Linde–Buzo–Gray algorithm

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The Linde–Buzo–Gray algorithm (named after its creators Yoseph Linde, Andrés Buzo and Robert M. Gray, who designed it in 1980){{Cite journal| doi = 10.1109/TCOM.1980.1094577| issn = 0090-6778| volume = 28| issue = 1| pages = 84–95| last1 = Linde| first1 = Y.| last2 = Buzo| first2 = A.| last3 = Gray| first3 = R.| title = An Algorithm for Vector Quantizer Design| journal = IEEE Transactions on Communications| access-date = 2023-12-28| date = 1980| s2cid = 18530691| url = https://ieeexplore.ieee.org/document/1094577}} is an iterative vector quantization algorithm to improve a small set of vectors (codebook) to represent a larger set of vectors (training set), such that it will be locally optimal. It combines Lloyd's Algorithm with a splitting technique in which larger codebooks are built from smaller codebooks by splitting each code vector in two. The core idea of the algorithm is that by splitting the codebook such that all code vectors from the previous codebook are present, the new codebook must be as good as the previous one or better. {{Cite book| edition = 1| publisher = Springer| isbn = 978-1-4613-6612-6| last1 = Gray| first1 = R.| last2 = Gersho| first2 = A.| title = Vector Quantization and Signal Compression| date = 1992| doi = 10.1007/978-1-4615-3626-0| url = https://doi.org/10.1007/978-1-4615-3626-0}}{{rp|361-362}}

Description

The Linde–Buzo–Gray algorithm may be implemented as follows:

algorithm linde-buzo-gray is

input: set of training vectors training, codebook to improve old-codebook

output: codebook that is twice the size and better or as good as old-codebook

new-codebook ← {}

for each old-codevector in old-codebook do

insert old-codevector into new-codebook

insert old-codevector + {{epsilon}} into new-codebook where {{epsilon}} is a small vector

return lloyd(new-codebook, training)

algorithm lloyd is

input: codebook to improve, set of training vectors training

output: improved codebook

do

previous-codebookcodebook

clusters ← divide training into |codebook| clusters, where each cluster contains all vectors in training who are best represented by the corresponding vector in codebook

for each cluster cluster in clusters do

the corresponding code vector in codebook ← the centroid of all training vectors in cluster

while difference in error representing training between codebook and previous-codebook > {{epsilon}}

return codebook

References