MaskStreaksTask

class lsst.meas.algorithms.MaskStreaksTask(config: Config | None = None, *, name: str | None = None, parentTask: Task | None = None, log: logging.Logger | lsst.utils.logging.LsstLogAdapter | None = None)

Bases: Task

Find streaks or other straight lines in image data.

Nearby objects passing through the field of view of the telescope leave a bright trail in images. This class uses the Kernel Hough Transform (KHT) (Fernandes and Oliveira, 2007), implemented in lsst.houghtransform. The procedure works by taking a binary image, either provided as put or produced from the input data image, using a Canny filter to make an image of the edges in the original image, then running the KHT on the edge image. The KHT identifies clusters of non-zero points, breaks those clusters of points into straight lines, keeps clusters with a size greater than the user-set threshold, then performs a voting procedure to find the best-fit coordinates of any straight lines. Given the results of the KHT algorithm, clusters of lines are identified and grouped (generally these correspond to the two edges of a strea) and a profile is fit to the streak in the original (non-binary) image.

Methods Summary

find(maskedImage)	Find streaks in a masked image.
run(maskedImage)	Find and mask streaks in a masked image.

Methods Documentation

find(maskedImage)

Find streaks in a masked image.

Parameters

maskedImagelsst.afw.image.maskedImage

The image in which to search for streaks.

Returns

resultlsst.pipe.base.Struct

Results as a struct with attributes:

originalLines

Lines identified by kernel hough transform.

lineClusters

Lines grouped into clusters in rho-theta space.

lines

Final result for lines after line-profile fit.

mask

2-d boolean mask where detected lines are True.

run(maskedImage)

Find and mask streaks in a masked image.

Finds streaks in the image and modifies maskedImage in place by adding a mask plane with any identified streaks.

Parameters

maskedImagelsst.afw.image.Exposure or lsst.afw.image.maskedImage

The image in which to search for streaks. The mask detection plane corresponding to config.detectedMaskPlane must be set with the detected pixels. The mask will have a plane added with any detected streaks, and with the mask plane name set by self.config.streaksMaskPlane.

Returns

resultlsst.pipe.base.Struct

Results as a struct with attributes:

originalLines

Lines identified by kernel hough transform.

lineClusters

Lines grouped into clusters in rho-theta space.

lines

Final result for lines after line-profile fit.