example of surface profiling in slam

# Authors: Tianqi SONG <tianqisong0117@gmail.com>

# License: BSD (3-clause)
# sphinx_gallery_thumbnail_number = 2

importation of slam modules

import numpy as np
import trimesh.visual.color

import slam.surface_profiling as surfpf
import slam.io as sio

loading an example mesh

mesh = sio.load_mesh("data/example_mesh.gii")

Select a vertex and get the coordinate and normal.

vert_index = 1000
vert0 = mesh.vertices[vert_index]
norm0 = mesh.vertex_normals[vert_index]

Set the parameters for surface profiling initial direction of rotation, rotation angle, length and number of sampling steps

init_rot_dir = np.array([1, 1, 1]) - vert0
rot_angle = 10
r_step = 0.1
max_samples = 45

Surface profiling

profile_points = surfpf.surface_profiling_vert(
    vert0, norm0, init_rot_dir, rot_angle, r_step, max_samples, mesh
)

Visualize result

prof_points_mesh = profile_points.reshape(
    profile_points.shape[0] * profile_points.shape[1], 3
)
prof_points_colors = np.zeros(prof_points_mesh.shape)
points_mesh = trimesh.points.PointCloud(
    prof_points_mesh, colors=np.array(prof_points_colors, dtype=np.uint8)
)

# set the points colors
red, yellow, green, blue = [
    [255, 0, 0, 255],
    [255, 255, 0, 255],
    [0, 255, 0, 255],
    [0, 0, 255, 255],
]
color_i = np.zeros(4)
for i in range(len(prof_points_mesh)):
    degree = i / max_samples
    num_profiles = int(360 / rot_angle)
    segment_color = num_profiles / 3

    if degree <= segment_color:
        color_i = trimesh.visual.color.linear_color_map(
            degree / segment_color, [red, yellow]
        )
    elif segment_color < degree <= segment_color * 2:
        color_i = trimesh.visual.color.linear_color_map(
            degree / segment_color - 1, [yellow, green]
        )
    elif segment_color * 2 < degree <= num_profiles:
        color_i = trimesh.visual.color.linear_color_map(
            degree / segment_color - 2, [green, blue]
        )
    points_mesh.colors[i] = np.array(color_i)

# create a scene with the mesh and profiling points
#scene = trimesh.Scene([points_mesh, mesh])
#scene.show(smooth=False)