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Zhang Y, Chen F, Peng Z, Zou W, Nie M, Zhang C. Two-way focal stack fusion for light field saliency detection. APPLIED OPTICS 2023; 62:9057-9065. [PMID: 38108742 DOI: 10.1364/ao.500999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 11/02/2023] [Indexed: 12/19/2023]
Abstract
To improve the accuracy of saliency detection in challenging scenes such as small objects, multiple objects, and blur, we propose a light field saliency detection method via two-way focal stack fusion. The first way extracts latent depth features by calculating the transmittance of the focal stack to avoid the interference of out-of-focus regions. The second way analyzes the focused distribution and calculates the background probability of the slice, which can distinguish the foreground from the background. Extracting the potential cues of the focal stack through the two different ways can improve saliency detection in complex scenes. Finally, a multi-layer cellular automaton optimizer is utilized to incorporate compactness, focus, center prior, and depth features to obtain the final salient result. Comparison and ablation experiments are performed to verify the effectiveness of the proposed method. Experimental results prove that the proposed method demonstrates effectiveness in challenging scenarios and outperforms the state-of-the-art methods. They also verify that the depth and focus cues of the focal stack can enhance the performance of previous methods.
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Zhang Y, Chen F, Peng Z, Zou W, Zhang C. Exploring Focus and Depth-Induced Saliency Detection for Light Field. ENTROPY (BASEL, SWITZERLAND) 2023; 25:1336. [PMID: 37761635 PMCID: PMC10530224 DOI: 10.3390/e25091336] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/30/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023]
Abstract
An abundance of features in the light field has been demonstrated to be useful for saliency detection in complex scenes. However, bottom-up saliency detection models are limited in their ability to explore light field features. In this paper, we propose a light field saliency detection method that focuses on depth-induced saliency, which can more deeply explore the interactions between different cues. First, we localize a rough saliency region based on the compactness of color and depth. Then, the relationships among depth, focus, and salient objects are carefully investigated, and the focus cue of the focal stack is used to highlight the foreground objects. Meanwhile, the depth cue is utilized to refine the coarse salient objects. Furthermore, considering the consistency of color smoothing and depth space, an optimization model referred to as color and depth-induced cellular automata is improved to increase the accuracy of saliency maps. Finally, to avoid interference of redundant information, the mean absolute error is chosen as the indicator of the filter to obtain the best results. The experimental results on three public light field datasets show that the proposed method performs favorably against the state-of-the-art conventional light field saliency detection approaches and even light field saliency detection approaches based on deep learning.
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Affiliation(s)
- Yani Zhang
- School of Electrical and Electronic Engineering, Chongqing University of Technology, Chongqing 400054, China; (Y.Z.); (Z.P.); (C.Z.)
| | - Fen Chen
- School of Electrical and Electronic Engineering, Chongqing University of Technology, Chongqing 400054, China; (Y.Z.); (Z.P.); (C.Z.)
- Faculty of Information Science and Engineering, Ningbo University, No. 818, Ningbo 315211, China;
| | - Zongju Peng
- School of Electrical and Electronic Engineering, Chongqing University of Technology, Chongqing 400054, China; (Y.Z.); (Z.P.); (C.Z.)
- Faculty of Information Science and Engineering, Ningbo University, No. 818, Ningbo 315211, China;
| | - Wenhui Zou
- Faculty of Information Science and Engineering, Ningbo University, No. 818, Ningbo 315211, China;
| | - Changhe Zhang
- School of Electrical and Electronic Engineering, Chongqing University of Technology, Chongqing 400054, China; (Y.Z.); (Z.P.); (C.Z.)
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Duan F, Wu Y, Guan H, Wu C. Saliency Detection of Light Field Images by Fusing Focus Degree and GrabCut. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22197411. [PMID: 36236507 PMCID: PMC9573000 DOI: 10.3390/s22197411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/17/2022] [Accepted: 09/27/2022] [Indexed: 06/12/2023]
Abstract
In the light field image saliency detection task, redundant cues are introduced due to computational methods. Inevitably, it leads to the inaccurate boundary segmentation of detection results and the problem of the chain block effect. To tackle this issue, we propose a method for salient object detection (SOD) in light field images that fuses focus and GrabCut. The method improves the light field focus calculation based on the spatial domain by performing secondary blurring processing on the focus image and effectively suppresses the focus information of out-of-focus areas in different focus images. Aiming at the redundancy of focus cues generated by multiple foreground images, we use the optimal single foreground image to generate focus cues. In addition, aiming at the fusion of various cues in the light field in complex scenes, the GrabCut algorithm is combined with the focus cue to guide the generation of color cues, which realizes the automatic saliency target segmentation of the image foreground. Extensive experiments are conducted on the light field dataset to demonstrate that our algorithm can effectively segment the salient target area and background area under the light field image, and the outline of the salient object is clear. Compared with the traditional GrabCut algorithm, the focus degree is used instead of artificial Interactively initialize GrabCut to achieve automatic saliency segmentation.
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Affiliation(s)
- Fuzhou Duan
- Engineering Research Center of Spatial Information Technology, MOE, Capital Normal University, 105 West Third Ring North Road, Haidian District, Beijing 100048, China
- Key Lab of 3D Information Acquisition and Application, MOE, Capital Normal University, 105 West Third Ring North Road, Haidian District, Beijing 100048, China
| | - Yanyan Wu
- Engineering Research Center of Spatial Information Technology, MOE, Capital Normal University, 105 West Third Ring North Road, Haidian District, Beijing 100048, China
- Key Lab of 3D Information Acquisition and Application, MOE, Capital Normal University, 105 West Third Ring North Road, Haidian District, Beijing 100048, China
| | - Hongliang Guan
- Engineering Research Center of Spatial Information Technology, MOE, Capital Normal University, 105 West Third Ring North Road, Haidian District, Beijing 100048, China
- Key Lab of 3D Information Acquisition and Application, MOE, Capital Normal University, 105 West Third Ring North Road, Haidian District, Beijing 100048, China
- Academy for Multidisciplinary Studies, Capital Normal University, 105 West Third Ring North Road, Haidian District, Beijing 100048, China
| | - Chenbo Wu
- Engineering Research Center of Spatial Information Technology, MOE, Capital Normal University, 105 West Third Ring North Road, Haidian District, Beijing 100048, China
- Key Lab of 3D Information Acquisition and Application, MOE, Capital Normal University, 105 West Third Ring North Road, Haidian District, Beijing 100048, China
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CSA-Net: Deep Cross-Complementary Self Attention and Modality-Specific Preservation for Saliency Detection. Neural Process Lett 2022. [DOI: 10.1007/s11063-022-10875-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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High Edge-Quality Light-Field Salient Object Detection Using Convolutional Neural Network. ELECTRONICS 2022. [DOI: 10.3390/electronics11071054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The detection result of current light-field salient object detection methods suffers from loss of edge details, which significantly limits the performance of subsequent computer vision tasks. To solve this problem, we propose a novel convolutional neural network to accurately detect salient objects, by digging effective edge information from light-field data. In particular, our method is divided into four steps. Firstly, the network extracts multi-level saliency features from light-field data. Secondly, edge features are extracted from low-level saliency features and optimized by ground-truth guidance. Then, to sufficiently leverage high-level saliency features and edge features, the network hierarchically fuses them in a complementary manner. Finally, spatial correlations between different levels of fused features are considered to detect salient objects. Our method can accurately locate salient objects with exquisite edge details, by extracting clear edge information and accurate saliency information and fully fusing them. We conduct extensive evaluations on three widely used benchmark datasets. The experimental results demonstrate the effectiveness of our method, and it is superior to eight state-of-the-art methods.
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Zhou T, Fan DP, Cheng MM, Shen J, Shao L. RGB-D salient object detection: A survey. COMPUTATIONAL VISUAL MEDIA 2021; 7:37-69. [PMID: 33432275 PMCID: PMC7788385 DOI: 10.1007/s41095-020-0199-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/07/2020] [Indexed: 06/12/2023]
Abstract
Salient object detection, which simulates human visual perception in locating the most significant object(s) in a scene, has been widely applied to various computer vision tasks. Now, the advent of depth sensors means that depth maps can easily be captured; this additional spatial information can boost the performance of salient object detection. Although various RGB-D based salient object detection models with promising performance have been proposed over the past several years, an in-depth understanding of these models and the challenges in this field remains lacking. In this paper, we provide a comprehensive survey of RGB-D based salient object detection models from various perspectives, and review related benchmark datasets in detail. Further, as light fields can also provide depth maps, we review salient object detection models and popular benchmark datasets from this domain too. Moreover, to investigate the ability of existing models to detect salient objects, we have carried out a comprehensive attribute-based evaluation of several representative RGB-D based salient object detection models. Finally, we discuss several challenges and open directions of RGB-D based salient object detection for future research. All collected models, benchmark datasets, datasets constructed for attribute-based evaluation, and related code are publicly available at https://github.com/taozh2017/RGBD-SODsurvey.
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Affiliation(s)
- Tao Zhou
- Inception Institute of Artificial Intelligence (IIAI), Abu Dhabi, United Arab Emirates
| | - Deng-Ping Fan
- Inception Institute of Artificial Intelligence (IIAI), Abu Dhabi, United Arab Emirates
| | | | - Jianbing Shen
- Inception Institute of Artificial Intelligence (IIAI), Abu Dhabi, United Arab Emirates
| | - Ling Shao
- Inception Institute of Artificial Intelligence (IIAI), Abu Dhabi, United Arab Emirates
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Zhang M, Ji W, Piao Y, Li J, Zhang Y, Xu S, Lu H. LFNet: Light Field Fusion Network for Salient Object Detection. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2020; 29:6276-6287. [PMID: 32365027 DOI: 10.1109/tip.2020.2990341] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work, we propose a novel light field fusion network-LFNet, a CNNs-based light field saliency model using 4D light field data containing abundant spatial and contextual information. The proposed method can reliably locate and identify salient objects even in a complex scene. Our LFNet contains a light field refinement module (LFRM) and a light field integration module (LFIM) which can fully refine and integrate focusness, depths and objectness cues from light field image. The LFRM learns the light field residual between light field and RGB images for refining features with useful light field cues, and then the LFIM weights each refined light field feature and learns spatial correlation between them to predict saliency maps. Our method can take full advantage of light field information and achieve excellent performance especially in complex scenes, e.g., similar foreground and background, multiple or transparent objects and low-contrast environment. Experiments show our method outperforms the state-of-the-art 2D, 3D and 4D methods across three light field datasets.
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Piao Y, Li X, Zhang M, Yu J, Lu H. Saliency Detection via Depth-induced Cellular Automata on Light Field. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2019; 29:1879-1889. [PMID: 31613755 DOI: 10.1109/tip.2019.2942434] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Incorrect saliency detection such as false alarms and missed alarms may lead to potentially severe consequences in various application areas. Effective separation of salient objects in complex scenes is a major challenge in saliency detection. In this paper, we propose a new method for saliency detection on light field to improve the saliency detection in challenging scenes. We construct an object-guided depth map, which acts as an inducer to efficiently incorporate the relations among light field cues, by using abundant light field cues. Furthermore, we enforce spatial consistency by constructing an optimization model, named Depth-induced Cellular Automata (DCA), in which the saliency value of each superpixel is updated by exploiting the intrinsic relevance of its similar regions. Additionally, the proposed DCA model enables inaccurate saliency maps to achieve a high level of accuracy. We analyze our approach on one publicly available dataset. Experiments show the proposed method is robust to a wide range of challenging scenes and outperforms the state-of-the-art 2D/3D/4D (light-field) saliency detection approaches.
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