public class HTVQEncode extends Transformer
The matrix must be of dimensions that are amenable to this method. (i.e. 2x1, 2x2, 4x2, 4x4, etc.) Instead of performing a full-search vector quantization during execution, all the optimal encoding vectors are calculated before hand and stored in a lookup table. (This is known as Table-lookup Vector Quantization). However, for large vector sizes the lookup tables are unmanageably large. This actor approximates a full search VQ by storing the lookup tables hierarchically. The encoding is broken up into stages, and at each stage a number of 2x1 table lookup VQs are performed. For example, starting with a 4x2 vector in the first stage, codebook 0 (which operates on raw pixels) is used 4 times, resulting in a 2x2 vector of codewords. In the second stage, codebook 1 is used twice, resulting in a 2x1 vector. Lastly, a single 2x1 VQ using codebook 2 (which operates on codewords representing 2x2 vectors) returns a single codeword for the 4x2 vector.
The input is an IntMatrixToken corresponding to the block to be encoded. The values in this matrix are assumed to be between 0 and 255. The output is an IntToken with value between 0 and 255. Integers are used here because of the minimal byte support in Ptolemy or JAVA. The size of the input matrix should be the same as the parameters blockHeight and blockWidth.
The codebook is specified as a binary file that will be read during initialization. This file actually contains five sets of codebooks and lookups tables. The first set is for 2x1 blocks, the second is for 2x2 blocks, etc. (Thus the supplied codebook is only sufficient for block sizes up to 8x4 pixels.) In each set, the codebook precedes the lookup-tables. The codebook consists of all 256 codevectors, row scanned from top to bottom. The lookup table consists of 64K entries (one for each pair of codewords from the previous stage). Each entry in the lookup table is an 8-bit codeword.
Stage 0: 2x1 block size codebook = 256 blocks x 2 bytes = 512 bytes lookup tables = 65536 entries x 1 byte = 65536 bytes Stage 1: 2x2 block size codebook = 256 blocks x 4 bytes = 1024 bytes lookup tables = 65536 entries x 1 byte = 65536 bytes Stage 2: 4x2 block size codebook = 256 blocks x 8 bytes = 2048 bytes lookup tables = 65536 entries x 1 byte = 65536 bytes Stage 3: 4x4 block size codebook = 256 blocks x 16 bytes = 4096 bytes lookup tables = 65536 entries x 1 byte = 65536 bytes Stage 4: 8x4 block size codebook = 256 blocks x 32 bytes = 8192 bytes lookup tables = 65536 entries x 1 byte = 65536 bytes
The supplied codebook was trained using images from the USC image archive and is suitable for most general applications.
For more information here are some interesting references:
A. Gersho and R. M. Gray, Vector Quantization and Signal Compression. Kluwer Academic Publishers, Boston, 1992.
P. C. Chang, J. May, R. M. Gray, "Hierarchical Vector Quantizers with Table Lookup Encoders," International Conference on Acoustics Speech and Signal Processing, pp. 1452-1455, 1985.
M. Vishwanath and P. Chou, "An Efficient Algorithm for Hierarchical Compression of Video," International Conference on Image Processing, vol. 3, pp. 275-279, Nov. 1994
Entity.ContainedObjectsIterator| Modifier and Type | Field and Description |
|---|---|
Parameter |
blockCount
The number of blocks to be encoded during each firing.
|
Parameter |
blockHeight
The width, in pixels, of the block to encode.
|
Parameter |
blockWidth
The width, in pixels, of the block to encode.
|
Parameter |
codeBook
A Parameter of type String, giving the location of the codebook data
file relative to the root classpath.
|
Parameter |
input_tokenConsumptionRate
The input rate.
|
Parameter |
output_tokenProductionRate
The output rate.
|
input, output_typesValid_actorFiringListeners, _initializables, _notifyingActorFiring, _stopRequested_changeListeners, _changeLock, _changeRequests, _debugging, _debugListeners, _deferChangeRequests, _elementName, _isPersistent, _verbose, _workspace, ATTRIBUTES, CLASSNAME, COMPLETE, CONTENTS, DEEP, FULLNAME, LINKSCOMPLETED, NOT_READY, STOP_ITERATING| Constructor and Description |
|---|
HTVQEncode(CompositeEntity container,
java.lang.String name)
Construct an actor in the specified container with the specified
name.
|
| Modifier and Type | Method and Description |
|---|---|
java.lang.Object |
clone(Workspace workspace)
Clone the actor into the specified workspace.
|
void |
fire()
Fire this actor.
|
void |
initialize()
Initialize this actor.
|
_containedTypeConstraints, _customTypeConstraints, _defaultTypeConstraints, _fireAt, _fireAt, attributeTypeChanged, clone, isBackwardTypeInferenceEnabled, newPort, typeConstraintList, typeConstraints_actorFiring, _actorFiring, _declareDelayDependency, addActorFiringListener, addInitializable, connectionsChanged, createReceivers, declareDelayDependency, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, isFireFunctional, isStrict, iterate, newReceiver, outputPortList, postfire, prefire, preinitialize, pruneDependencies, recordFiring, removeActorFiringListener, removeDependency, removeInitializable, setContainer, stop, stopFire, terminate, wrapup_adjustDeferrals, _checkContainer, _getContainedObject, _propagateExistence, getContainer, instantiate, isAtomic, isOpaque, moveDown, moveToFirst, moveToIndex, moveToLast, moveUp, propagateExistence, setName_addPort, _description, _exportMoMLContents, _removePort, _validateSettables, connectedPortList, connectedPorts, containedObjectsIterator, getAttribute, getPort, getPorts, linkedRelationList, linkedRelations, portList, removeAllPorts, setClassDefinition, uniqueName_setParent, exportMoML, getChildren, getElementName, getParent, getPrototypeList, isClassDefinition, isWithinClassDefinition_addAttribute, _adjustOverride, _attachText, _cloneFixAttributeFields, _containedDecorators, _copyChangeRequestList, _debug, _debug, _debug, _debug, _debug, _executeChangeRequests, _getIndentPrefix, _isMoMLSuppressed, _markContentsDerived, _notifyHierarchyListenersAfterChange, _notifyHierarchyListenersBeforeChange, _propagateValue, _removeAttribute, _splitName, _stripNumericSuffix, addChangeListener, addDebugListener, addHierarchyListener, attributeChanged, attributeDeleted, attributeList, attributeList, decorators, deepContains, depthInHierarchy, description, description, event, executeChangeRequests, exportMoML, exportMoML, exportMoML, exportMoML, exportMoMLPlain, getAttribute, getAttributes, getChangeListeners, getClassName, getDecoratorAttribute, getDecoratorAttributes, getDerivedLevel, getDerivedList, getDisplayName, getFullName, getModelErrorHandler, getName, getName, getSource, handleModelError, isDeferringChangeRequests, isOverridden, isPersistent, lazyContainedObjectsIterator, message, notifyOfNameChange, propagateValue, propagateValues, removeAttribute, removeChangeListener, removeDebugListener, removeHierarchyListener, requestChange, setClassName, setDeferringChangeRequests, setDerivedLevel, setDisplayName, setModelErrorHandler, setPersistent, setSource, sortContainedObjects, toplevel, toString, validateSettables, workspaceequals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, waitcreateReceivers, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, newReceiver, outputPortListisFireFunctional, isStrict, iterate, postfire, prefire, stop, stopFire, terminateaddInitializable, preinitialize, removeInitializable, wrapupdescription, getContainer, getDisplayName, getFullName, getName, getName, setNamegetDerivedLevel, getDerivedList, propagateValuepublic Parameter codeBook
public Parameter blockCount
public Parameter blockWidth
public Parameter blockHeight
public Parameter input_tokenConsumptionRate
public Parameter output_tokenProductionRate
public HTVQEncode(CompositeEntity container, java.lang.String name) throws IllegalActionException, NameDuplicationException
container - The container.name - The name of this adder within the container.IllegalActionException - If the actor cannot be contained
by the proposed container.NameDuplicationException - If the name coincides with
an actor already in the container.public java.lang.Object clone(Workspace workspace) throws java.lang.CloneNotSupportedException
clone in class TypedAtomicActorworkspace - The workspace for the new object.java.lang.CloneNotSupportedException - If a derived class contains
an attribute that cannot be cloned.NamedObj.exportMoML(Writer, int, String),
NamedObj.setDeferringChangeRequests(boolean)public void fire()
throws IllegalActionException
fire in interface Executablefire in class AtomicActor<TypedIOPort>IllegalActionException - If a contained method throws it.public void initialize()
throws IllegalActionException
initialize in interface Initializableinitialize in class AtomicActor<TypedIOPort>IllegalActionException - If the parameters do not have
legal values, or the codebook file cannot be read.