Vector quantizer
First Claim
1. An input vector quantizer for encoding digital signals with high efficiency for transmission between transmitting and receiving sides and wherein a first codebook of fixed contents is included at each of said transmitting and receiving sides, said vector quantizer comprising one or more random access second codebooks having a learning function and being connected to the intermediate hierarchy of said first codebook, means for transmitting input vector and deciding information for matching of codebooks in the transmitting and receiving sides, and a means for executing, at a high speed, vector quantization through parallel use of said first codebook and said random access one or more second codebooks in a tree-searched minimum distortion process for sequentially storing said input vectors, as the new quantizing representative vectors into said one or more second codebooks when the minimum distortion in the tree-searched vector quantization is larger than threshold value, vectors previously stored in said one or more second codebooks.
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Abstract
A vector quantizer which transmits the input vector of the time when the minimum distortion is larger than the preset distortion threshold value and stores such input vector into the second code book as the new quantizing representative vector for the use in the successive vector quantizing processes. Further, since the first and second code book constitute in the form of tree-structure, calculation for search may be executed at a high speed.
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Citations
17 Claims
- 1. An input vector quantizer for encoding digital signals with high efficiency for transmission between transmitting and receiving sides and wherein a first codebook of fixed contents is included at each of said transmitting and receiving sides, said vector quantizer comprising one or more random access second codebooks having a learning function and being connected to the intermediate hierarchy of said first codebook, means for transmitting input vector and deciding information for matching of codebooks in the transmitting and receiving sides, and a means for executing, at a high speed, vector quantization through parallel use of said first codebook and said random access one or more second codebooks in a tree-searched minimum distortion process for sequentially storing said input vectors, as the new quantizing representative vectors into said one or more second codebooks when the minimum distortion in the tree-searched vector quantization is larger than threshold value, vectors previously stored in said one or more second codebooks.
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4. An interframe vector quantization encoding and decoding apparatus comprising:
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a frame memory for storing video signals corresponding to at least one frame; a subtractor for subtracting interframe forecast video signal series read from said frame memory to input video signal series and obtaining interframe difference signal series; a vector quantization encoding and decoding unit for selectively performing scalar quantization or vector quantization of an input vector based on wave form distortion calculated in a process where the mean value separation of the input vector, obtained by blocking the interframe forecast video signal, is subjected to vector encoding quantization by an inner product vector quantization encoder if the wave form distortion is larger than threshold value and updating code books in sequence and used to perform subsequent encoding and decoding operation, or for updating the code books in sequence based on the value that the minimum distortion, obtained in the quantization process of performing mean value separation normalization vector quantization, is weighted by amplitude gain and performing the encoding and decoding operation and obtaining the encoding data and the decoding interframe difference signal series; an adder for adding the decoding difference signal series to the interframe forecast video signal series and outputting the decoding video signal series to said frame memory; a variable length encoding unit for converting the encoding data into variable length encoding and outputting variable length encoding data; a transmission buffer for storing the variable length encoding data temporarily and smoothing the amount of generating information and outputting it as transmission data at a constant speed and also estimating the amount of generating information in one frame unit; and an encoding control unit for generating encoding control parameters to perform adaptive control of operation of said vector quantization encoding and decoding unit based on the amount of generating information in one frame unit. - View Dependent Claims (5)
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6. An interframe vector quantizer comprising:
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a band dividing unit for converting input video signal series into a plurality of frequency band separation input video signal series divided per space frequency band; a first frame memory for storing one frame of the frequency band separation input video signal series outputted from said band dividing unit, and for outputting one frame of prescribed frequency band input video signal series in time division; a second frame memory for supplying frame delay to prescribed frequency band decoding video signal series outputted by an adder hereinafter described and for generating prescribed frequency band interframe forecast signal; a subtractor for subtracting prescribed frequency band interframe forecast signal outputted by said second frame memory from prescribed frequency band input video signal series outputted by said first frame memory and for generating prescribed frequency band interframe difference signal; a dynamic vector quantization encoding unit for performing dynamic vector quantization encoding of prescribed frequency band interframe difference signal outputted by said subtractor in accuracy corresponding to level of space frequency and for generating prescribed frequency band encoding data; an encoding control unit for controlling write/read of said first frame memory and said second frame memory and for controlling vector quantization characteristics of said dynamic vector quantization encoding unit; a dynamic vector quantization decoding unit for converting prescribed frequency band encoding data generated in said dynamic vector quantization encoding unit into prescribed frequency band interframe decoding difference signal; an adder for adding prescribed frequency band interframe decoding difference signal from said dynamic vector quantization decoding unit to prescribed frequency band interframe forecast signal from said second frame memory and for generating prescribed frequency band decoding video signal series and inputting it to said second frame memory; a variable length encoding unit for performing variable length encoding of prescribed frequency band encoding data outputted by said dynamic vector quantization encoding unit; a buffer for temporarily storing data subjected to variable length encoding from said variable length encoding unit; and a line interface for transmitting the variable length encoded data outputted from said buffer as transmission signal.
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7. A multimedia data transmission system for transmitting data between a sending side and a receiving side comprising:
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a means for configuring transmission frames of 80/160/320/480/560-bit lengths having the repetition frequency of 100 Hz uniformly collecting 80 basic time slots, specified without relation to the transmission rate, of 1/2/4/6/7-bit lengths having the repetition frequency of 8 kHz corresponding to the transmission rate of 8/16/32/48/56 Kbps, a means for configuring a multiframe by uniformly collecting 16 transmission frames without relation to the transmission rate, a means for multiplexing a multimedia data, in every basic time slot, transmission frame or multiframe having a code transmission rate which is an integer multiple of 8 Kbps or matching said transmission frames or multiframe, and a communication control means for notifying the receiving side by arranging and transmitting a synchronous code for identifying the partition of the transmission frames and the multiframes and bit assigning information indicating the bit assignment of multimedia data to a predetermined bit in the basic time slot. - View Dependent Claims (8, 9)
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10. In an interframe encoding apparatus for encoding, with high performance, a series of input video signals introducing conditional replenishment in unit of block, an encoding control system characterized in that a means is provided for controlling a threshold value to be applied to the entire part of frame so that, in case a predetermined value which is smaller than a block discriminating threshold value already used once is to be set as a new block discriminating threshold value in the process as a controlling a block discriminating threshold value for executing said conditional replenishment in unit of frame, a new block threshold value is set to a value which is reduced step by step, while sequentially widening the region within the frame to which said threshold value is applied, and such threshold value is finally set to said predetermined value.
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11. An encoding system comprising means for executing sequential frame encoding of selected regions of the frame to which a new block discrimination threshold value is applied, such that the area covered by said sequential frame encoding is enlarged up to the region sequentially designated in a predetermined sequence synchronized by the sending and receiving, signals means for setting said selected regions in unit portions of the frame so that the entire frame as a whole is subjected to sequential frame encoding after a selected sequence of said selected regions representing a constant total framing time, and means for transmitting the sequence information indicating passage of such total frame time for each frame and for periodically executing a frame/interframe mixed encoding mode for the interframe encoding of the regions of said frame other than said selected regions, wherein said frame/interframe mixed encoding mode and the interframe encoding mode using threshold value control are switched applicably.
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12. An image encoding transmission apparatus with motion compensating processing of sequential frames comprising:
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a preprocessing means for reading a dynamic image signal for each frame, producing a pixel signal through A/D conversion, forming blocks each of which is formed by a predetermined number of adjacent pixels on the image and generating image vector signal consisting of pixel signal groups for each block, a motion compensating means for generating a plurality of reference blocks with reference to the current block unit from a reproduced signal of the previous frame and detecting a motion vector of the image vector signal by searching the reference block which is most approximated to the image vector signal, a vector quantizing encoding means for compressing and encoding such image vector signal on the basis of the searched reference block and motion vector by utilizing correlation between frames, a second buffer for sending, frame by frame, the encoded image vector signal to the transmission line, and a vector quantizing decoding means for decoding the image vector signal encoded in the vector quantizing encoding means and generating reproduced signal by adding the vector signal of reference block searched to the obtained decoded vector signal, characterized by further comprising; an encoding accuracy control means for changing the encoding accuracy of the vector quantizing encoding means at the predetermined period in accordance with the amount of send encoding information of the encoded image vector signal to be temporarily stored in the send buffer, an adaptive spatial filter for executing a smoothing process of the reproduced signal to use pixel values including, at a predetermined ratio, pixel values approximated to each pixel value of the reproduced signal, and a smoothing characteristic control means for controlling ON/OFF conditions of smoothing process of the adaptive spatial filter on the basis of the motion vector, enhancing a degree of smoothing operation of adaptive spatial filter in case the encoding accuracy is low and lowering the degree of smoothing operation in case the encoding accuracy is high.
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13. A vector quantizing encoding and transmission apparatus for encoding and transmitting data between transmitting and receiving sides comprising:
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a preprocessing means for reading a video signal, forming blocks, each of which is comprised of a specified number of adjacent pixels of image and generating input vector to output it, a codebook for previously storing a plurality of the representative vector for quantization which is a pattern of input vector for given predetermined index data, and a vector quantizing encoding means for selecting the representative vector for quantization which is most approximated to the input vector from the codebook and outputting the index data of representative vector for quantization as the video transmitting data, said apparatus further comprising; an encoding control means for measuring selection frequency of representative vector for quantization, executing code assigning control to assign a short code length index data sequentially to the vectors from the representative vector for quantization having a high selection frequency depending on the result of measurement, comparing a minimum distortion value of the representative vector for quantization selected at the time of vector quantization and the input vector with a threshold value for vector update, and rewriting the input vector, when said minimum distortion value is larger than the threshold value, to the representative vector for quantization with low selection frequency to send update discrimination information, index data and update representative vector, and a decoding control means for rewriting the representative vector for quantization of codebook in the receiving side in accordance with the update discrimination information received, measuring selection frequency of the representative vector for quantization from the index data received and assigning a short index data sequentially from the representative vector for quantization with high selection frequency on the basis of the result of measurement, wherein the index data of representative vector for quantization and the representative vector for quantization in the codebook are updated in accordance with the transmitting image.
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- 14. Learning-type vector quantizer for effectively encoding digital signals of an input image, wherein it comprises an upstream fixed codebook composed of a plurality of representative quantization vectors, a downstream random access variable codebook and encoder-decoders for vector-quantization operation different in block size connected respectively to each codebook, so that, if no encode operation is carried out in an upstream vector quantization encoder, effective vector quantization operation is carried out in a downstream vector quantization encoder using a predetermined threshold value on the input image divided into pieces by reducing the production of information.
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17. Learning-type vector quantizer for encoding data for transmission between a transmission side and a reception side, wherein at the time of vector quantization of input vectors using a plurality of representative quantization vectors stored in a random access code book, representative quantization vectors having indexes selected from the code book are rearranged according to the order of the selection, and when the minimum distortion at the time of the vector quantization for an input vector is larger than a predetermined value, the input vector is taken as the representative quantization vector and the latter replaces the oldest selected representative quantization vector derived from the rearrangement of the indexes to form a code book having a learning function, and in order to make the code books at the transmission side and the reception side the same, the input vector is transmitted to the reception side from the transmission side to carry out vector quantization using the newly formed code book.
Specification