Merge pull request #1696 from pierotofy/321

More memory efficient find_features_homography

VERSION

@@ -1 +1 @@
-3.2.0
+3.2.1

opendm/multispectral.py

@@ -504,6 +504,28 @@ def find_features_homography(image_gray, align_image_gray, feature_retention=0.7
 
     # Detect SIFT features and compute descriptors.
     detector = cv2.SIFT_create(edgeThreshold=10, contrastThreshold=0.1)
+
+    h,w = image_gray.shape
+    max_dim = max(h, w)
+
+    max_size = 2048
+    if max_dim > max_size:
+        if max_dim == w:
+            f = max_size / w
+        else:
+            f = max_size / h
+        image_gray = cv2.resize(image_gray, None, fx=f, fy=f, interpolation=cv2.INTER_AREA)
+        h,w = image_gray.shape
+
+    if align_image_gray.shape[0] != image_gray.shape[0]:
+        fx = image_gray.shape[1]/align_image_gray.shape[1]
+        fy = image_gray.shape[0]/align_image_gray.shape[0]
+
+        align_image_gray = cv2.resize(align_image_gray, None, 
+                        fx=fx, 
+                        fy=fy,
+                        interpolation=(cv2.INTER_AREA if (fx < 1.0 and fy < 1.0) else cv2.INTER_LANCZOS4))
+
     kp_image, desc_image = detector.detectAndCompute(image_gray, None)
     kp_align_image, desc_align_image = detector.detectAndCompute(align_image_gray, None)