Accurate state estimation (tracing) of Deformable Linear Objects (DLOs) such as cables is a critical challenge for data centers, manufacturing, construction, homes, and surgery, where precise cable management directly impacts operational safety and efficiency. However, resolving the state of multiple monochrome cables amid foreground and background clutter poses challenges due to occlusions, overlap, and ambiguous crossings. We present Two-way Routing And Cable Estimation (TRACE), which combines bi-directional cable tracing with interactive perception primitives-Divergence Push and Cluster Dilation-to actively resolve ambiguities. Evaluation with 110 physical experiments suggests that TRACE can increase the percentage of cable length correctly traced in complex scenarios (with up to 4 cables and 40 crossings) from ~60% with the strongest prior method, HANDLOOM 2.0, to ~90%, outperforming RT-DLO, Nano Banana Pro, and ChatGPT 5.2 as well. For a trial run on a workstation with an NVIDIA GeForce RTX 4090 GPU, the average computation time is 0.4 seconds per cable. Project website: https://trace-paper.github.io/.
Figures & tables
Fig. 2 : Overview of the TRACE architecture using the MANIP [ 23 ] framework. The system first processes the overhead RGB image to detect occlusions by comparing the TRACE-predicted cable state with object masks. If an occlusion is detected, a foreground object decluttering primitive is executed. Then, divergence points are identified via bi-directional tracing and classified as tangential crossings or cable clusters, activating the corresponding interactive perception primitive.
Fig. 3 : (Left): the Cable Distance Transform (CDT) , similar to a Voronoi diagram, maps each pixel value to the Euclidean distance between the pixel and the nearest cable (white). Ridgelines (red) are from the CDT using a Hessian-based filtering algorithm and highlight potential paths for robot trajectory planning while minimizing unintended cable interaction. Divergence points (circled) indicate ambiguous intersections, resolved through targeted push primitives. (Right): a Divergence Push primitive starts along a ridgeline at one end and moves through the divergence point to attempt separation at tangential crossings.
Fig. 4 : TRACE’s bi-directional tracing that identifies divergence points on 2 cables. (Left): cable traces initialized starting from 2 connectors of the same cable. (Right): overlapping cable traces are shown in orange; a divergence point in blue arises when the traces diverge into two non-overlapping paths.
Fig. 5 : Four examples; each column represents a different tier. The first row shows the initial scene with cluttered cables and external objects, the second row displays the initial predicted traces with occlusions, the third row shows the completed traces after object decluttering and interactive perception primitives.
Tier 1
Tier 2
Tier 3
Tier 4
# Cables
2
2
3
4
Avg # Crossings
12
15
30
40
# Tangential Crossings
2
3
3-4
4-5
# Foreground Objects
3-4
3-4
3-4
3-4
TABLE I : Tiers of complexity for evaluation
Primitive
Tier 1
Tier 2
Tier 3
Tier 4
Bimanual Decl.
1.19 (36.5)
1.53 (34.8)
1.33 (19.2)
1.27 (16.1)
Cluster Dilation
0.19 (5.8)
0.53 (12.1)
1.00 (14.4)
2.80 (35.6)
Divergence Push
1.88 (57.6)
2.33 (53.1)
4.60 (66.4)
3.80 (48.3)
Total
3.25 (100)
4.40 (100)
6.93 (100)
7.87 (100)
TABLE II : Average number of interactive perception primitives used per trial (over 60 trials), reported as count (% of total). Cluster dilation is used more as scene context increases.
Tier 1
Tier 2
Tier 3
Tier 4
TRACE (No Clutter)
99.1%
91.2%
94.2%
89.4%
TRACE (Background Clutter)
78.7%
77.3%
66.2%
65.3%
TABLE III : Average percent of cable length correctly traced (20 trials).
Fig. 6 : (Left) Without foreground clutter—Average percent of cable length correctly traced comparing TRACE and HANDLOOM 2.0 for 50 physical experiments. Tracing results for HANDLOOM 2.0 were sourced from MANIP [ 23 ] . (Right) With foreground clutter—Average percent of cable length correctly traced using TRACE with bimanual decluttering for 60 physical experiments. Vertical bars represent one standard deviation of the mean.
Fig. 7 : Colored cables are relatively easy to trace in contrast to monochrome cables: TRACE execution with background clutter, with colored cables (Top) and white cables (Bottom). (Top Left) Initial scene with colored cables and background clutter. (Top Right) Color-thresholded segmentation masks correctly trace 100% of cables. (Bottom Left) The initial configuration of white cables placed on a visually complex tabletop with distractor textures and objects. (Bottom Right) The reconstructed cable traces after bi-directional tracing and the application of interactive perception primitives, demonstrating robustness to spurious edges and background variability.
Fig. 8 : Baseline method RT-DLO performs poorly even on non-cluttered backgrounds, where cables are visually unambiguous. (a) On a cropped region, RT-DLO correctly traces only 48.2% of the total cable length while TRACE traces 100.0%; the red arrow marks the divergence point at which RT-DLO’s trace fails. (b) On a full cable scene, RT-DLO recovers only a fraction of the cable length: (left) original image, (center) RT-DLO trace overlaid on the original, and (right) the isolated RT-DLO result.
Method
Computation Time
Initial
Final
Improvement
RT-DLO
0.05s
57.1%
76.0%
18.9%
TRACE
0.40s
68.3%
97.5%
29.2%
Increase
19.6%
28.3%
TABLE IV : Average percentage of cable length correctly traced in small image crops, comparing TRACE and RT-DLO over 10 trials without background clutter.
Fig. 9 : Nano Banana Pro outputs on complex cable scenes, showing fragmented and topologically inconsistent traces compared to TRACE. (Left) Initial scene. (Right) Nano Banana Pro output. Note the hallucinated green cable appearing from the bottom of the right USB hub.
Method
Initial
Final
Nano Banana Pro
37.5%
34.8%
ChatGPT 5.2
19.5%
26.8%
TRACE
40.2%
89.3%
TABLE V : Average percentage of cable length correctly trace in full-scene images with foreground clutter, comparing TRACE to Nano Banana Pro and ChatGPT 5.2. Initial and Final correspond to images taken before and after the interactive perception primitives.
Fig. 10 : TRACE on 2 scenes with increased cable count (6 cables, left; 8 cables, right). Cables densely cover nearly the entire workspace, leaving minimal visible background and creating highly occluded scenes.
Dexterous manipulation of deformable objects demands continuous fingertip-level regulation of pressure, friction, and incipient slip. We study one of the most challenging cases: dexterous cable tracing, feeding a cable through the hand with repeated pinch-and-curl motions of the thumb and index finger. We introduce Touch2Trace, a tactile-driven imitation-learning system for this task, and provide, to our knowledge, the first systematic real-world characterization of how encoder pretraining, control rate, temporal context, and spatial resolution each shape policy performance. The winning learning recipe combines a tactile encoder pretrained for a custom 32 x 32 piezoresistive sensor (TacV5) via self-supervised learning with a lightweight transformer policy trained on teleoperated demonstrations via behavior cloning, deployed at 60 Hz on a Tesollo DG-5F hand. Tactile feedback without vision or explicit cable-state estimation significantly improves tracing performance versus a proprioception-only baseline: from 0.2 cm to 20.1 cm mean distance and 0% to 93% success rate, with zero-shot transfer to unseen cables and routing conditions. The results quantify the influence of key parameters in tactile-driven systems for reliable dexterous deformable object manipulation.
CableDex is a computer vision system that addresses the time-consuming and inaccurate manual measurement of cable length on industrial reels from a single photograph captured with a mobile phone. The system combines camera calibration, instance segmentation, pose estimation, and volumetric calculation to estimate the cable length across five different reel types and various cable sizes. This system is based on an instance segmentation model trained on 1,000 manually annotated images, achieving 99.5% mAP50 with an inference time of 5.66 ms per image. Evaluated on 75 reels across five reel types, the system achieves a MAPE of 4.90%, within the 10% error tolerance commonly accepted in industrial cable-reel measurement. The demonstration presents the end-to-end pipeline, from reel label scanning and image capture to segmentation and length estimation, through the mobile application.
Francisco Guillén, Ricardo Almeida, Bruno Silva +1
University of Beira Interior · NOVA-LINCS UBI, Portugal · COFICAB Portugal +1
Global communications rely on subsea cable infrastructure that remains vulnerable to damage from natural hazards and human activity. Autonomous underwater vehicles (AUVs) offer an efficient means to inspect long sections of exposed cable, but uncertainty in cable route maps, small cable diameters and partial burial makes continuous tracking a challenge. This paper presents a novel cable search and tracking method that leverages uncertain prior cable route maps. Graph-based optimisation continuously update the cable route to remain consistent with visual observations. Route uncertainty is constrained as a function of distance from observations using physics-based catenary models that account for cable parameters (i.e., lay depth, diameter, and density), bounding the search space to physically feasible regions and improving search efficiency. Cable detection is performed using a semi-supervised classifier running in real-time on-board a camera-equipped AUV. These detections both update the graph-based optimisation and enable visual cable tracking. When tracking is lost due to misclassification, burial or imperfect control, the bounded search space enables efficient recovery. The approach was demonstrated in field trials using the University of Southampton's Smarty200 AUV. The system successfully located the cable despite deliberate errors in it initial cable route map, updating this to be consistent with observations and using visual tracking to inspect up to 59% of a 120m test cable, with successful recovered after tracking loss.
Ibrahim Fadhil Djauhari, Adrian Bodenmann, Samuel Simmons +6
Southampton Marine & Maritime Institute, University of Southampton, UK · Sonardyne International Ltd., Yately, UK · Institute of Industrial Science, The University of Tokyo, Japan