JP2005184477A - Device and method for encoding picture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a picture encoding device for suppressing overflow of picture data to be encoded, and also to provide a picture encoding method. <P>SOLUTION: A monitor camera system 100 comprises: a buffer 102 for successively inputting picture data with a unit time length and storing them; and a three-field time encoder 105 for encoding the stored picture data with the unit time length, within a time shorter than the unit time length when the picture data with the unit time length are stored in the buffer 102, and for outputting the encoded picture data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image encoding apparatus and an image encoding method for encoding image data in a photographing system such as a surveillance camera system.

  2. Description of the Related Art Conventionally, there has been proposed a surveillance camera system that stores an image taken by a surveillance camera and can use the recorded image for investigation or the like when a crime occurs.

  A first block diagram of a conventional surveillance camera system is shown in FIG. In the surveillance camera system 500 shown in FIG. 6, the encoder 504 can compress image data for one field per field time (unit time corresponding to an image of one field). This encoder 504 is an ITU-R (International Telecommunication Union-Radiocommunication sector) BT.R, which is generated by multiplexing all or part of image data corresponding to each channel of 16 cameras 502a to 502p. Image data conforming to the 656 standard (hereinafter referred to as “multiplexed image data”) is compressed by one field in one field time. The recording disk 506 can record image data for one field per field time. The recording disk 506 records one field of image data compressed by the encoder 504 in one field time.

  FIG. 7 shows a timing chart in the monitoring camera system 500 shown in FIG. As shown in this timing chart, the encoder 504 can compress image data for one field per field time, and the recording disk 506 records image data for one field per field time. In such a case, the multiplexed image data output from the camera 502 is compressed by the encoder 504 in one field time without being overflowed, and is recorded by the recording disk 506 in the next one field time.

In addition, even if the image data output from the camera is compressed, if the compressed image data does not become a predetermined size or less, the image data is not further compressed, but a part of the compressed image data is reduced to a predetermined size. There has been proposed an image compression apparatus for recording with a size smaller than or equal to the size (see, for example, Patent Document 1). When the compressed image data exceeds a predetermined size, the image compression apparatus having a configuration in which the compressed image data is further compressed increases the time required for the compression process, and the input image data overflows. As a result, frames may be dropped. However, in the conventional image compression apparatus, no further compression is performed and a part of the image data after compression is reduced, so that the encoder can compress the image data for one field per one field time. In addition, when the recording disk can record one field of image data per one field time, it is possible to prevent an image from dropping due to an overflow of input image data.
JP 2003-158740 A (page 1-7, FIG. 1)

  However, when image compression based on correlation between a plurality of image data corresponding to each channel is performed for each channel of a plurality of cameras, the encoder may compress image data for one field per field time. Even when the recording disk can record one field of image data per field time, there may be a case where sufficient throughput cannot be obtained as a whole system.

  This will be described with reference to FIGS. A second block diagram of a conventional surveillance camera system is shown in FIG. In the surveillance camera system 700 shown in FIG. 8, image compression based on correlation between image data for four fields (image compression with four field correlation) is performed.

  The buffer 703 is a BT-BT of ITU-R obtained by multiplexing data of images taken by all or a part of the 16 cameras 702a to 702p. Multiplexed image data conforming to the 656 standard is input, and each image data in the multiplexed image data is stored for each channel number (camera channel number) of the camera 702 that generated the image data. Further, the buffer 703 outputs the corresponding camera channel number to the encode request queue 704 when image data corresponding to any channel is accumulated for four fields. The encoding request queue 704 receives and holds the camera channel number from the buffer 703.

  The encoder 705 can perform 4-field correlation image compression in 4 field times. The encoder 705 obtains a camera channel number corresponding to image data that can be compressed by referring to the camera channel number held in the encode request queue 704. Further, the encoder 706 reads out image data for four fields corresponding to the obtained camera channel number from the buffer 704 in four field times, and performs image compression with four field correlation. The recording disk 706 can record four fields of image data per four field hours. The recording disk 706 records the compressed image data obtained by the four-field correlation image compression by the encoder 705 in four field times.

  FIG. 9 shows an operation state of the encoder 705 in the monitoring camera system 700 shown in FIG.

  In FIG. 9, at field time 1, image data corresponding to camera channel number 9 (CH9) is stored in buffer 703 for four fields, and image data corresponding to camera channel number 13 (CH13) is stored in five fields. Minutes are accumulated. Here, if the image data corresponding to the camera channel number 9 (CH9) is stored in the buffer 703 for four fields earlier than the image data corresponding to the camera channel number 13 (CH13), the head of the encoding request queue 704 is assumed. Holds the camera channel number 9 (CH9), and subsequently holds the camera channel number 13 (CH13). In this case, the encoder 705 reads the image data for four fields corresponding to the camera channel number 9 (CH9) from the buffer 703 in the next field time 2, and performs image compression with four field correlation until the field time 5.

  At field time 5 when the operation of the encoder 705 ends, image data corresponding to the camera channel number 13 (CH13) is accumulated in the buffer 703 for six fields, and the camera channel number 13 (in the encode request queue 704). CH13) is retained. In this case, the encoder 705 reads the image data for four fields corresponding to the camera channel number 13 (CH13) from the buffer 703 at the next field time 6, and performs image compression with four field correlation until the field time 9.

  In the field time 9 when the operation of the encoder 705 ends, there is no image data corresponding to each channel stored in the buffer 703 having more than four fields. Also not retained. In this case, the encoder 705 is in an inoperative state in the next field time 10 to 13.

  Further, at the field time 13 when the non-operating state of the encoder 705 ends, image data corresponding to the camera channel number 11 (CH11) is stored in the buffer 703 for four fields, and the image data corresponding to the camera channel number 12 (CH12). Are stored for 4 fields respectively. Here, the image data corresponding to the camera channel number 11 (CH11) is stored in the buffer 703 for the field time 10, and the image data corresponding to the camera channel number 12 (CH12) is stored at the field time 13. Sometimes four fields are stored in the buffer 703. For this reason, the camera channel number 11 (CH11) is held at the head of the encode request queue 704, and then the camera channel number 12 (CH12) is held. In this case, the encoder 705 reads the image data for four fields corresponding to the camera channel number 11 (CH11) from the buffer 703 at the next field time 14, and performs image compression with four field correlation until the field time 17.

  When the operation state of the encoder 705 is as shown in FIG. 9, the throughput of the encoder 705 is 4/4 because the image compression is 4 field correlation in 4 field time, and the operation rate of the encoder 705 is 12 out of 16 field time. If the field time operation is 3/4, the number of fields (output average throughput) of the image data processed and output per field time by the encoder 705 in the field time 2 to 17 is calculated as follows. Multiply by 3/4. That is, the average output throughput of the encoder 705 is lower than 1 (field / field time), which is the number of fields (input throughput) of image data stored in the buffer 703 per field time. Further, once the encoder 705 is in an inoperative state, the average output throughput will not be restored to 1 (field / field time) even if the encoder 705 is continuously in an operational state thereafter. As a result, the input image data is likely to overflow.

  The present invention has been made to solve the conventional problems, and an object of the present invention is to provide an image encoding apparatus and an image encoding method in which overflow of image data to be encoded is suppressed.

  The image encoding apparatus according to the present invention includes an image data storage unit that sequentially inputs and stores unit time length image data, and the unit time length when the unit time length image data is stored in the image data storage unit. Image data encoding means for encoding the image data of the unit time length stored in the image data storage means and outputting the encoded image data within a time shorter than the length is provided.

  With this configuration, when image data of unit time length is accumulated, the image data of the unit time length is encoded within a time shorter than the unit time length, and the overflow of the image data to be encoded is suppressed. Is done.

  The image encoding apparatus of the present invention further comprises image data storage detecting means for detecting that the unit time length of image data has been stored in the image data storage means for the number of encoding processing units, and the image data encoding means However, when it is detected by the image data storage detection means that the unit time length of image data has been stored in the image data storage means, the unit time length of the number of encoding processing units The image data can be encoded.

  With this configuration, the image data encoding means can easily recognize that the image data of the unit time length has been stored in the image data storage means for the number of encoding processing units, and can quickly start compressing the image data. It becomes.

  Further, the image encoding apparatus of the present invention may be configured such that the image data encoding means performs encoding based on a correlation between image data having a unit time length corresponding to the number of encoding processing units.

  With this configuration, even when encoding based on correlation between image data is performed, overflow of image data to be encoded is suppressed.

  The image encoding apparatus according to the present invention may further include an image data recording unit that records the image data encoded by the image data encoding unit within a time shorter than the unit time length.

  With this configuration, even when encoded image data is recorded, overflow of the image data to be encoded is suppressed.

  Further, in the image encoding apparatus of the present invention, the image data storage means sequentially inputs and stores the image data multiplexed with the unit time length image data corresponding to a plurality of channels, and the image data encoding means However, when image data having a unit time length corresponding to one of the plurality of channels is stored in the image data storage unit, the image data having the unit time length can be encoded.

  With this configuration, when image data in which unit time length image data corresponding to a plurality of channels is multiplexed is stored, unit time length image data corresponding to any of the plurality of channels is sequentially encoded. Can be.

  The image encoding apparatus of the present invention may be configured such that the image data encoding unit reads out the unit time length of image data stored in the image data storage unit, performs compression, and outputs the compressed data.

  With this configuration, even when encoding is compression of image data, overflow of image data to be encoded is suppressed.

  The image encoding method of the present invention includes an image data storage step for sequentially inputting and storing unit time length image data, and when the unit time length image data is stored in the image data storage step, An image data encoding step of encoding the accumulated image data of the unit time length within a time shorter than the unit time length and outputting the encoded image data.

  The image encoding method of the present invention further includes an image data accumulation detecting step for detecting that the unit time length of image data is accumulated for the number of encoding processing units, and the image data encoding step includes the image data accumulation step. When it is detected in the step that the unit time length of image data has been accumulated for the number of encoding processing units, the unit time length of image data for the number of encoding processing units can be encoded. .

  The image encoding method of the present invention includes an image data recording step for recording the image data of the unit time length encoded in the image encoding step within a time shorter than the unit time length. Can do.

  In the image encoding method of the present invention, the image data accumulation step sequentially inputs and accumulates image data obtained by multiplexing the unit time length image data corresponding to a plurality of channels, and the image data encoding step However, when the unit time length image data corresponding to one of the plurality of channels is stored in the image data storage step, the unit time length image data may be encoded.

  In the present invention, when the image data storage means stores image data of unit time length, the image data encoding means encodes the image data of the unit time length within a time shorter than the unit time length. That is, since the number of image data to be encoded per unit time in the operating state of the image data encoding unit is larger than the number of image data to be stored per unit time by the image data storage unit, the overflow of the image data to be encoded is suppressed. It becomes possible.

  Hereinafter, a surveillance camera system to which an image encoding apparatus according to an embodiment of the present invention is applied will be described with reference to the drawings.

  FIG. 1 shows a block diagram of a surveillance camera system to which an image encoding apparatus according to an embodiment of the present invention is applied. The surveillance camera system 100 shown in FIG. 1 stores 16 cameras 102a to 102p (hereinafter, these cameras 102a to 102p are collectively referred to as “camera 102” as appropriate) and image data generated by the camera 102. A buffer 103 that performs encoding, an encoding request queue 104 that holds a channel number (camera channel number) of the camera 102 that generated the image data to be encoded, a three-field time encoder 105 that encodes the image data, and a three-field time And a three-field time recording disk 106 for recording image data after encoding by the encoder 105. In the following, it is assumed that image data is compressed as an encoding process by the three-field time encoder 105.

  The operation of the surveillance camera system 100 configured as described above will be described with reference to FIGS. 2 and the operation shown in FIG. 3 are performed in parallel.

  First, FIG. 2 will be described. The cameras 102a to 102p shoot a predetermined range such as a road to be monitored, a station premises, or a room, and generate unit time length image data. Camera channel numbers CH1 to CH16 are associated with the channels of the cameras 102a to 102p. The unit time length means a time corresponding to one field image. The buffer 103 is a BT-BT of the ITU-R obtained by multiplexing image data generated by all or part of the cameras 102a to 102p. Image data compliant with the 656 standard (hereinafter referred to as “multiplexed image data”) is input, and each image data in the multiplexed image data is set for each camera channel number of the channel of the camera 102 that generated the image data. (S101).

  Further, the buffer 102 determines whether or not image data corresponding to any one of the channels of the camera 102 has been accumulated for four fields (S102). When the image data corresponding to the channel of any camera 102 is not accumulated for four fields, the buffer 103 repeats the processing (S101) and subsequent steps for accumulating the multiplexed image data from the camera 102 for each camera channel number.

  On the other hand, when the buffer 102 accumulates image data corresponding to the channel of any camera 102 for four fields, the buffer 102 stores the camera channel number of the channel of the camera 102 that generated the image data accumulated for the four fields in the encoding request queue. It outputs to 104 (S103). The encoding request queue 104 has an input / output structure in FIFO (First In First Out) format, and holds the camera channel number from the buffer 102 (S104). Thereafter, the processing after storing the multiplexed image data from the camera 102 for each camera channel number (S101) by the buffer 103 is repeated.

  Next, FIG. 3 will be described. The three-field time encoder 105 can read out image data for four fields at a time corresponding to a three-field image (three-field time), and can output the compressed image by performing four-field correlation. That is, the 3-field time encoder 105 can compress image data for 4/3 fields per field time.

  The three-field time encoder 105 determines whether or not the camera channel number is held in the encode request queue 104 (S201). When the camera channel number is held in the encode request queue 104, the three-field time encoder 105 reads the held camera channel number, and outputs the image data corresponding to the read camera channel number from the buffer 103 to 4. The field is read (step 202). At this time, the read camera channel number is deleted from the encoding request queue 104. Further, when five or more fields of image data to be read are stored in the buffer 103, the three-field time encoder 105 reads four fields in order from the previously stored image data. Further, the 3-field time encoder 105 performs 4-field correlation image compression for 3 fields time including the readout time for the read image data for 4 fields, and outputs it to the 3-field time recording disk 106 (S203). .

  The 3-field time recording disc 106 can record compressed image data for 4 fields in 3 field times. That is, the 3-field time encoder 105 can record the compressed image data for 4/3 fields per field time. The three-field time recording disk 106 records the compressed image data obtained by the four-field correlation image compression by the three-field time encoder 105 in three field times (step 204). Thereafter, the operations after the determination (S201) on whether or not the camera channel number is held in the encoding request queue 104 by the three-field time encoder 105 are repeated.

  Next, the operation status of the three-field time encoder 105 corresponding to the number of fields of image data will be described with reference to FIGS.

  First, FIG. 4 will be described. The transition of the number of fields of the image data in FIG. 4 is the same as the transition of the number of fields of the image data in FIG. In FIG. 4, field times 1 to 17 each have a time length of one field time.

  In FIG. 4, at field time 1, image data corresponding to camera channel number 9 (CH9) is stored in the buffer 103 for four fields, and image data corresponding to camera channel number 13 (CH13) is stored in five fields. Minutes are accumulated. Here, it is assumed that the image data corresponding to the camera channel number 9 (CH9) is stored in the buffer 103 for four fields earlier than the image data corresponding to the camera channel number 13 (CH13). At the head of 104, camera channel number 9 (CH9) is held, and subsequently camera channel number 13 (CH13) is held. In this case, the three-field time encoder 105 reads out image data for four fields corresponding to the camera channel number 9 (CH9) from the buffer 103 in the next field time 2, and includes this read time for three field times (field At time 2 to 4), image compression with 4-field correlation is performed and output to the 3-field time recording disk 106. Note that, in the field time 2, even after the 3-field time encoder 105 reads out image data for 4 fields corresponding to the camera channel number 9 (CH 9) from the buffer 103, the buffer 103 stores the camera channel number 9 (CH 9). The image data for one field corresponding to is stored in the buffer 103 at field time 2, and the image data for one field corresponding to the camera channel number 9 (CH9) is newly input to the buffer 103 and stored. Means that

  At field time 4 when the operation of the three-field time encoder 105 ends, image data corresponding to the camera channel number 13 (CH13) is stored in the buffer 103 for six fields, and the encoding request queue 104 stores the camera channel. Number 13 (CH13) is retained. In this case, the three-field time encoder 105 reads out image data for four fields corresponding to the camera channel number 13 (CH13) from the buffer 103 in the next field time 5, and includes this read time for three field times (field At time 5 to 7), 4-field correlation image compression is performed and output to the 3-field time recording disk 106.

  In the field time 7 at which the operation of the three-field time encoder 105 ends, no image data corresponding to each channel stored in the buffer 103 has more than four fields. For this reason, nothing is held in the encoding request queue 104. In this case, the three-field time encoder 105 is in an inoperative state in the next three field times (field times 8 to 10).

  Next, at the field time 10 when the non-operating state of the 3-field time encoder 105 ends, image data corresponding to the camera channel number 11 (CH11) is accumulated in the buffer 103 for 4 fields, and the encode request queue 104 stores the image data. , Camera channel number 11 (CH11) is held. In this case, the three-field time encoder 105 reads the image data for four fields corresponding to the camera channel number 11 (CH11) from the buffer 103 in the next field time 11, and includes the three-field time (field) including this read time. At time 11 to 13), 4-field correlation image compression is performed and output to the 3-field time recording disk 106.

  Next, at the field time 13 when the operation of the three-field time encoder 105 ends, the buffer 103 stores image data corresponding to the camera channel number 12 (CH12) for four fields, and the encode request queue 104 stores the camera data. Channel number 12 (CH12) is held. In this case, the three-field time encoder 105 reads image data for four fields corresponding to the camera channel number 12 (CH12) from the buffer 103 at the next field time 14, and includes the three-field time (field) including this read time. At time 14 to 16), 4-field correlation image compression is performed and output to the 3-field time recording disk 106.

  Further, at the field time 16 when the operation of the three-field time encoder 105 is completed, the image data corresponding to the camera channel number 13 (CH13) is stored in the buffer 103 for four fields, and the camera channel is stored in the encode request queue 104. Number 13 (CH13) is retained. In this case, the three-field time encoder 105 reads out image data for four fields corresponding to the camera channel number 13 (CH13) from the buffer 103 in the next field time 17, and includes the readout time in three field times. 4-field correlation image compression is performed and output to the 3-field time recording disk 106.

  When the operation state of the three-field time encoder 105 is as shown in FIG. 4, the throughput of the three-field time encoder 105 is 4/3 because the image compression is four-field correlation in three field times, and the three-field time encoder 105 If the operation rate is 13/16 because it operates for 13 field hours out of 16 field hours, the 3-field time encoder 105 in the field times 2 to 17 processes and outputs image data per field time. The number of fields (average output throughput) is 13/12 multiplied by these. That is, it is increased from 3/4, which is the conventional average output throughput in FIG. Therefore, it is possible to prevent the input image data from overflowing as compared with the prior art. Further, since the frequency with which the three-field time encoder 105 reads image data from the buffer 103 is increased as compared with the conventional case, the usage rate of the buffer 103 can be reduced. For this reason, the capacity of the buffer 103 can be reduced.

  Next, FIG. 5 will be described. In FIG. 5, field times 1 to 17 each have a time length of one field time as in FIG.

  In FIG. 5, at field time 1, buffer 103 stores image data corresponding to camera channel number 6 (CH6) for 4 fields, image data corresponding to camera channel number 10 (CH10) for 6 fields, camera channel. Image data corresponding to number 12 (CH12) is stored for five fields, and image data corresponding to camera channel number 15 (CH15) is stored for four fields. Here, the image data corresponding to the camera channel number 10 (CH10), the image data corresponding to the camera channel number 12 (CH12), and the camera channel number are arranged in order of time until the image data for four fields is accumulated. Assuming that the image data corresponding to 6 (CH6) and the image data corresponding to the camera channel number 15 (CH15) are in this order, the camera channel number 10 (CH10) and the camera channel number 12 are stored in the encode request queue 104. The camera channel numbers are held in the order of (CH12), camera channel number 6 (CH6), and camera channel number 15 (CH15). In this case, the three-field time encoder 105 reads out image data for four fields corresponding to the camera channel number 10 (CH10) from the buffer 103 in the next field time 2, and includes the three field times (fields) including this read time. At time 2 to 4), image compression with 4-field correlation is performed and output to the 3-field time recording disk 106.

  In the field time 4 when the operation of the three-field time encoder 105 is finished, the buffer 103 has 5 fields of image data corresponding to the camera channel number (CH12) and 4 image data corresponding to the camera channel number 6 (CH6). Image data corresponding to field and camera channel number 15 (CH15) is accumulated for each of four fields, and the encoding request queue 104 stores camera channel number 12 (CH12), camera channel number 6 (CH6), and camera channel. Camera channel numbers are held in the order of number 15 (CH15). In this case, the 3-field time encoder 105 reads out image data for 4 fields corresponding to the camera channel number 12 (CH12) from the buffer 103 in the next field time 5, and includes 3 fields time (field) including this readout time. At time 5 to 7), 4-field correlation image compression is performed and output to the 3-field time recording disk 106.

  At field time 7 when the operation of the three-field time encoder 105 ends, image data corresponding to the camera channel number 6 (CH6) is stored in the buffer 103 for four fields, and the image corresponding to the camera channel number 15 (CH15). Data is accumulated for each of four fields, and camera channel numbers are held in the encoding request queue 104 in the order of camera channel number 6 (CH6) and camera channel number 15 (CH15). Further, at field time 7, image data corresponding to the camera channel number 13 (CH13) is accumulated in the buffer 103 for four fields, and the camera channel number 15 (CH15) is followed by the camera channel in the encode request queue 104. Number 13 (CH13) is retained. In this case, the three-field time encoder 105 reads out image data for four fields corresponding to the camera channel number 6 (CH6) from the buffer 103 at the next field time 8, and includes the read time for three field times (field At time 8 to 10), 4-field correlation image compression is performed and output to the 3-field time recording disk 106.

  Next, at the field time 10 when the operation of the three-field time encoder 105 ends, image data corresponding to the camera channel number 15 (CH15) corresponds to the camera channel number 13 (CH13) in the buffer 103 for four fields. Image data is stored for each of four fields, and camera channel numbers are held in the encoding request queue 104 in the order of camera channel number 15 (CH15) and camera channel number 13 (CH13). In this case, the three-field time encoder 105 reads the image data for four fields corresponding to the camera channel number 15 (CH15) from the buffer 103 in the next field time 11, and includes the three field times (fields) including this read time. At time 11 to 13), 4-field correlation image compression is performed and output to the 3-field time recording disk 106.

  Next, at field time 13 when the operation of the three-field time encoder 105 ends, image data corresponding to the camera channel number 13 (CH13) is accumulated in the buffer 103 for four fields, and the encoding request queue 104 stores the camera data. Channel number 13 (CH13) is held. In this case, the three-field time encoder 105 reads out image data for four fields corresponding to the camera channel number 13 (CH13) from the buffer 103 at the next field time 14, and includes the three-field time (field) including this read time. At time 11 to 13), 4-field correlation image compression is performed and output to the 3-field time recording disk 106.

  After the field time 14, image data corresponding to the camera channel number 2 (CH2) is accumulated in the buffer 103 for four fields, and the camera channel number 2 (CH2) is held in the encode request queue 104. After field time 15, image data corresponding to camera channel number 1 (CH1) is accumulated in the buffer 103 for four fields, and the camera channel number 2 (CH2) follows the camera channel in the encode request queue 104. Number 1 (CH1) is retained. For this reason, at the field time 16 when the operation of the three-field time encoder 105 ends, the image data corresponding to the camera channel number 2 (CH2) corresponds to the camera channel number 1 (CH1) in the buffer 103 for four fields. Four fields of image data are accumulated, and the camera channel numbers are held in the encoding request queue 104 in the order of camera channel number 2 (CH2) and camera channel number 1 (CH1). In this case, the three-field time encoder 105 reads out image data for four fields corresponding to the camera channel number 2 (CH2) from the buffer 103 in the next field time 17, and includes the readout time in three field times. 4-field correlation image compression is performed and output to the 3-field time recording disk 106.

  When the operation state of the three-field time encoder 105 is as shown in FIG. 5, the throughput of the three-field time encoder 105 is 4/3 because the image compression of the four-field correlation is performed in three field times, and the three-field time encoder 105 If the operation rate of 16 is 16/16 out of 16 field hours, it is 16/16. Therefore, the 3-field time encoder 105 in the field times 2 to 17 processes and outputs image data per field time. The number of fields (average output throughput) is 4/3 multiplied by these, and is larger than 1 (field / field time) which is the number of fields (input throughput) of image data stored in the buffer 103 per field time. Value. Therefore, it is possible to prevent the input image data from overflowing. Further, as in the operation in FIG. 4, the frequency at which the three-field time encoder 105 reads image data from the buffer 103 is increased as compared with the prior art, so the usage rate of the buffer 103 can be reduced, and the capacity of the buffer 103 can be reduced. It becomes possible.

  In the above-described embodiment of the present invention, image data is input in units of fields and encoded and recorded. However, it may be input in units of frames and encoded and recorded.

  In the above-described embodiment of the present invention, the case where the image compression based on the correlation between the image data of the four fields is described, but the image compression based on the correlation between the image data of two fields or more or two frames or more is described. The present invention can be applied even when the above is performed.

  Further, in the above-described embodiment, the 3-field time encoder 105 has a processing capability capable of compressing image data of 4/3 fields per field time, but more than 1 field per field time, Alternatively, the present invention can be applied as long as it has a processing capability capable of compressing image data of one frame or more per frame time. Also, the image data input to the buffer 103 is the ITU-R BT. It may be other than the image data based on the 656 standard.

  As described above, the image encoding device and the image encoding method according to the present invention have an effect that it is possible to suppress overflow of image data to be encoded, and are useful as an image encoding device and an image encoding method. .

1 is a block diagram of a surveillance camera system to which an image encoding apparatus according to an embodiment of the present invention is applied. First flowchart showing the operation of the surveillance camera system to which the image encoding device of the embodiment of the present invention is applied. 2nd flowchart which shows operation | movement of the surveillance camera system to which the image encoding apparatus of embodiment of this invention is applied. The figure which shows the 1st operation | movement condition of the 3 field time encoder in the surveillance camera system to which the image encoding apparatus of embodiment of this invention is applied. The figure which shows the 2nd operation | movement condition of the 3 field time encoder in the surveillance camera system to which the image encoding apparatus of embodiment of this invention is applied. Block diagram of a conventional first surveillance camera system Timing chart of conventional first surveillance camera system Block diagram of a conventional second surveillance camera system The figure which shows the operation | movement condition of the encoder in the conventional 2nd surveillance camera system

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Surveillance camera system 102a-102p Camera 103 Buffer 104 Encoding request queue 105 3 field time encoder 106 3 field time recording disk

Claims (10)

Image data storage means for sequentially inputting and storing image data of unit time length;
When the unit time length image data is stored in the image data storage unit, the unit time length image data stored in the image data storage unit is encoded within a time shorter than the unit time length. And an image data encoding means for outputting the encoded image data. The image data storage means has image data storage detection means for detecting that the unit time length of image data has been stored for the number of encoding processing units,
The image data encoding unit detects the number of encoding processing units when the image data storage detecting unit detects that the unit time length of image data has been stored in the image data storage unit. The image encoding apparatus according to claim 1, wherein the image data is encoded with a unit time length of minutes. 3. The image encoding apparatus according to claim 1, wherein the image data encoding means performs encoding based on correlation between image data having a unit time length corresponding to the number of encoding processing units. 4. The image encoding according to claim 1, further comprising image data recording means for recording the image data encoded by the image data encoding means within a time shorter than the unit time length. 5. apparatus. The image data storage means sequentially inputs and stores image data obtained by multiplexing the unit time length image data corresponding to a plurality of channels,
The image data encoding means encodes the unit time length image data when the image data storage means stores image data of a unit time length corresponding to any of the plurality of channels. The image encoding device according to claim 1, wherein the image encoding device is an image encoding device. 6. The image encoding apparatus according to claim 1, wherein the image data encoding unit reads out the unit time length of image data stored in the image data storage unit, performs compression, and outputs the compressed image data. . An image data storage step of sequentially inputting and storing image data of unit time length; and
When the image data of the unit time length is accumulated in the image data accumulation step, the accumulated image data of the unit time length is encoded within a time shorter than the unit time length. And an image data encoding step for outputting image data. An image data storage detection step for detecting that the unit time length of image data is stored for the number of encoding processing units;
In the image data encoding step, when it is detected in the image data storage step that the unit time length of image data has been stored for the number of units of encoding processing, the unit time length of images for the number of units of encoding processing 8. The image encoding method according to claim 7, wherein the data is encoded. 9. The image according to claim 7, further comprising an image data recording step of recording the image data of the unit time length encoded in the image encoding step within a time shorter than the unit time length. Encoding method. The image data accumulation step sequentially inputs and accumulates image data obtained by multiplexing the unit time length image data corresponding to a plurality of channels,
The image data encoding step encodes the unit time length image data when the unit time length image data corresponding to any of the plurality of channels is stored in the image data storage step. 10. The image encoding method according to claim 7, wherein the image encoding method is any one of claims 7 to 9.

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