Revisiting Model Stitching In the Foundation Model Era

Fuente: arXiv
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Auteurs principaux: Mai, Zheda, Zhang, Ke, Wang, Fu-En, Wang, Zixiao Ken, Chen, Albert Y. C., Xia, Lu, Sun, Min, Chao, Wei-Lun, Kuo, Cheng-Hao
Format: Preprint
Publié: 2026
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author Mai, Zheda
Zhang, Ke
Wang, Fu-En
Wang, Zixiao Ken
Chen, Albert Y. C.
Xia, Lu
Sun, Min
Chao, Wei-Lun
Kuo, Cheng-Hao
author_facet Mai, Zheda
Zhang, Ke
Wang, Fu-En
Wang, Zixiao Ken
Chen, Albert Y. C.
Xia, Lu
Sun, Min
Chao, Wei-Lun
Kuo, Cheng-Hao
contents Model stitching, connecting early layers of one model (source) to later layers of another (target) via a light stitch layer, has served as a probe of representational compatibility. Prior work finds that models trained on the same dataset remain stitchable (negligible accuracy drop) despite different initializations or objectives. We revisit stitching for Vision Foundation Models (VFMs) that vary in objectives, data, and modality mix (e.g., CLIP, DINOv2, SigLIP 2) and ask: Are heterogeneous VFMs stitchable? We introduce a systematic protocol spanning the stitch points, stitch layer families, training losses, and downstream tasks. Three findings emerge. (1) Stitch layer training matters: conventional approaches that match the intermediate features at the stitch point or optimize the task loss end-to-end struggle to retain accuracy, especially at shallow stitch points. (2) With a simple feature-matching loss at the target model's penultimate layer, heterogeneous VFMs become reliably stitchable across vision tasks. (3) For deep stitch points, the stitched model can surpass either constituent model at only a small inference overhead (for the stitch layer). Building on these findings, we further propose the VFM Stitch Tree (VST), which shares early layers across VFMs while retaining their later layers, yielding a controllable accuracy-latency trade-off for multimodal LLMs that often leverage multiple VFMs. Taken together, our study elevates stitching from a diagnostic probe to a practical recipe for integrating complementary VFM strengths and pinpointing where their representations align or diverge.
format Preprint
id arxiv_https___arxiv_org_abs_2603_12433
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Revisiting Model Stitching In the Foundation Model Era
Mai, Zheda
Zhang, Ke
Wang, Fu-En
Wang, Zixiao Ken
Chen, Albert Y. C.
Xia, Lu
Sun, Min
Chao, Wei-Lun
Kuo, Cheng-Hao
Computer Vision and Pattern Recognition
Artificial Intelligence
Machine Learning
Model stitching, connecting early layers of one model (source) to later layers of another (target) via a light stitch layer, has served as a probe of representational compatibility. Prior work finds that models trained on the same dataset remain stitchable (negligible accuracy drop) despite different initializations or objectives. We revisit stitching for Vision Foundation Models (VFMs) that vary in objectives, data, and modality mix (e.g., CLIP, DINOv2, SigLIP 2) and ask: Are heterogeneous VFMs stitchable? We introduce a systematic protocol spanning the stitch points, stitch layer families, training losses, and downstream tasks. Three findings emerge. (1) Stitch layer training matters: conventional approaches that match the intermediate features at the stitch point or optimize the task loss end-to-end struggle to retain accuracy, especially at shallow stitch points. (2) With a simple feature-matching loss at the target model's penultimate layer, heterogeneous VFMs become reliably stitchable across vision tasks. (3) For deep stitch points, the stitched model can surpass either constituent model at only a small inference overhead (for the stitch layer). Building on these findings, we further propose the VFM Stitch Tree (VST), which shares early layers across VFMs while retaining their later layers, yielding a controllable accuracy-latency trade-off for multimodal LLMs that often leverage multiple VFMs. Taken together, our study elevates stitching from a diagnostic probe to a practical recipe for integrating complementary VFM strengths and pinpointing where their representations align or diverge.
title Revisiting Model Stitching In the Foundation Model Era
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2603.12433