def aspect_ratio(im, lines, D, v, O):
vx, vy = v
C0, C1 = C0_C1(lines, v)
im_h, im_w = im.shape
m = -(vx - O[0]) / (vy - O[1])
L0 = Line.from_point_slope(C0.first_base(), m)
L1 = Line.from_point_slope(C1.first_base(), m)
perp = L0.altitude(v)
p0, p1 = L0.intersect(perp), L1.intersect(perp)
h_img = norm(p0 - p1)
L = Line(m, -m * O[0] - (f**2) / (vy - O[1]))
F = L.altitude(v).intersect(L)
_, x0r, y0r, w0r, h0r = lines[-1][-1]
p0r = np.array([x0r + w0r / 2.0, y0r + h0r])
F_C0r = Line.from_points(F, p0r)
q0 = F_C0r.intersect(L0)
l_img = norm(q0 - p0)
debug = cv2.cvtColor(im, cv2.COLOR_GRAY2BGR)
L0.draw(debug)
L1.draw(debug)
L.draw(debug, color=GREEN)
F_C0r.draw(debug, color=RED)
lib.debug_imwrite('aspect.png', debug)
# Convergence line perp to V=(vx, vy, f)
# y = -vx / vy * x + -f^2 / vy
alpha = atan2(norm(p1 - O), f)
theta = acos(f / sqrt((vx - O[0])**2 + (vy - O[1])**2 + f**2))
beta = pi / 2 - theta
lp_img = abs(D[0][-1] - D[0][0])
wp_img = norm(np.diff(D.T, axis=0), axis=1).sum()
print('h_img:', h_img, 'l\'_img:', lp_img, 'alpha:', alpha)
print('l_img:', l_img, 'w\'_img:', wp_img, 'beta:', beta)
r = h_img * lp_img * cos(alpha) / (l_img * wp_img * cos(alpha + beta))
return r
def vanishing_point(lines, v0, O):
C0 = lines[-1] if v0[1] < 0 else lines[0]
others = lines[:-1] if v0[1] < 0 else lines[1:]
domain = np.linspace(C0.left(), C0.right(), N_LONGS + 2)[1:-1]
C0_points = np.array([domain, C0.model(domain)]).T
longitudes = [Line.from_points(v0, p) for p in C0_points]
lefts = [longitudes[0].text_line_intersect(line)[0] for line in others]
rights = [longitudes[-1].text_line_intersect(line)[0] for line in others]
valid_mask = [line.left() <= L and R < line.right() \
for line, L, R in zip(others, lefts, rights)]
valid_lines = [C0] + compress(others, valid_mask)
derivs = [line.model.deriv() for line in valid_lines]
print('valid lines:', len(others))
convergences = []
for longitude in longitudes:
intersects = [
longitude.text_line_intersect(line) for line in valid_lines
]
tangents = [Line.from_point_slope(p, d(p[0])) \
for p, d in zip(intersects, derivs)]
convergences.append(Line.best_intersection(tangents))
# x vx + y vy + f^2 = 0
# m = -vx / vy
# b = -f^2 / vy
L = Line.fit(convergences)
# shift into O-origin coords
L_O = L.offset(-O)
vy = -(f**2) / L_O.b
vx = -vy * L_O.m
v = np.array((vx, vy)) + O
debug = cv2.cvtColor(bw, cv2.COLOR_GRAY2BGR)
for t in tangents:
t.draw(debug, color=RED)
for longitude in longitudes:
longitude.draw(debug)
L.draw(debug, color=GREEN)
lib.debug_imwrite('vanish.png', debug)
return v, f, L
