Merge pull request #459 from AstarVienna/kl/round_psfs

Added function to round the edges of square PSF kernels

scopesim/effects/psfs/psf_base.py

@@ -40,6 +40,7 @@ def __init__(self, **kwargs):
             "bkg_width": -1,
             "wave_key": "WAVE0",
             "normalise_kernel": True,
+            "rounded_edges": True,
             "rotational_blur_angle": 0,
             "report_plot_include": True,
             "report_table_include": False,
@@ -70,6 +71,11 @@ def apply_to(self, obj, **kwargs):
                     # makes a copy of kernel
                     kernel = rotational_blur(kernel, rot_blur_angle)
 
+                # Round the edges of kernels so that the silly square stars
+                # don't appear anymore
+                if self.meta.get("rounded_edges", False) and kernel.ndim == 2:
+                    kernel = self._round_kernel_edges(kernel)
+
                 # normalise psf kernel      KERNEL SHOULD BE normalised within get_kernel()
                 # if from_currsys(self.meta["normalise_kernel"], self.cmds):
                 #    kernel /= np.sum(kernel)
@@ -115,6 +121,15 @@ def get_kernel(self, obj):
             self.kernel = np.ones((1, 1))
         return self.kernel
 
+    @staticmethod
+    def _round_kernel_edges(kernel: np.ndarray) -> np.ndarray:
+        x, y = np.array(kernel.shape) // 2
+        threshold = min(kernel[x, 0], kernel[x, -1],
+                        kernel[0, y], kernel[-1, y])
+        kernel[kernel < threshold] = 0.
+        # TODO: maybe masked array here?
+        return kernel
+
     def plot(self, obj=None, **kwargs):
         fig, axes = figure_factory()
 

scopesim/effects/psfs/semianalytical.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 """Currently only contains the AnisoCADO connection."""
+from warnings import warn
 
 import numpy as np
 from scipy.interpolate import RectBivariateSpline
@@ -121,8 +122,6 @@ def get_kernel(self, fov):
 
         self._kernel = self._psf_object.psf_latest
         self._kernel /= np.sum(self._kernel)
-        if self.meta["rounded_edges"]:
-            self._round_kernel_edges()
 
         return self._kernel
 
@@ -136,15 +135,14 @@ def remake_kernel(self, x):
             [um] if float
 
         """
+        warn("The 'remake_kernel' method was unused and thus deprecated and "
+             "will be removed in a future release. If you are using this "
+             "method, pleas let us know by creating an issue at: "
+             "https://github.com/AstarVienna/ScopeSim/issues",
+             DeprecationWarning, stacklevel=2)
         self._kernel = None
         return self.get_kernel(x)
 
-    def _round_kernel_edges(self):
-        y, x = np.array(self._kernel.shape).astype(int) // 2
-        threshold = np.min([self._kernel[y, 0], self._kernel[y, -1],
-                            self._kernel[0, x], self._kernel[-1, x]])
-        self._kernel[self._kernel < threshold] = 0.
-
     @property
     def wavelength(self):
         # FIXME: expensive property...

scopesim/tests/tests_effects/test_PSF.py

@@ -60,9 +60,9 @@ def test_returns_rotated_kernel_array_has_same_sum(self, angle):
 
         # With blur
         implane = basic_image_plane()
-        implane.data[75,75] = 1
+        implane.data[75, 75] = 1
 
-        psf = PSF(rotational_blur_angle=angle)
+        psf = PSF(rotational_blur_angle=angle, rounded_edges=False)
         psf.kernel = basic_kernel()
         implane = psf.apply_to(implane)
 
@@ -157,7 +157,7 @@ def test_convolves_with_3D_cube(self):
             plt.subplot(231)
             plt.imshow(implane.data[1, :, :])
 
-        psf = PSF(rotational_blur_angle=15, bkg_width=5)
+        psf = PSF(rotational_blur_angle=15, bkg_width=5, rounded_edges=False)
         psf.kernel = basic_kernel(n=63)
         implane = psf.apply_to(implane)