Abstract: An information processing apparatus and an information processing method capable of accurately, efficiently determining a key region from a structured document which includes a plurality of regions without imposing operation burden on a user are provided.

Abstract: Secret information is shared by a group of members by giving each member a first share of the information. To reconstruct the secret information, a subgroup consisting of some or all of the members generate second shares from their first shares, and distribute the second shares to the other members of the subgroup. Each member of the subgroup performs an operation on the second shares it receives and one second share it generated itself to obtain an intermediate result. The intermediate results are transmitted to one or more members of the subgroup, or to a central facility, where the original secret information is obtained from a further operation performed on the intermediate results. The original secret information can thereby be obtained without compromising the secrecy of the first shares, and without forcing the members to reveal their identities.

Abstract: When a segment of a compressively coded stream of moving-picture data is rendered unusable by an error, usable decoded data are discarded in a range adjacent to the unusable segment, to avoid picture defects that might result from the use of incorrectly decoded data. The discarding range may extend from one end or from both ends of the unusable segment. When the data are coded in two or more different modes, two or more corresponding ranges of different lengths may be set.

Abstract: A moving picture coded by inter-frame coding, with motion compensation, is decoded by an apparatus that stores at least two previously decoded frames, together with information identifying any erroneous parts of the previously decoded frames. The current frame is decoded with reference to a predicted frame assembled from decodable parts of the previous frames. When a motion vector points to a non-decodable part of a previous frame, it is extended farther back to a decodable part of an earlier frame. The extension can be made linearly, or by using previous motion vectors. Picture distortion caused by error propagation is thereby reduced.

Abstract: Each of consecutively transmitted frames representing motion images is composed of a given number of blocks. A SAD cumulative value representing an image variation history is derived per block. Blocks to be refreshed, i.e. to be intraframe-coded, are selected based on the SAD cumulative values. Specifically, a given number of the blocks whose corresponding SAD cumulative values are larger among all the SAD cumulative values are selected, or those blocks whose corresponding SAD cumulative values are greater than a threshold value are selected. Thus, the blocks which actually require “refresh” can be preferentially refreshed.

Abstract: Each of consecutively transmitted frames representing motion images is composed of a given number of blocks. A SAD cumulative value representing an image variation history is derived per block. Blocks to be refreshed, i.e. to be intraframe-coded, are selected based on the SAD cumulative values. Specifically, a given number of the blocks whose corresponding SAD cumulative values are larger among all the SAD cumulative values are selected, or those blocks whose corresponding SAD cumulative values are greater than a threshold value are selected. Thus, the blocks which actually require “refresh” can be preferentially refreshed.

Abstract: A data reception unit having improved robustness against synchronization code errors. In data transmission, the synchronization code is always located in the headers of coded data contained in the package payload. Where the number of synchronization code bit errors falls below a threshold value, decoding is performed ignoring the errors. Where the number of bit errors exceeds the threshold value, the encoded data in the packet is discarded. Robustness against errors are modified through manipulation of the threshold value in response to transmission path type and error status.

Abstract: A picture coder and a picture coding method which quickly recover the degraded picture quality of partitions, which could not be decoded due to a data error or a data loss, without increasing the amount of coding. A picture coding method or a picture coder is operable for coding picture data of a frame which is divided into a plurality of partitions, each partition being coded in a temporal correlation coding method or in an intra-picture coding method, wherein one or more partitions are determined to be refreshed for each frame or for each plurality of frames and wherein partitions determined to be refreshed are coded in the intra-picture coding method. A temporal change amount for each partition is calculated and, based on the temporal change amount for each partition, one or more partitions are determined to be refreshed.

Abstract: A moving picture transmission system enhances the quality of a demand-refreshed image without increasing the amount of code to be transmitted. When a picture data error has been detected, a reception side coder transmits to a transmission side decoder information concerning the location of the error detected in a picture frame. Upon receipt of this information, for several frames, beginning with the picture frame that is distorted by the error and continuing up until the picture frame preceding the frame to be transmitted, the transmission side determines a portion that may be distorted by the occurrence of the error or by the transmission of the error, and a picture portion that may be affected by distortion when picture data are to be coded in the inter-frame coding mode.

Abstract: A coded moving-picture signal consists of segments, each having a start code, header information, and coded picture data. The picture data are coded according to a self-resynchronizing variable-length coding rule. During decoding, if an error is recognized, this coding rule is applied in order to resynchronize; the coded data from the resynchronization point up to the next start code are stored in a memory; then the memory contents are decoded. According to a first aspect of the invention, the header information is coded according to the same variable-length coding rule, except for group header information appearing immediately after the start code. According to a second aspect of the invention, the start code is followed by all the header information in the segment, then by all the coded picture data in the segment.