Determine the parameters of a shape model.

determine_shape_model_params determines certain parameters of a shape model automatically from the model image Template. The parameters to be determined can be specified with Parameters. determine_shape_model_params can be used to determine the same parameters that are determined automatically when the respective parameter in create_shape_model or create_scaled_shape_model is set to 'auto': the number of pyramid levels (Parameters = 'num_levels'), the angle step length (Parameters = 'angle_step'), the scale step length (Parameters = 'scale_step'), the kind of optimization (Parameters = 'optimization'), the threshold (Parameters = 'contrast') or the hysteresis thresholds (Parameters = 'contrast_hyst') for the contrast, the minimum size of the object parts (Parameters = 'min_size'), and the minimum contrast (Parameters = 'min_contrast'). By passing a tuple of the above values in Parameters, an arbitrary combination of these parameters can be determined. If all of the above parameters should be determined, the value 'all' can be passed. In this case both hysteresis thresholds are determined, i.e., the operator behaves like passing 'contrast_hyst' instead of 'contrast'. determine_shape_model_params is mainly useful to determine the above parameters before creating the model, e.g., in an interactive system, which makes suggestions for these parameters to the user, but enables the user to modify the suggested values.

The automatically determined parameters are returned as a name-value pair in ParameterName and ParameterValue. The parameter names in ParameterName are identical to the names in Parameters, where, of course, the value 'all' is replaced by the actual parameter names. An exception is the parameter 'contrast_hyst', for which the two values 'contrast_low' and 'contrast_high' are returned.

The remaining parameters (NumLevels, AngleStart, AngleExtent, ScaleMin, ScaleMax, Optimization, Metric, Contrast, and MinContrast) have the same meaning as in create_scaled_shape_model. The description of these parameters can be looked up with this operator. These parameters are used by determine_shape_model_params to calculate the parameters to be determined in the same manner as in create_shape_model and create_scaled_shape_model.

Note that in determine_shape_model_params some parameters appear that can also be determined automatically (NumLevels, Optimization, Contrast, MinContrast). If these parameters should not be determined automatically, i.e., their name is not passed in ParameterName, the corresponding parameters must contain valid values and must not be set to 'auto'. In contrast, if these parameters are to be determined automatically, their values are treated in the following way: If the optimization or the (hysteresis) contrast is to be determined automatically, i.e., ParameterName contains the value 'optimization' or 'contrast' ('contrast_hyst'), the values passed in Optimization and Contrast are ignored. In contrast, if the maximum number of pyramid levels or the minimum contrast is to be determined automatically, i.e., ParameterName contains the value 'num_levels' or 'min_contrast', you can let HALCON determine suitable values and at the same time specify an upper or lower boundary, respectively:

If the maximum number of pyramid levels should be specified in advance, NumLevels can be set to the particular value. If in this case Parameters contains the value 'num_levels', the computed number of pyramid levels is at most NumLevels. If NumLevels is set to 'auto' (or 0 for backwards compatibility), the number of pyramid levels is determined without restrictions as large as possible.

If the minimum contrast should be specified in advance, MinContrast can be set to the particular value. If in this case Parameters contains the value 'min_contrast', the computed minimum contrast is at least MinContrast. If MinContrast is set to 'auto', the minimum contrast is determined without restrictions.

If the parameters are valid, the operator determine_shape_model_params returns the value 2 (H_MSG_TRUE). If necessary an exception is raised. If the parameters NumLevels and Contrast are chosen such that the model contains too few points, or the input image does not contain a sufficient number of significant features, the error 8510 is raised.

determine_shape_model_params is reentrant and processed without parallelization.

draw_region, reduce_domain, threshold

create_shape_model, create_scaled_shape_model

find_shape_model, find_scaled_shape_model, find_shape_models, find_scaled_shape_models

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