lsst.ip.isr.vignette Namespace Reference

Classes
class	VignetteConfig
class	VignetteTask

Functions
	setValidPolygonCcdIntersect (ccdExposure, fpPolygon, log=None)
	maskVignettedRegion (exposure, polygon, maskPlane="NO_DATA", vignetteValue=None, log=None)

Function Documentation

maskVignettedRegion()

lsst.ip.isr.vignette.maskVignettedRegion	(		exposure,
			polygon,
			maskPlane = "NO_DATA",
			vignetteValue = None,
			log = None )

Add mask bit to image pixels according to vignetted polygon region.

NOTE: this function could be used to mask and replace pixels associated
with any polygon in the exposure pixel coordinates.

Parameters
----------
exposure : `lsst.afw.image.Exposure`
    Image whose mask plane is to be updated.
polygon : `lsst.afw.geom.Polygon`
    Polygon region defining the vignetted region in the pixel coordinates
    of ``exposure``.
maskPlane : `str`, optional
    Mask plane to assign vignetted pixels to.
vignetteValue : `float` or `None`, optional
    Value to assign to the image array pixels within the ``polygon``
    region.  If `None`, image pixel values are not replaced.
log : `logging.Logger`, optional
    Log object to write to.

Raises
------
RuntimeError
    Raised if no valid polygon exists.

Definition at line 144 of file vignette.py.

def maskVignettedRegion(exposure, polygon, maskPlane="NO_DATA", vignetteValue=None, log=None):
    """Add mask bit to image pixels according to vignetted polygon region.
 
    NOTE: this function could be used to mask and replace pixels associated
    with any polygon in the exposure pixel coordinates.
 
    Parameters
    ----------
    exposure : `lsst.afw.image.Exposure`
        Image whose mask plane is to be updated.
    polygon : `lsst.afw.geom.Polygon`
        Polygon region defining the vignetted region in the pixel coordinates
        of ``exposure``.
    maskPlane : `str`, optional
        Mask plane to assign vignetted pixels to.
    vignetteValue : `float` or `None`, optional
        Value to assign to the image array pixels within the ``polygon``
        region.  If `None`, image pixel values are not replaced.
    log : `logging.Logger`, optional
        Log object to write to.
 
    Raises
    ------
    RuntimeError
        Raised if no valid polygon exists.
    """
    log = log if log else logging.getLogger(__name__)
    if not polygon:
        log.info("No polygon provided.  Masking nothing.")
        return
 
    fullyIlluminated = True
    if not all(polygon.contains(exposure.getBBox().getCorners())):
        fullyIlluminated = False
    log.info("Exposure is fully illuminated? %s", fullyIlluminated)
 
    if not fullyIlluminated:
        # Scan pixels.
        mask = exposure.getMask()
        xx, yy = np.meshgrid(np.arange(0, mask.getWidth(), dtype=float),
                             np.arange(0, mask.getHeight(), dtype=float))
 
        vignMask = ~(polygon.contains(xx, yy))
 
        bitMask = mask.getPlaneBitMask(maskPlane)
        maskArray = mask.getArray()
        maskArray[vignMask] |= bitMask
        log.info("Exposure contains {} vignetted pixels which are now masked with mask plane {}.".
                 format(np.count_nonzero(vignMask), maskPlane))
 
        if vignetteValue is not None:
            imageArray = exposure.getImage().getArray()
            imageArray[vignMask] = vignetteValue
            log.info("Vignetted pixels in image array have been replaced with {}.".format(vignetteValue))

setValidPolygonCcdIntersect()

lsst.ip.isr.vignette.setValidPolygonCcdIntersect	(		ccdExposure,
			fpPolygon,
			log = None )

Set valid polygon on ccdExposure associated with focal plane polygon.

The ccd exposure's valid polygon is the intersection of fpPolygon,
a valid polygon in focal plane coordinates, and the ccd corners,
in ccd pixel coordinates.

Parameters
----------
ccdExposure : `lsst.afw.image.Exposure`
    Exposure to process.
fpPolygon : `lsst.afw.geom.Polygon`
    Polygon in focal plane coordinates.
log : `logging.Logger`, optional
    Log object to write to.

Definition at line 109 of file vignette.py.

def setValidPolygonCcdIntersect(ccdExposure, fpPolygon, log=None):
    """Set valid polygon on ccdExposure associated with focal plane polygon.
 
    The ccd exposure's valid polygon is the intersection of fpPolygon,
    a valid polygon in focal plane coordinates, and the ccd corners,
    in ccd pixel coordinates.
 
    Parameters
    ----------
    ccdExposure : `lsst.afw.image.Exposure`
        Exposure to process.
    fpPolygon : `lsst.afw.geom.Polygon`
        Polygon in focal plane coordinates.
    log : `logging.Logger`, optional
        Log object to write to.
    """
    # Get ccd corners in focal plane coordinates
    ccd = ccdExposure.getDetector()
    fpCorners = ccd.getCorners(cameraGeom.FOCAL_PLANE)
    ccdPolygon = afwGeom.Polygon(fpCorners)
    # Get intersection of ccd corners with fpPolygon
    try:
        intersect = ccdPolygon.intersectionSingle(fpPolygon)
    except afwGeom.SinglePolygonException:
        intersect = None
    if intersect is not None:
        # Transform back to pixel positions and build new polygon
        ccdPoints = ccd.transform(intersect, cameraGeom.FOCAL_PLANE, cameraGeom.PIXELS)
        validPolygon = afwGeom.Polygon(ccdPoints)
        ccdExposure.getInfo().setValidPolygon(validPolygon)
    else:
        if log is not None:
            log.info("Ccd exposure does not overlap with focal plane polygon.  Not setting validPolygon.")