def updateVerticesOrder(vertices, marker_center, pattern_center):
dists = []
for i in range(len(vertices)):
dists.append(
(i, abs(ut.distanceP2L(marker_center, pattern_center,
vertices[i]))))
dists = sorted(dists, key=operator.itemgetter(1))
corner_idx = dists[0][0] if ut.distanceP2P(vertices[dists[0][0]], pattern_center) \
> ut.distanceP2P(vertices[dists[1][0]], pattern_center) else dists[1][0]
return np.append(vertices[corner_idx:], vertices[:corner_idx])
def updateVerticesOrder(vertices, marker_center, pattern_center): ''' Reorder the vertices so that the first point is the corner vertex of the pattern. Input: vertices: Vertices of the marker - numpy.array marker_center: Center of the marker - numpy.array pattern_center: Center of the pattern - numpy.array Output: New vertices in right order - numpy.array ''' dists = [] for i in range(len(vertices)): dists.append((i, abs(ut.distanceP2L(marker_center, pattern_center, vertices[i])))) dists = sorted(dists, key=operator.itemgetter(1)) corner_idx = dists[0][0] if ut.distanceP2P(vertices[dists[0][0]], pattern_center) \ > ut.distanceP2P(vertices[dists[1][0]], pattern_center) else dists[1][0] return np.append(vertices[corner_idx:], vertices[:corner_idx])
def getVertices(contour, marker_center): ''' Find the four vertices of marker in its corresponding contour. Input: contour: Marker contour - numpy.array marker_center: Marker center point - numpy.array Output: Array of vertices of marker - numpy.array ''' # Find the min rotated rect of 'contour' # We divide the contour and min rect into four quadrants minRect = cv2.minAreaRect(contour) # Get vertices of the min rect #rectVertices = cv2.cv.BoxPoints(minRect) rectVertices = cv2.boxPoints(minRect) dists_to_marker_center = np.zeros((4, 1)) vertices = np.array([None] * 4) for P in contour: P = P[0] dists_to_rect_vertices = [] for rectVertex in rectVertices: rectVertex = np.array(rectVertex) dists_to_rect_vertices.append(ut.distanceP2P(P, rectVertex)) # Determine which quadrant that P locates in section_idx = np.argmin(dists_to_rect_vertices) dist_to_marker_center = ut.distanceP2P(P, marker_center) if dist_to_marker_center > dists_to_marker_center[section_idx]: dists_to_marker_center[section_idx] = dist_to_marker_center vertices[section_idx] = P return vertices
def getVertices(contour, marker_center):
minRect = cv2.minAreaRect(contour)
rectVertices = cv2.boxPoints(minRect)
dists_to_marker_center = np.zeros((4, 1))
vertices = np.array([None] * 4)
for P in contour:
P = P[0]
dists_to_rect_vertices = []
for rectVertex in rectVertices:
rectVertex = np.array(rectVertex)
dists_to_rect_vertices.append(ut.distanceP2P(P, rectVertex))
section_idx = np.argmin(dists_to_rect_vertices)
dist_to_marker_center = ut.distanceP2P(P, marker_center)
if dist_to_marker_center > dists_to_marker_center[section_idx]:
dists_to_marker_center[section_idx] = dist_to_marker_center
vertices[section_idx] = P
return vertices
def detectQRcode(src):
gray_img = cv2.cvtColor(src, cv2.COLOR_BGR2GRAY)
gray_img = cv2.GaussianBlur(gray_img, (3, 3), 0)
th, thresh_img = cv2.threshold(gray_img, thresh, thresh_max_value,
cv2.THRESH_BINARY)
canny_img = cv2.Canny(thresh_img, canny_thresh1, canny_thresh2)
# cv2.imshow("canny",canny_img)
# cv2.waitKey(0)
contours, hierarchy = cv2.findContours(canny_img, cv2.RETR_TREE,
cv2.CHAIN_APPROX_SIMPLE)
hierarchy = hierarchy[0]
marker_candidate = []
for i in range(len(hierarchy)):
j, count = i, 0
while hierarchy[j][2] != -1:
j = hierarchy[j][2]
count += 1
if count == 5:
marker_candidate.append(i)
if len(marker_candidate) < 3:
raise MarkerNumError('Number of detected markers is less than 3')
else:
marker_candidate = marker_candidate[-3:]
mass_centers = []
for contour in contours:
M = cv2.moments(contour)
if M['m00'] == 0:
mass_centers.append((0, 0))
else:
mass_centers.append(
np.array((int(M['m10'] / M['m00']), int(M['m01'] / M['m00']))))
A = marker_candidate[0]
B = marker_candidate[1]
C = marker_candidate[2]
# cv2.circle(src, tuple(mass_centers[A]), 15, (255,0,0), 4)
# cv2.circle(src, tuple(mass_centers[B]), 15, (255,0,0), 4)
# cv2.circle(src, tuple(mass_centers[C]), 15, (255,0,0), 4)
# cv2.imshow("xx",src)
# cv2.waitKey(0)
AB = ut.distanceP2P(mass_centers[A], mass_centers[B])
BC = ut.distanceP2P(mass_centers[B], mass_centers[C])
AC = ut.distanceP2P(mass_centers[A], mass_centers[C])
#确定三个定位图案的位置
top_left, top_right, bot_left = None, None, None
P, Q = None, None
if AB > BC and AB > AC:
top_left, P, Q = C, A, B
elif BC > AB and BC > AC:
top_left, P, Q = A, B, C
elif AC > AB and AC > BC:
top_left, P, Q = B, A, C
if np.cross(mass_centers[P] - mass_centers[top_left],
mass_centers[Q] - mass_centers[top_left]) < 0:
bot_left, top_right = P, Q
else:
bot_left, top_right = Q, P
#确定四个角点
pattern_center = None
top_left_vertices, top_right_vertices, bot_left_vertices = None, None, None
pattern_center = np.array(((mass_centers[P][0] + mass_centers[Q][0]) // 2, \
(mass_centers[P][1] + mass_centers[Q][1]) // 2))
top_left_vertices = getVertices(contours[top_left], mass_centers[top_left])
top_right_vertices = getVertices(contours[top_right],
mass_centers[top_right])
bot_left_vertices = getVertices(contours[bot_left], mass_centers[bot_left])
top_left_vertices = updateVerticesOrder(top_left_vertices,
mass_centers[top_left],
pattern_center)
top_right_vertices = updateVerticesOrder(top_right_vertices,
mass_centers[top_right],
pattern_center)
bot_left_vertices = updateVerticesOrder(bot_left_vertices,
mass_centers[bot_left],
pattern_center)
M1, M2 = None, None
bot_right_corner = None
M1 = top_right_vertices[1] if ut.distanceP2P(top_right_vertices[1], mass_centers[top_left]) \
> ut.distanceP2P(top_right_vertices[-1], mass_centers[top_left]) else top_right_vertices[-1]
M2 = bot_left_vertices[1] if ut.distanceP2P(bot_left_vertices[1], mass_centers[top_left]) \
> ut.distanceP2P(bot_left_vertices[-1], mass_centers[top_left]) else bot_left_vertices[-1]
bot_right_corner = ut.intersection(top_right_vertices[0], M1,
bot_left_vertices[0], M2)
return np.array([
top_left_vertices[0], top_right_vertices[0], bot_right_corner,
bot_left_vertices[0]
])
def detectQRCode(src):
'''
Extract four QR code corner coordinates from the input image src.
Input:
src: input image - np.ndarray
Output:
vertices: Image coordinates of QR code corners in the order of
Top Left -> Top Right -> Bottom Right -> Bottom Left
(w.r.t the code itself not the image)
- np.array
'''
# Grayscale image
gray_img = cv2.cvtColor(src, cv2.COLOR_BGR2GRAY)
# Threshold
th, thresh_img = cv2.threshold(gray_img, thresh, thresh_max_value, cv2.THRESH_BINARY)
# Canny to extract edges
canny_img = cv2.Canny(thresh_img, canny_thresh1, canny_thresh2)
# Find contours
_,contours,hierarchy = cv2.findContours(canny_img, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
hierarchy = hierarchy[0]
'''
Find indices of the three markers of QR code in list 'contours'.
Store the indices in list 'marker_candidate'.
Only three elements should be included.
'''
marker_candidate = []
for i in range(len(hierarchy)):
j, count = i, 0
# 'hierarchy[i]' format: [Next, Previous, First_Child, Parent]
while hierarchy[j][2] != -1:
# Keep searching for child in next level
j = hierarchy[j][2]
count += 1
# Markers have nested contours with a total of six levels
if count == 5:
marker_candidate.append(i)
if len(marker_candidate) < 3:
raise MarkerNumError('Number of detected markers is less than 3')
else:
marker_candidate = marker_candidate[-3:]
'''
Compute moments of contours to obtain the mass centers.
'''
mass_centers = []
for contour in contours:
M = cv2.moments(contour)
if M['m00'] == 0:
mass_centers.append((0, 0))
else:
mass_centers.append(np.array((int(M['m10'] / M['m00']), int(M['m01'] / M['m00']))))
'''
Find which one of the three candidates is Top Left marker, Top Right marker and Bot Left marker, respectively
'''
A = marker_candidate[0]
B = marker_candidate[1]
C = marker_candidate[2]
AB = ut.distanceP2P(mass_centers[A], mass_centers[B])
BC = ut.distanceP2P(mass_centers[B], mass_centers[C])
AC = ut.distanceP2P(mass_centers[A], mass_centers[C])
top_left, top_right, bot_left = None, None, None
P, Q = None, None
# In triangle ABC, the vertex not involved in the longest side is the mass center of 'top_left' contour.
if AB > BC and AB > AC:
top_left, P, Q = C, A, B
elif BC > AB and BC > AC:
top_left, P, Q = A, B, C
elif AC > AB and AC > BC:
top_left, P, Q = B, A, C
d = ut.distanceP2L(mass_centers[P], mass_centers[Q], mass_centers[top_left])
slope = ut.slope(mass_centers[P], mass_centers[Q])
if slope is None:
bot_left, top_right = P, Q
elif slope < 0 and d < 0:
bot_left, top_right = P, Q
elif slope > 0 and d < 0:
top_right, bot_left = P, Q
elif slope < 0 and d > 0:
top_right, bot_left = P, Q
elif slope > 0 and d > 0:
bot_left, top_right = P, Q
pattern_center = None
top_left_vertices, top_right_vertices, bot_left_vertices = None, None, None
# Get the pattern center
pattern_center = np.array(((mass_centers[P][0] + mass_centers[Q][0]) // 2, \
(mass_centers[P][1] + mass_centers[Q][1]) // 2))
# Get markers vertices
top_left_vertices = getVertices(contours[top_left], mass_centers[top_left])
top_right_vertices = getVertices(contours[top_right], mass_centers[top_right])
bot_left_vertices = getVertices(contours[bot_left], mass_centers[bot_left])
top_left_vertices = updateVerticesOrder(top_left_vertices, mass_centers[top_left], pattern_center)
top_right_vertices = updateVerticesOrder(top_right_vertices, mass_centers[top_right], pattern_center)
bot_left_vertices = updateVerticesOrder(bot_left_vertices, mass_centers[bot_left], pattern_center)
'''
Find the fourth Bottom Right corner of the pattern.
'''
M1, M2 = None, None
bot_right_corner = None
M1 = top_right_vertices[1] if ut.distanceP2P(top_right_vertices[1], mass_centers[top_left]) \
> ut.distanceP2P(top_right_vertices[-1], mass_centers[top_left]) else top_right_vertices[-1]
M2 = bot_left_vertices[1] if ut.distanceP2P(bot_left_vertices[1], mass_centers[top_left]) \
> ut.distanceP2P(bot_left_vertices[-1], mass_centers[top_left]) else bot_left_vertices[-1]
bot_right_corner = ut.intersection(top_right_vertices[0], M1, bot_left_vertices[0], M2)
if bot_right_corner is None:
raise IntersectionError('Bottom line and right line do not intersect')
return np.array([top_left_vertices[0], top_right_vertices[0], bot_right_corner, bot_left_vertices[0]])