From 728f190bbd92b354c4f3f5ac9dca5143b21d28f8 Mon Sep 17 00:00:00 2001
From: Robin Bijl <r.a.bijl@student.tudelft.nl>
Date: Thu, 30 May 2019 11:37:14 +0200
Subject: [PATCH] adds realign function to scans
---
zesje/scans.py | 32 +++++++++++++++++++++++++++++++-
1 file changed, 31 insertions(+), 1 deletion(-)
diff --git a/zesje/scans.py b/zesje/scans.py
index 8d99d0f4..d2b7197b 100644
--- a/zesje/scans.py
+++ b/zesje/scans.py
@@ -15,7 +15,7 @@ from pylibdmtx import pylibdmtx
from .database import db, Scan, Exam, Page, Student, Submission, Solution, ExamWidget
from .datamatrix import decode_raw_datamatrix
-from .images import guess_dpi, get_box
+from .images import guess_dpi, get_box, fix_corner_markers
from .factory import make_celery
from .pregrader import add_feedback_to_solution
@@ -788,3 +788,33 @@ def check_corner_keypoints(image_array, keypoints):
if max(corners.values()) > 1:
raise RuntimeError("Found multiple corner markers in the same corner")
+
+
+def realign_image(image_array, keypoints=None,
+ reference_keypoints=None):
+
+ if(keypoints is None):
+ keypoints = find_corner_marker_keypoints(image_array)
+ check_corner_keypoints(image_array, keypoints)
+
+ if (len(keypoints) != 4):
+ keypoints = fix_corner_markers(keypoints, image_array.shape)
+
+ # use standard keypoints if no custom ones are provided
+ if (reference_keypoints is None):
+ reference_keypoints = [(59, 59), (1179, 59), (59, 1693), (1179, 1693)]
+
+ rows, cols, _ = image_array.shape
+
+ keypoints_32 = np.float32(keypoints)
+
+ reference_keypoints_32 = np.float32(reference_keypoints)
+
+ # get the transformation matrix
+ M = cv2.getPerspectiveTransform(keypoints_32, reference_keypoints_32)
+ # apply the transformation matrix
+ return_image = cv2.warpPerspective(image_array, M, (cols, rows))
+
+ return_keypoints = find_corner_marker_keypoints(return_image)
+
+ return return_image, return_keypoints
--
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