add rotation

btk/draw_blends.py

@@ -133,6 +133,7 @@ def __init__(
         save_path=None,
         seed=DEFAULT_SEED,
         apply_shear=False,
+        augment_data=False,
     ):
         """Initializes the DrawBlendsGenerator class.
 
@@ -164,6 +165,10 @@ def __init__(
                             as None, results will not be saved.
             seed (int): Integer seed for reproducible random noise realizations.
             apply_shear (float): Whether to apply the shear specified in catalogs to galaxies.
+                                If set to True, sampling function must add 'g1', 'g2' columns.
+            augment_data (float): If set to True, augment data by adding a random rotation to every
+                                galaxy drawn. Rotation added is recorded via `btk_rotation` column
+                                output.
         """
         self.blend_generator = BlendGenerator(
             catalog, sampling_function, batch_size, shifts, indexes, verbose
@@ -174,6 +179,7 @@ def __init__(
         self.batch_size = self.blend_generator.batch_size
         self.max_number = self.blend_generator.max_number
         self.apply_shear = apply_shear
+        self.augment_data = augment_data
 
         if isinstance(surveys, Survey):
             self.surveys = [surveys]
@@ -369,6 +375,12 @@ def render_mini_batch(self, blend_list, psf, wcs, survey, seedseq_minibatch, ext
             blend.add_column(x_peak)
             blend.add_column(y_peak)
 
+            # add rotation, if requested
+            if self.augment_data:
+                rng = np.random.default_rng(seedseq_minibatch.generate_state(1))
+                theta = rng.uniform(0, 360, size=len(blend))
+                blend.add_column(Column(theta), name="btk_rotation")
+
             n_bands = len(survey.available_filters)
             iso_image_multi = np.zeros((self.max_number, n_bands, pix_stamp_size, pix_stamp_size))
             blend_image_multi = np.zeros((n_bands, pix_stamp_size, pix_stamp_size))
@@ -506,6 +518,8 @@ def render_single(self, entry, filt, psf, survey, extra_data):
         pix_stamp_size = int(self.stamp_size / survey.pixel_scale.to_value("arcsec"))
         try:
             gal = get_catsim_galaxy(entry, filt, survey)
+            if self.augment_data:
+                gal.rotate(galsim.Angle(entry["btk_rotation"], unit=galsim.degrees))
             if self.apply_shear:
                 if "g1" in entry.keys() and "g2" in entry.keys():
                     gal = gal.shear(g1=entry["g1"], g2=entry["g2"])
@@ -628,6 +642,8 @@ def render_single(self, entry, filt, psf, survey, extra_data):
         gal = galsim_catalog.makeGalaxy(
             entry["btk_index"], gal_type=self.gal_type, noise_pad_size=0
         ).withFlux(gal_flux)
+        if self.augment_data:
+            gal.rotate(galsim.Angle(entry["btk_rotation"], unit=galsim.degrees))
         if self.apply_shear:
             if "g1" in entry.keys() and "g2" in entry.keys():
                 gal = gal.shear(g1=entry["g1"], g2=entry["g2"])