lsst.afw.detection.multiband Namespace Reference

Classes
class	MultibandFootprint

Functions
def	getSpanSetFromImages (images, thresh=0, xy0=None)
def	heavyFootprintToImage (heavy, fill=np.nan, bbox=None, imageType=MaskedImage)

Function Documentation

getSpanSetFromImages()

def lsst.afw.detection.multiband.getSpanSetFromImages	(		images,
			thresh = 0,
			xy0 = None
	)

Create a Footprint from a set of Images

Parameters
----------
images : `lsst.afw.image.MultibandImage` or list of `lsst.afw.image.Image`, array
    Images to extract the footprint from
thresh : `float`
    All pixels above `thresh` will be included in the footprint
xy0 : `lsst.geom.Point2I`
    Location of the minimum value of the images bounding box
    (if images is an array, otherwise the image bounding box is used).

Returns
-------
spans : `lsst.afw.geom.SpanSet`
    Union of all spans in the images above the threshold
imageBBox : `lsst.afw.detection.Box2I`
    Bounding box for the input images.

Definition at line 35 of file multiband.py.

def getSpanSetFromImages(images, thresh=0, xy0=None):
    """Create a Footprint from a set of Images
 
    Parameters
    ----------
    images : `lsst.afw.image.MultibandImage` or list of `lsst.afw.image.Image`, array
        Images to extract the footprint from
    thresh : `float`
        All pixels above `thresh` will be included in the footprint
    xy0 : `lsst.geom.Point2I`
        Location of the minimum value of the images bounding box
        (if images is an array, otherwise the image bounding box is used).
 
    Returns
    -------
    spans : `lsst.afw.geom.SpanSet`
        Union of all spans in the images above the threshold
    imageBBox : `lsst.afw.detection.Box2I`
        Bounding box for the input images.
    """
    # Set the threshold for each band
    if not hasattr(thresh, "__len__"):
        thresh = [thresh] * len(images)
 
    # If images is a list of `afw Image` objects then
    # merge the SpanSet in each band into a single Footprint
    if isinstance(images, MultibandBase) or isinstance(images[0], Image):
        spans = SpanSet()
        for n, image in enumerate(images):
            mask = image.array > thresh[n]
            mask = Mask(mask.astype(np.int32), xy0=image.getBBox().getMin())
            spans = spans.union(SpanSet.fromMask(mask))
        imageBBox = images[0].getBBox()
    else:
        # Use thresh to detect the pixels above the threshold in each band
        thresh = np.array(thresh)
        if xy0 is None:
            xy0 = Point2I(0, 0)
        mask = np.any(images > thresh[:, None, None], axis=0)
        mask = Mask(mask.astype(np.int32), xy0=xy0)
        spans = SpanSet.fromMask(mask)
        imageBBox = mask.getBBox()
    return spans, imageBBox
 
 

heavyFootprintToImage()

def lsst.afw.detection.multiband.heavyFootprintToImage	(		heavy,
			fill = np.nan,
			bbox = None,
			imageType = MaskedImage
	)

Create an image of a HeavyFootprint

Parameters
----------
heavy : `HeavyFootprint`
    The HeavyFootprint to insert into the image
fill: number
    Number to fill the pixels in the image that are not
    contained in `heavy`.
bbox : `Box2I`
    Bounding box of the output image.
imageType : `type`
    This should be either a `MaskedImage` or `Image` and describes
    the type of the output image.

Returns
-------
image : `lsst.afw.image.MaskedImage` or `lsst.afw.image.Image`
    An image defined by `bbox` and padded with `fill` that
    contains the projected flux in `heavy`.

Definition at line 80 of file multiband.py.

def heavyFootprintToImage(heavy, fill=np.nan, bbox=None, imageType=MaskedImage):
    """Create an image of a HeavyFootprint
 
    Parameters
    ----------
    heavy : `HeavyFootprint`
        The HeavyFootprint to insert into the image
    fill: number
        Number to fill the pixels in the image that are not
        contained in `heavy`.
    bbox : `Box2I`
        Bounding box of the output image.
    imageType : `type`
        This should be either a `MaskedImage` or `Image` and describes
        the type of the output image.
 
    Returns
    -------
    image : `lsst.afw.image.MaskedImage` or `lsst.afw.image.Image`
        An image defined by `bbox` and padded with `fill` that
        contains the projected flux in `heavy`.
    """
    if bbox is None:
        bbox = heavy.getBBox()
    image = imageType(bbox, dtype=heavy.getImageArray().dtype)
    image.set(fill)
    heavy.insert(image)
    return image