[refactor] SubImage → SubImageExtract, add SubImageCombine

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/tests/test_faces_sub_image.py

@@ -5,7 +5,7 @@ import matplotlib.pyplot as plt
 
 from rbm.model import Model
 from rbm.entity import Entity, EntityParams, TrainingParams
-from image.sub_image import SubImage, normalize
+from image.sub_image import SubImageExtract, normalize
 from rbm.matrix import Mat, np, convert
 from rbm.status import CheckpointStatus
 
@@ -38,7 +38,7 @@ class TestModel(Model):
 
 
 def pad_to_stride(img: numpy.ndarray) -> numpy.ndarray:
-	"""Pad so (H - PATCH) and (W - PATCH) are divisible by STRIDE (required by SubImage.check)."""
+	"""Pad so (H - PATCH) and (W - PATCH) are divisible by STRIDE (required by SubImageExtract.check)."""
 	h, w = img.shape[:2]
 	ph = (-h) % STRIDE if h >= PATCH else PATCH - h
 	pw = (-w) % STRIDE if w >= PATCH else PATCH - w
@@ -86,8 +86,8 @@ def load_patches(data_dir: str, n_images: int = N_IMAGES, start: int = 0):
 
 
 def load_image_patches(path: str):
-	"""Extract normalised patches from a single image via SubImage; return (patches, nx_steps, ny_steps)."""
-	sub = SubImage(PATCH, PATCH, STRIDE, STRIDE)
+	"""Extract normalised patches from a single image via SubImageExtract; return (patches, nx_steps, ny_steps)."""
+	sub = SubImageExtract(PATCH, PATCH, STRIDE, STRIDE)
 	img = cv2.imread(path)
 	img = pad_to_stride(img)
 	h, w = img.shape[:2]