Voxgraph
Voxgraph 以一組相互重疊的符號距離函數(SDF)子地圖表示環境。前端依固定時間間隔把連續點雲以 voxblox 光線投射整合成 TSDF 子地圖,子地圖完成後再計算歐氏符號距離場(ESDF),並以 marching cubes 取出等值面點。後端以位姿圖最佳化各子地圖的位置與偏航角,約束包括里程計、外部迴圈閉合(例如 DBoW2)以及作者提出的免對應配準約束:把一個子地圖的等值面點轉入相鄰子地圖的 ESDF,直接讀取距離值作為殘差,並依體素權重隨機只取 5% 殘差以降低計算量。系統以地圖為中心,不重新估計完整軌跡,並在搭載 Intel i7-8650U 的六旋翼無人機上以 Ouster OS1 光達或 RealSense D415 即時運作。
本頁內容
Map-centric SDF-submap SLAM: overlapping TSDF/ESDF submaps are aligned by a pose graph over x, y, z and yaw using odometry, external loop closures and correspondence-free ESDF registration residuals (iso-surface points of one submap looked up in its neighbour's ESDF), with weight-proportional residual sub-sampling that keeps global optimization real time on an MAV CPU.
技術屬性
欄位內容為文獻擷取紀錄的原文用語(英文),以原文為據;「未查證」表示本研究尚未讀到該資訊,不代表該方法不具備此能力。
| 感測輸入 | 3D LiDAR Ouster OS1 (64-beam) in the outdoor MAV field experiment、RGB-D camera Intel RealSense D415 (pointclouds) in the indoor MAV experiment、Odometry input from a time-synchronized camera-IMU running ROVIO visual-inertial odometry; VI-sensor stereo and IMU in the indoor dataset、RTK-GNSS used only as trajectory ground truth |
|---|---|
| 原文測試平台 | UAV (hexacopter MAV; four outdoor flights of about 400 m at a search and rescue training site)、UAV (MAV with RGB-D camera and VI-sensor in an underground industrial space at ETH Zurich; dataset from C-blox)、simulation (RotorS, LiDAR-equipped MAV flying around a multi-story building) |
| 狀態估計 | Pose-graph nonlinear least squares over submap poses in R3 x SO(2) (x, y, z, yaw; roll and pitch taken from gravity-aligned odometry) with odometry and loop-closure terms (Mahalanobis) and registration terms (weighted squared ESDF distance); per-scan poses come from the external visual-inertial odometry (ROVIO) and are kept fixed relative to their submap |
| 資料關聯 | Correspondence-free submap-to-submap registration: iso-surface points of one submap are transformed into the overlapping submap and its trilinearly interpolated ESDF value is the residual; overlapping pairs found with axis-aligned bounding boxes; residuals randomly sub-sampled per solver iteration with probability proportional to voxel weight (5% sampling ratio used) |
| 時間表示 | discrete poses; per-scan odometry poses stored relative to their submap |
| 去畸變 | LiDAR undistortion runs as a component in the field experiment (listed in the CPU breakdown, Fig. 6); the method is not described |
| 迴圈閉合 | External, source-agnostic loop closures between two sensor frames are converted into constraints between the submaps that contain them (DBoW2 place recognition on VI-sensor images in the RGB-D experiment); registration constraints link overlapping submaps, while wide loops rely on the external loop closures (Secs. VI-B, VIII-B2) |
| 全域最佳化 | Pose graph over all submap poses, re-solved when each new submap is added; maximum global optimization time about 4 s in the field experiments |
| 地圖表示 | collection of overlapping TSDF submaps built at a fixed frequency by ray casting into spatially hashed voxel blocks (voxblox), each with an ESDF and marching-cubes iso-surface points; submaps can be fused into one global map |
| 先驗資訊 | none (assumes gravity direction observable from the odometry front end) |
| 可輸出幾何 | globally aligned SDF submap collection and fused global volumetric map; trajectory obtained by projecting submap-relative odometry with the optimised submap poses |
| 計算需求 | CPU only; Intel NUC Core i7-8650U carried by the MAV; fewer than 3 CPU threads (230 to 305% where 100% is one hyper-thread); global optimization uses 44% of one core; RGB-D dataset processed on a desktop CPU with 5 cm voxels (Sec. VIII-B) |
使用設備
原文使用的感測器、運算硬體與載具(equipment)。型號保留原文寫法,連結到設備頁中同一型號的歸併名稱;角色依原文用途分為方法輸入、資料集感測器、執行運算平台、參考或真值量測(reference or ground truth)與比較對象設備。
| 類別 | 型號(原文寫法) | 角色 | 資料集 | 原文規格 | 出處 |
|---|---|---|---|---|---|
| LiDAR | Ouster OS1 | 方法輸入 | 未標示 | 64 beam (Fig. 5 caption) | (Reijgwart et al., 2020, Sec. VIII-B; Fig. 5) |
| 慣性量測單元(IMU) | time-synchronized IMU (model not reported) | 方法輸入 | 未標示 | feeds ROVIO visual-inertial odometry | (Reijgwart et al., 2020, Sec. VIII-B; Fig. 5) |
| GNSS 接收器 | RTK-GNSS system (model not reported) | 參考或真值量測 | 未標示 | attached to the MAV; used for trajectory evaluation only | (Reijgwart et al., 2020, Sec. VIII-B1; Fig. 5) |
| 相機 | monocular camera (model not reported) | 方法輸入 | 未標示 | time-synchronized with IMU; feeds ROVIO visual-inertial odometry | (Reijgwart et al., 2020, Sec. VIII-B; Fig. 5) |
| 雙目相機 | VI-sensor (visual-inertial sensor of Nikolic et al. [36]) | 方法輸入 | indoor MAV industrial dataset of C-blox [26] | images used for DBoW2 loop closures and odometry in the indoor dataset | (Reijgwart et al., 2020, Sec. VIII-B2) |
| RGB-D 相機 | Intel RealSense D415 Depth Camera歸入:Intel RealSense D415 | 方法輸入 | indoor MAV industrial dataset of C-blox [26] | produces RGB-D data; indoor dataset processed with 5 cm voxels | (Reijgwart et al., 2020, Sec. VIII-B, VIII-B2) |
| 載具平台 | hexacopter MAV | 方法輸入 | 未標示 | carries 64-beam LiDAR, monocular camera, synchronized IMU and RTK-GNSS | (Reijgwart et al., 2020, Sec. VIII-B; Fig. 5) |
| 運算硬體 | Intel NUC Core i7-8650U | 執行運算平台 | 未標示 | carried by the MAV; all calculations on board; 800% maximum load (8 hyper-threads) | (Reijgwart et al., 2020, Abstract; Sec. VIII-B) |
| 運算硬體 | desktop CPU (model not reported) | 執行運算平台 | 未標示 | used to process the RGB-D industrial dataset | (Reijgwart et al., 2020, Sec. VIII-B2) |
作者報告的優勢與限制
優勢
- Globally consistent volumetric map computed on the MAV CPU; ATE RMSE 0.83, 0.59, 0.94 and 0.52 m on four 400 m flights, lower than its ROVIO input, VINS-Mono and LOAM (Table I, Sec. VIII-B1)
- In simulation, sub-sampling registration residuals down to about 5% showed no observable change in ESDF or trajectory RMSE while solver time fell linearly (Sec. VIII-A, Fig. 4)
- External loop closures removed gross map distortion in the RGB-D industrial dataset where submap registration alone could not (Sec. VIII-B2, Fig. 9)
限制
- Higher CPU load than the compared trajectory estimators (230 to 305% versus 125 to 159%), which the authors attribute to computing the volumetric map (Table I, Sec. VIII-B1)
- Wide-baseline loops cannot be corrected by submap registration alone and require an external place-recognition source (Sec. VIII-B2)
- Field evaluation uses RTK-GNSS trajectory error as a proxy for map quality; reconstruction error against reference geometry is reported only in simulation (Sec. VIII-A, VIII-B1)
- Submap poses are optimized in 4 DoF, relying on gravity-aligned odometry (Sec. III)
營建工程相關證據
論文未在施工現場測試。室外實驗在瑞士 Wangen an der Aare 的搜救訓練場,場景含倒塌結構瓦礫堆與穿越建築物的室內外轉換(Fig. 1、Sec. VIII-B1);室內 RGB-D 實驗在 ETH Zürich 的地下工業空間。場地幾何精度只以 RTK-GNSS 軌跡誤差作為代理指標。其 OS1-64 無人機資料集後來被 Blanco-Claraco, 2025 與 Millane et al., 2024 用作評估資料。
原文驗證環境:模擬、獨立參考量測
報告的性能數據
以下是原文作者報告的性能數值(author-reported results),不是本研究重新量測的結果。每張圖只並列同一個比較組(comparison group,同一張表、同一組實驗設定)內的方法;不同比較組之間的數值不可直接比較,也不構成排名。
本方法共出現在 2 個比較組,合計 10 筆紀錄。
Reijgwart et al., 2020 · Table I 本方法 8 筆
表格設定(擷取紀錄原文):Four MAV flights (about 400 m each) at the Wangen an der Aare search and rescue training site; RTK-GNSS ground truth; each system run 10 times and averages reported; 4-DoF alignment for visual-inertial systems and 6-DoF for LOAM; '-' means the estimator diverged (Reijgwart et al., 2020, Table I)
RMSE (m),Voxgraph MAV field dataset (this paper) · t0
只並列這張表在相同設定下報告的方法;以「本方法:」開頭者為本頁方法。失敗、未執行與未報告以標記呈現,不是 0。
按 Tab 進入圖表後,用上下方向鍵逐一瀏覽各類別,Esc 關閉提示框;也可開啟表格檢視閱讀全部數值。
這些是 Reijgwart et al., 2020 在此表設定下報告的數值(author-reported results),只能在同一個比較組內對照,不代表方法在其他資料或設定下的表現。
資料來源作者報告值(Reijgwart et al., 2020, Table I)
| 方法(原文寫法) | 報告值 | 出處 |
|---|---|---|
| ROVIO (odometry input to Voxgraph) | 4.55 m | (Reijgwart et al., 2020, Table I) |
| Voxgraph本方法原文提出 | 0.83 m | (Reijgwart et al., 2020, Table I) |
| Vins-Mono | 5.51 m | (Reijgwart et al., 2020, Table I) |
| Loam | 2.64 m | (Reijgwart et al., 2020, Table I) |
Reijgwart et al., 2020 · Text Sec.VIII-B1 本方法 2 筆
資料集與序列Voxgraph MAV field dataset (this paper) · t0 to t3
表格設定(擷取紀錄原文):Global optimization time over 10 trials of each of 4 trajectories; text gives only the maximum (Reijgwart et al., 2020, Text Sec.VIII-B1)
maximum runtime for global optimization,Voxgraph MAV field dataset (this paper) · t0 to t3
這張表在此指標與資料序列只列出本方法一筆,沒有可並列的其他方法,因此不畫圖,數值與出處見下表。這是 Reijgwart et al., 2020 在此表設定下報告的數值(author-reported results),不代表方法在其他資料或設定下的表現。
| 方法(原文寫法) | 報告值 | 出處 |
|---|---|---|
| Voxgraph本方法原文提出硬體:Intel NUC Core i7-8650U (on board) | 4 s僅報告範圍註記(擷取紀錄):other: approximate value ('~4 s' in Sec. VIII-B1; the abstract says less than 4 s) | (Reijgwart et al., 2020, Sec. VIII-B1; Fig. 8; Abstract (120x80 m map optimized in less than 4 s)) |
來源
Reijgwart et al., 2020
(2020)Voxgraph: Globally Consistent, Volumetric Mapping Using Signed Distance Function SubmapsIEEE Robotics and Automation Letters, 5(1):227-234
DOI 10.1109/lra.2019.2953859arXiv 2004.13154程式碼
同儕審查已出版已讀全文近十年查證後修正
相關版本
- 預印本:Voxgraph (arXiv v1, RA-L accepted version header) https://arxiv.org/abs/2004.13154
- 程式碼釋出:ethz-asl/voxgraph https://github.com/ethz-asl/voxgraph
- 前身方法:C-blox: A Scalable and Consistent TSDF-based Dense Mapping Approach (IROS 2018), cited as the authors' previous submap work [26] 10.1109/IROS.2018.8593427
程式碼:https://github.com/ethz-asl/voxgraph(授權:BSD-2-Clause (LICENSE file checked))。有公開程式碼不等於已被重現,也不代表目前版本與論文版本相同。