JP2008053894A - Packet communication method and communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packet communication method in which degradation in reproduction quality of digital data is suppressed without increasing the transmission quantity, and also to provide a communication system. <P>SOLUTION: In the packet communication method, a packet transmission means comprises steps of: rearranging a plurality of unit data in a predetermined order within reproduced information such that unit data adjacent during reproduction of information are not included in one packet; generating a plurality of packets while including every predetermined number of unit data in the packet based on the order of a plurality of unit data rearranged at the step for rearranging the data in a predetermined order; and extracting the unit data from a packet received at a packet receiving step and rearranging the unit data thus extracted in the reproducible order. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a packet communication method for transmitting reproduction information including a plurality of unit data converted from analog to digital in a packet, and a two-dimensional spread communication system using the packet communication method.

  In general, digital communication such as packet communication is designed to increase redundancy by inserting additional bits (error correction code, etc.) into the packet in order to detect and correct errors (bit errors) that occur during packet transmission. Has been made. However, the higher the redundancy is increased by increasing the number of such additional bits, the larger the packet size, the higher the throughput required for the packet transmission path.

  A plurality of unit data converted from analog signals such as audio signals and image signals to digital signals (unit data is the basic unit of data obtained as a result of sampling. In this case, when the reproduction digital data composed of data corresponding to one pixel is transmitted using a packet, the reproduction digital data is divided and distributed to each packet. In general, the reproduced digital data distributed in one packet is composed of a plurality of unit data that are temporally or spatially continuous. In addition to the reproduced digital data, the packet includes communication digital data such as transmission / reception synchronization adjustment bits, headers, and footers. When digital data for communication such as transmission / reception synchronization adjustment bits, headers, and footers causes a bit error, the receiving side cannot recognize the packet itself (this is called packet loss). If a packet is lost during transmission, naturally, on the receiving side, reproduced digital data contained in the packet is lost. Since the reproduction digital data included in the packet includes temporally or spatially continuous unit data as described above, when an image or the like is reproduced from only the received packet, a plurality of adjacent pixels are defective. There is a problem that the reproduction quality of the image is remarkably deteriorated.

  As a countermeasure against such packet loss, generally, a method of resending the same packet as the lost packet is used. For example, in Patent Document 1, when the occurrence of a packet loss is confirmed when receiving image or audio information carried by the TCP protocol, the receiving terminal side reliably transmits the image or audio information by the retransmission means. It is described that it can be received. Patent Document 2 describes that when a packet communication method using TCP / IP is applied, there is a retransmission process, so that highly reliable transmission is realized.

  By the way, Patent Document 3 describes an image signal processing apparatus that employs a packet communication system for transmission of an image signal acquired from a capsule endoscope. This image signal processing apparatus uses a two-dimensional diffusion communication technique, which is a communication technique for transmitting a signal (packet) by relaying using a plurality of elements without forming individual wirings. The image signal is transmitted to a desired position.

JP 2000-151680 A JP-A-10-56479 JP 2005-295518 A

  As described above, in the packet communication method, when packet loss occurs, packet retransmission processing is performed in order to suppress degradation in reproduction quality. However, when packet retransmission processing is performed, highly reliable transmission can be realized, but a transmission path having high throughput is required.

  In addition, in an image signal processing apparatus as shown in Patent Document 3, in order to suppress a decrease in reproduction quality when packet loss occurs, a high-performance and high-performance element is used to relay a signal. You must get throughput.

  In view of the above circumstances, an object of the present invention is to provide a packet communication method and a communication system capable of suppressing deterioration in reproduction quality of digital data without increasing the transmission amount.

  In order to solve the above problems, the present invention provides a packet communication method for transmitting reproduction information composed of a plurality of unit data in a plurality of packets by using at least a packet transmission unit and a packet reception unit. Data for rearranging the plurality of unit data in a predetermined order in the reproduction information so that the packet transmission means does not include unit data that will be adjacent when the reproduction information is reproduced in one packet A packet generation step of generating a plurality of packets by including unit data in a predetermined number of packets based on the order of the plurality of unit data rearranged by the data order rearrangement step; A packet transmission step of transmitting a plurality of packets generated by the packet generation step; A packet receiving means for receiving at least one of the plurality of packets transmitted in the packet transmitting step, and extracting unit data from the packet received in the packet receiving step, And a data order reproduction step of rearranging the unit data in a reproducible order.

  Therefore, according to the present invention, even if some packets are lost in the packet transmission path, the unit data included in the reproduction information is discretely lost, and thus the defect is less noticeable during reproduction. Therefore, it is possible to suppress deterioration in quality during reproduction without retransmitting the packet. That is, it is possible to suppress degradation in reproduction quality without increasing the transmission amount due to packet reproduction.

  In the packet communication method according to the present invention, when the number of packets received by the packet reception step is smaller than the number of packets transmitted by the packet transmission step, the packet reception means receives the packet reception step. The method further includes a data interpolation step of interpolating unit data included in the packet that could not be performed. According to this configuration, it is possible to interpolate the unit data that has been discretely missing, and therefore, it is possible to further suppress degradation in reproduction quality.

  Further, in the packet communication method according to the present invention, the data interpolation step is based on unit data adjacent to the unit data included in the packet that could not be received by the packet reception step at the time of reproduction. The substitute data calculated in this way is generated, and interpolation is performed by inserting the substitute data into the position where the unit data included in the packet that could not be received in the packet receiving step should be rearranged.

  More specifically, when N unit data is included in one packet in the packet generation step, the data order rearrangement step includes at least N−1 reproductions between unit data adjacent to each other during reproduction. Insert unit data that is sometimes not adjacent.

  The unit data includes pixel data for reproducing an image. In the data order rearranging step, the reproduction information may be included so that one packet does not include pixel data that is spatially adjacent when the plurality of pixel data is reproduced as an image. The plurality of pixel data are rearranged in a predetermined order.

  The packet transmitting means and the packet receiving means can transmit and receive a packet via a packet relay means, and the packet transmitting step transmits a packet to the packet relay means, and the packet receiving step includes A packet is received from the packet relay means.

  The present invention is also directed to a reproduction of the reproduction information in one packet in a two-dimensional spread communication system using a packet communication method capable of transmitting reproduction information composed of a plurality of unit data divided into a plurality of packets. The data order rearranging means for rearranging the plurality of unit data in a predetermined order in the reproduction information and the data order rearranging means so as not to include unit data that will sometimes be adjacent Packet generation means for generating a plurality of packets by including a predetermined number of unit data in a packet based on the order of the plurality of unit data, and packet transmission means for transmitting the plurality of packets generated by the packet generation means And receiving at least one of a plurality of packets transmitted by the packet transmitting means. Second communication means comprising: packet receiving means for extracting unit data from the packet received by the packet receiving means, and rearranging the extracted unit data in a reproducible order. And at least one third communication unit having a function of receiving a packet transmitted by the first communication unit and transmitting the packet to the second communication unit. A spread communication system is provided.

  In addition, when the number of packets received by the packet receiving unit is smaller than the number of packets transmitted by the packet transmitting unit, the second communication unit is included in the packet that could not be received by the packet receiving unit. It further has a data interpolation means for interpolating the unit data.

  Further, the data interpolation means generates substitute data calculated based on unit data adjacent to the unit data included in the packet that could not be received by the packet receiving means during reproduction, and the packet receiving means The unit data included in the packet that could not be received by the interpolation is inserted by inserting the substitute data at a position where the unit data should be rearranged.

  Further, when N unit data is included in one packet in the packet generating means, the data order rearranging means may be adjacent to at least N-1 pieces of unit data between adjacent unit data at the time of reproduction. It is characterized by inserting no unit data.

  The first communication unit, the second communication unit, and the third communication unit are incorporated in one communication chip, and communication is performed by using a plurality of the communication chips.

  Therefore, according to the present invention, it is possible to provide a packet communication method and a communication system that can suppress deterioration in reproduction quality of reproduction information without increasing the transmission amount.

  Hereinafter, a packet communication method and a communication system using the packet communication method according to the present invention will be described with reference to the drawings. In the embodiment of the present invention, the packet communication method will be described in the case where an image signal wirelessly transmitted from a capsule endoscope is transmitted by a two-dimensional spread communication technique. However, the packet communication method according to the present invention is not limited to the application to the two-dimensional spread communication technique, and any packet communication method may be used for reproducing digital data converted from analog signals such as audio signals and image signals. It can be implemented.

  FIG. 1 is a diagram for explaining a two-dimensional spread communication system (hereinafter referred to as a communication system 100) to which a packet communication method according to the present invention is applied. The communication system 100 is a system using two-dimensional spread signal transmission (2D-DST) technology. In the embodiment of the present invention, the communication system 100 has the appearance of a clothing (jacket). The communication system 100 has a function of receiving a radio signal transmitted from the body of the patient 1 by the capsule endoscope around the body of the patient 1, performing predetermined signal processing, and transmitting the signal by packet communication.

  Next, details of the communication system 100 will be described. The communication system 100 includes a 2D-DST board 200, a 2D-DST chip 220, and a control unit 250. The 2D-DST substrate 200 is a flexible sheet-like member, and is molded in a jacket shape that covers a part of the body of the patient 1. The plurality of 2D-DST chips 220 scattered in the 2D-DST board 200 have an antenna function for receiving a radio signal including image data transmitted from the capsule endoscope, a packet transmission / reception function, and the like. A control unit 250 is connected to the 2D-DST board 200. The control unit 250 is attached so as to be positioned near the waist of the patient 1 and collects image data from the capsule endoscope acquired by each 2D-DST chip 220 and a function for controlling each 2D-DST chip 220. And have a function to manage.

  Further, the 2D-DST chip 220 can transmit packets sequentially by transmitting and receiving signals to and from adjacent chips. Therefore, the communication system 100 can transmit a packet to a desired position by relaying the 2D-DST chip 220 without having a circuit pattern.

  FIG. 2 is a diagram for explaining the function of each chip when a packet is transmitted using the 2D-DST chip 220. The capsule endoscope C1 includes an imaging element such as a CCD, and transmits an image signal output by imaging to the outside of the patient 1 including a radio signal.

  The 2D-DST chip 220 serves as one of a packet transmission chip (S1), a packet relay chip (T1), and a packet reception chip (R1) depending on the situation. Each 2D-DST chip 220 has an antenna function, and the 2D-DST chip 220 that has received the radio signal from the capsule endoscope C1 plays a role as the packet transmission chip S1. Note that there is a possibility that a plurality of 2D-DST chips 220 may receive a radio signal at the same time. In such a case, for example, the 2D-DST chip 220 determined to have the highest reception strength is the packet reception chip R1. Such control may be performed. In addition, the approximate position of the capsule endoscope C1 can be specified by the position of the packet receiving chip R1.

  The packet transmission chip S1 has a function of performing signal processing such as amplification on the received radio signal, an analog-digital conversion (A / D) function (including sampling according to the pixel), and image digital data as “reproduction information” Has a function of transmitting the packet in a packet. In the embodiment of the present invention, when image digital data is included in a packet, a process of changing the temporal (or spatial) order of pixel data (unit data) constituting the image digital data is performed. At least one packet relay chip T1 is selected and transmitted so that the packet transmitted by the packet transmission chip S1 finally reaches the packet reception chip R1. That is, the packet relay chip T1 has a function of receiving a packet and transmitting the packet immediately. The packet receiving chip R1 is, for example, the 2D-DST chip 220 closest to the control unit 250, and can receive the packet and supply the packet to the control unit 250.

  FIG. 3 is a schematic diagram showing the contents of the packet 10 transmitted by the packet transmission chip S1 (FIG. 2). The packet 10 includes a synchronization bit part 11, a header part 12, a data part 13, and a footer part 14. The header portion 12 includes data such as a transmission source ID, a reception destination ID, a packet number, a data type, and a data length. The data portion 13 includes a part of image digital data.

  FIG. 4 is a flowchart showing processing of the packet communication method according to the present invention. This flowchart is processing performed by the packet transmission chip S1, the packet relay chip T1, and the packet reception chip R1 shown in FIG. 2, and starts when the packet transmission chip S1 receives a radio signal from the capsule endoscope C1. It shall be. For example, steps S101 to S107 are performed by the packet transmission chip S1, step S109 is performed by the packet relay chip T1, and steps S111 to S119 are performed by the packet reception chip R1. Note that the processing from step S113 to step S119 is not limited to the packet reception chip R1, and may be performed by the control unit 250, for example.

  In step S101, various signal processing (demodulation, amplification, A / D conversion, etc.) is performed on the radio signal. The image signal, which was an analog signal, is sampled in units of pixels and becomes image digital data composed of pixel data. Next, in step S103, processing for rearranging the pixel data in the image digital data is performed. Here, rearrangement is made in such an order that adjacent pixel data is not included in one packet temporally (or spatially when an image is reproduced).

  In step S105, a process of including the pixel data rearranged in step S103 in the data portion 13 of the packet 10 in order from the beginning of the order is performed, and the synchronization bit portion 11, header portion 12, and footer portion 14 are also included. The process of generating a packet is performed by including necessary data.

  In step S107, the packet generated in step S105 is transmitted. The packet relay chip T1 that has received the packet further transmits the packet (step S109). In the two-dimensional spread communication technique, the packet relay chip T1 is selected so as to provide the shortest path between the packet transmission chip S1 and the packet reception chip R1. Further, a packet transmitted from the 2D-DST chip 220 such as the packet relay chip T1 may be received by the plurality of 2D-DST chips 220. In the two-dimensional spread communication technology, since the control unit 250 grasps and controls which chip is the packet relay chip T1 that is the shortest route in advance, 2D other than the 2D-DST chip 220 selected as the route is used. -Even if the DST chip 220 receives a packet, the packet is not transmitted thereafter.

  In step S111, the packet receiving chip R1 receives a packet transmitted via the packet relay chip T1. In step S113, data order reproduction processing is performed in which the pixel data rearranged in step S103 is rearranged in the original reproducible order.

  In step S115, it is determined whether or not there is a packet loss. For example, in the header portion 12 of the packet 10, the packet No. Is attached, and if a consecutive number is assigned to each packet in step S105, the loss of the packet can be determined. Alternatively, in step S113, when the order of the pixel data is rearranged, the loss of the packet can be determined based on whether or not there is missing pixel data. If there is a packet loss (step S115: YES), the process proceeds to step S117. If there is no packet loss (step S115: NO), the process proceeds to step S119.

  In step S117, a process for interpolating pixel data lost due to packet loss is performed. This interpolation processing is performed based on the value of the pixel data adjacent to the missing pixel data in a state where the pixel data is rearranged. In step S119, image digital data composed of pixel data is stored and accumulated.

  According to the processing as described above, even if some packets are lost in the packet transmission path, the missing pixel data included in the image digital data becomes discrete during reproduction and is interpolated to some extent. As a result, pixel defects are less noticeable. Therefore, it is possible to suppress deterioration in quality during reproduction without retransmitting the packet. That is, it is possible to suppress degradation in reproduction quality without increasing the transmission amount due to packet reproduction.

  Next, a specific example of processing by the packet communication method according to the present invention will be described with reference to FIG. For example, data for one pixel is 8-bit A / D converted. That is, the pixel data is shown in 256 steps. FIG. 5A shows a part of the image digital data after AD conversion. For example, it is assumed that image digital data generated by A / D conversion is composed of a total of 64 data of pixel data D00 to D63. Pixel data D00 to D63 are data that are consecutive in the order of their numbers. Further, the upper part of FIG. 5A shows the value of each pixel data in a graph.

  FIG. 5B is a diagram illustrating the image digital data after the order of the pixel data is changed. It is assumed that data for 8 pixels is included in one packet (all 8 packets). For example, packet 1 includes data for eight pixels of D00, D08, D16, D24, D32, D40, D48, and D56. Next, packet 2 includes data for eight pixels D01, D09, D17, D25, D33, D41, D49, and D57. That is, at least seven pieces of pixel data are inserted between continuous pixel data (successfully, the seven pieces of pixel data to be inserted do not include continuous pixel data). Furthermore, when the order of the pixel data is changed, when image digital data is reproduced as an image, adjacent pixels (for example, pixels arranged at eight positions around one pixel) are not included in one packet. It is preferable to do so.

  FIG. 5C is a diagram illustrating digital image data when the packet reception chip R1 (FIG. 2) receives a packet, for example. In this example, it is assumed that packet 2 is lost. That is, it becomes image digital data in which data for eight pixels of pixel data D01, D09, D17, D25, D33, D41, D49, and D57 is missing. FIG. 5D shows the image digital data after the data order reproduction process (step S113) is performed from this state.

  FIG. 5D is a diagram showing the arrangement of pixel data after the data order is reproduced in the upper part, and the lower part shows the value of each pixel data as a graph. Then, it can be seen that pixel data is missing every 7 pixels due to the disappearance of packet 2. That is, it can be seen that pixel data is not continuously lost in a one-dimensional array of image digital data.

  In FIG. 5B, seven pixel data are inserted between consecutive pixel data. However, at least seven pixel data may be inserted, and the order can be changed in various forms. Therefore, the rearrangement of the pixel data performed by the packet communication method according to the present invention is not limited to the arrangement shown in FIG.

Next, the data interpolation process (step S117) when a packet is lost will be described with a specific example. FIG. 6 is a diagram schematically showing a part on the screen displayed when image digital data is reproduced. For convenience of explanation, only 9 pixels (P11, P12, P13, P21, P22, P23, P31, P32, P33) on the screen are shown. In the embodiment of the present invention, when pixel data of P22 is missing, interpolation processing of P222 is performed using surrounding pixel data. The interpolation processing is generally performed when a new intermediate pixel is created based on adjacent pixels in a full color CCD or the like. For example, the value of P22 ′ is calculated by the following equation.
P22 '= a * (P12 + P21 + P23 + P32) + b * (P11 + P13 + P31 + P33)
Here, a is a coefficient representing weighting in the direction orthogonal to P22, and b is a coefficient representing weighting in the diagonal direction of P22. In the embodiment of the present invention, since it is unlikely that adjacent pixel data is lost, such processing can be executed.

  FIG. 7 is a diagram schematically illustrating a case where interpolation processing is performed on the image digital data after packet transmission illustrated in FIG. 5C by the method illustrated in FIG. FIG. 7A shows a state similar to the upper stage of FIG. Interpolation processing as shown in FIG. 6 is performed on the missing pixel data D01, D09, D17... To calculate D01 ′, D09 ′, D17 ′. FIG. 7B shows a state in which the calculated pixel data is inserted. In the image digital data, the data missing portion (FIG. 5D) is averaged. Therefore, by applying the packet communication method of the present invention, even if a packet is lost, it is possible to display the image without greatly degrading the image without retransmitting the packet.

It is an external view which shows an example of the communication system using the packet communication method which concerns on this invention. It is a figure for demonstrating the function of 2D-DST chip | tip. It is a figure which shows the content of a packet. It is a flowchart which shows the process of the packet communication method which concerns on this invention. The specific example of the packet communication method which concerns on this invention is shown. It is a figure which shows typically a part on the screen displayed when reproducing | regenerating image digital data. It is a figure which shows the case where the interpolation process is performed with respect to the packet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Packet 11 Synchronization bit part 12 Header part 13 Data part 14 Footer part 100 Communication system 200 2D-DST board 220 2D-DST chip 250 Control part

Claims (13)

In a packet communication method for transmitting reproduction information composed of a plurality of unit data divided into a plurality of packets by using at least a packet transmission means and a packet reception means,
The packet transmission means is
A data order rearranging step for rearranging the plurality of unit data in a predetermined order in the reproduction information so that unit data that will be adjacent when the reproduction information is reproduced is not included in one packet;
Based on the order of the plurality of unit data rearranged by the data order rearrangement step, a packet generation step of generating a plurality of packets by including unit data in a predetermined number of packets,
A packet transmission step of transmitting a plurality of packets generated by the packet generation step;
The packet receiving means
A packet receiving step of receiving at least one of the plurality of packets transmitted by the packet transmitting step;
A data sequence reproduction step of extracting unit data from the packet received by the packet reception step and rearranging the extracted unit data in a reproducible order;
A packet communication method characterized by comprising: The packet receiving means
A data interpolation step for interpolating unit data included in a packet that could not be received by the packet reception step when the number of packets received by the packet reception step is less than the number of packets transmitted by the packet transmission step The packet communication method according to claim 1, further comprising:   The data interpolation step generates substitute data calculated based on unit data adjacent to the unit data included in the packet that could not be received by the packet reception step during reproduction, and received by the packet reception step. 3. The packet communication method according to claim 2, wherein interpolation is performed by inserting the substitute data at a position where the unit data included in the packet that could not be originally rearranged.   When N unit data is included in one packet in the packet generation step, the data order rearranging step is a unit that is not adjacent at least N-1 reproductions between unit data that are adjacent at the time of reproduction. 4. The packet communication method according to claim 1, wherein data is inserted.   The packet communication method according to claim 1, wherein the unit data is pixel data for reproducing an image.   In the reproduction information, the data order rearrangement step is performed in the reproduction information so that a single packet does not include pixel data that is spatially adjacent when the plurality of pixel data is reproduced as an image. 6. The packet communication method according to claim 5, wherein the plurality of pixel data are rearranged in a predetermined order. The packet transmitting means and the packet receiving means are capable of transmitting and receiving packets via a packet relay means,
The packet transmission step transmits a packet to the packet relay means;
7. The packet communication method according to claim 1, wherein the packet receiving step receives a packet from the packet relay means.   The packet communication method according to claim 7, wherein the packet relay unit includes a plurality of chips. In a two-dimensional spread communication system using a packet communication method capable of transmitting reproduction information composed of a plurality of unit data divided into a plurality of packets,
Data order rearranging means for rearranging the plurality of unit data in a predetermined order in the reproduction information so that unit data that will be adjacent when reproducing the reproduction information is not included in one packet; Based on the order of the plurality of unit data rearranged by the data order rearranging means, packet generating means for generating a plurality of packets by including a predetermined number of unit data in a packet, and generating by the packet generating means Packet transmitting means for transmitting a plurality of packets, and a first communication means,
Packet receiving means for receiving at least one of a plurality of packets transmitted by the packet transmitting means, unit data can be extracted from the packet received by the packet receiving means, and the extracted unit data can be reproduced. A second communication means having a data order reproduction means for rearranging in a proper order;
At least one third communication unit having a function of receiving a packet transmitted by the first communication unit and transmitting the packet to the second communication unit;
A two-dimensional diffusion communication system comprising: The second communication means is
Data interpolating means for interpolating unit data included in a packet that could not be received by the packet receiving means when the number of packets received by the packet receiving means is less than the number of packets transmitted by the packet transmitting means The two-dimensional spread communication system according to claim 9, further comprising:   The data interpolating unit generates substitute data calculated based on unit data adjacent to the unit data included in the packet that could not be received by the packet receiving unit during reproduction, and received by the packet receiving unit 11. The two-dimensional spread communication system according to claim 10, wherein interpolation is performed by inserting the substitute data at a position where the unit data included in the packet that could not be originally rearranged.   In the case where N unit data is included in one packet in the packet generation means, the data order rearranging means is a unit that is not adjacent at least N-1 reproductions between unit data adjacent at the time of reproduction. Data is inserted, The two-dimensional spreading | diffusion communication system in any one of Claim 9 to 11 characterized by the above-mentioned.   The first communication unit, the second communication unit, and the third communication unit are incorporated in one communication chip, and communication is performed by using a plurality of the communication chips. The two-dimensional diffusion communication system according to any one of claims 9 to 12.

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