def closest_point_to_a_ray(point, ray):
"""
Definition to calculate the point on a ray that is closest to given point.
Parameters
----------
point : list
Given point in X,Y,Z.
ray : ndarray
Given ray.
Returns
---------
closest_point : ndarray
Calculated closest point.
"""
from odak.raytracing import propagate_a_ray
if len(ray.shape) == 2:
ray = ray.reshape((1, 2, 3))
p0 = ray[:, 0]
p1 = propagate_a_ray(ray, 1.)
if len(p1.shape) == 2:
p1 = p1.reshape((1, 2, 3))
p1 = p1[:, 0]
p1 = p1.reshape(3)
p0 = p0.reshape(3)
point = point.reshape(3)
closest_distance = -np.dot((p0 - point), (p1 - p0)) / np.sum((p1 - p0)**2)
closest_point = propagate_a_ray(ray, closest_distance)[0]
return closest_point
def get_triangle_normal(triangle, triangle_center=None):
"""
Definition to calculate surface normal of a triangle.
Parameters
----------
triangle : ndarray
Set of points in X,Y and Z to define a planar surface (3,3). It can also be list of triangles (mx3x3).
triangle_center : ndarray
Center point of the given triangle. See odak.raytracing.center_of_triangle for more. In many scenarios you can accelerate things by precomputing triangle centers.
Returns
----------
normal : ndarray
Surface normal at the point of intersection.
"""
triangle = np.asarray(triangle)
if len(triangle.shape) == 2:
triangle = triangle.reshape((1, 3, 3))
normal = np.zeros((triangle.shape[0], 2, 3))
direction = np.cross(triangle[:, 0] - triangle[:, 1],
triangle[:, 2] - triangle[:, 1])
if type(triangle_center) == type(None):
normal[:, 0] = center_of_triangle(triangle)
else:
normal[:, 0] = triangle_center
normal[:, 1] = direction / np.sum(direction, axis=1)[0]
if normal.shape[0] == 1:
normal = normal.reshape((2, 3))
return normal
def point_to_ray_distance(point, ray_point_0, ray_point_1):
"""
Definition to find point's closest distance to a line represented with two points.
Parameters
----------
point : ndarray
Point to be tested.
ray_point_0 : ndarray
First point to represent a line.
ray_point_1 : ndarray
Second point to represent a line.
Returns
----------
distance : float
Calculated distance.
"""
distance = np.sum(
np.cross((point - ray_point_0), (point - ray_point_1))**2) / np.sum(
(ray_point_1 - ray_point_0)**2)
return distance
def distance_between_two_points(point1, point2):
"""
Definition to calculate distance between two given points.
Parameters
----------
point1 : list
First point in X,Y,Z.
point2 : list
Second point in X,Y,Z.
Returns
----------
distance : float
Distance in between given two points.
"""
point1 = np.asarray(point1)
point2 = np.asarray(point2)
if len(point1.shape) == 1 and len(point2.shape) == 1:
distance = np.sqrt(np.sum((point1 - point2)**2))
elif len(point1.shape) == 2 or len(point2.shape) == 2:
distance = np.sqrt(np.sum((point1 - point2)**2, axis=1))
return distance
def intersect_parametric(ray,
parametric_surface,
surface_function,
surface_normal_function,
target_error=0.00000001,
iter_no_limit=100000):
"""
Definition to intersect a ray with a parametric surface.
Parameters
----------
ray : ndarray
Ray.
parametric_surface : ndarray
Parameters of the surfaces.
surface_function : function
Function to evaluate a point against a surface.
surface_normal_function : function
Function to calculate surface normal for a given point on a surface.
target_error : float
Target error that defines the precision.
iter_no_limit : int
Maximum number of iterations.
Returns
----------
distance : float
Propagation distance.
normal : ndarray
Ray that defines a surface normal for the intersection.
"""
if len(ray.shape) == 2:
ray = ray.reshape((1, 2, 3))
error = [150, 100]
distance = [0, 0.1]
iter_no = 0
while np.abs(np.max(np.asarray(error[1]))) > target_error:
error[1], point = intersection_kernel_for_parametric_surfaces(
distance[1], ray, parametric_surface, surface_function)
distance, error = propagate_parametric_intersection_error(
distance, error)
iter_no += 1
if iter_no > iter_no_limit:
return False, False
if np.isnan(np.sum(point)):
return False, False
normal = surface_normal_function(point, parametric_surface)
return distance[1], normal
def distance_between_point_clouds(points0, points1):
"""
A definition to find distance between every point in one cloud to other points in the other point cloud.
Parameters
----------
points0 : ndarray
Mx3 points.
points1 : ndarray
Nx3 points.
Returns
----------
distances : ndarray
MxN distances.
"""
c = points1.reshape((1, points1.shape[0], points1.shape[1]))
a = np.repeat(c, points0.shape[0], axis=0)
b = points0.reshape((points0.shape[0], 1, points0.shape[1]))
b = np.repeat(b, a.shape[1], axis=1)
distances = np.sqrt(np.sum((a - b)**2, axis=2))
return distances
def roi(image, location=[0, 100, 0, 100], threshold=[0, 1, 0, 1]):
"""
Definition to get the lines from a target ROI.
Parameters
----------
image : ndarray
a 2D image to be sliced (nxm).
location : ndarray
Locations for taking the ROI.
threshold : list
Threshold below and above these numbers.
Returns
-------
line_x : ndarray
Line slice.
line_y : ndarray
Line slice.
"""
img = image[location[0]:location[1], location[2]:location[3]]
if len(img.shape) == 3:
img = np.sum(img, axis=2)
line_x = img[:, int(img.shape[1] / 2)]
line_y = img[int(img.shape[0] / 2), :]
line_x = np.asarray(line_x)
line_y = np.asarray(line_y)
line_x = line_x - np.amin(line_x)
line_x = line_x / np.amax(line_x)
line_y = line_y - np.amin(line_y)
line_y = line_y / np.amax(line_y)
line_x[line_x < threshold[0]] = 0
line_x[line_x > threshold[1]] = 1
line_y[line_y < threshold[2]] = 0
line_y[line_y > threshold[3]] = 1
return line_x, line_y, img
