit 36, and a third compressed data storage unit 310.

The second compressed data transmission unit 27 of the image generation server 200 transmits the compressed data (the hash value and the frame image associated with the hash value) generated by the moving image compression unit 24 and stored in the compressed data storage unit 210 to the Internet. The image data is transmitted to the image storage server 300 via 500.

The compressed data transmitted from the second compressed data transmission unit 27 to the image storage server 300 is not the same as the compressed data transmitted from the first compressed data transmission unit 25 ′ to the client device 100. Also, the transmission timing is not the same. For example, the second compressed data transmission unit 27 transmits a set of frequently used frame images and corresponding hash values to the image storage server 300 asynchronously with the first compressed data transmission unit 25 ′.

Specifically, the second compressed data transmission unit 27 monitors the storage content of the compressed data storage unit 210, counts the number of hash values associated with one frame image, and determines a predetermined number (for example, When the number of frames becomes three or more, the pair of the frame image and the hash value is transmitted to the image storage server 300.

In response to the hash list acquisition request sent from the hash list acquisition unit 17 of the client device 100, the hash list transmission unit 28 receives the hash value list stored as a hash table in the compressed data storage unit 210 from the client device 100. Send to. As will be described later, the hash list acquisition request includes information for specifying which hash table of the plurality of hash tables stored in the compressed data storage unit 210 is requested to be acquired. .

The communication I / F unit 31 of the image storage server 300 communicates with the client device 100 and the image generation server 200 via the Internet 500. The second compressed data receiving unit 32 receives the compressed data transmitted by the second compressed data transmitting unit 27 of the image generation server 200. The second compressed data storage unit 33 stores the compressed data received by the second compressed data receiver 33 in the third compressed data storage unit 310.

The request reception unit 34 receives an image acquisition request sent together with a hash value from the frame image acquisition unit 19 of the client device 100 via the Internet 500. When the request reception unit 34 receives an image acquisition request together with the hash value, the frame image transmission unit 35 reads the frame image associated with the hash value from the third compressed data storage unit 310 and transmits the frame image to the client device 100. .

The hash list acquisition unit 17 of the client device 100 transmits a hash list acquisition request to the image generation server 200 in response to an operation of an operation unit (not shown) by the user, whereby the hash of the compressed data storage unit 210 is transmitted from the image generation server 200. Get a list of hash values stored in the table.

Here, the user can specify a desired hash table from among a plurality of hash tables stored in the compressed data storage unit 210. The designation method is arbitrary. For example, an operation for designating one of a plurality of hash tables stored in the compressed data storage unit 210 through a predetermined input screen provided from the image generation server 200 and displayed on the monitor of the client device 100 By performing the above, it is possible to specify a desired hash table.

Note that even if a hash value is displayed as a list of hash tables or identification information of the hash table is displayed, it is difficult for the user to know which video the hash table relates to. Therefore, for example, frame images associated with the hash value stored at the head of the hash table may be displayed as a list of thumbnail images.

Alternatively, when the request transmission unit 12 transmits an image acquisition request to the image generation server 200, the user operates the operation unit (not shown) and inputs desired information (for example, the name of a moving image). The information is transmitted to the image generation server 200 together with the image acquisition request. Then, when the hash table of moving image data is stored in the compressed data storage unit 210, the desired information may be stored in association with each other and displayed in a list of hash tables.

The hash value existence determination unit 18 uses the second compressed data storage unit 110 of the client device 100 and the third value of the image storage server 300 as the hash values included in the hash list acquired by the hash list acquisition unit 17. Whether or not the compressed data storage unit 310 or the compressed data storage unit 210 of the image generation server 200 has already been stored is checked in order of increasing network distance from the client device 100. This is sequentially performed for each hash value or a plurality of hash values.

Here, the network distance means a round trip time through a relay device placed in the middle of a communication path from a certain node to a certain other node. When the client apparatus 100 is a departure node, the client apparatus 100 itself has the shortest network distance. On the other hand, which of the image generation server 200 and the image storage server 300 is closer to the network distance from the client device 100 depends on the situation.

It should be noted that the hash value existence determination unit 18 obtains information on the region and country where the image generation server 200 and the image storage server 300 are installed from each of the

servers

200 and 300 according to the physical distance to the region or country. Thus, it is possible to estimate which is closer to the network distance. In the following description, it is assumed that the image storage server 300 has a shorter network distance from the client than the image generation server 200.

In this case, the hash value existence determination unit 18 first stores the first hash value in the hash list acquired by the hash list acquisition unit 17 in the first second compressed data storage unit 110 of the client device 100. Check whether it is done. If the first hash value is stored in the first second compressed data storage unit 110, the hash value presence / absence determination unit 18 ends the presence / absence determination operation of the first hash value at that time.

On the other hand, when the first hash value is not stored in the first second compressed data storage unit 110, the hash value presence / absence determination unit 18 then selects the third compressed data storage unit 310 of the image storage server 300. To check whether the first hash value is stored. If the first hash value is stored in the third compressed data storage unit 310, the hash value presence / absence determination unit 18 ends the first hash value existence determination operation at that time.

If the first hash value is not stored in the third compressed data storage unit 310, the hash value existence determination unit 18 next selects the compressed data storage unit 210 of the image generation server 200 with the longest network distance. To check whether the first hash value is stored.

The hash value presence / absence determination unit 18 sequentially performs such an operation one by one for the second and subsequent hash values included in the hash list. Or you may carry out collectively about several hash values. It is also possible to check the image generation server 200 and the image storage server 300 at the same time.

Here, whether or not the hash value is already stored in the compressed data storage unit 210 of the image generation server 200 and the third compressed data storage unit 310 of the image storage server 300 is confirmed by communication from the hash value existence determination unit 18. This is realized by sending a hash value to the image generation server 200 and the image storage server 300 via the I / F unit 11 to make an inquiry.

The inquiry response unit 29 of the image generation server 200 and the inquiry response unit 36 of the image storage server 300 perform a process of responding to an inquiry transmitted from the hash value existence determination unit 18 of the client device 100. That is, the

inquiry response units

29 and 36 receive the hash value transmitted from the hash value presence / absence determination unit 18 and confirm whether or not it is already stored in the compressed

data storage units

210 and 310. Then, the confirmation result of whether or not it is stored is returned to the hash value existence determination unit 18 of the client device 100.

The frame image acquisition unit 19 converts the nodes from the client device 100, the image generation server 200, and the image storage server 300 that have been determined that the hash value has already been stored by the hash value existence determination unit 18 to the hash value. Get the associated frame image. Then, the acquired frame images are sequentially supplied to the moving image reproducing unit 15b ″.

In addition to the functions described in the first and second embodiments, the moving image reproducing unit 15b ″ has a function of executing moving image reproduction using a plurality of frame images acquired by the frame image acquiring unit 19. The moving image playback function described in the first and second embodiments is performed when the moving image generation unit 23 generates moving image data, compresses the moving image data by the moving image compression unit 24, transmits it to the client device 100, and reproduces it in real time. It is a function to use.

On the other hand, the video playback function added in the third embodiment is a function that is suitable for use when playing back video data generated in the past for confirmation again. In this case, the user obtains a hash list by specifying a desired hash table, and obtains each frame image corresponding to each hash value in the hash list from the nearest network distance. The communication time can be shortened. Thereby, a moving image can be reproduced in a shorter time.

In the third embodiment, the configuration including one client device 100 and one image storage server 300 has been described. However, a plurality of client devices 100 and a plurality of image storage servers 300 may be provided. For example, a plurality of client devices 100 may be connected by a LAN (Local Area Network), and the plurality of client apparatuses 100, the image generation server 200, and the plurality of image storage servers 300 may be connected by the Internet 500.

In this case, the hash value existence determination unit 18 determines the presence / absence of the hash value in the hash list in the order of its own client device 100 and another client device 100 in the same LAN, and then the image generation server 200 and the plurality of images. The presence or absence of hash values is determined in order from the storage server 300 with the shortest network distance.

In the third embodiment, the second compressed data transmission unit 27 has described an example in which a pair of frequently used frame images and corresponding hash values is transmitted to the image storage server 300. Is not limited to this. For example, the same compressed data as the compressed data transmitted by the first compressed data transmission unit 25 may be transmitted to the image storage server 300 and stored.

In the first to third embodiments, the example in which each frame image of the moving image data generated by the moving image generating unit 23 is stored in the compressed data storage unit 210 while being thinned out by the image thinning unit 24c is described. The invention is not limited to this. For example, the image generation server 200 performs frame compression by performing intra-frame compression (JPEG, JPEG2000, WebP, HEVC-MSP, etc.) or inter-frame compression (difference data generation, etc.) for each frame image constituting the moving image data. The image processing apparatus may further include a compression calculation unit that generates an image, and the hash calculation unit 24a, the hash table generation unit 24b, and the image thinning unit 24c may perform processing using a frame compressed image instead of the frame image.

In the first to third embodiments, the system in which the client apparatus 100 and the image generation server 200 are connected via the Internet 500 has been described as an example. However, the present invention is not limited to this. For example, the moving image generation unit 23, the moving image compression unit 24 and the compressed data storage unit 210 in FIG. 3 and the moving image expansion unit 15 in FIG. 2 may be provided in one stand-alone terminal.

In the first to third embodiments, the example in which the moving image data is generated by the camera shooting or the screen capture of the smartphone has been described. However, the present invention is not limited to this. That is, the present invention can be applied to any system in which the image generation server 200 generates moving image data or reads it from a database in response to an image acquisition request output from the client device 100. .

In the first to third embodiments, an example in which the client apparatus 100 and the image generation server 200 are connected via the Internet 500 is shown, but the present invention is not limited to this. For example, the client apparatus 100 and the image generation server 200 can be connected by any communication network regardless of wired / wireless, LAN / WAN, or the like.

In addition, each of the first to third embodiments described above is merely an example of a specific example for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. It will not be. That is, the present invention can be implemented in various forms without departing from the gist or the main features thereof.

DESCRIPTION OF SYMBOLS 13 Compressed data receiving part 14 Compressed data preservation | save part 15 Movie expansion | decompression part 15a Hash

value reading part

15b, 15b "Movie reproduction | regeneration part 16 Inquiry response part 17 Hash list acquisition part 18 Hash value existence determination part 19 Frame image acquisition part 23 Movie generation part 24 video compression unit 24a hash calculation unit 24b hash

table generation unit

24c, 24c ′

image thinning unit

25, 25 ′ compressed data transmission unit (first compressed data transmission unit)
26 feature amount determination unit 27 second compressed data transmission unit 28 hash list transmission unit 29 inquiry response unit 32 second compressed data reception unit 33 second compressed data storage unit 35 frame image transmission unit 36 inquiry response unit

Claims

A hash calculation unit that performs a hash operation on each frame image constituting the moving image data and calculates a hash value as a feature quantity that can identify the identity of the frame image;
A hash table generation unit that generates a hash table formed by listing a plurality of hash values calculated for each frame image by the hash calculation unit in the order of the frame images and stores the hash table in a compressed data storage unit;
Among the frame images, a plurality of frame images having different hash values calculated by the hash calculation unit are stored in the compressed data storage unit in association with different hash values in the hash table, and the hash value is An image compression apparatus comprising: an image thinning unit that stores only one of the plurality of frame images in the compressed data storage unit in association with the same hash value in the hash table .
The image thinning unit determines whether the hash value calculated by the hash calculation unit is already stored in the hash table of the compressed data storage unit, and only when it is determined that the hash value is not stored. The moving image compression apparatus according to claim 1, wherein a frame image corresponding to the hash value is stored in the compressed data storage unit.
The hash table generation unit generates another hash table for each of a plurality of moving image data and stores the hash table in the compressed data storage unit,
The image thinning unit determines whether the hash value calculated by the hash calculation unit for certain moving image data has already been stored in at least one of the plurality of hash tables generated for the plurality of moving image data. The frame data corresponding to the hash value is stored in the compressed data storage unit only when it is determined that the hash value is not stored in any hash table. Video compression device.
For each frame image constituting the moving image data, further comprising a compression operation unit for generating a frame compressed image by performing intra-frame compression or inter-frame compression,
4. The hash calculation unit, the hash table generation unit, and the image thinning unit perform processing using the frame compressed image instead of the frame image. The moving picture compression apparatus as described.
A moving image compression / decompression system comprising the moving image compression device according to any one of claims 1 to 3 and a moving image decompression device,
The video expansion device
A hash value reading unit that sequentially reads the plurality of hash values from the hash table stored in the compressed data storage unit;
A moving image reproducing unit that sequentially reads out a plurality of frame images corresponding to the plurality of hash values read by the hash value reading unit from the compressed data storage unit and reproduces a moving image; Video compression / decompression system.
A video compression / decompression system comprising an image generation server having the video compression device according to claim 1 and a client device having a video decompression device,
The image generation server
A compressed data transmission unit that transmits the hash table generated by the moving image compression device and a plurality of frame images associated with the hash values of the hash table to the client device as compressed data;
The client device
A compressed data receiving unit that receives the compressed data transmitted by the compressed data transmitting unit of the image generation server;
A compressed data storage unit for storing the compressed data received by the compressed data receiving unit in a second compressed data storage unit;
The moving image decompression device for decompressing the compressed data stored in the second compressed data storage unit,
The video expansion device
A hash value reading unit that sequentially reads the plurality of hash values from the hash table stored in the second compressed data storage unit;
A moving image reproducing unit that sequentially reads out a plurality of frame images corresponding to the plurality of hash values read out by the hash value reading unit from the second compressed data storage unit and reproduces a moving image; A featured video compression / decompression system.
The image thinning unit included in the moving image compression apparatus determines whether the hash value calculated by the hash calculation unit is already stored in the hash table of the compressed data storage unit, and determines that it is not stored. 7. The moving image compression / decompression system according to claim 6, wherein a frame image corresponding to the hash value is stored in the compressed data storage unit only when the hash value is set.
The hash table generation unit included in the video compression device generates another hash table for each of a plurality of video data and stores the hash table in the compression data storage unit,
The image thinning unit determines whether the hash value calculated by the hash calculation unit for certain moving image data has already been stored in at least one of the plurality of hash tables generated for the plurality of moving image data. The frame image corresponding to the hash value is stored in the compressed data storage unit only when it is determined that it is not stored in any hash table. Video compression / decompression system.
The image generation server
A feature amount determination unit that determines whether or not the hash value calculated by the hash calculation unit is stored in the second compressed data storage unit of the client device;
The compressed data transmission unit is configured to provide the frame image and the corresponding hash only when the hash value is determined not to be stored in the second compressed data storage unit of the client device by the feature amount determination unit. When the value is transmitted to the client device as the compressed data, and the hash value is determined by the feature amount determination unit to be stored in the second compressed data storage unit of the client device, the hash value 9. The moving picture compression apparatus according to claim 8, wherein only the compressed data is transmitted to the client apparatus as the compressed data.
A video compression / decompression system comprising an image generation server comprising the video compression device according to any one of claims 1 to 3, an image storage server device, and a client device,
The image generation server
The moving image compression apparatus that compresses the moving image data to be compressed by the hash calculation unit, the hash table generation unit, and the image thinning unit;
A first compressed data transmission unit that transmits the hash table generated by the moving image compression apparatus and a plurality of frame images associated with the hash values of the hash table to the client apparatus as compressed data;
A second compressed data transmission unit that transmits the hash value generated by the moving image compression apparatus and the frame image associated therewith to the image storage server;
The image storage server
A second compressed data receiver that receives the compressed data transmitted by the second compressed data transmitter of the image generation server;
A second compressed data storage unit for storing the compressed data received by the second compressed data receiving unit in a third compressed data storage unit;
A frame image transmission unit that reads a frame image associated with the hash value from the third compressed data storage unit and transmits the frame image to the client device when an image acquisition request is sent from the client device together with the hash value; Prepared,
The client device
A first compressed data receiver for receiving the compressed data transmitted by the first compressed data transmitter of the image generation server;
A first compressed data storage unit for storing the compressed data received by the first compressed data receiving unit in a second compressed data storage unit;
A hash list acquisition unit for acquiring a list of hash values stored in the hash table from the image generation server;
The hash values included in the hash list acquired by the hash list acquisition unit are the compressed data storage unit of the image generation server, the second compressed data storage unit of the client device, and the third of the image storage server. A hash value presence / absence determining unit for confirming whether or not the compressed data storage unit is already stored in the order of the network distance from the client device;
Among the nodes of the image generation server, the client device, and the image storage server, the frame image associated with the hash value from the node determined by the hash value existence determination unit that the hash value has already been stored A frame image acquisition unit for acquiring
A moving image compression / decompression system comprising: a moving image reproduction unit that reproduces a moving image using a plurality of frame images acquired by the frame image acquisition unit.
The image generation server further includes a compression arithmetic unit that generates a frame compressed image by performing intra-frame compression or inter-frame compression for each frame image constituting the moving image data,
The moving image compression / decompression system according to any one of claims 5 to 10, wherein the frame compressed image is used instead of the frame image.