Cog3DCameraCalibrationValidator Class

Cognex VisionPro

This class provides the ability to verify a set of camera calibrations accurately reflects the current intrinsic parameters for a set of cameras as well as the relative positions of the cameras. Note that the size of the set of camera calibrations and the size of the set of cameras can be 1.

The verification requires as input the original camera calibrations and a set of calibration features that have been extracted from a newly acquired set of images. The verification outputs the 2D and 3D residuals characterizing the current accuracy of the image acquisition system. These "current" accuracies can be compared to the "baseline" accuracies computed at the time of the original camera calibration. The results of the comparison determine whether or not the image acquisition system is still in calibration.

Due to the nature of the validation procedure (positioning a calibration plate in an arbitrary pose), the validation cannot determine if the world coordinate system has changed. Validation can only determine if the camera intrinsics are out of calibration, and if the camera positions RELATIVE TO EACH OTHER have changed.

Inheritance Hierarchy

System Object
  System MarshalByRefObject
    Cognex.VisionPro.Implementation CogObjectBase
      Cognex.VisionPro.Implementation CogSerializableObjectBase
        Cognex.VisionPro3D Cog3DCameraCalibrationValidator

Namespace: Cognex.VisionPro3D
Assembly: Cognex.VisionPro3D (in Cognex.VisionPro3D.dll) Version: 65.1.0.0

Syntax

C++

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[SerializableAttribute]
public class Cog3DCameraCalibrationValidator : CogSerializableObjectBase, 
	IDisposable

[SerializableAttribute]
public class Cog3DCameraCalibrationValidator : CogSerializableObjectBase, 
	IDisposable

<SerializableAttribute>
Public Class Cog3DCameraCalibrationValidator 
	Inherits CogSerializableObjectBase 
	Implements IDisposable

<SerializableAttribute>
Public Class Cog3DCameraCalibrationValidator 
	Inherits CogSerializableObjectBase 
	Implements IDisposable

[SerializableAttribute]
public ref class Cog3DCameraCalibrationValidator : public CogSerializableObjectBase, 
	IDisposable

[SerializableAttribute]
public ref class Cog3DCameraCalibrationValidator : public CogSerializableObjectBase, 
	IDisposable

The Cog3DCameraCalibrationValidator type exposes the following members.

Constructors

	Name	Description
	Cog3DCameraCalibrationValidator	Construct this default Cog3DCameraCalibrationValidator.
	Cog3DCameraCalibrationValidator(Cog3DCameraCalibrationValidator)
	Cog3DCameraCalibrationValidator(SerializationInfo, StreamingContext)

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Methods

	Name	Description
	CreateObjRef	Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.)
	Dispose
	Dispose(Boolean)
	Equals	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Execute	Use the specified calibration features and the specified camera calibrations to compute 2 camera calibration validation results. The first result (validationResultUsingOriginalCalibrations) contains the residuals when the specified camera calibrations are used. The second result (validationResultUsingRecomputedExtrinsics) contains the residuals after a new set of extrinsic parameters are computed using the specified calibration features. Note that for the case of a single camera, the two results should be exactly equal to each other.
	Finalize	(Overrides Object Finalize .)
	GetAttributes	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetClassName	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetComponentName	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetConverter	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetDefaultEvent	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetDefaultProperty	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetEditor	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetEvents	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetEvents( Attribute )	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetLifetimeService	Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
	GetObjectData	(Overrides CogSerializableObjectBase GetObjectData(SerializationInfo, StreamingContext).)
	GetProperties	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetProperties( Attribute )	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetPropertyOwner	Implements the corresponding member of the ICustomTypeDescriptor interface. May be overridden in derived classes to provide custom type information. (Inherited from CogObjectBase.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	InitializeLifetimeService	Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	MemberwiseClone(Boolean)	Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.)
	ToString	Returns a String that represents the current Object. (Inherited from Object.)

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Remarks

A "baseline" validation should be performed immediately after camera calibration. That baseline validation step should involve multiple view sets so it is possible to estimate the distribution of 2D residuals and 3D residuals. The "baseline" validation measurements should be stored for future comparison.

Then, at some arbitrary time (usually after the system performed vision tasks for a period of time), the user acquires images of the same calibration plate in some set of (preferrably, the same) poses and executes camera calibration validation to get the "current" measurements. Finally, the user compares the "current" validation measurements with the "baseline".

If the "current" measurements agree with the "baseline" measurements to a satisfactory degree, then the system is in calibration and the user does not need to perform any recalibration. If the measurement computed using the "recomputed extrinsics" satisfactorily agrees, but the measurement computed using the existing "camera calibration" do not satisfactorily agrees, then the user needs to perform extrinsic calibration. If neither validation measurements agree, then the user needs to perform full recalibration.