Organizations: School of CyberScience and Technology, Sun Yat-sen University, Shenzhen Campus, Shenzhen 518107, China. · the College of Computing and Data Science, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798. · School of Computer Science (National Pilot Software Engineering School), Beijing University of Posts and Telecommunications, Beijing 100876, China.
Discovering camouflaged objects is a challenging task in computer vision due to the high similarity between camouflaged objects and their surroundings. While the problem of camouflaged object detection over sequential video frames has received increasing attention, the scale and diversity of existing video camouflaged object detection (VCOD) datasets are greatly limited, which hinders the deeper analysis and broader evaluation of recent deep learning-based algorithms with data-hungry training strategy. To break this bottleneck, in this paper, we construct CAMotion, a high-quality benchmark covers a wide range of species for camouflaged moving object detection in the wild. CAMotion comprises various sequences with multiple challenging attributes such as uncertain edge, occlusion, motion blur, and shape complexity, etc. The sequence annotation details and statistical distribution are presented from various perspectives, allowing CAMotion to provide in-depth analyses on the camouflaged object's motion characteristics in different challenging scenarios. Additionally, we conduct a comprehensive evaluation of existing SOTA models on CAMotion, and discuss the major challenges in VCOD task. The benchmark is available at https://www.camotion.focuslab.net.cn, we hope that our CAMotion can lead to further advancements in the research community.
Figures & tables
Fig. 1: Examples of our CAMotion dataset with corresponding pixel-level annotations. The first and third rows contain original images; the second and last rows contain corresponding pixel-wise ground truth annotations.
Dataset
Year
Publication
Type
#Img.
#Ann. Img.
#Species
Bbox. GT
Mask GT
CAD [ 5 ]
2016
ECCV
Video
839
181
6
✗
✓
CHAMELEON [ 2 ]
2018
-
Image
76
76
27 ∗
✗
✓
CAMO [ 1 ]
2019
CVIU
Image
2,500
1,250
97 ∗
✗
✓
COD10K [ 3 ]
2020
CVPR
Image
10,000
5,066
69
✓
✓
MoCA [ 7 ]
2020
ACCV
Video
37,250
7,617
67
✓
✗
CAMO++ [ 8 ]
2021
TIP
Image
5,500
5,500
93
✓
✓
TABLE I: Statistics of camouflage datasets. ∗ indicates that the #Species is not reported in the original paper and is counted by us.
Fig. 2: Dataset features and species examples from CAMotion dataset. (a) Taxonomic structure of CAMotion. (b) The scale and species comparison between existing COD dataset and CAMotion. (c) The attributes distribution in frame-level and sequence-level. (d) Examples of the Ray-finned Fish class in CAMotion. Please zoom in for details.
Fig. 3: Visualization of the challenging attributes in CAMotion. Best viewed in color and zoomed in for details.
Fig. 4: Examples of refined initial annotations. White denotes unchanged regions; red and green indicate over-annotated and previously missing regions in the original annotations, respectively. Please zoom in for details.
Attr
Description
MO
Multiple Objects : image contains at least two objects.
BO
Big Object : ratio between object area and image area ≥ 0.15.
SO
Small Object : ratio between object area and image area ≤ 0.02.
UE
Uncertain Edge : the foreground and background areas around object have similar colors and textures.
OC
Occlusion : the object is partially occluded.
SC
Shape Complexity : object contains thin parts (e.g., animal foot).
TABLE II: List and description of the eight attributes that characterize videos in CAMotion.
Fig. 5: Statistics for CAMotion dataset. (a) Object sizes distribution. (b) The distribution of video durations. (c) Global/local contrast distribution. (d) Motion statistics of the camouflaged objects.
Methods
Publications
CAMotion
MoCA-Mask
Sα↑
Fβw↑
Eϕm↑
M↓
mDic↑
mIoU↑
Sα↑
Fβw↑
Eϕm↑
M↓
mDic↑
mIoU↑
MGL-R [ 15 ]
CVPR’21
0.542
0.176
0.604
0.078
0.195
0.129
0.493
0.034
0.519
0.059
0.048
0.033
PFNet [ 80 ]
CVPR’21
0.669
0.425
0.780
0.050
0.463
0.359
0.558
0.142
0.633
0.026
0.172
0.118
UGTR [ 81 ]
ICCV’21
0.687
0.403
0.720
0.048
0.440
0.342
0.493
0.048
0.459
0.088
0.078
0.049
SegMaR [ 76 ]
CVPR’22
0.645
0.377
0.695
0.049
0.402
0.311
0.542
0.129
0.544
0.024
0.139
0.093
ZoomNet [ 13 ]
CVPR’22
0.675
0.440
0.693
0.044
0.456
0.365
0.582
0.201
0.682
0.026
0.236
0.197
TABLE III: Quantitative comparison with 18 cutting-edge methods on CAMotion and MoCA-Mask testing datasets. Notes ↑/↓ denotes the higher/lower the better, and the best and second best are bolded and underlined for highlighting, respectively. ‡ indicates that the first-frame annotation is removed during both training and testing for fair comparison.
TABLE IV: Sα and M results for cross-dataset generalization. The selected ZoomNeXt is trained on one (rows) dataset and tested on all datasets (columns). “Self” refers to training and testing on the same dataset (same as diagonal), and “Mean Others” refers to averaging performance on all except self.
Fig. 6: Visual comparison with state-of-the-art methods in challenging scenarios, i.e. , shape complexity (Rows 1-4) and occlusion (Rows 5-8). Please zoom in for details.
Fig. 7: Optical flow and depth properties visualization. Each group comprises the original image, pixel-level annotation, optical flow, and depth map. Please zoom in for details.
Fig. 12: Detailed classification of the total frame count across different species. Please zoom in for details.
Fig. 13: Examples of our CAMotion dataset with corresponding pixel-level annotations, optical flow and depth map. Each group is arranged as the original image, optical flow, depth map and pixel-level annotation. Please zoom in for details.
Fig. 14: Visualization of the challenging attributes in CAMotion. Best viewed in color and zoom in for details.
Fig. 15: Examples of fine-tuning initial annotations. The white color denotes unchanged areas, while the red and green indicate the original and refined annotations, respectively. Please zoom in for details.
Fig. 16: Visualization of the bounding box annotations in CAMotion. Best viewed in color and zoom in for details.
Fig. 17: Visual comparison with state-of-the-art methods on CAMotion. Please zoom in for details.
Figure 26
Fig. 20: Failure cases on both HGINet and ZoomNeXt. Please zoom in for details.
Video Camouflaged Object Detection (VCOD) is currently constrained by the scarcity of challenging benchmarks and the limited robustness of models against erratic motion dynamics. Existing methods often struggle with Motion-Induced Appearance Instability and Temporal Feature Misalignment caused by complex motion scenarios. To address the data bottleneck, we present YUV20K, a pixel-level annoated complexity-driven VCOD benchmark. Comprising 24,295 annotated frames across 91 scenes and 47 kinds of species, it specifically targets challenging scenarios like large-displacement motion, camera motion and other 4 types scenarios. On the methodological front, we propose a novel framework featuring two key modules: Motion Feature Stabilization (MFS) and Trajectory-Aware Alignment (TAA). The MFS module utilizes frame-agnostic Semantic Basis Primitives to stablize features, while the TAA module leverages trajectory-guided deformable sampling to ensure precise temporal alignment. Extensive experiments demonstrate that our method significantly outperforms state-of-the-art competitors on existing datasets and establishes a new baseline on the challenging YUV20K. Notably, our framework exhibits superior cross-domain generalization and robustness when confronting complex spatiotemporal scenarios. Our code and dataset will be available at https://github.com/K1NSA/YUV20K
Yiyu Liu, Shuo Ye, Chao Hao +1
Yiyu Liu, Shuo Ye, Chao Hao and Zitong Yu are with the Department of Computer Science, Great Bay University, Dongguan, Guangdong, 523000, China
Camouflaged object detection has improved substantially, but most standard benchmarks evaluate models only on clean images. This is not realistic because real cameras often capture blur, sensor noise, weather effects, and compression artifacts. We present COD10K-C, a corruption robustness benchmark based on COD10K. It includes 8 corruption types and 5 severity levels, giving 40 conditions and 81,040 evaluation pairs in total. We evaluate three popular camouflaged object detection models, SINet-v2, PFNet, and ZoomNet, as well as a lightweight model called RobustCODLite. All models show clear performance drops on corrupted images. Motion blur and Gaussian blur cause the largest drops, with SINet-v2 losing 18.5 Dice points under motion blur. Brightness and fog are less harmful. RobustCODLite uses corruption augmentation, a frequency-prior branch, and an uncertainty-consistency loss. It retains 92.3% of its clean Dice score under corruption, compared with 87.7% for SINet-v2, 84.8% for ZoomNet, and 84.1% for PFNet. On the hardest corruptions, RobustCODLite matches or outperforms models that perform better on clean data. We will release the COD10K-C GitHub repository to support future research in robust camouflaged object detection.
Camouflaged object detection (COD) aims to segment objects that are visually concealed in their surroundings and has attracted increasing attention in recent years. However, most existing COD methods are developed under a closed-world assumption, where each input image is assumed to contain a camouflaged object. This assumption ignores realistic scenarios with pure backgrounds or non-camouflaged objects, causing existing models to produce severe false positives when deployed in open-world environments. To address this limitation, we propose OPC16K, a large-scale benchmark for realistic COD. OPC16K contains 16,245 images from 14 sources and is carefully organized into camouflaged-object images, pure background images, and non-camouflaged-object images, enabling comprehensive evaluation of both segmentation quality and negative-sample rejection. Based on this benchmark, we further propose OPCNet, a presence-aware camouflage network that reformulates COD from a pure segmentation task into a joint problem of object localization and camouflage existence reasoning. Specifically, OPCNet introduces hierarchical existence reasoning to distinguish CO, BG, and NOCOD scenarios, similarity-aware camouflage relation modeling to capture foreground-background camouflage cues, and existence-aware feature refinement to regulate segmentation features with existence predictions. Extensive experiments on OPC16K demonstrate that OPCNet achieves superior performance under the proposed realistic COD evaluation protocol, significantly reducing false positives on negative samples while maintaining accurate camouflaged-object segmentation. Code and dataset will be released at https://github.com/2231122/OPCOD.
Huafeng Chen, Yueming Lyu, Chenyang Si +3
School of Intelligence Science and Technology, Nanjing University · Department of Computing, Imperial College London