depth_map_to_stl,_2.py

# -*- coding: utf-8 -*-
"""Depth map to STL, 2.ipynb

Automatically generated by Colaboratory.

Original file is located at
    https://colab.research.google.com/drive/1dttpXakpLFlKuMk8byAOl_zry5MvpCmK

Depth Map to STL

Uses numpy-stl to create files

Each square of four pixels is divided into two triangles

Processing time is ~2min per megapixel

Project is at https://github.com/BillFSmith/depth_map_to_stl

Example depth map from https://johnflower.org/sites/default/files/2018-07/08-new-plymouth-15m-dem-n-mt-taranaki_5.png
"""

#@title Press Ctrl + F9 to run code

print("Depth maps only show relative depth, so the division of the maximum depth and the width of the image is needed.")
print("E.g. an object that is 10cm tall and 20cm wide, the value would be 0.5")
height_div_width = input('Enter desired value for image depth/width: ')
print('')
print("Upload depth maps:")

from google.colab import files
uploaded = files.upload()

!pip install numpy-stl
import numpy as np
from stl import mesh
import cv2

file_names = list(uploaded.keys())

for file_name in file_names:
    im = cv2.imread(file_name, cv2.IMREAD_UNCHANGED)
    im_array = np.array(im) #.transpose((1, 0, 2))
    im_array = np.rot90(im_array, -1, (0,1))

    mesh_size = [im_array.shape[0],im_array.shape[1]]

    mesh_max = np.max(im_array)

    if len(im_array.shape) == 3:
        scaled_mesh = mesh_size[0] * float(height_div_width) * im_array[:,:,0] / mesh_max
    else:
        scaled_mesh = mesh_size[0] * float(height_div_width) * im_array / mesh_max
    # rand_mesh = np.random.rand(mesh_size[0],mesh_size[1])

    mesh_shape = mesh.Mesh(np.zeros((mesh_size[0] - 1) * (mesh_size[1] - 1) * 2, dtype=mesh.Mesh.dtype))

    for i in range(0, mesh_size[0]-1):
        for j in range(0, mesh_size[1]-1):
            mesh_num = i * (mesh_size[1]-1) + j

            mesh_shape.vectors[2 * mesh_num][2] = [i, j, scaled_mesh[i,j]]
            mesh_shape.vectors[2 * mesh_num][1] = [i, j+1, scaled_mesh[i,j+1]]
            mesh_shape.vectors[2 * mesh_num][0] = [i+1, j, scaled_mesh[i+1,j]]

            mesh_shape.vectors[2 * mesh_num + 1][0] = [i+1, j+1, scaled_mesh[i+1,j+1]]
            mesh_shape.vectors[2 * mesh_num + 1][1] = [i, j+1, scaled_mesh[i,j+1]]
            mesh_shape.vectors[2 * mesh_num + 1][2] = [i+1, j, scaled_mesh[i+1,j]]

    mesh_shape.save(str(file_name) + '.stl')
    files.download(str(file_name) + '.stl')