Module i2pp.core.interpolators.interpolator_nodes

Interpolates pixel values from image-data to mesh-data.

Classes

class InterpolatorNodes
Expand source code 
class InterpolatorNodes(Interpolator):
    """Subclass of Interpolator for mapping 3D image data to finite element
    mesh nodes.

    This class extends Interpolator and specializes in assigning pixel values
    from 3D image data to finite element mesh elements by interpolating at
    their nodes. This approach is used when `interpolation_method` is set to
    "nodes".
    """

    def compute_element_data(
        self, dis: Discretization, image_data: ImageData
    ) -> list[Element]:
        """Calculates the mean interpolated pixel value for each FEM element
        based on its node values.

        This method determines the pixel values at the nodes of each element
        in the discretization by first transforming their coordinates into
        the image grid coordinate system. It then interpolates the pixel values
        at these transformed positions and computes their mean to assign a
        representative value to the element.

        Arguments:
            dis (Discretization): The FEM discretization containing elements
                and node coordinate data.
            image_data (ImageData): The 3D image dataset, including voxel
                values, spatial positioning, and metadata.

        Returns:
            list[Element]: A list of FEM elements, each assigned a mean
            interpolated pixel value.
        """

        node_grid_coords = self.world_to_grid_coords(
            dis.nodes.coords, image_data.orientation, image_data.position
        )

        node_values = self.interpolate_image_values_to_points(
            node_grid_coords, image_data
        )

        node_positions = np.array(
            [
                get_node_position_of_element(ele.node_ids, dis.nodes.ids)
                for ele in dis.elements
            ]
        )

        for i, ele in tqdm(
            enumerate(dis.elements),
            total=len(dis.elements),
            desc="Processing Elements",
        ):
            ele_nodes = node_values[node_positions[i]]

            ele.data = (
                np.nanmean(ele_nodes, axis=0)
                if not np.all(np.isnan(ele_nodes))
                else np.full(image_data.pixel_type.num_values, np.nan)
            )

            if np.all(np.isnan(ele.data)):
                self.nan_elements += 1

        self._log_interpolation_warnings()

        return dis.elements

Subclass of Interpolator for mapping 3D image data to finite element mesh nodes.

This class extends Interpolator and specializes in assigning pixel values from 3D image data to finite element mesh elements by interpolating at their nodes. This approach is used when interpolation_method is set to "nodes".

Initialize the Interpolator.

Ancestors

Methods

def compute_element_data(self,
dis: Discretization,
image_data: ImageData) ‑> list[Element]
Expand source code 
def compute_element_data(
    self, dis: Discretization, image_data: ImageData
) -> list[Element]:
    """Calculates the mean interpolated pixel value for each FEM element
    based on its node values.

    This method determines the pixel values at the nodes of each element
    in the discretization by first transforming their coordinates into
    the image grid coordinate system. It then interpolates the pixel values
    at these transformed positions and computes their mean to assign a
    representative value to the element.

    Arguments:
        dis (Discretization): The FEM discretization containing elements
            and node coordinate data.
        image_data (ImageData): The 3D image dataset, including voxel
            values, spatial positioning, and metadata.

    Returns:
        list[Element]: A list of FEM elements, each assigned a mean
        interpolated pixel value.
    """

    node_grid_coords = self.world_to_grid_coords(
        dis.nodes.coords, image_data.orientation, image_data.position
    )

    node_values = self.interpolate_image_values_to_points(
        node_grid_coords, image_data
    )

    node_positions = np.array(
        [
            get_node_position_of_element(ele.node_ids, dis.nodes.ids)
            for ele in dis.elements
        ]
    )

    for i, ele in tqdm(
        enumerate(dis.elements),
        total=len(dis.elements),
        desc="Processing Elements",
    ):
        ele_nodes = node_values[node_positions[i]]

        ele.data = (
            np.nanmean(ele_nodes, axis=0)
            if not np.all(np.isnan(ele_nodes))
            else np.full(image_data.pixel_type.num_values, np.nan)
        )

        if np.all(np.isnan(ele.data)):
            self.nan_elements += 1

    self._log_interpolation_warnings()

    return dis.elements

Calculates the mean interpolated pixel value for each FEM element based on its node values.

This method determines the pixel values at the nodes of each element in the discretization by first transforming their coordinates into the image grid coordinate system. It then interpolates the pixel values at these transformed positions and computes their mean to assign a representative value to the element.

Arguments

dis (Discretization): The FEM discretization containing elements and node coordinate data. image_data (ImageData): The 3D image dataset, including voxel values, spatial positioning, and metadata.

Returns

list[Element]
A list of FEM elements, each assigned a mean

interpolated pixel value.

Inherited members