""" ETH3D multi-view benchmark, used for line matching evaluation. """ import logging import os import shutil import zipfile from pathlib import Path import cv2 import numpy as np import torch from ..geometry.wrappers import Camera, Pose from ..settings import DATA_PATH from ..utils.image import ImagePreprocessor, load_image from .base_dataset import BaseDataset from .utils import scale_intrinsics logger = logging.getLogger(__name__) def read_cameras(camera_file, scale_factor=None): """Read the camera intrinsics from a file in COLMAP format.""" with open(camera_file, "r") as f: raw_cameras = f.read().rstrip().split("\n") raw_cameras = raw_cameras[3:] cameras = [] for c in raw_cameras: data = c.split(" ") fx, fy, cx, cy = np.array(list(map(float, data[4:]))) K = np.array([[fx, 0.0, cx], [0.0, fy, cy], [0.0, 0.0, 1.0]], dtype=np.float32) if scale_factor is not None: K = scale_intrinsics(K, np.array([scale_factor, scale_factor])) cameras.append(Camera.from_calibration_matrix(K).float()) return cameras def qvec2rotmat(qvec): """Convert from quaternions to rotation matrix.""" return np.array( [ [ 1 - 2 * qvec[2] ** 2 - 2 * qvec[3] ** 2, 2 * qvec[1] * qvec[2] - 2 * qvec[0] * qvec[3], 2 * qvec[3] * qvec[1] + 2 * qvec[0] * qvec[2], ], [ 2 * qvec[1] * qvec[2] + 2 * qvec[0] * qvec[3], 1 - 2 * qvec[1] ** 2 - 2 * qvec[3] ** 2, 2 * qvec[2] * qvec[3] - 2 * qvec[0] * qvec[1], ], [ 2 * qvec[3] * qvec[1] - 2 * qvec[0] * qvec[2], 2 * qvec[2] * qvec[3] + 2 * qvec[0] * qvec[1], 1 - 2 * qvec[1] ** 2 - 2 * qvec[2] ** 2, ], ] ) class ETH3DDataset(BaseDataset): default_conf = { "data_dir": "ETH3D_undistorted", "grayscale": True, "downsize_factor": 8, "min_covisibility": 500, "batch_size": 1, "two_view": True, "min_overlap": 0.5, "max_overlap": 1.0, "sort_by_overlap": False, "seed": 0, } def _init(self, conf): self.grayscale = conf.grayscale self.downsize_factor = conf.downsize_factor # Set random seeds np.random.seed(conf.seed) torch.manual_seed(conf.seed) # Auto-download the dataset if not (DATA_PATH / conf.data_dir).exists(): logger.info("Downloading the ETH3D dataset...") self.download_eth3d() # Form pairs of images from the multiview dataset self.img_dir = DATA_PATH / conf.data_dir self.data = [] for folder in self.img_dir.iterdir(): img_folder = Path(folder, "images", "dslr_images_undistorted") depth_folder = Path(folder, "ground_truth_depth/undistorted_depth") depth_ext = ".png" names = [img.name for img in img_folder.iterdir()] names.sort() # Read intrinsics and extrinsics data cameras = read_cameras( str(Path(folder, "dslr_calibration_undistorted", "cameras.txt")), 1 / self.downsize_factor, ) name_to_cam_idx = {name: {} for name in names} with open( str(Path(folder, "dslr_calibration_jpg", "images.txt")), "r" ) as f: raw_data = f.read().rstrip().split("\n")[4::2] for raw_line in raw_data: line = raw_line.split(" ") img_name = os.path.basename(line[-1]) name_to_cam_idx[img_name]["dist_camera_idx"] = int(line[-2]) T_world_to_camera = {} image_visible_points3D = {} with open( str(Path(folder, "dslr_calibration_undistorted", "images.txt")), "r" ) as f: lines = f.readlines()[4:] # Skip the header raw_poses = [line.strip("\n").split(" ") for line in lines[::2]] raw_points = [line.strip("\n").split(" ") for line in lines[1::2]] for raw_pose, raw_pts in zip(raw_poses, raw_points): img_name = os.path.basename(raw_pose[-1]) # Extract the transform from world to camera target_extrinsics = list(map(float, raw_pose[1:8])) pose = np.eye(4, dtype=np.float32) pose[:3, :3] = qvec2rotmat(target_extrinsics[:4]) pose[:3, 3] = target_extrinsics[4:] T_world_to_camera[img_name] = pose name_to_cam_idx[img_name]["undist_camera_idx"] = int(raw_pose[-2]) # Extract the visible 3D points point3D_ids = [id for id in map(int, raw_pts[2::3]) if id != -1] image_visible_points3D[img_name] = set(point3D_ids) # Extract the covisibility of each image num_imgs = len(names) n_covisible_points = np.zeros((num_imgs, num_imgs)) for i in range(num_imgs - 1): for j in range(i + 1, num_imgs): visible_points3D1 = image_visible_points3D[names[i]] visible_points3D2 = image_visible_points3D[names[j]] n_covisible_points[i, j] = len( visible_points3D1 & visible_points3D2 ) # Keep only the pairs with enough covisibility valid_pairs = np.where(n_covisible_points >= conf.min_covisibility) valid_pairs = np.stack(valid_pairs, axis=1) self.data += [ { "view0": { "name": names[i][:-4], "img_path": str(Path(img_folder, names[i])), "depth_path": str(Path(depth_folder, names[i][:-4])) + depth_ext, "camera": cameras[name_to_cam_idx[names[i]]["dist_camera_idx"]], "T_w2cam": Pose.from_4x4mat(T_world_to_camera[names[i]]), }, "view1": { "name": names[j][:-4], "img_path": str(Path(img_folder, names[j])), "depth_path": str(Path(depth_folder, names[j][:-4])) + depth_ext, "camera": cameras[name_to_cam_idx[names[j]]["dist_camera_idx"]], "T_w2cam": Pose.from_4x4mat(T_world_to_camera[names[j]]), }, "T_world_to_ref": Pose.from_4x4mat(T_world_to_camera[names[i]]), "T_world_to_target": Pose.from_4x4mat(T_world_to_camera[names[j]]), "T_0to1": Pose.from_4x4mat( np.float32( T_world_to_camera[names[j]] @ np.linalg.inv(T_world_to_camera[names[i]]) ) ), "T_1to0": Pose.from_4x4mat( np.float32( T_world_to_camera[names[i]] @ np.linalg.inv(T_world_to_camera[names[j]]) ) ), "n_covisible_points": n_covisible_points[i, j], } for (i, j) in valid_pairs ] # Print some info print("[Info] Successfully initialized dataset") print("\t Name: ETH3D") print("----------------------------------------") def download_eth3d(self): data_dir = DATA_PATH / self.conf.data_dir tmp_dir = data_dir.parent / "ETH3D_tmp" if tmp_dir.exists(): shutil.rmtree(tmp_dir) tmp_dir.mkdir(exist_ok=True, parents=True) url_base = "https://cvg-data.inf.ethz.ch/ETH3D_undistorted/" zip_name = "ETH3D_undistorted.zip" zip_path = tmp_dir / zip_name torch.hub.download_url_to_file(url_base + zip_name, zip_path) with zipfile.ZipFile(zip_path, "r") as zip_ref: zip_ref.extractall(tmp_dir) shutil.move(tmp_dir / zip_name.split(".")[0], data_dir) def get_dataset(self, split): return ETH3DDataset(self.conf) def _read_image(self, img_path): img = load_image(img_path, grayscale=self.grayscale) shape = img.shape[-2:] # instead of INTER_AREA this does bilinear interpolation with antialiasing img_data = ImagePreprocessor({"resize": max(shape) // self.downsize_factor})( img ) return img_data def read_depth(self, depth_path): if self.downsize_factor != 8: raise ValueError( "Undistorted depth only available for low res" + " images(downsize_factor = 8)." ) depth_img = cv2.imread(depth_path, cv2.IMREAD_ANYDEPTH) depth_img = depth_img.astype(np.float32) / 256 return depth_img def __getitem__(self, idx): """Returns the data associated to a pair of images (reference, target) that are co-visible.""" data = self.data[idx] # Load the images view0 = data.pop("view0") view1 = data.pop("view1") view0 = {**view0, **self._read_image(view0["img_path"])} view1 = {**view1, **self._read_image(view1["img_path"])} view0["scales"] = np.array([1.0, 1]).astype(np.float32) view1["scales"] = np.array([1.0, 1]).astype(np.float32) # Load the depths view0["depth"] = self.read_depth(view0["depth_path"]) view1["depth"] = self.read_depth(view1["depth_path"]) outputs = { **data, "view0": view0, "view1": view1, "name": f"{view0['name']}_{view1['name']}", } return outputs def __len__(self): return len(self.data)