HIRI-ViT: Scaling Vision Transformer with High Resolution Inputs
Ting Yao, Yehao Li, Yingwei Pan, Tao Mei
TL;DR
HIRI-ViT introduces a principled five-stage CNN+ViT backbone designed for high-resolution inputs by decomposing CNN operations into two parallel branches that process high- and low-resolution features. The architecture features a High Resolution Stem and High Resolution Blocks, along with Inverted Residual Downsampling, BN/LN normalization choices, and a bi-directional EMA distillation strategy to stabilize training. Empirical results across ImageNet-1K, COCO, and ADE20K demonstrate state-of-the-art accuracy within practical computational budgets, notably achieving 84.3% Top-1 on ImageNet-1K at 448×448 with around 5 GFLOPs for the S variant and 85.7% for larger configurations at similar resolutions. The design generalizes to other backbones, underscoring the versatility of the two-branch, high-resolution scaling approach for CNN+ViT hybrids.
Abstract
The hybrid deep models of Vision Transformer (ViT) and Convolution Neural Network (CNN) have emerged as a powerful class of backbones for vision tasks. Scaling up the input resolution of such hybrid backbones naturally strengthes model capacity, but inevitably suffers from heavy computational cost that scales quadratically. Instead, we present a new hybrid backbone with HIgh-Resolution Inputs (namely HIRI-ViT), that upgrades prevalent four-stage ViT to five-stage ViT tailored for high-resolution inputs. HIRI-ViT is built upon the seminal idea of decomposing the typical CNN operations into two parallel CNN branches in a cost-efficient manner. One high-resolution branch directly takes primary high-resolution features as inputs, but uses less convolution operations. The other low-resolution branch first performs down-sampling and then utilizes more convolution operations over such low-resolution features. Experiments on both recognition task (ImageNet-1K dataset) and dense prediction tasks (COCO and ADE20K datasets) demonstrate the superiority of HIRI-ViT. More remarkably, under comparable computational cost ($\sim$5.0 GFLOPs), HIRI-ViT achieves to-date the best published Top-1 accuracy of 84.3% on ImageNet with 448$\times$448 inputs, which absolutely improves 83.4% of iFormer-S by 0.9% with 224$\times$224 inputs.
