使用 Open3D 从点云生成网格并保存问题

Question

我有一个根据一些图像计算的点云，我试图从该点生成一个网格（3D 表面）。我可以成功创建点云，但我无法从该云创建网格并保存我创建的网格。我在下面分享了我的完整代码。

我使用的图书馆：

开放3D 数值模拟 Matplotlib 操作系统 追溯

import open3d as o3d
import numpy as np
import cv2
import matplotlib.pyplot as plt
import os
import traceback

def read_point_cloud(file_path):
    try:
        if not os.path.exists(file_path):
            raise FileNotFoundError(f"Dosya bulunamadı: {file_path}")

        if not os.access(file_path, os.R_OK):
            raise PermissionError(f"Dosya erişim izni yok: {file_path}")

        ply = o3d.io.read_point_cloud(file_path)
        if ply.is_empty():
            raise ValueError("Nokta bulutu boş veya geçersiz.")

        return ply

    except Exception as e:
        print(f"Error in read_point_cloud: {e}")
        traceback.print_exc()
        raise

def generate_depth_map(points, width, height):
    try:
        depth_map = np.zeros((height, width), dtype=np.float32)
        for point in points:
            x, y, z = point
            u = int(np.clip(x, 0, width - 1))  # Ölçekleme ve sınır kontrolü
            v = int(np.clip(y, 0, height - 1))  # Ölçekleme ve sınır kontrolü
            depth_map[v, u] = z
        return depth_map

    except Exception as e:
        print(f"Error in generate_depth_map: {e}")
        traceback.print_exc()
        raise

def refine_depth_map(depth_map):
    try:
        min_val = np.min(depth_map)
        max_val = np.max(depth_map)
        print(f"Min depth value: {min_val}, Max depth value: {max_val}")
        if max_val > min_val:
            depth_map_normalized = (depth_map - min_val) / (max_val - min_val) * 255
        else:
            depth_map_normalized = np.zeros_like(depth_map)
        depth_map_uint8 = np.clip(depth_map_normalized, 0, 255).astype(np.uint8)
        return depth_map_uint8

    except Exception as e:
        print(f"Error in refine_depth_map: {e}")
        traceback.print_exc()
        raise

def plot_depth_map(depth_map):
    try:
        plt.imshow(depth_map, cmap='viridis')
        plt.colorbar()
        plt.title('Depth Map')
        plt.show()
    except Exception as e:
        print(f"Error in plot_depth_map: {e}")
        traceback.print_exc()
        raise

def depth_map_to_point_cloud(depth_map):
    try:
        height, width = depth_map.shape
        points = []
        for v in range(height):
            for u in range(width):
                z = depth_map[v, u]
                if z > 0:  # Depth value should be positive
                    x = u
                    y = v
                    points.append([x, y, z])

        points = np.array(points)
        print(f"Number of valid points: {len(points)}")
        if len(points) == 0:
            raise ValueError("No valid points found to create point cloud.")

        point_cloud = o3d.geometry.PointCloud()
        point_cloud.points = o3d.utility.Vector3dVector(points)
        return point_cloud

    except Exception as e:
        print(f"Error in depth_map_to_point_cloud: {e}")
        traceback.print_exc()
        raise

def point_cloud_to_mesh(point_cloud):
    alpha = 0.1
    mesh = o3d.geometry.TriangleMesh.create_from_point_cloud_alpha_shape(point_cloud, alpha)
    return mesh

def save_mesh(mesh, file_path):
    print(f"Saving mesh to {file_path}")
    try:
        dir_name = os.path.dirname(file_path)
        if not os.path.exists(dir_name):
            os.makedirs(dir_name)

        o3d.io.write_triangle_mesh(file_path, mesh)
        print("Mesh saved successfully")
    except Exception as e:
        print(f"Error in save_mesh: {e}")
        traceback.print_exc()
        raise

def main():
    file_path = './dataset/mini6.ply'
    output_file_dir = './output/'

    width, height = 640, 480

    try:
        ply = read_point_cloud(file_path)

        points = np.asarray(ply.points)
        depth_map = generate_depth_map(points, width, height)
        refined_depth_map = refine_depth_map(depth_map)

        depth_point_cloud = depth_map_to_point_cloud(refined_depth_map)

        mesh = point_cloud_to_mesh(depth_point_cloud)

        if not os.path.exists(output_file_dir):
            os.makedirs(output_file_dir)

        output_file = os.path.join(output_file_dir, "output_mesh.ply")
        save_mesh(mesh, output_file)

    except Exception as e:
        print(f"Bir hata oluştu: {e}")
        traceback.print_exc()

if __name__ == "__main__":
    main()

我遇到的问题：

我可以成功创建点云，但即使 point_cloud_to_mesh 函数指示它已创建网格，但当我尝试保存创建的网格时遇到问题。在应该保存网格的地方，没有保存任何内容，或者看起来网格没有创建。

错误信息：

在网格创建过程中我没有收到任何错误消息，但是当我调用 save_mesh 函数时，网格文件不会保存。 问题：

我在网格创建或保存部分代码时犯了错误吗？您对此有何建议？ 我不确定我是否正确使用了 create_from_point_cloud_alpha_shape 函数。在这种情况下 Alpha 值合适吗？ 任何帮助将不胜感激！谢谢。 ❤️

Answer 1

在不知道你的点云是什么样子的情况下很难知道发生了什么，但我的猜测是你的 alpha 值太小而无法生成包络，所以你试图保存一个空网格。

这个有什么作用？

saved = o3d.io.write_triangle_mesh(file_path, mesh, print_progress=True)
if saved:
    print("Mesh saved successfully")
else:
    print("Something went wrong")