distortion correction preview refactoring

Author: dkazanc

httomolibgpu/prep/alignment.py

@@ -33,7 +33,7 @@
 else:
     map_coordinates = Mock()
 
-from typing import Dict, List
+from typing import Dict, List, Tuple
 
 __all__ = [
     "distortion_correction_proj_discorpy",
@@ -48,7 +48,8 @@
 def distortion_correction_proj_discorpy(
     data: cp.ndarray,
     metadata_path: str,
-    preview: Dict[str, List[int]],
+    shift: Tuple[int, int] = (0, 0),
+    step: Tuple[int, int] = (1, 1),
     order: int = 1,
     mode: str = "reflect",
 ):
@@ -63,11 +64,11 @@ def distortion_correction_proj_discorpy(
         The path to the file containing the distortion coefficients for the
         data.
 
-    preview : Dict[str, List[int]]
-        A dict containing three key-value pairs:
-        - a list containing the `start` value of each dimension
-        - a list containing the `stop` value of each dimension
-        - a list containing the `step` value of each dimension
+    shift: tuple, optional
+         Centers of distortion in x (from the left of the image) and y directions (from the top of the image).
+
+    step: tuple, optional
+         Steps in x and y directions respectively. They need to be not larger than one.
 
     order : int, optional.
         The order of the spline interpolation.
@@ -90,12 +91,10 @@ def distortion_correction_proj_discorpy(
 
     # Use preview information to offset the x and y coords of the center of
     # distortion
-    shift = preview["starts"]
-    step = preview["steps"]
-    x_dim = 1
-    y_dim = 0
-    step_check = max([step[i] for i in [x_dim, y_dim]]) > 1
-    if step_check:
+    det_x_step = step[0]
+    det_y_step = step[1]
+
+    if det_y_step > 1 or det_x_step > 1:
         msg = (
             "\n***********************************************\n"
             "!!! ERROR !!! -> Method doesn't work with the step in"
@@ -104,12 +103,13 @@ def distortion_correction_proj_discorpy(
         )
         raise ValueError(msg)
 
-    x_offset = shift[x_dim]
-    y_offset = shift[y_dim]
-    xcenter = xcenter - x_offset
-    ycenter = ycenter - y_offset
+    det_x_shift = shift[0]
+    det_y_shift = shift[1]
+
+    xcenter = xcenter - det_x_shift
+    ycenter = ycenter - det_y_shift
 
-    height, width = data.shape[y_dim + 1], data.shape[x_dim + 1]
+    height, width = data.shape[1], data.shape[2]
     xu_list = cp.arange(width) - xcenter
     yu_list = cp.arange(height) - ycenter
     xu_mat, yu_mat = cp.meshgrid(xu_list, yu_list)

tests/test_prep/test_alignment.py

@@ -40,8 +40,9 @@ def test_correct_distortion(
     im_host = imread(path)
     im = cp.asarray(im_host)
 
-    preview = {"starts": [0, 0], "stops": [im.shape[0], im.shape[1]], "steps": [1, 1]}
-    corrected_data = implementation(im, distortion_coeffs_path, preview).get()
+    shift = (0, 0)
+    step = (1, 1)
+    corrected_data = implementation(im, distortion_coeffs_path, shift, step).get()
 
     assert_allclose(np.mean(corrected_data), mean_value)
     assert np.max(corrected_data) == max_value