hillas_parameters¶
-
ctapipe.image.
hillas_parameters
(geom, image)[source]¶ Compute Hillas parameters for a given shower image.
Implementation uses a PCA analogous to the implementation in src/main/java/fact/features/HillasParameters.java from https://github.com/fact-project/fact-tools
The image passed to this function can be in three forms:
>>> from ctapipe.image.hillas import hillas_parameters >>> from ctapipe.image.tests.test_hillas import create_sample_image, compare_hillas >>> geom, image, clean_mask = create_sample_image(psi='0d') >>> >>> # Fastest >>> geom_selected = geom[clean_mask] >>> image_selected = image[clean_mask] >>> hillas_selected = hillas_parameters(geom_selected, image_selected) >>> >>> # Mid (1.45 times longer than fastest) >>> image_zeros = image.copy() >>> image_zeros[~clean_mask] = 0 >>> hillas_zeros = hillas_parameters(geom, image_zeros) >>> >>> # Slowest (1.51 times longer than fastest) >>> image_masked = np.ma.masked_array(image, mask=~clean_mask) >>> hillas_masked = hillas_parameters(geom, image_masked) >>> >>> compare_hillas(hillas_selected, hillas_zeros) >>> compare_hillas(hillas_selected, hillas_masked)
Each method gives the same result, but vary in efficiency
- Parameters
- geom: ctapipe.instrument.CameraGeometry
Camera geometry
- imagearray_like
Charge in each pixel
- Returns
- HillasParametersContainer:
container of hillas parametesr