From 3d4d4d5b6e9093c99bc5b6a0ac6ade4af8cda73c Mon Sep 17 00:00:00 2001
From: Robin Bijl <r.a.bijl@student.tudelft.nl>
Date: Fri, 24 May 2019 12:37:39 +0200
Subject: [PATCH] adds documentation of params for box is filled
---
zesje/pregrader.py | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/zesje/pregrader.py b/zesje/pregrader.py
index 0aedfb64..03252aeb 100644
--- a/zesje/pregrader.py
+++ b/zesje/pregrader.py
@@ -56,6 +56,34 @@ def add_feedback_to_solution(submission, page, page_img, corner_keypoints):
def box_is_filled(box, page_img, corner_keypoints, marker_margin=72/2.54, threshold=225, cut_padding=0.1, box_size=11):
+ """
+ A function that finds the checkbox in a general area and then checks if it is filled in.
+
+ Params
+ ------
+ box: (int, int)
+ The coordinates of the top left (x,y) of the checkbox in points.
+ page_img: np.array
+ A numpy array of the image scan
+ corner_keypoints: (float,float)
+ The x coordinate of the left markers and the y coordinate of the top markers,
+ used as point of reference since scans can deviate from the original.
+ (x,y) are both in pixels.
+ marker_margin: float
+ The margin between the corner markers and the edge of a page when generated.
+ threshold: int
+ the threshold needed for a checkbox to be considered marked range is between 0 (fully black)
+ and 255 (absolutely white).
+ cut_padding: float
+ The extra padding when retrieving an area where the checkbox is in inches.
+ box_size: int
+ the size of the checkbox in points.
+
+ Output
+ ------
+ True if the box is marked, else False.
+ """
+
# shouldn't be needed, but some images are drawn a bit weirdly
y_shift = 5
# create an array with y top, y bottom, x left and x right. use the marker margin to allign to the page.
@@ -118,6 +146,8 @@ def box_is_filled(box, page_img, corner_keypoints, marker_margin=72/2.54, thresh
x3, y3, w3, h3 = cv2.boundingRect(coords3)
res_rect = bin_im[new_y + y3: new_y + y3 + h3, new_x + x3: new_x + x3 + w3]
+ # if the found box is smaller than a certain threshold
+ # it means that we only found a little bit of white and the box is filled
res_x, res_y, *_ = res_rect.shape
if(res_x < 0.333 * box_size_px or res_y < 0.333 * box_size_px):
return True
--
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