_footprintContinued.py

Go to the documentation of this file.

# This file is part of afw.
#
# Developed for the LSST Data Management System.
# This product includes software developed by the LSST Project
# (https://www.lsst.org).
# See the COPYRIGHT file at the top-level directory of this distribution
# for details of code ownership.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
 
__all__ = []  # import this module only for its side effects
 
from typing import TYPE_CHECKING
 
if TYPE_CHECKING:
    from lsst.afw.image import Image
 
import numpy as np
 
from lsst.utils import continueClass
 
from lsst.geom import Point2I
from ._detection import Footprint
 
 
def getFootprintIntersection(
    footprint1: Footprint,
    footprint2: Footprint,
    copyPeaks: bool = True,
) -> Footprint:
    """Calculate the intersection of two Footprints.
 
    Parameters
    ----------
    footprint1: Footprint
        The first Footprint.
    footprint2: Footprint
        The second Footprint.
    copyFromFirst: bool
        Whether or not to copy the peaks from the first Footprint.
 
    Returns
    -------
    result:
        The Footprint containing the intersection of the two footprints.
    """
    # Create the intersecting footprint
    spans = footprint1.spans.intersect(footprint2.spans)
    result = Footprint(spans)
    result.setPeakSchema(footprint1.peaks.getSchema())
 
    if copyPeaks:
        # Only copy peaks that are contained in the intersection
        for peak in footprint1.peaks:
            if spans.contains(Point2I(peak.getIx(), peak.getIy())):
                # Add a copy of the entire peak record to preserve the ID
                result.peaks.append(peak)
    return result
 
 
@continueClass
class Footprint:  # noqa: F811
    def computeFluxFromArray(self, image: np.ndarray, xy0: Point2I) -> float:
        """Calculate the total flux in the region of an image array
        contained in this Footprint.
 
        Parameters
        ----------
        image:
            Array containing the pixels to extract.
        xy0:
            The origin of the image array.
 
        Returns
        flux:
            Flux from the image in pixels contained in the footprint.
        """
        return self.spans.flatten(image, xy0).sum()
 
    def computeFluxFromImage(self, image: "Image") -> float:
        """Calculate the total flux in the region of an Image contained in
        this Footprint.
 
        Parameters
        ----------
        image:
            Image to extract.
 
        Returns
        -------
        flux:
            Flux from the image pixels contained in the footprint.
        """
        return self.computeFluxFromArray(image.array, image.getXY0())
 
    def intersect(self, other: Footprint, copyPeaks: bool = True) -> Footprint:
        """Calculate the intersection of this Footprint with another Footprint.
 
        Parameters
        ----------
        other:
            The other Footprint.
        copyPeaks:
            Whether or not to copy the peaks from this Footprint.
            Note: the peaks in other are always ignored.
 
        Returns
        -------
        result:
            The Footprint containing the intersection of the two footprints.
        """
        return getFootprintIntersection(self, other, True)