else:
return ransac.least_squares(sample)
+ def score(self, est, dist):
+ cons = []
+ score = 0
+ a, b, c = est
+ dst = lambda (x, y): abs(a * x + b * y + c) / sqrt(a*a+b*b)
+ for p in self.data:
+ d = dst(p)
+ if d <= dist:
+ cons.append(p)
+ score += min(d, dist)
+ return score, cons
+
def intersection((a1, b1, c1), (a2, b2, c2)):
delim = float(a1 * b2 - b1 * a2)
x = (b1 * c2 - c1 * b2) / delim
pyplot.scatter([center[0]], [center[1]], color='r')
pyplot.xlim(0, size[0])
pyplot.ylim(0, size[1])
+ pyplot.gca().invert_yaxis()
fig.canvas.draw()
size_f = fig.canvas.get_width_height()
buff = fig.canvas.tostring_rgb()
# TODO comments
# TODO threshold
-
def points_to_line((x1, y1), (x2, y2)):
return (y2 - y1, x1 - x2, x2 * y1 - x1 * y2)
def initial(self):
return random.sample(self.data, 2)
+ def score(self, est, dist):
+ cons = []
+ score = 0
+ a, b, c = est
+ dst = lambda (x, y): abs(a * x + b * y + c) / sqrt(a*a+b*b)
+ for p in self.data:
+ d = dst(p)
+ if d <= dist:
+ cons.append(p)
+ score += min(d, dist)
+ return score, cons
+
def iterate(model, distance):
- consensus = 0
+ score = float("inf")
consensual = model.initial()
- while (len(consensual) > consensus):
- consensus = len(consensual)
+ estimate = model.get(consensual)
+ new_score, consensual = model.score(estimate, distance)
+ while (new_score < score):
+ score = new_score
try:
estimate = model.get(consensual)
except NP.linalg.LinAlgError:
pass
- consensual = filter_near(model.data, estimate, distance)
- return consensus, estimate, consensual
+ estimate = model.get(consensual)
+ new_score, consensual = model.score(estimate, distance)
+ return score, estimate, consensual
def estimate(data, dist, k, modelClass=Linear_model):
model = modelClass(data)
- best = 0
+ best = float("inf")
estimate = None
consensual = None
for i in xrange(0, k):
new, new_estimate, new_consensual = iterate(model, dist)
- if new > best:
+ if new < best:
best = new
estimate = new_estimate
consensual = new_consensual