CoRL 2026 (Spotlight)

DeTacDual-branch Decoupling of Texture and Force Signals in Vision-Based Tactile Sensors

Zhirui Zhang1,2Yunkai Tang1,2Jiahang Li1,2Fan Fei1,2Jinnuo Zhang3Kairan Ding1,2Jieji Ren3,†Yandong Guo2Boxin Shi1,†

1 Peking University2 AI2 Robotics3 Shanghai Jiao Tong University

Peking UniversityAI² RoboticsShanghai Jiao Tong University

† Corresponding authors

Abstract

Vision-based tactile sensors enable fine-grained perception for dexterous robotic manipulation, but current marker-based designs tightly couple surface texture and contact force signals within a single observation. Existing data-driven decoupling methods rely on serial mask-based inpainting, which suffers from mask-sizing dilemmas caused by physical indentation effects, error retention, and lack of real paired data for supervision. To address these challenges, we propose DeTac, a novel dual-branch generative framework that concurrently extracts clean shading and marker images from a single mixed tactile image. DeTac leverages full-image synthesis to naturally bypass mask dependency and introduces a cross-branch synergistic optimization that enables mutual supervision, effectively preventing error retention. Furthermore, we construct a strictly aligned, real-world paired tactile dataset using custom hardware to provide high-quality supervision. Extensive experiments demonstrate that DeTac achieves state-of-the-art decoupling accuracy, significantly facilitating downstream surface reconstruction and force estimation tasks while exhibiting cross-sensor generalization.

Motivation

Embedded markers enable force estimation but obscure surface texture and introduce indentation artifacts in the surrounding elastomer. Serial inpainting pipelines face a mask-sizing dilemma: small masks leave artifacts, while large masks discard useful texture. Localization errors also propagate into restoration, and synthetic training pairs miss real physical effects.

DeTac jointly recovers shading and markers through full-image generation and cross-branch supervision, trained on aligned real-world pairs.

DeTac concurrently recovers clean shading and marker images from a single mixed tactile observation.
DeTac concurrently recovers clean shading and marker images from a single mixed tactile observation.

Method

A dual-branch generative framework jointly restores surface shading and extracts markers for tactile perception.

Overall pipeline of DeTac: shading restoration and marker extraction with cross-branch synergistic optimization.
Overall pipeline of DeTac: shading restoration and marker extraction with cross-branch synergistic optimization.

Dual-branch prediction. A conditional diffusion model restores the full shading image, while a lightweight convolutional network extracts a soft marker image from the same observation. This avoids predefined inpainting masks and preserves both surface geometry and marker displacement information.

Cross-branch optimization. A surrounding indentation loss focuses restoration on marker neighborhoods. A change-marker consistency loss links the restored appearance changes to marker locations, allowing the two branches to guide one another.

Dataset

1,080 paired tactile samples · 54 objects · 20 contact poses per object

Hardware design and data acquisition setup for collecting aligned shading and mixed tactile observations.
Hardware design and data acquisition setup for collecting aligned shading and mixed tactile observations.

We capture aligned shading and mixed images on the same sensor before and after marker fabrication. A dedicated mechanical structure keeps contact poses repeatable, providing real paired supervision that includes marker-induced indentation effects.

54 paired tactile examples in 12 rows and 9 columns. Odd rows show mixed images with markers; even rows show the corresponding shading images directly below.
One paired example from each of the 54 texture units. Odd rows show mixed tactile images; even rows show the corresponding marker-free shading images directly below. Click to enlarge.

Results

Shading restoration

DeTac suppresses marker traces and surrounding indentation artifacts while preserving fine surface texture. Restoring the full image produces shading closer to the ground truth; the ablation study confirms the importance of supervision around marker neighborhoods.

Qualitative comparison of shading restoration results.
Qualitative comparison of shading restoration results.

Marker extraction

DeTac recovers complete marker patterns with precise boundaries for displacement tracking. Restoration-induced appearance changes help refine marker locations, and the ablation results support the benefit of cross-branch supervision.

Qualitative comparison of marker extraction results.
Qualitative comparison of marker extraction results.

Cross-sensor generalization

DeTac restores high-quality shading under different internal illumination and on a different sensor type, demonstrating cross-sensor generalization beyond the appearance of the training sensor.

Generalization results across different internal illuminations and sensor types.
Generalization results across different internal illuminations and sensor types.

Force estimation

The extracted markers preserve contact-induced displacement for force estimation. More precise marker localization translates into more accurate force estimates, with the lowest mean force error among the evaluated inputs.

Force estimation results using extracted markers.
Force estimation results using extracted markers.

Surface reconstruction

Restored shading reduces marker-induced geometric distortions in photometric stereo reconstruction. The resulting meshes better capture the contact surface, consistent with the lower reconstruction errors reported in the paper.

Surface reconstruction from raw mixed images and DeTac-restored shading images.

Fabric classification

Using the same classifier trained on markerless tactile images, DeTac-restored shading improves fabric classification without retraining the classifier. Classification relies solely on tactile signals, with overall accuracy increasing from 50.0% to 84.4%.

Robot fabric classification using raw mixed images (left) and DeTac-restored shading images (right).

BibTeX

@misc{zhang2026detacdualbranchdecouplingtexture,
      title={DeTac: Dual-branch Decoupling of Texture and Force Signals in Vision-Based Tactile Sensors},
      author={Zhirui Zhang and Yunkai Tang and Jiahang Li and Fan Fei and Jinnuo Zhang and Kairan Ding and Jieji Ren and Yandong Guo and Boxin Shi},
      year={2026},
      eprint={2610.16463},
      archivePrefix={arXiv},
      primaryClass={cs.RO},
      url={https://arxiv.org/abs/2610.16463},
}

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