create_planar_uncalib_deformable_modelT_create_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel (Operator)

Name

create_planar_uncalib_deformable_modelT_create_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel — Creates a deformable model for uncalibrated, perspective matching.

Signature

Description

The operator create_planar_uncalib_deformable_modelcreate_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel prepares a template, which is passed in the image TemplateTemplateTemplateTemplatetemplate, as a deformable model used for uncalibrated perspective matching. The ROI of the model is passed as the domain of TemplateTemplateTemplateTemplatetemplate.

The planar uncalibrated matching can be used to detect planar objects or planar subparts of non-planar objects that are distorted by a projective view.

This is an alternative to create_shape_modelcreate_shape_modelCreateShapeModelCreateShapeModelCreateShapeModel, create_scaled_shape_modelcreate_scaled_shape_modelCreateScaledShapeModelCreateScaledShapeModelCreateScaledShapeModel and create_aniso_shape_modelcreate_aniso_shape_modelCreateAnisoShapeModelCreateAnisoShapeModelCreateAnisoShapeModel, where typically the search image must be rectified by calibrate_camerascalibrate_camerasCalibrateCamerasCalibrateCamerasCalibrateCameras and gen_image_to_world_plane_mapgen_image_to_world_plane_mapGenImageToWorldPlaneMapGenImageToWorldPlaneMapGenImageToWorldPlaneMap beforehand.

In contrast to create_shape_model_3dcreate_shape_model_3dCreateShapeModel3dCreateShapeModel3dCreateShapeModel3d there is no need to pre-generate different views of an object, resulting into a smaller memory consumption. Hence, in case of a planar perspectively distorted object, create_planar_uncalib_deformable_modelcreate_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel should be preferred.

The model is generated using multiple image pyramid levels and is stored in memory. The output parameter ModelIDModelIDModelIDModelIDmodelID is a handle for this model, which is used in subsequent calls to find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel.

Input parameters in detail

NumLevels:

The number of pyramid levels is determined with the parameter NumLevelsNumLevelsNumLevelsNumLevelsnumLevels. It should be chosen as large as possible because by this the time necessary to find the object is significantly reduced. On the other hand, NumLevelsNumLevelsNumLevelsNumLevelsnumLevels must be chosen such that the model is still recognizable and contains a sufficient number of points on the highest pyramid level. If not enough model points are generated, the number of pyramid levels is reduced internally until enough model points are found on the highest pyramid level. If this procedure would lead to a model with no pyramid levels, i.e., if the number of model points is already too small on the lowest pyramid level, create_planar_uncalib_deformable_modelcreate_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel returns with an error message. If NumLevelsNumLevelsNumLevelsNumLevelsnumLevels is set to 'auto'"auto""auto""auto""auto", create_planar_uncalib_deformable_modelcreate_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel determines the number of pyramid levels automatically. The automatically computed number of pyramid levels can be queried using get_deformable_model_paramsget_deformable_model_paramsGetDeformableModelParamsGetDeformableModelParamsGetDeformableModelParams. In rare cases, it might happen that create_planar_uncalib_deformable_modelcreate_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel determines a value for the number of pyramid levels that is too large or too small. If the number of pyramid levels is chosen too large, the model may not be recognized in the image or it may be necessary to select very low parameters for MinScore or Greediness in find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel in order to find the model. If the number of pyramid levels is chosen too small, the time required to find the model in find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel increases. In these cases, the number of pyramid levels should be selected using the output of inspect_shape_modelinspect_shape_modelInspectShapeModelInspectShapeModelInspectShapeModel.

Angle and Scale parameters:

Note that the parameters AngleStartAngleStartAngleStartAngleStartangleStart, AngleExtentAngleExtentAngleExtentAngleExtentangleExtent, ScaleRMaxScaleRMaxScaleRMaxScaleRMaxscaleRMax, and ScaleCMaxScaleCMaxScaleCMaxScaleCMaxscaleCMax are not used by this operator. Instead, they have to be specified within the operator find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel. ScaleRMinScaleRMinScaleRMinScaleRMinscaleRMin and ScaleCMinScaleCMinScaleCMinScaleCMinscaleCMin can be relevant if you expect matches that are smaller than in the original image TemplateTemplateTemplateTemplatetemplate. Then, if NumLevelsNumLevelsNumLevelsNumLevelsnumLevels is set to 'auto'"auto""auto""auto""auto", the number of used pyramid levels may decrease.

Generally, the parameters AngleStepAngleStepAngleStepAngleStepangleStep, ScaleRStepScaleRStepScaleRStepScaleRStepscaleRStep and ScaleCStepScaleCStepScaleCStepScaleCStepscaleCStep can be determined automatically. The automatically computed angle and scale step lengths can be queried using get_deformable_model_paramsget_deformable_model_paramsGetDeformableModelParamsGetDeformableModelParamsGetDeformableModelParams. For more information about how these parameters work, please refer to the operator find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel.

Optimization:

For particularly large models, it may be useful to reduce the number of model points by setting OptimizationOptimizationOptimizationOptimizationoptimization to a value different from 'none'"none""none""none""none". If OptimizationOptimizationOptimizationOptimizationoptimization = 'none'"none""none""none""none", all model points are stored. In all other cases, the number of points is reduced according to the value of OptimizationOptimizationOptimizationOptimizationoptimization. If the number of points is reduced, it may be necessary in find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel to set the parameter Score and Greediness to a smaller value. For small models, the reduction of the number of model points does not result in a speed-up of the search because in this case usually significantly more potential instances of the model must be examined. If OptimizationOptimizationOptimizationOptimizationoptimization is set to 'auto'"auto""auto""auto""auto", create_planar_uncalib_deformable_modelcreate_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel automatically determines the reduction of the number of model points.

Contrast:

The parameter ContrastContrastContrastContrastcontrast determines the contrast the model points (edges) must have. The contrast is a measure for local gray value differences between the object and the background and between different parts of the object. ContrastContrastContrastContrastcontrast should be chosen such that only the significant features of the template are used for the model. ContrastContrastContrastContrastcontrast can also contain a tuple with two values. In this case, the model is segmented using a method similar to the hysteresis threshold method used in edges_imageedges_imageEdgesImageEdgesImageEdgesImage. Here, the first element of the tuple determines the lower threshold, while the second element determines the upper threshold. For more information about the hysteresis threshold method, see hysteresis_thresholdhysteresis_thresholdHysteresisThresholdHysteresisThresholdHysteresisThreshold. If ContrastContrastContrastContrastcontrast is set to 'auto'"auto""auto""auto""auto", create_planar_uncalib_deformable_modelcreate_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel determines the two above described values automatically. Alternatively, only the contrast ('auto_contrast'"auto_contrast""auto_contrast""auto_contrast""auto_contrast") or the hysteresis thresholds ('auto_contrast_hyst'"auto_contrast_hyst""auto_contrast_hyst""auto_contrast_hyst""auto_contrast_hyst") can be determined automatically. The remaining values that are not determined automatically can additionally be passed in the form of a tuple. In certain cases, it might happen that the automatic determination of the contrast thresholds is not satisfying. For example, a manual setting of these parameters should be preferred if certain model components should be included or suppressed because of application-specific reasons or if the object contains several different contrasts. Therefore, the contrast thresholds should be automatically determined with determine_deformable_model_paramsdetermine_deformable_model_paramsDetermineDeformableModelParamsDetermineDeformableModelParamsDetermineDeformableModelParams and subsequently verified using inspect_shape_modelinspect_shape_modelInspectShapeModelInspectShapeModelInspectShapeModel before calling create_planar_uncalib_deformable_modelcreate_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel. Note that MinContrastMinContrastMinContrastMinContrastminContrast influences the automatic contrast estimation, and hence also the estimation of the minimum size.

MinContrast:

With MinContrastMinContrastMinContrastMinContrastminContrast, it can be determined which minimal contrast the model must have in the recognition performed by find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel. In other words, this parameter separates the model from the noise in the image. Therefore, a good choice is the range of gray value changes caused by the noise in the image. If, for example, the gray values fluctuate within a range of 10 gray levels, MinContrastMinContrastMinContrastMinContrastminContrast should be set to 10. Obviously, MinContrastMinContrastMinContrastMinContrastminContrast must be smaller than ContrastContrastContrastContrastcontrast. If the model should be recognized in very low contrast images, MinContrastMinContrastMinContrastMinContrastminContrast must be set to a correspondingly small value. If the model should be recognized even if it is severely occluded, MinContrastMinContrastMinContrastMinContrastminContrast should be slightly larger than the range of gray value fluctuations created by noise in order to ensure that the position and rotation of the model are extracted robustly and accurately by find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel. If MinContrastMinContrastMinContrastMinContrastminContrast is set to 'auto'"auto""auto""auto""auto", the minimum contrast is determined automatically based on the noise in the model image. Consequently, an automatic determination only makes sense if the image noise during the recognition is similar to the noise in the model image. Furthermore, in some cases it is advisable to increase the automatically determined value in order to increase the robustness against occlusions (see above). The automatically computed minimum contrast can be queried using get_deformable_model_paramsget_deformable_model_paramsGetDeformableModelParamsGetDeformableModelParamsGetDeformableModelParams. The MinContrastMinContrastMinContrastMinContrastminContrast of a deformable model can later be changed with the help of set_deformable_model_paramset_deformable_model_paramSetDeformableModelParamSetDeformableModelParamSetDeformableModelParam.

Metric:

The parameter MetricMetricMetricMetricmetric determines the conditions under which the model is recognized in the image. If MetricMetricMetricMetricmetric = 'use_polarity'"use_polarity""use_polarity""use_polarity""use_polarity", the object in the image and the model must have the same contrast. If, for example, the model is a bright object on a dark background, the object is found only if it is also brighter than the background. If MetricMetricMetricMetricmetric = 'ignore_global_polarity'"ignore_global_polarity""ignore_global_polarity""ignore_global_polarity""ignore_global_polarity", the object is found in the image also if the contrast reverses globally. In the above example, the object hence is also found if it is darker than the background. The runtime of find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel will increase slightly in this case. If MetricMetricMetricMetricmetric = 'ignore_part_polarity'"ignore_part_polarity""ignore_part_polarity""ignore_part_polarity""ignore_part_polarity", the the contrast polarity is allowed to change only between different parts of the model, whereas the polarity of model points that are within the same model part must not change. Please note that the term 'ignore_part_polarity'"ignore_part_polarity""ignore_part_polarity""ignore_part_polarity""ignore_part_polarity" is capable of being misunderstood. It means that polarity changes between neighboring model parts do not influence the score, and hence are ignored. If MetricMetricMetricMetricmetric = 'ignore_local_polarity'"ignore_local_polarity""ignore_local_polarity""ignore_local_polarity""ignore_local_polarity", the model is found even if the contrast changes for each individual model point. This mode can, for example, be useful if the object consists of a part with medium gray value, within which either darker or brighter sub-objects lie. In this case the runtime of find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel increases significantly. The above four metrics can only be applied to single-channel images. If a multichannel image is used as the model image or as the search image only the first channel will be used (and no error message will be returned). If MetricMetricMetricMetricmetric = 'ignore_color_polarity'"ignore_color_polarity""ignore_color_polarity""ignore_color_polarity""ignore_color_polarity", the model is found even if the color contrast changes locally. This is, for example, the case if parts of the object can change their color, e.g., from red to green. In particular, this mode is useful if it is not known in advance in which channels the object is visible. In this mode, the runtime of find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel can also increase significantly. The metric 'ignore_color_polarity'"ignore_color_polarity""ignore_color_polarity""ignore_color_polarity""ignore_color_polarity" can be used for images with an arbitrary number of channels. If it is used for single-channel images it has the same effect as 'ignore_local_polarity'"ignore_local_polarity""ignore_local_polarity""ignore_local_polarity""ignore_local_polarity". It should be noted that for MetricMetricMetricMetricmetric = 'ignore_color_polarity'"ignore_color_polarity""ignore_color_polarity""ignore_color_polarity""ignore_color_polarity" the number of channels in the model creation with create_planar_uncalib_deformable_modelcreate_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel and in the search with find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel can be different. This can, for example, be used to create a model from a synthetically generated single-channel image. Furthermore, it should be noted that the channels do not need to contain a spectral subdivision of the light (like in an RGB image). The channels can, for example, also contain images of the same object that were obtained by illuminating the object from different directions.

GenParamName, GenParamValue:

With the help of the generic parameters GenParamNameGenParamNameGenParamNameGenParamNamegenParamName and GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue, the user can set parameters for the deformable model generation that are needed only in rare cases. Currently, it is used to adapt the average size of the sub-parts that the deformable model should consist of. Here, GenParamNameGenParamNameGenParamNameGenParamNamegenParamName should be set to 'part_size' and GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue should be set to 'small', 'medium' or 'big'. For objects that consist of many small contours, 'small' should be selected. For objects that consist of only big contours, 'big' should be set. Optionally, GenParamNameGenParamNameGenParamNameGenParamNamegenParamName = 'min_size'"min_size""min_size""min_size""min_size" can determine a threshold for the selection of significant model components based on the size of the components, i.e., components that have fewer points than the minimum size specified in the corresponding GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue are suppressed. This threshold for the minimum size is divided by two for each successive pyramid level. The center of gravity of the domain (region) of the model image TemplateTemplateTemplateTemplatetemplate is used as the origin (reference point) of the model. A different origin for the model can be set with set_deformable_model_originset_deformable_model_originSetDeformableModelOriginSetDeformableModelOriginSetDeformableModelOrigin.

Execution Information

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Processed without parallelization.

This operator returns a handle. Note that the state of an instance of this handle type may be changed by specific operators even though the handle is used as an input parameter by those operators.

Parameters

Result

If the parameters are valid, the operator create_planar_uncalib_deformable_modelcreate_planar_uncalib_deformable_modelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModelCreatePlanarUncalibDeformableModel returns the value 2 (H_MSG_TRUE). If necessary an exception is raised.

Possible Predecessors

determine_deformable_model_paramsdetermine_deformable_model_paramsDetermineDeformableModelParamsDetermineDeformableModelParamsDetermineDeformableModelParams

Possible Successors

set_deformable_model_originset_deformable_model_originSetDeformableModelOriginSetDeformableModelOriginSetDeformableModelOrigin, set_deformable_model_paramset_deformable_model_paramSetDeformableModelParamSetDeformableModelParamSetDeformableModelParam, get_deformable_model_contoursget_deformable_model_contoursGetDeformableModelContoursGetDeformableModelContoursGetDeformableModelContours, find_planar_uncalib_deformable_modelfind_planar_uncalib_deformable_modelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModelFindPlanarUncalibDeformableModel, get_deformable_model_paramsget_deformable_model_paramsGetDeformableModelParamsGetDeformableModelParamsGetDeformableModelParams, write_deformable_modelwrite_deformable_modelWriteDeformableModelWriteDeformableModelWriteDeformableModel, clear_deformable_modelclear_deformable_modelClearDeformableModelClearDeformableModelClearDeformableModel

Alternatives

read_deformable_modelread_deformable_modelReadDeformableModelReadDeformableModelReadDeformableModel

Module

Matching