Set the clutter parameters of a shape model.
set_shape_model_clutter sets the clutter parameters of the shape
ModelID. In particular, a region is defined relative to the
model contours, in which no (or too faint) clutter edges should occur in the
This is helpful, e.g., if it is a special characteristic of the model
that, in specific parts near to the model, structures are missing.
For example, within the HDevelop example program
find_shape_model_clutter.hdev, the model corresponds to a ball in a
ball grid array (BGA). As the ball grid array represents a repeating pattern,
many matches are returned when matching is applied without considering the
neighborhood of the model. By defining a clutter region, the search can be
restricted to specific instances of the model.
For matches found in a search image, edges within the clutter region
increase the resulting clutter values. These are returned by
in the parameter
Score, following the common values measuring
how much of the model is visible in the image.
Note that the input parameter
MinScore of those operators
additionally expects information specifying the maximum
clutter value up to which matches should be returned.
For more information regarding the setting of
please refer to the respective operator reference.
To define the clutter region relative to the model contours, you need the
ClutterRegion and the transformation matrix
that maps the model contours to the respective position where the object
appears in an image. Typically, you obtain them by searching for a model
instance in an image, e.g., with the operator
the transformation matrix can be determined with the procedure
get_hom_mat2d_from_matching_result using the respective output
parameters of the search. The region
ClutterRegion is specified
within the same image. Note that
ClutterRegion should contain the
regions around the superfluous edges that are typical for all expected
manifestations of the matches. We recommend that the clutter region is
chosen larger than necessary when large scale ranges are
searched. Furthermore, choosing the clutter region not too near to the
expected model contours can increase the robustness.
ClutterContrast determines the contrast the edges
in the clutter region must have in order to be counted as clutter. In
many applications, the parameter
Contrast, which has been used to
create the shape model, is also a reasonable choice for
ClutterContrast may not be smaller than the parameter
MinContrast of the shape model, otherwise an error is raised at
The polarity of the found clutter edges is ignored, i.e., bright objects on a
dark background will yield the same clutter value as dark objects on a
bright background, independent of the parameter
Metric of the
Please note that of all shape-based matching results, clutter values are
affected the most when a variation of illumination occurs.
GenParamName set to 'clutter_border_mode', the
behavior of the clutter value can be influenced in cases where the clutter
region of a found match is not entirely contained in the image domain. The
corresponding values for 'clutter_border_mode'
GenParamValue) can be 'clutter_border_average' or
GenParamValue is set to 'clutter_border_average'
(default), the hidden part of the clutter region is assumed to be filled on
average as is its visible part. If the clutter region is not visible at all,
the clutter value of the found match is set to 0.0.
GenParamValue is set to 'clutter_border_empty', the
clutter region is assumed to be empty where it is not visible.
GenParamValue set to 'clutter_border_average'
results in higher clutter values.
The use of clutter parameters can be disabled and enabled by calling
set_shape_model_param. For newly created shape models, the use of
clutter parameters is disabled. After calling
set_shape_model_clutter, the use of clutter parameters is enabled.
Depending on the activation status for the use of clutter parameters, the find
find_shape_model, expect a different number of
entries in the input parameter
MinScore. The set clutter parameters
and the value of 'use_clutter' can be queried using the operator
This operator modifies the state of the following input parameter:
During execution of this operator, access to the value of this parameter must be synchronized if it is used across multiple threads.
Region where no clutter should occur.
ModelID(input_control, state is modified) shape_model
Handle of the model.
Minimum contrast of clutter in the search images.
Default value: 128
List of values: 'clutter_border_mode'
→(real / integer / string)
List of values: 'clutter_border_average', 'clutter_border_empty'
* * Create a shape model. read_image (ImageModel, '/bga_gap/bga_gap_01.png') gen_circle (ROI, 753.869, 551.624, 28.4027) reduce_domain (ImageModel, ROI, ImageReduced) create_aniso_shape_model (ImageReduced, 'auto', rad(0), rad(0), 'auto', 0.95, 1.05, 'auto', 0.95, 1.05, 'auto', 'auto', 'use_polarity', 'auto', 'auto', ModelID) * * Specify the clutter parameters. find_aniso_shape_model (ImageModel, ModelID, rad(0), rad(0), 0.95, 1.05, 0.95, 1.05, 0.83, 0, 0.0, 'least_squares', 0, 0.0, Row, Column, Angle, ScaleR, ScaleC, Score) get_hom_mat2d_from_matching_result (Row, Column, Angle, ScaleR, ScaleC, HomMat2D) * gen_circle (ROI_0, 700.655, 548.666, 21.6273) gen_circle (ROI_1_0, 810.655, 550.611, 21.6273) union2 (ROI_0, ROI_1_0, ClutterRegion) * ClutterContrast := 12 * * Set the clutter parameters into shape model. set_shape_model_clutter (ClutterRegion, ModelID, HomMat2D, ClutterContrast, , ) * * Use the shape model to detect objects with a small amount of clutter read_image (Image,'/bga_gap/bga_gap_02.png') MaxClutter := 0.09 find_aniso_shape_model (Image, ModelID, rad(0), rad(0), 0.95, 1.05, 0.95, 1.05, [0.83, MaxClutter], 0, 0.0, 'least_squares', [4, 3], 0.0, Row, Column, Angle, ScaleR, ScaleC, Score) * * Visualize the matches dev_display_shape_matching_results (ModelID, ['green', 'red'], Row, Column, Angle, ScaleR, ScaleC, 0) Clutter := Score[|Score|/2:|Score|-1] Score := Score[0:|Score|/2-1] dev_inspect_ctrl ([Score, Clutter])
If the parameters are valid, the operator
returns the value 2 (H_MSG_TRUE). If necessary an exception is raised.