| Operators |
set_texture_inspection_model_param — Set parameters of a texture inspection model.
set_texture_inspection_model_param( : : TextureInspectionModel, GenParamName, GenParamValue : )
The operator set_texture_inspection_model_param is used to manipulate the parameters of a texture inspection model TextureInspectionModel. The current parameter settings can be queried with the operator get_texture_inspection_model_param.
For an explanation of the concept of the texture inspection see the introduction of chapter Inspection / Texture Inspection.
General parameters:
Determines the number of pyramid levels used within the texture inspection process. The number of pyramid levels affects the inspection results as well as the runtime of train_texture_inspection_model and apply_texture_inspection_model. Per default the number of levels is estimated by the size of the training images. It should be noted, that no more than 5 pyramid levels are used by the estimation process.
Changing this parameter can require a complete new training of the texture inspection model. No retraining is required if the number of levels of a trained texture inspection model are merely reduced.
If the texture in your images is very coarse, the lower pyramid levels may not be needed for a successful inspection. Then you can save a lot of runtime by setting the levels of interest explicitly with 'levels'.
Values: integer values larger or equal to 1 or 'auto'
Default: 'auto'
Determines the pyramid levels used within the texture inspection process. The number of pyramid levels affects the inspection results as well as the runtime of train_texture_inspection_model and apply_texture_inspection_model. Per default the pyramid levels are determined by the value of 'num_levels'. If for example 'num_levels' is set to four, then the texture inspection is performed for levels 1 to 4. If all available levels should be trained, the value has to be set to 'auto'.
Changing this parameter can require a complete new training of the texture inspection model. No retraining is required if the number of levels of a trained texture inspection model are merely reduced.
If the texture in your images is very coarse, the lower pyramid levels may not be needed for a successful inspection. Then you can save a lot of runtime by excluding unwanted levels by setting the pyramid levels with 'levels' explicitly.
In order to avoid confusions regarding the returned tuple length, 'levels' can only be set alone i.e. without passing any other parameter to set_texture_inspection_model_param.
Values: a monotonically increasing tuple of integer values larger or equal to 1, or 'auto'
Default: 'auto'
This parameter determines whether or not a result handle is returned by apply_texture_inspection_model. If set to 'true', the individual pyramid level results can be queried from the texture result handle with get_texture_inspection_result_object. This is useful for debugging and fine tuning.
If set to 'false', apply_texture_inspection_model only returns a novelty region.
Values: 'true', 'false'
Default: 'false'
Parameters which influence the automatic novelty threshold calculation:
This parameter sets the values of the novelty thresholds, which distinguish between defective and non-defective texture. The novelty thresholds are passed as a tuple and are set for all pyramid levels at once. Therefore, the number of elements must be equal to the number of pyramid levels 'num_levels'.
Setting the novelty thresholds prior to training has no effect since the training automatically determines novelty thresholds. Hence the novelty thresholds should be adapted after the training. A typical use case is the fine tuning to optimize the results of apply_texture_inspection_model. Please note, if the novelty thresholds have been set explicitly, a new call of train_texture_inspection_model will re-estimate the novelty thresholds automatically and overwrite any explicitly set novelty thresholds.
It is possible to add an index to set the novelty threshold of a specific pyramid level. For example, 'novelty_threshold_3' sets the novelty threshold for the third pyramid level.
Values: integer or float values larger or equal to 0 and smaller or equal to 710
Default: Is determined by train_texture_inspection_model
This parameter influences the sensitivity of the novelty thresholds which are determined during the training with train_texture_inspection_model. Per default 'sensitivity' is set to 0.0, which means the novelty thresholds from the training are used directly when calling apply_texture_inspection_model. If a negative value for the parameter 'sensitivity' is used, the value is added to the novelty boundaries. Hence, a sensitivity value below 0.0 increments the novelty thresholds and therefore leads to potentially fewer detected errors. If instead a positive value is set, the novelty thresholds are decremented which leads to potentially more detected errors.
The automatically determined novelty thresholds can be changed after the training with the parameter 'novelty_threshold'.
Values: float or integer value
Default: 0.0
Parameters that influence the texture features:
Determines the method used to normalize the texture features. A normalization is required if the lighting between different images is not consistent. If set to 'weber', the patches are normalized in accordance with the Weber-Fechner law. If the parameter is set to 'none', no feature normalization is performed.
Changing this parameter requires a complete new training of the texture inspection model.
Values: 'none', 'weber'
Default: 'none'
If set to 'true', the texture features are sorted in a way to obtain a certain amount of rotational invariance. Sorting the features leads to a loss of feature information and generally makes the texture inspection less sensitive. Also, the runtime is slightly increased. If the parameter is set to 'false', the texture features are not sorted.
Alternatively, it is possible to capture all possible rotations within the training images. Increasing the training images leads to an increase of the training time.
Changing this parameter requires a complete new training of the texture inspection model.
Values: 'true', 'false'
Default: 'false'
This parameter determines the diameter of the extracted texture feature patches in pixels. Higher patch sizes increase the runtime significantly. Therefore this parameter should only be changed with great care. First try to change the image resolution or the number of pyramids used.
Changing this parameter requires a complete new training of the texture inspection model.
Values: odd integer values between 1 and 11
Default: 5
Advanced parameters that influence the GMM classifiers:
Internally, the texture inspection model uses a Gaussian Mixture Model (GMM) classifier. In general, it is recommended not to change the GMM parameters, but for experienced users this is still possible.
Changing these parameters requires a new training of the texture inspection model.
In the following, the parameters which influence the GMM classifiers are described. For more information on classification with GMM classifiers, see create_class_gmm and train_class_gmm.
This parameter determines the standard deviation of the Gaussian noise which is added to the training samples (see add_sample_class_gmm).
Values: integer or float values larger or equal to 0.0
Default: 0.0
This parameter determines the minimum number of Gaussian distributions per class. 'gmm_pmincenters' cannot be set to a value larger than the current value of 'gmm_pmaxcenters'.
Values: integer value larger or equal to 1 and less or equal to 'gmm_pmaxcenters'
Default: 12
This parameter determines the maximum number of Gaussian distributions per class. 'gmm_pmaxcenters' cannot be set to a value smaller than the current value of 'gmm_pmincenters'.
Values: integer value larger or equal to 'gmm_pmincenters'
Default: 12
This parameter determines the type of preprocessing used to transform the feature vectors.
Values: 'principal_components', 'none'
Default: 'none'
This parameter manipulates the preprocessing in case 'principal_components' is chosen as the preprocessing method. More specifically, it determines the dimension of the transformed feature vectors. It needs to be chosen such that it is smaller than the feature dimension, which is PatchSize PatchSize. If the PatchSize is changed such that PatchSize PatchSize gmm_ncomp, the parameter is manipulated accordingly.
Values: integer value larger or equal to 1
Default: 15
This parameter determines the initialization value for the random number generator, which is required to initialize the GMM with random values.
Values: integer value
Default: 42
This parameter determines the maximum number of iterations of the expectation maximization algorithm.
Values: integer values larger or equal to 0
Default: 100
This parameter determines the threshold for the relative change of the error for the expectation maximization algorithm to terminate.
Values: integer or float value larger or equal to 0 and smaller than 1.0
Default: 0.001
This parameter determines the regularization value for preventing covariance matrix singularity within the training process.
Values: integer or float values larger or equal to 0 and smaller than 1.0
Default: 0.0001
If parameters of a texture inspection model are manipulated after a successful call of train_texture_inspection_model, the texture inspection model usually needs to be retrained. Depending on which parameters are changed, different parts of the training need to be recalculated.
A manipulation of the parameters 'gmm_*' requires a new training of the classifiers. Since a new classifier yields different novelty scores, the novelty thresholds also need to be recalculated. The parameter 'patch_*' requires a complete new training of the texture inspection model. The parameters 'num_levels' and 'levels' require a retraining if the number of levels is increased or levels are set which were not trained beforehand. For example, setting 'levels' from [1,2,3] to [1,3] does not require a retraining. The operator 'gen_result_handle' has no effect on a trained texture inspection model and can be manipulated without requiring any retraining.
This operator modifies the state of the following input parameter:
The value of this parameter may not be shared across multiple threads without external synchronization.Handle of the texture inspection model.
Name of the model parameter to be adjusted.
Default value: 'gen_result_handle'
List of values: 'gen_result_handle', 'gmm_em_max_iter', 'gmm_em_regularize', 'gmm_em_threshold', 'gmm_ncomp', 'gmm_pmaxcenters', 'gmm_pmincenters', 'gmm_preprocessing', 'gmm_randseed', 'gmm_sigma', 'levels', 'novelty_threshold', 'num_levels', 'patch_normalization', 'patch_rotational_robustness', 'patch_size', 'sensitivity'
New value of the model parameter.
Default value: 'true'
List of values: 5, 'auto', 'false', 'none', 'normalization', 'principal_components', 'true', 'weber'
* Create texture inspection model
create_texture_inspection_model ('basic', TextureInspectionModel)
* Set parameters
set_texture_inspection_model_param (TextureInspectionModel, \
'gen_result_handle', 'true')
* Make this short example fast:
set_texture_inspection_model_param (TextureInspectionModel, \
'gmm_em_max_iter', 1)
* Read and add training images
read_image (TrainImage, 'carpet/carpet_01')
add_texture_inspection_model_image (TrainImage, TextureInspectionModel, \
Indices)
* Train the model
train_texture_inspection_model (TextureInspectionModel)
* Read and apply a test image
read_image (TestImage, 'carpet/carpet_02')
apply_texture_inspection_model (TestImage, DefectCandidates, \
TextureInspectionModel, \
TextureInspectionResultID)
* Clean up
clear_texture_inspection_model (TextureInspectionModel)
clear_texture_inspection_result (TextureInspectionResultID)
The operator set_texture_inspection_model_param returns the value 2 (H_MSG_TRUE) if the given parameters are valid and within acceptable range. Otherwise, an exception will be raised.
create_texture_inspection_model
add_texture_inspection_model_image, train_texture_inspection_model
get_texture_inspection_model_param
Matching
| Operators |