fact_image_cleaning#

ctapipe.image.cleaning.fact_image_cleaning(geom, image, arrival_times, picture_threshold=4, boundary_threshold=2, min_number_neighbors=2, time_limit=5)[source]#

Clean an image by selection pixels that pass the fact cleaning procedure.

Cleaning contains the following steps: 1: Find pixels containing more photons than a threshold t1 2: Remove pixels with less than N neighbors 3: Add neighbors of the remaining pixels that are above a lower threshold t2 4: Remove pixels with less than N neighbors arriving within a given timeframe 5: Remove pixels with less than N neighbors 6: Remove pixels with less than N neighbors arriving within a given timeframe

Parameters:
geom: `ctapipe.instrument.CameraGeometry`

Camera geometry information

image: array

pixel values

arrival_times: array

pixel timing information

picture_threshold: float or array

threshold above which all pixels are retained

boundary_threshold: float or array

threshold above which pixels are retained if they have a neighbor already above the picture_thresh

min_number_neighbors: int

Threshold to determine if a pixel survives cleaning steps. These steps include checks of neighbor arrival time and value

time_limit: int or float

arrival time limit for neighboring pixels

Returns:
A boolean mask of clean pixels.

References

See [Tem16] and for implementation [BNB+19].