def find_corners(refined_line_list):
"""
Finds corners (without deciding which is which)
:param refined_line_list:
:return: list of corners
"""
if len(refined_line_list) != 4:
raise ValueError("ERROR: wrong number of lines")
base_line = refined_line_list[0]
i = 1
j = -1
max_dot_product = -1
n = len(refined_line_list)
while i < n:
a1, b1, rho1 = unpack_line(base_line)
a2, b2, rho2 = unpack_line(refined_line_list[i])
cur_dot_product = abs(dot_product(a1, b1, a2, b2))
if cur_dot_product > max_dot_product:
max_dot_product = cur_dot_product
j = i
i += 1
corners = []
for l in [0, j]:
k = 0
while k < n:
if k != 0 and k != j:
a1, b1, rho1 = unpack_line(refined_line_list[l])
a2, b2, rho2 = unpack_line(refined_line_list[k])
try:
corners.append(line_instersection(a1, b1, rho1, a2, b2, rho2))
except ValueError:
#should not happen
print("ERROR: parallel lines passed through postprocessor")
corners.append((0, 0))
k += 1
return corners
def splice_lines(hough_line_list, x_window_size, y_window_size, x_pt, y_pt, parallel_lines_margin, dot_product_threshold):
"""
Splices close lines in region into one line
:param hough_line_list:
:param window_size:
:param x_pt:
:param y_pt:
:param parallel_lines_margin:
:param dot_product_threshold:
:return: list of four lines
"""
refined_line_list = []
i = 0
n = len(hough_line_list)
#Iterates through lines
while i < n:
line1 = hough_line_list[i]
a1, b1, rho1 = unpack_line(line1)
j = i + 1
#Iterates through the rest of lines trying to find nearly parallel lines
while j < n:
line2 = hough_line_list[j]
a2, b2, rho2 = unpack_line(line2)
try:
x, y = line_instersection(a1, b1, rho1, a2, b2, rho2)
except ValueError as e:
if str(e) == "Overlap":
del hough_line_list[j]
n -= 1
continue
if str(e) == "Parallel":
if abs(rho2 - rho1) < parallel_lines_margin:
del hough_line_list[j]
n -= 1
continue
else:
j += 1
continue
#Lines intersect in rectangle and almost parallel
if x_pt <= x <= x_pt + x_window_size and y_pt <= y <= y_pt + y_window_size and abs(dot_product(a1, b1, a2, b2)) > dot_product_threshold:
mean_weight = (line1[2] + line2[2])/2
spliced_line = splice_line(a1, b1, rho1, a2, b2, rho2, mode="grad")
line1 = (spliced_line[0], spliced_line[1], mean_weight)
del hough_line_list[j]
n -= 1
else:
j += 1
refined_line_list.append(line1)
i += 1
return refined_line_list