Signal compression using index mapping technique for the sharing of quantization tables

• US 5,920,853 A
• Filed: 08/23/1996
• Issued: 07/06/1999
• Est. Priority Date: 08/23/1996
• Status: Expired due to Term

• Current Assignee: AIM IP, LLC
• Original Assignee: Rockwell International Corporation
• Inventors: Benyassine, Adil, Su, Huan-Yu, Shlomot, Eyal
• Primary Examiner(s): Von Buhr, Maria N.
• Application Number:
  US08/702,780
• Time in Patent Office: 1,047 Days
• Field of Search: 395/2.09, 395/200.77, 704/500, 704/222, 704/230, 707/1, 707/3, 348/384, 348/405, 348/414, 348/417, 348/418, 348/422, 382/232, 382/253, 382/305
• US Class Current: 1/1
• CPC Class Codes: G06T 9/008 Vector quantisation
• CPC Class Codes: H03M 7/3082 Vector coding for television signals, see H04N19/94
• CPC Class Codes: Y10S 707/99931 Database or file accessing

Abstract

A signal compression system includes a coder and a decoder. The coder includes an extract unit for extracting an input feature vector from an input signal, a coder memory unit for storing a predesigned vector quantization (VQ) table for the coder such that the coder memory unit uses a set of primary indices to address entries within the pre-designed VQ table, a coder mapping unit for mapping indices from a set of secondary indices to the first set of indices, and a search unit for searching for one index out of the set of secondary indices, wherein the index from the set of secondary indices corresponds to an entry in the coder memory unit, and the entry best represents the input feature vector according to some predetermined criteria. On the decoder side, the decoder includes a decoder memory unit for storing the same pre-designed VQ table and set of primary indices as the coder memory unit, a decoder mapping unit, and a retrieval unit, wherein the entry indicated by the index best represents the input feature vector.

Claims

1. A system for coding and decoding feature vectors of a signal transmitted through a communications channel, comprising a coder and a decoder, wherein:

a) the coder comprises;

extraction means for extracting an input feature vector from the signal;

coder memory means for storing one pre-designed VQ table for the coder, the coder memory means using a set of primary indices to address entries within the pre-designed VQ table;

coder mapping unit for mapping indices from a set of fixed length secondary indices to the set of primary indices, the set of secondary indices corresponding to one pre-selected subset of the pre-designed VQ table;

search means coupled to the coder mapping unit for searching for one index out of the set of secondary indices, wherein the one index from the set of secondary indices corresponds to one index from the set of primary indices which corresponds to an entry in the coder memory means, wherein the entry in the coder memory means which best represents the input feature vector according to predetermined criteria;

b) the decoder comprises;

decoder memory means for storing the same at least one pre-designed VQ table as stored by the coder memory means, the decoder memory means also using the set of primary indices to address entries within the pre-designed VQ table;

decoder mapping unit for mapping the one index from the set of secondary indices to one index from the set of primary indices;

retrieval means for retrieving an entry from the decoder memory means by mapping the one index from the set of primary indices as mapped by the decoder mapping unit to one entry from the decoder memory means, wherein the entry best represents the input feature vector.

2. A system according to claim 1, wherein:

the coder mapping unit comprises a lookup table; and

the decoder mapping unit comprises a lookup table.

3. A coder for coding feature vectors of a signal for processing, comprising:

extraction means for extracting an input feature vector from the signal;

coder memory means for storing one pre-designed VQ table for the coder, the coder memory means using a set of primary indices to address entries within the pre-designed VQ table;

coder mapping unit for mapping indices from a set of fixed length secondary indices to the set of primary indices, the set of secondary indices corresponding to one pre-selected subset of the pre-designed VQ table;

search means coupled to the coder mapping unit for searching for one index out of the set of secondary indices, wherein the one index from the set of secondary indices corresponds to one index from the set of primary indices which corresponds to an entry in the coder memory means, wherein the entry in the coder memory means best represents the input feature vector according to predetermined criteria to an entry in the coder memory means which best represents the input feature vector according to predetermined criteria.

4. A decoder for decoding a feature vector of a signal received from a coder having a pre-designed VQ table, a set of primary indices, and a set of fixed length secondary indices associated therewith, said decoder comprising:

decoder memory means for storing the pre-designed VQ table and a pre-selected subset of the pre-designed VQ table associated with the set of secondary indices, wherein the decoder memory means uses the set of primary indices to address entries within the pre-designed VQ table;

decoder mapping unit for mapping an index from the set of secondary indices to an index from the set of primary indices;

retrieval means for retrieving an entry from the decoder memory means by mapping the index from the set of primary indices as mapped by the decoder mapping unit to an entry from the decoder memory means, wherein the entry best represents the feature vector.

5. A system for coding and decoding feature vectors of a signal transmitted through a communications channel, comprising a coder and a decoder, wherein:

a) the coder comprises;

extraction means for extracting an input feature vector from the signal;

coder memory means for storing at least one pre-designed VQ table for the coder, the coder memory means using at least one set of primary indices to address entries within the at least one pre-designed VQ table;

at least one coder mapping unit for mapping indices from at least one set of fixed length secondary indices to the at least one set of primary indices, the at least one set of secondary indices corresponding to at least one pre-selected subset of the pre-designed VQ table;

search means coupled to the coder mapping means for searching for at least one index out of the at least one set of secondary indices, wherein the at least one index from the at least one set of secondary indices corresponds to at least one index from the at least one set of primary indices which corresponds to at least one entry in the coder memory means, wherein the at least one entry in the coder memory means best represents the input feature vector according to predetermined criteria to at least one entry in the coder memory means which best represents to the input feature vector according to predetermined criteria;

b) the decoder comprises;

decoder memory means for storing at least one pre-designed VQ table which is the same as stored by the coder memory means, the decoder memory means also using at least one set of primary indices to address entries within the at least one pre-designed VQ table;

decoder mapping unit for mapping the at least one index from the least one set of secondary indices to the at least one set of primary indices;

retrieval means for retrieving at least one entry from the decoder memory means by mapping the at least one index from the at least one set of primary indices as mapped by the decoder mapping unit to at least one entry from the decoder memory means, wherein the at least one entry best represents the input feature vector.

6. A coder for coding feature vectors of a signal, comprising:

extraction means for extracting an input feature vector from the signal;

coder memory means for storing at least one pre-designed VQ table for the coder, the coder memory means using at least one set of primary indices to address entries within the at least one pre-designed VQ table;

at least one coder mapping unit for mapping indices from at least one set of fixed length secondary indices to the at least one set of primary indices, the at least one set of secondary indices corresponding to at least one pre-selected subset of the pre-designed VQ table;

search means coupled to the coder mapping means for searching for at least one index out of the at least one set of secondary indices, wherein the at least one index corresponds to at least one index from the at least one set of primary indices which corresponds to at least one entry in the coder memory means, wherein the at least one entry in the coder memory means best represents the input feature vector according to predetermined criteria to at least one entry in the coder memory means which best represents to the input feature vector according to predetermined criteria.

7. A decoder for decoding a feature vector of a signal, which is coded by a coder comprising coder memory means with at least one pre-designed VQ table, said decoder comprising:

decoder memory means for storing said at least one pre-designed VQ table and a pre-selected subset of the pre-designed VQ table associated with a set of fixed length secondary indices, wherein the decoder memory means uses at least one set of primary indices to address entries within the at least one pre-designed VQ table;

decoder mapping unit for mapping at least one index from the set of secondary indices to the at least one set of primary indices;

retrieval means for retrieving at least one entry from the decoder memory means by mapping the at least one index as mapped by the decoder mapping unit to at least one entry from the decoder memory means, wherein the at least one entry best represents the feature vector.

8. A coder for coding feature vectors of a signal, comprising:

extraction means for extracting an input feature vector from the signal;

coder memory means for storing first, second and third pre-designed VQ tables for the coder, the coder memory means using first, second and third sets of primary indices to address entries within the first, second and third pre-designed VQ tables, respectively;

three (3) coder mapping units for mapping indices from a first set of fixed length secondary indices to the first set of primary indices and from a second set of fixed length secondary indices to the second and third sets of primary indices, wherein the first and second sets of secondary indices correspond to 3 subsets of the first, second and third sets of primary indices of the first, second and third pre-designed VQ tables, respectively;

search means coupled to the 3 coder mapping units for searching for 2 secondary indices out of the first and second sets of secondary indices, wherein each of the 2 secondary indices from the first and second sets of secondary indices corresponds to 3 indices from the first, second and third sets of primary indices which correspond to 3 entries in the coder memory means'"'"' 3 pre-designed VQ tables, wherein the 3 entries best represent the input feature vector according to predetermined criteria.

9. The system according to claim 8, wherein the 3 coder mapping units are implemented using first, second and third lookup tables, wherein:

first lookup table comprises;

{96, 52, 20, 54, 86, 114, 82, 68, 36, 121, 48, 92, 18, 120, 94, 124, 50, 125, 4, 100, 28, 76, 12, 117, 81, 22, 90, 116, 127, 21, 108, 66};

second lookup table comprises;

{31, 21, 9, 3, 10, 2, 19, 26, 4, 3, 11, 29, 15, 27, 21, 12}; and

third lookup table comprises;

{16, 1, 0, 0, 8, 25, 22, 20, 19, 23, 20, 31, 4, 31, 20, 31}.

10. The system according to claim 8, wherein the 3 coder mapping units comprise:

first means for generating a mapping from a secondary index to a primary index in accordance with a first set of ordered pairs of secondary and primary indices respectfully, comprising;

{0,96}, {1,52},{2,20}, {3,54}, {4,86}, {5,114},{6,82}, {7,68}, {8,36}, {9,121},{10,48}, {11, 92}, {12,18}, {13,120}, {14,94}, {15,124}, {16,50}, {17,125}, {18,4}, {19,100}, {20,28}, {21,76}, {22,12}, {23,117}, {24,81}, {25,22}, {26,90}, {27,116}, {28,127}, {29,21}, {30, 108}, {31,66};

second means for generating a mapping from a secondary index to a primary index in accordance with a second set of ordered pairs of secondary and primary indices respectively, comprising;

{0,31}, {1,21}, {2,9}, {3,3}, {4,10}, {5,2}, {6,19}, {7,26}, {8,4}, {9,3}, {10,11}, {11,29}, {12,15}, {13,27}, {14,21}, {15,12};

third means for generating a mapping from a secondary index to a primary index in accordance with a third set of ordered pairs of secondary and primary indices respectively, comprising;

{0,16}, {1,1}, {2,0}, {3,0}, {4,8}, {5,25}, {6,22}, {7,20}, {8,19}, {9,23}, {10,20}, {11,31}, {12,4}, {13,31}, {14,20}, {15,31}.

11. A decoder for decoding a feature vector of a coded signal based on a first and second set of fixed length secondary indices, wherein the coded signal has been coded by a coder with first, second and third pre-designed VQ tables, comprising:

means for receiving the first and second secondary indices;

decoder memory means for storing the first, second and third pre-designed VQ tables which are the same VQ tables as stored by the coder, the decoder memory means using first, second and third sets of primary indices to address entries within the first, second and third pre-designed VQ tables;

three (3) decoder mapping units for mapping the first secondary index to a first primary index out of the first set of primary indices, and mapping the second secondary index to second and third primary indices out of the second and third sets of primary indices;

retrieval means for retrieving 3 entries from the decoder memory means by mapping the first, secondary and third primary indices as mapped by the three decoder mapping units to 3 entries from the decoder memory means, wherein the 3 entries best represent the feature vector.

12. A system for coding and decoding feature vectors of a signal transmitted through a communications channel, comprising a coder and a decoder, wherein:

a) the coder comprises;

extraction means for extracting an input feature vector from the signal;

coder memory means for storing first, second and third pre-designed VQ tables for the coder, the coder memory means using first, second and third sets of primary indices to address entries within the first, second and third pre-designed VQ tables, respectively;

three (3) coder mapping units for mapping indices from a first set of fixed-length secondary indices to the first set of primary indices and from a second set of fixed-length secondary indices to the second and third sets of primary indices, the first and second sets of secondary indices corresponding to 3 subsets of the first, second and third sets of primary indices of the first, second and third pre-designed VQ tables, respectively;

search means coupled to the 3 coder mapping units for searching for 2 secondary indices out of the first and second sets of secondary indices, wherein each of the 2 secondary indices from the first and second sets of secondary indices corresponds to 3 entries from the first, second and third set of primary indices, wherein the 3 entries best represent the input feature vector according to predetermined criteria; and

b) the decoder comprises;

means for receiving the first and second secondary indices;

decoder memory means for storing the first, second and third pre-designed VQ tables, the decoder memory means using first, second and third sets of primary indices to address entries within the first, second and third pre-designed VQ tables;

three (3) decoder mapping units for mapping the first secondary index to a first primary index out of the first set of primary indices, and mapping the second secondary index to second and third primary indices out of the second and third sets of primary indices;

retrieval means for retrieving 3 entries from the decoder memory means by mapping the first, second and third primary indices as mapped by the three decoder mapping units to 3 entries from the decoder memory means, wherein the 3 entries best represent the input feature vector.

13. The system according to claim 12, wherein said signal comprises an encoded speech signal comprising a speech period and a silence period, and wherein said speech period is encoded in accordance with said three pre-designed VQ tables, and said silence period is encoded in defined with said first and second set of secondary indices.

14. The system according to claim 12, wherein the 3 coder mapping units are implemented using first, second and third lookup tables, wherein:

first lookup table comprises;

{96, 52, 20, 54, 86, 114, 82, 68, 36, 121, 48, 92, 18, 120, 94, 124, 50, 125, 4, 100, 28, 76, 12, 117, 81, 22, 90, 116, 127, 21, 108, 66};

second lookup table comprises;

{31, 21, 9, 3, 10, 2, 19, 26, 4, 3, 11, 29, 15, 27, 21, 12}; and

third lookup table comprises;

{16, 1, 0, 0, 8, 25, 22, 20, 19, 23, 20, 31, 4, 31, 20, 31}.

15. The system according to claim 12, wherein the 3 coder mapping units comprise:

first means for generating a mapping from a secondary index to a primary index in accordance with a first set of ordered pairs of secondary and primary indices respectfully, comprising;

{0,96}, {1,52}, {2,20}, {3,54}, {4,86}, {5,114}, {6,82}, {7,68},{8,36}, {9,121},{10,48}, {11, ρ

}, {12,18}, {13,120}, {14,94}, {15,124}, {16,50}, {17,125}, {18,4}, {19,100}, {20,28}, {21,76}, {22,12}, {23,117}, {24,81}, {25,22}, {26,90}, {27,116}, {28,127}, {29,21}, {30, 108}, {31,66};

second means for generating a mapping from a secondary index to a primary index in accordance with a second set of ordered pairs of secondary and primary indices respectively, comprising;

{0,31}, {1,21}, {2,9}, {3,3}, {4,10}, {5,2}, {6,19}, {7,26}, {8,4}, {9,2}, {10,11}, {11,29}, {12,15}, {13,27}, {14,21}, {15,12};

third means for generating a mapping from a secondary index to a primary index in accordance with a third set of ordered pairs of secondary and primary indices respectively, comprising;

{0,16}, {1,1}, {2,0}, {3,0}, {4,8}, {5,25}, {6,22}, {7,20}, {8,19}, {9,23}, {10,20}, {11,31}, {12,4}, {13,31}, {14,20}, {15,31}.