BaseRegisC - BaseRegisC is an Abstract Base Class, which is reference counted (Big Object) and provides the core operations for doing point set registration.

Developer Documentation

Centre for Vision, Speech & Signal Processing

Comments:
BaseRegisC is an Abstract Base Class, which is reference counted (Big Object) and provides the core operations for doing point set registration.

To avoid an accumulating error, a vector set workMovPointsM is defined which is initialized as a copy of startMovPointsM. A nearest neighbour search is performed on the fixed object. The result of this search is stored in the vector set fixM, which contains all the corresponding nearest neighbour points to workMovPointsM.

workMovPointsM and fixM will be registered and the transformation of this single iteration step is stored in rtKM. After each iteration, deltaRtKM is applied to all previous transformations, so that rtKM represents the RigidTransC to transform startMovPointsM -> fixM. The next iteration starts with workMovPointsM = rtKM o startMovPointsM, again nearest neighbour search and so on.

The returned RigidTransC of BaseRegisC contains the transformation

rtKM o (guess o startMovPointsM) = fixM

To accelerate the time expensive process of iteration, the user may select prediction (based on Besl & McKay 92), which demands less iterations.

There are further quality improving features that can be switched on and off. These are Surface Normal Check, Boundary Check and Distance Check.

The user also has the facility of choosing the method to be used to calculate the Mean Square Error.

When using the trace mode, printouts are given on each iteration step. Some of the fields are only relevant when using the prediction. Hence there fields will be blank, indicated by ------.

 #i       - iteration number
 #pts     - number of random points on moveable surface
 #w       - number of weights minus the sum of weights
 RMS      - RMS value
 % 1st    - Comparison of the current & very 1st RMS value in %
 |Trans|  - Translation occured from previous translation
 %Tn-1    - Comparison of the last & current total translation value in %
 %Texp    - Comparison of the expected & current total translation in %
 Rotation - Current Rotation in degrees
 %Rn-1    - Comparison of the last & current total rotation in %
 %Rexp    - Comparison of the expected and current rotation in %
 NCA      - Indicates whether weights were affected by the Normal Angle Check
 BCA      - Indicates whether weights were affected by the Boundary Check
 DCA      - Indicates whether weights were affected by the Distance Check
 Thek_1   - Angle in 7D space between previous last two registration vectors
 Thetak   - Angle in 7D space between last two registration vectors
 PRP      - Prediction is Possible (Good Alignment Between last two 
            registration vectors)
 CDP      - Can Do Prediction (Parabola, Line Based or Max Allowable Update)
 PUO      - Permanent Prediction Update Occured (YES/NO)
 MSEk     - Value of MSE before attempted prediction update
 MSEp     - Value of MSE after (temporary/permanent) prediction update

FindNearest returns the vector set fixM containing the closest surface points to a given set of points workMovPointsM. It also needs an array of weights. Points that have their weight value less than NearZero will be completely ignored. Note that the derived class will provide the virtual GetNNPairs() function, which is required by FindNearest. An error message will be given by FindNearest if the sum of all weights is zero, the program will then be terminated since it is then impossible to proceed.

All vector sets that are passed to the constructors must have the same number of entries i=1...N.

There are various options provided by the constructor and member functions, which affect results obtained, except the trace option.

Trace

0 : No information is displayed.
1 : All information is displayed; the amount of detail displayed depends whether the Basic ICP or Accelerated ICP is being used.

Check Boundary

keepBoundaryPoints : Do not modify weight values of boundary points.
discardBoundaryPoints : Boundary point weight values are modified accordingly to the distance and standard deviation.

Check Normals

noAngleCheck : No normal angle check is performed.
doAngleCheck : A normal angle check is performed and each point's weight is weight is modified appropriately.

Distance Check

noDistanceCheck : Do not perform distance check.
doDistanceCheck : Perform distance check and modify each point's weight appropriately.

MSE Calculation

standardMse : Use the standard MSE calculation method.
madEstimator : Use the Median Absolute Deviation Estimator Method.

Parent Classes:

Derived Classes:

Variables:

int iterationNumberM;: Number of iterations for Monte Carlo
double sigma8SurfaceM;: Sigma8_surface for Monte Carlo
MatrixC covarianceM;: Covariance for Monte Carlo
VectorSetC startMovPointsM;: Initial position of moving object points
VectorSetC startMovNormalsM;: Original normals (not transformed)
int nptsM;: Actual number of points, which maybe random
EnumBoundary boundaryM;: Whether to modify boundary point's weights
const double NearZeroM;: Used for equal to zero tests
VectorSetC fixM;: Nearest neighbour points on fixed object
VectorSetC fixNormalsM;: Normal's of NN points on fixed object
RealSArray1dC fixDistancesM;: Distance's between NN points on fixed object and points with moving object
VectorSetC workMovPointsM;: Points on the moving object
VectorSetC workMovNormalsM;: Normal's of points on moving object
SArray1dC weightM;: Weights associated with the points on the moving object
const double NormTheta0M;
const double NormTheta1M;
RigidTransC expectRtM;: Expected RT
int maxIterM;: Maximum number of iterations
double rmsThreshM;: RMS error threshold
double firstRmsM;: First_rms error (if trace>0)
EnumPrediction predictionM;: noPrediction : No linear prediction
prediction : Do linear prediction
BooleanT traceM;: Printout
EnumAngle normalsM;: Surface normal check
EnumMseCalculation mseCalcM;: MSE Calculation Type
EnumSigmaCheck sigmaM;: Distances check Not currently used
EnumRegWay regWayM;: regis : Regis or
pRegis : PRegis to estimate the transformation
SceModT regTypeM;: scene_scene : scene_scene
model_scene : model_scene
double mseKM;: Current value of MSE (MSE_k)
double mseK_1M;: Previous value of MSE (MSE_k-1)
double mseK_2M;: Previous Previous value of MSE (MSE_k-2)
double accMseK_1M;: Previous Value of MSE after accelerated iteration
double accMseK_2M;: Previous Previous value of MSE after acceleration
RigidTransC rtKM;: Current translation & rotation
RigidTransC rtK_1M;: Previous translation & rotation
RigidTransC rtK_2M;: Previous previous translation & rotation
double thetaKM;: Angle in 7D space between last two registration vectors
double thetaK_1M;: Angle in 7D space between previous last two registration vectors
RigidTransC deltaRtKM;: Translation & rotation in one basic iteration
RigidTransC accRtK_1M;: Previous total translation and rotation from the accelerated ICP algoritm
int normalAngleAffectedWeightsM;
int boundaryCheckAffectedWeightsM;
int distanceCheckAffectedWeightsM;
int predictionGoodAlignmentM;
int doPredictionUpdateM;: Used In Accelerated ICP Also
double mseBeforePredictionM;
double predictionMseM;
int predictionUpdateOccurredM;
int histM;: Indicates whether to store history
DListC historyM;: Holds history information

Methods:

BaseRegisC(void)

Null Constructor

BaseRegisC(VectorSetC & movpts,VectorSetC & movnmls,const int & npoints = 200,const int & trace = 0)

Constructor

movpts	IN: Points on the the moveable object
movnmls	IN: Normals of points on moveable object
npoints	IN: Number of points on moveable
trace	IN: 1 = Detailed prints & saves data
	0 = No prints, no savings

Passing moving points & their normals, as well as number of points, and trace option. The fixed surface is stored within the derived class.

BaseRegisC(const int & npoints,const int & trace = 0)

Constructor

npoints	IN: Number of points on the moveable object
	(No Default, so as to remove ambiguity
	with the null constructor)
trace	IN: 1 = Detailed prints & saves data
	0 = No prints, no savings

Passing number of points and trace option. The moving points are passed via the derived class. The fixed surface is stored within the derived class.

~BaseRegisC()

Destructor

void SetExpectedRT(const RigidTransC & exp = RigidTransC())

Sets the expected Final translation & rotation.

exp	IN: Expected final Translation and Rotation

This is so that it can be compared with the actual translation and rotation at the end of the print out. It also allows errors to be computed.

void SetMaxIter(const int & iteration = 1000)

Maximum number of iterations before terminating the registration.

iteration	IN: Maximum number of iterations

void SetPrediction(const EnumPrediction & prediction = noPrediction)

Whether to use prediction or basic ICP.

prediction	IN: noPrediction = No Prediction
	prediction = Perform Prediction

void SetRMSThresh(const double & ratioThres = 0.99)

Set threshold for RMS error.

ratioThres	IN: ratio threshold

Termination occurs when 2 successive ratios exceed ratioThres. See IterationBreak() for details.

void SetRegWay(const EnumRegWay & regWay = regis)

Chooses the function which will calculate the transform to move the moveable onto the new nearest neighbours on the fixed surface.

regWay	IN: regis = Regis
	pRegis = PRegis

THE DEFAULT IS THE ONLY OPTION CURRENTLY USED !!!!

void SetRegType(const SceModT & regType = scene_scene)

Defines the registration type.

regType	IN: scene_scene = scene_scene
	model_scene = model_scene

THE DEFAULT IS THE ONLY OPTION CURRENTLY USED !!!!

void SetMSECalculation(const EnumMseCalculation & mseCalc = standardMse)

Sets the calculation type for the MSE.

mseCalc	IN: standardMse = Standard MSE
	madEstimator = Uses the MAD Estimator

void SetBoundaryCheck(const EnumBoundary & bound = discardBoundaryPoints)

Whether to modify weights of NN pairs that are on the boundary of fixed.

bound	IN: keepBoundaryPoints = Don't modify weight values
	discardBoundaryPoints = Modify weight values accordingly

void SetNormalCheck(const EnumAngle & normal = noAngleCheck)

Whether to modify weights of NN pairs that have significantly different normal values.

normal	IN: noAngleCheck = Don't do normal angle check
	doAngleCheck = Do normal angle check

void SetDistanceCheck(const EnumSigmaCheck & sigma = noDistanceCheck)

Whether to modify weights of NN pairs that have significantly greater distances between them & the moving object, compared to the rest overall.

sigma	IN: noDistanceCheck = Don't do distance check
	doDistanceCheck = Do distance check

void SetHistory(const int & hst = 0)

Used to set whether a history of RTs (RigidTransforms) are kept.

hst	IN: 0 = Do not keep history of RTs
	1 = Keep a history of each RT obtained
	after each iteration

Note: Call this function before PerformRegistration().

void SaveHistory2Com(const char * comfname,const char * movfname)

Uses the history information and creates a .com file.

comfname	IN: Filename for .com file
movfname	IN: Filename of the moveable file

Note: Call this function after you have called PerformRegistration().

RigidTransC PerformRegistration(RigidTransC guess)

Execute registration with initial guess, return desired RT.

guess	IN: Initial guess

void GetNNPairs(VectorSetC & fixPts,VectorSetC & workMovPts,VectorSetC & fixNormals,RealSArray1dC & fixDists,SArray1dC<double> & wght,int & boundCheckAffectedWeights)

Get Nearest Neighbours.

fixPts	IN: Fixed points
workMovPts	IN: Workable moveable points
fixNormals	IN: Normals associated with fixPts
fixDists	IN: Distances between NN points on fixed object
	and points on moving object
wght	I&O: Weights associated with points on moveable
boundCheckAffectedWeights	OUT: Whether any weights were
	affected by the boundary check

Method of how this is achieved is defined in the derived classes.

double CheckBoundary(const double & distance)

Returns a weight value to modify a point's weight value accordingly to the distance passed associated with the NN Pair, i.e. weight[point] *= return_value.

distance	IN: Distance between NN Pair

double MSE()

Compute the average mean square error.

Method used depends on calculation type chosen by the user, determined by the call to SetMSECalculation().

void NormAngleCheck(VectorSetC & movNormals,VectorSetC & fixNrm,SArray1dC<double> & wght)

Check angle between normals and modify weights accordingly.

movNormals	IN: Normals associated with moveable
fixNrm	IN: Normals associated with fixM
wght	I&O: Weights associated with points on moveable

void DistanceCheck(const RealSArray1dC & fixDists,SArray1dC<double> & wght)

Checks distance against the standard deviation and modifies the weights accordingly.

fixDists	IN: Distances between NN Pairs
wght	I&O: Weights associated with points on moveable

void FindNearest(VectorSetC & workMovPts,VectorSetC & workMovNmls,VectorSetC & fixPts,VectorSetC & fixNmls,SArray1dC<double> & wght)

Finds nearest neighbours using GetNNPairs().

workMovPts	IN: Working moveable surface
workMovNmls	IN: Normals of working moveable
fixPts	OUT: NN on fixed surface.
fixNmls	OUT: Normals of NN on fixed.
wght	I&O: Weights associated with points

This is defined in derived class. It calculates the MSE, applies the rejection criteria (quality improvement checks) which are optional. If Quality Improvement Checks are used then the weights are updated.

NOTE: All vector sets and the array must have the same size. (Not tested)

void DoTransformation()

Transform the moving set as estimated.

int IterationBreak(const int & iteration)

Used to determine whether registration is completed.

iteration	IN: Current Iteration

In other words whether the criterion has been met.

It checks whether iteration==max_iter and/or the rms error has changed below the threshold.

BooleanT BasicIterate(const int & iteration)

Performs one Basic ICP iteration.

iteration	IN: Current Iteration

BooleanT AcceleratedIterate(const int & iteration)

Performs one Accelerated ICP Iteration.

iteration	IN: Current Iteration

void PrintHeader(void)

Prints out header information, which includes key symbol information.

void PrintResults(const int & iteration)

Compute and print results of one iteration.

iteration	IN: Current Iteration

void FinalResults()

Print the final translation and rotation.

void Savings()

Saves translation, rotation and rms error.

Currently not implemented!!!

VectorC RigidT_TO_VectorC7(RigidTransC & r)

Takes a RigidTransC and returns it as a VectorC. (RigidTransC -> VectorC).

r	IN: RigidTransC

RigidTransC VectorC7_TO_RigidT(VectorC & qq)

Takes a VectorC and returns it as a RigidTransC. (VectorC -> RigidTransC).

qq	IN : VectorC

NOTE: The involved quaternion is assumed to be valid.

#include "amma/BRefCntV.hh"

BodyRefCounterVC & Copy() const: Creat a copy of this object.
BooleanT operator==(const BodyRefCounterVC & oth) const: Compair identitys.
BooleanT operator!=(const BodyRefCounterVC & oth) const: Compair identitys.
BooleanT Save(ostream & out) const: Save to ostream.

#include "amma/BRefCnt.hh"

void AddReference(): Another reference to the object has been created.
void RemoveReference(): One reference to the object was deleted.
Locking scheme -------------- The object is possible to lock (to make constant). The scheme assumes that the object is created, it can be locked, after that it can only be destroyed. The locked object cannot be unlocked. This locking scheme is very useful during debugging, using assert() function, when it is necassary to check that object is treated as constant and the constancy is not violated by any casting or passing through the copy constructor of shared objects.
void SetConst(void) const: This locks the object.
Often objects you wish to lock are already const.
void SetConst(void): This locks the object.
BooleanT IsConst(void) const: Returns TRUE if the object is locked, ie. it is assumed to be constant.
BooleanT IsNotConst(void) const: Returns TRUE if the object is unlocked.
ie. there is no special information if the object is constant or not. Counter state information -------------------------
BooleanT ToBeDeleted() const: Returns TRUE if there is only one reference to the object and the whole object or its reference counting part can be deleted.
BooleanT ToBeDeletedRemoveIgnoreNoRemove(): Decrement refrence by 1 return true if this leaves no refrences to the object.
BooleanT ToBeDeletedRemove(): Decrement refrence by 1 return true if this leaves no refrences to the object. This also checks the NoRemove flag.
BooleanT BodyMightBeDeleted() const: Returns TRUE if the reference counted part of the object can be deleted, ie. flag NOREMOVE is false .
BooleanT IsCountZero() const: Are there any refrences left ?
BooleanT BRCPtrCanDeleteObject() const: Used by BRRCPtrC to establish if an object has ZERO refrences and can be deleted.
IntT Count() const: Returns the current state of the counter, ie. how many references to this object exist.
const BodyRefCounterC & operator=(const BodyRefCounterC & b): It has not meaning to assign object 'b' to this object because it would destroy a history of the object which is counted. So this is a dummy function.
BooleanT IsValidObject() const: Test if object is valid.
When amma check is disabled this always returns true.
BooleanT UserBitTest(IntT x) const: Test user flag.
void UserBitSet(IntT x,BooleanT setit = TRUE): Test user flag.
void UserBitZero(IntT x): Set bit to zero.
void ReportBRCError(char * Msg): Report error, used in BRCPtrC.
UIntT Hash() const: Hash on address of object.
void SetUndeletable(): Make object undeletable.
Usefull to prevent recursive deleting in graph structures. Only hackers need this function.
void ReportInvalidObject(char * Msg = 0) const: Tell user about validation failure.

#include "amma/RefCBase.hh"

LabelT Label() const: Returns the label of this reference counter.
The member function is useful mainly to recognize objects during debugging. The value of the label is uniquely defined pointer.

Programmer: Simon Cunnington , Documentation by CxxDoc: Tue Mar 20 10:49:27 2001

BaseRegisC

BaseRegisC is an Abstract Base Class, which is reference counted (Big Object) and provides the core operations for doing point set registration.

include	"amma/BaseRegis.hh"
User Level:	Default
Library:	POLREGIS
Example:	cri.cc
Section:	3D Surface.Registration
In Scope:	std