_projection_pixel_size. test projections and clean_images.

Author: j-c-c

src/aspire/source/simulation.py

@@ -124,7 +124,7 @@ def __init__(
                 f"`pixel_size`: {pixel_size} does not match volume pixel_size: {self.vols.pixel_size}."
                 " Setting `pixel_size` to user provided value: {pixel_size}."
             )
-        self._original_pixel_size = pixel_size
+        self._projection_pixel_size = pixel_size
 
         # Infer the details from volume when possible.
         super().__init__(
@@ -283,7 +283,7 @@ def _projections(self, indices):
             im_k = self.vols[k - 1].project(rot_matrices=rot)
             im[idx_k, :, :] = im_k.asnumpy()
 
-        return Image(im, pixel_size=self.pixel_size)
+        return Image(im, pixel_size=self._projection_pixel_size)
 
     @property
     def clean_images(self):
@@ -329,16 +329,13 @@ def _images(self, indices, clean_images=False):
         return self.generation_pipeline.forward(im, indices)
 
     def _apply_sim_filters(self, im, indices):
-        # Use original pixel_size when applying filters.
-        im.pixel_size = self._original_pixel_size
-
         im = self._apply_filters(
             im,
             self.sim_filters,
             self.filter_indices[indices],
         )
 
-        # Recover correct pixel_size
+        # Assign correct pixel_size
         im.pixel_size = self.pixel_size
 
         return im

tests/test_simulation.py

@@ -702,6 +702,38 @@ def test_cached_image_accessors():
     )
 
 
+def test_projections_and_clean_images_downsample():
+    """
+    Test `projections` and `clean_images` post downsample.
+    `projections` should remain unaltered and `clean_images` should
+    be resized with adjusted pixel_size.
+    """
+    n = 10
+    L = 32
+    L_ds = 21
+    px_sz = 1.23
+    ctf = [RadialCTFFilter(1.5e4)]
+
+    src = Simulation(
+        L=L,
+        n=n,
+        C=1,
+        noise_adder=WhiteNoiseAdder(var=0.123),
+        unique_filters=ctf,
+        pixel_size=px_sz,
+    )
+
+    src_ds = src.downsample(L_ds)
+
+    # Check pixel_size
+    np.testing.assert_allclose(src_ds.projections[:].pixel_size, px_sz)
+    np.testing.assert_allclose(src_ds.clean_images[:].pixel_size, px_sz * L / L_ds)
+
+    # Check image size
+    np.testing.assert_allclose(src_ds.projections[:].shape[-1], L)
+    np.testing.assert_allclose(src_ds.clean_images[:].shape[-1], L_ds)
+
+
 def test_save_overwrite(caplog):
     """
     Test that the overwrite flag behaves as expected.