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Journal of ZheJiang University (Engineering Science)  2026, Vol. 60 Issue (9): 1934-1941    DOI: 10.3785/j.issn.1008-973X.2026.09.010
    
Data-efficient lightweight model for real-time semantic segmentation
Hongwei LI(),Jianyang DING,Zhilei CHAI*()
School of Artificial Intelligence and Computer Science, Jiangnan University, Wuxi 214122, China
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Abstract  

An efficient lightweight model, U-SAM, was proposed aiming at the requirement for lightweight, high-precision and high-speed performance in real-time semantic segmentation task on edge device. A multi-scale dilated convolution fusion module was designed in the encoder stage based on an improved U-Net architecture in order to enhance feature representation capability and significantly reduce computational complexity. Channel attention and pixel attention mechanism were introduced in the decoder stage in order to achieve effective modeling of key feature information and cross-scale fusion. Self-attention mechanism and convolution operation were integrated in the bottleneck section in order to efficiently capture long-range dependency and improve the generalization capability of the model. Experiments on the small-scale CamVid dataset demonstrated that U-SAM required only about 1.3×106 parameters in order to achieve segmentation accuracy of 70.2% mIoU, with inference speed reaching 69 frame/s. The overall performance of U-SAM is significantly superior to several mainstream lightweight real-time semantic segmentation models, providing a high-performance solution for real-time semantic segmentation application in resource-constrained scenarios such as autonomous driving, intelligent surveillance and remote sensing satellite.



Key wordssemantic segmentation      real-time performance      lightweight model      small-scale dataset      dilated convolution      attention mechanism     
Received: 29 November 2025      Published: 20 July 2026
CLC:  TP 394  
Fund:  国家自然科学基金资助项目(61972180);中央高校基本科研业务费资助项目(JUSRP202501072);无锡市科技发展基金资助项目(K20241027).
Corresponding Authors: Zhilei CHAI     E-mail: 6233114016@stu.jiangnan.edu.cn;zlchai@jiangnan.edu.cn
Cite this article:

Hongwei LI,Jianyang DING,Zhilei CHAI. Data-efficient lightweight model for real-time semantic segmentation. Journal of ZheJiang University (Engineering Science), 2026, 60(9): 1934-1941.

URL:

https://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2026.09.010     OR     https://www.zjujournals.com/eng/Y2026/V60/I9/1934


用于实时语义分割的数据高效轻量模型

针对边缘设备实时语义分割任务对轻量化、高精度与高速度的要求,提出高效的轻量级模型U-SAM. 该模型基于改进的U-Net架构,在编码阶段设计多尺度空洞卷积融合模块,以增强特征表达能力并显著降低计算复杂度. 在解码阶段引入通道注意力与像素注意力机制,实现关键特征信息的有效建模与跨尺度融合. 在瓶颈部分融合自注意力机制与卷积操作,高效捕捉长距离依赖关系并提升模型泛化能力. 在小规模数据集CamVid上的实验表明,U-SAM仅需约1.3×106的参数量,即可达到70.2%的mIoU分割精度,推理速度达到69帧/s. U-SAM的综合性能显著优于多种主流轻量级实时语义分割模型,为自动驾驶、智能监控、遥感卫星等资源受限场景下的实时语义分割应用提供了高性能解决方案.


关键词: 语义分割,  实时性,  轻量模型,  小规模数据集,  空洞卷积,  注意力机制 
Fig.1 Overall architecture of U-SAM
Fig.2 Architecture of Encoder
Fig.3 Architecture of Decoder
Fig.4 Multi-head self-attention mechanism
Fig.5 Multi-scale fusion module
模型Np/106Dice/%IoU/%
Unet++[15]9.287.7880.72
Unet[16]31.288.6081.58
Attention UNet[17]31.488.6681.68
ConvUNeXt[18]3.589.8183.19
U-Lite[14]0.990.3983.63
U-SAM(本文方法)0.5190.2483.70
1.3290.7983.90
Tab.1 Performance comparison of different models on ISIC2018 dataset
类别模型输入尺寸主干网络GPUFLOPs/109Np/106v/(帧·s?1)mIoU/%
大型模型SegNet[19]360×480VGG-16Titan X106.5929.506055.6
DFANet[20]720×960XceptionTitan X7.8012064.7
ICNet[21]720×960PSPNet-50Titan X26.502867.1
MLFNet[22]720×960ResNet-34Titan XP13.035769.0
MGSeg[23]736×960ResNet-18Titan XP13.3012772.7
轻量模型ENet[24]360×480NoTitan X2.120.369651.3
NDNet[25]360×480NoTitan X1.160.507857.2
DABNet[26]360×480No1080 Ti3.490.7613666.4
FDDWNet[27]360×480No2080 Ti4.580.807966.9
LARNet[28]360×480No2080Ti0.9520467.1
BiLevelNet[29]360×480No30900.7068.2
FBSNet[8]360×480No2080 Ti7.970.6212068.9
MSCFNet[30]360×480NoTitan XP1.1511069.3
LETNet[31]360×480No30904.840.9520070.5
U-SAM(本文方法)360×480No4060 Ti4.431.326970.2
720×960No4060 Ti17.791.324470.4
Tab.2 Performance comparison of different models on CamVid dataset
模型v/(帧·s?1)Mp/106Ec/(W·h)
FDDWNet[27]412414.01
FBSNet[8]224115.25
LETNet[31]284384.32
U-SAM(本文方法)693423.84
Tab.3 Performance comparison under same environment
Fig.6 Visualization result of different network on CamVid dataset
Fig.7 Partial enlargement of visualization result
Fig.8 Feature visualization result of ISIC2018
模块结构Np/106v/(帧·s?1)mIoU/%
编码Dilation=[2,3,5,9]1.386769.3
Dilation=[2,3,5]1.327068.8
解码No CA+PA1.2911064.6
瓶颈No Transformer+CNN1.137765.9
Only Transformer1.267166.6
Only CNN1.197366.3
U-SAM[2,3,5,9]+[2,3,5]、
CA+PA、Transformer+CNN
1.326970.2
Tab.4 Ablation study of each module on CamVid dataset
Fig.9 Application of U-SAM image segmentation in inkjet printing
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