apply_metrology_model — Measure and fit the geometric shapes of all metrology objects of a metrology model.
apply_metrology_model locates the edges inside the measure regions of the metrology objects of the metrology model MetrologyHandle within Image and fits the corresponding geometric shapes to the resulting edge positions.
For an explanation of the concept of 2D metrology see the introduction of chapter 2D Metrology.
The measurements are performed as follows:
Determining the edge positions
Within the measure regions of the metrology objects, the positions of the edges are determined. The edge location is calculated internally with the operator measure_pos or fuzzy_measure_pos. The latter is used if at least one fuzzy function was set for the metrology objects with set_metrology_object_fuzzy_param.
Fitting geometric shapes to the edge positions
The geometric shapes of the metrology objects are adapted to fit optimally to the resulting edge positions. In particular, a RANSAC algorithm is used to select a set of initial edge positions that is necessary to create an instance of the specific geometric shape, e.g., three edge positions are selected for a metrology object of type circle. Then, those edge positions that are near the corresponding instance of the geometric shape are determined and, if the number of suitable edge positions is sufficient (see the generic parameter 'min_score' of set_metrology_object_param), are selected for the final fitting of the geometric shape. If the number of suitable edge positions is not sufficient, another set of initial edge positions is tested until a suitable selection of edge positions is found. Into the edge positions that are selected for the final fitting, the geometric shape is fitted and its parameters are stored in the metrology model. Note that more than one instance for each metrology object is returned if the generic parameter 'num_instances' is set to value larger than 1. This and other parameters can be set when adding the metrology objects to the metrology model or separately with the operator set_metrology_object_param. Note that for each instance of the metrology object different initial edge positions are used, i.e., a second instance is based on edge positions that were not already used for the fitting of the first instance. The algorithm stops either when 'num_instances' instances were found or if the remaining number of suitable initial edge positions is too low for a further fitting of the geometric shape.
Accessing the results
The results of the measurements can be accessed from the metrology model using get_metrology_object_result. Note that if more than one instance of an object is returned, the order of the returned instances is arbitrary and therefore no measure for the quality of the fitting. Note further that if the parameters 'camera_param' and 'plane_pose' were set for the metrology model using set_metrology_model_param, world coordinates are used for the fitting. Otherwise, image coordinates are used. The XLD contours for the measured objects can be obtained using get_metrology_object_result_contour.
Note that all measure regions of all metrology objects must be recomputed if the width or the height of the input Image is not equal to the width and height stored in the metrology object (e.g. set with set_metrology_model_image_size). This leads to longer execution times of the operator.
Note further that apply_metrology_model ignores the domain of Image for efficiency reasons (see also measure_pos).
This operator modifies the state of the following input parameter:
Handle of the metrology model.
If the parameters are valid, the operator apply_metrology_model returns the value 2 (H_MSG_TRUE). If necessary, an exception is raised.
add_metrology_object_generic, add_metrology_object_circle_measure, add_metrology_object_ellipse_measure, add_metrology_object_line_measure, add_metrology_object_rectangle2_measure, align_metrology_model, set_metrology_model_param, set_metrology_object_param
get_metrology_object_result, get_metrology_object_result_contour, get_metrology_object_measures
set_metrology_object_fuzzy_param, read_metrology_model, write_metrology_model