PANet: Patch-Aware Network for Light Field Salient Object Detection.

Salient object detection is a process of extracting an object which is visually attractive from a single image or a video. As a powerful technique for automatic image or video segmentation, saliency detection has been focused and studied recently. In this paper, we propose a novel method for salient object detection without training or learning-based techniques. The proposed framework consists of two major steps, the generation of saliency map candidates and the selection of an optimal saliency map. To generate saliency map candidates, prior maps based on combinations of RGB color components are proposed. To select the optimal saliency map among the candidates, we propose a compactness measure, which evaluates the degree to which the generated saliency maps show objects. As a result, among recent works on saliency detection, our saliency detection method achieves the highest performance in terms of saliency detection.

4D light field data record the scene from multiple views, thus implicitly providing beneficial depth cue for salient object detection in challenging scenes. Existing light field salient object detection (LF SOD) methods usually use a large number of views to improve the detection accuracy. However, using so many views for LF SOD brings difficulties to its practical applications. Considering that adjacent views in a light field are actually with very similar contents, in this work, we propose defining a more efficient pattern of input views, i. e., key sparse views, and design a network to effectively explore the depth cue from sparse views for LF SOD. Specifically, we firstly introduce a low rank-based statistical analysis to the existing LF SOD datasets, which allows us to conclude a fixed yet universal pattern for our key sparse views, including the number and positions of views. These views maintain the sufficient depth cue, but greatly lower the number of views to be captured and processed, facilitating practical applications. Then, we propose an effective solution with a key Complementary and Discriminative Interaction Module (CDIM) for LF SOD from key sparse views, named CDINet. The CDINet follows a two-stream structure to extract the depth cue from the light field stream (i. e., sparse views) and the appearance cue from the RGB stream (i. e., center view), generating features and initial saliency maps for each stream. The CDIM is tailored for inter-stream interaction of both these features and saliency maps, using the depth cue to complement the missing salient regions in RGB stream and discriminate the background distraction, to enhance the final saliency map further. Extensive experiments on three LF multi-view datasets demonstrate that our CDINet not only outperforms the state-of-the-art 2D methods, but also achieves competitive performance as compared with the state-of-the-art 3D and 4D methods. The code and results of our method are available at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/GilbertRC/LFSOD-CDINet</uri> .

Nowadays, ship detection in sea-sky background is not only useful in maritime visual surveillance, but also helpful in maritime search and rescue. Since ships are salient objects in infrared images with sea-sky background, we present a novel and effective algorithm based on saliency for ship detection in this situation. Our algorithm adopts global saliency, local saliency and background prior to generate saliency maps. Ships are finally segmented in saliency maps. Our algorithm is compared with four classic salient object detection algorithms. And experimental results show our algorithm outperforms the other four algorithms in qualitative and quantitative terms. Keyword list: ship detection ; salient object detection ; infrared image ; sea - sky background . 1. INTRODUCTION Since ships are important vehicles for sea transportation, ship detection in sea-sky background is extensively used in maritime visual surveillance and reconnaissance, avoidance of ship collision accidents, maritime search and rescue, etc. Infrared imaging systems can almost work in any environment and all-weather conditions with its visual capacity in darkness and frog, which makes it a very suitable tool in this application. In recent years, ship detection in infrared images with sea-sky background attracts increasing attention. Many methods are proposed in this field, including image segmentation methods [1-2] and morphological methods [3]. However, due to complex sea-sky environment and large variation of ship sizes, these methods cannot solve the issue completely. And since ships are often salient objects in infrared images with sea-sky background, some researchers have recently tried salient object detection ideas used in color images [4-6]. And the paper is focused on using salient object detection methods to solve the issue. Salient objects are objects which stand out in the image and attract most people ¶VLPPHGLDWHDWWHQWLRQ7KHVWDQGDUGway to detect salient ob MHFWVLVILUVWO\XVLQJVDOLHQF\GHWHFWLRQPHWKRGVWRJHQHUDWHVDOLHQF\PDSVLQZKLFKDSL[HO¶VJUH\value is proportional to its degree of saliency and then segmenting salient objects in saliency maps. Many salient detection methods can be divided into three categories: local contrast methods, global rarity methods and other methods. In local contrast methods, regions which have high contrast with local neighbouring regions are regarded as salient regions. Itti et al. [7] decompose an image into several feature maps . The saliency in each feature map is measured by local center-surround difference in several scales and saliency of different feature maps are integrated to a final saliency

There are two main areas in saliency detection: fixation prediction and salient object detection. Researchers always use bottom-up low-level features and straightforward rules for salient object detection. However these rules are unreliable in common scenes. As a result, most salient object detection technologies can gain a fine performance in limited situation. While in a more complex scene (such as PASCAL-S dataset), they may miss the really wanted salient objects. Fixation prediction is a technology of predicting the regions which can attract human's attention. Most fixation prediction technologies are based on the discoveries of neuroscience and cognitive psychology. Their rules for fixation prediction more accord with human's sensory mechanism. Thus, fixation map can provide a more reliable salient priori. Based on above reasons, we propose a novel salient object detection method with fixation priori. We refine fixation map to gain a reliable priori, and conduct salient object detection based on the priori. We perform experiment on two datasets, and find that our method outperforms the comparative state-of-art salient object detection technologies.

Compared with RGB images, light field images contain more abundant visual information, which is helpful to accurately detect salient objects in complex scenes. However, most of the existing light field saliency detection methods use single light field data or do not fully consider the differences and complementarities between different light field data, resulting in insufficient multi-modal fusion. To address these issues, a multi-modal feature fusion network is proposed, which makes full use of the rich visual information in the light field images to realize the accurate saliency object detection. The proposed network consists of two parallel subnets, which are used to process the micro-lens image array and all-foucs image respectively. Then the light field refinement module is used to refine the feature map extracted from the micro-lens array stream, and finally the multi-modal feature fusion is realized by the light field attention module to predict saliency objects more accurately. In order to verify the effectiveness of proposed method, extensive comparison with several existing light field saliency detection algorithms is carried on both Lytro-Illum and LFSD datasets. Experimental results show that the proposed method is superior to others in all evaluation metrics on Lytro-Illum dataset, and has desired generalization abilities on LFSD dataset.

Salient Object Detection (SOD) has received much attention from the research community due to its increasing applications in the areas such as object detection and recognition, image editing, image and video compression, video summarization and so on. Most of the SOD methods are proposed in literature presuming that the digital images in which salient objects is to be detected, are free from any kind of artifact. SOD in the presence of noise has received much less attention from research community. In this paper, we study and analyze popular salient object detection methods in the presence of Gaussian, Salt and Pepper and Speckle Noises. Extensive experiments are performed on two publicly available SOD datasets viz. MSRA5K and DUT OMRON. The performance of the methods are evaluated in terms of Precision, Recall and F-measure. It is found that Context Aware Saliency Detection (CA) method gives maximum Precision while Graph Based Visual Saliency (GB) gives maximum Recall and F-measure on both the datasets in presence of any of the three noises.

Many existing salient object detection methods are dedicated to fusing features from different levels of a pre-trained convolutional neural network (CNN). However, these methods can easily lead to internal discontinuities within the salient objects because of unreasonable feature fusion strategies and short-range dependencies resulting from common convolution and pooling operations. In this paper, we propose a novel non-local duplicate pooling (NLDP) network to overcome these internal discontinuities. NLDP begins by removing the first few convolutional layers of a classic CNN, which have small receptive fields and require large amounts of calculation. A novel duplicate pooling module (DPM) is then used to generate richer and more detailed saliency maps. This is achieved by constructing a double-pathway that can integrating partial feature maps. Within the DPM, a non-local module (NLM) is used to obtain long-range dependencies. This enhances the internal continuities between the saliency maps. Comprehensive experiments conducted on six benchmark datasets have confirmed the increased effectiveness and detection speed of our method in relation to other salient object detection methods.

Effectively capturing the multi-scale, multi-channel, and boundary features of target images is beneficial for improving the accuracy of salient object detection. A multichannel feature enhancement module (MFEM) is constructed by concatenating two feature maps along the channel, performing convolution activation, dot product addition, and convolution operations. An edge feature enhancement module (EFEM) is constructed by performing an inverse attention mechanism and Gaussian-Laplace transform on the predicted map, channel-wise concatenation, and convolution operations with the feature submap. Multi-scale features are extracted using a SwinTransformer encoder and enhanced using the MFEM. The enhanced features are then fused using a cross-attention mechanism for multi-level features. The fused feature map, the high-frequency feature map obtained by Gaussian-Laplace transforming the predicted map, and the external edge features are input into the EFEM to obtain the salient object detection results. This results in a novel salient object detection model with multi-scale, multi-channel, and boundary feature enhancement: MfENet. Experimental results show that the Mean Absolute Error (MAE), S-measure and F-measure accuracies of our method on the HKU-IS dataset are 0.018,0.924 and 0.959 respectively. These results demonstrate the effectiveness of our method. Furthermore, this work highlights the importance of multi-scale and boundary awareness in enhancing salient object detection, and its contribution to the technical field relevant to the theme of this conference.

Given that existing salient object detection methods cannot effectively predict the fine contours of salient objects when extracting local or global contexts and features, we propose a novel contour self-compensated network (CSCNet) to generate a more accurate saliency map with complete contour. Unlike the common binary saliency detection, we reconstruct the salient object detection problem into a multi-classification problem of the background, the salient object, and the salient contour, where the salient contour is used as the third label for ground truth. Meanwhile, the image and its superpixel map are concatenated as the input of our network to add more edge information. Also, a penalty loss is proposed to restrict the spatial relationship between the background, objects, and their contours. Experimentally, we evaluate the proposed CSCNet on six benchmark datasets in both accuracy and efficiency and evaluate the attribute-based performance on the SOC dataset. Compared with 13 state-of-the-art algorithms, our CSCNet can detect salient objects more accurately and completely without adding too many convolutional layers and parameters.

Object detection is one of the hot research issues for the Unmanned Aerial Vehicle (UAV). The main problem of object detection is the inaccuracy of object’s location. Most of the current studies focus on classifying and locating objects, while ignore the influence of pixel-level object detection. By utilizing the Salient Object Detection (SOD) method, we may improve the accuracy of object’s location. In this work, we refer to the structure of U-net, and present a network structure called UA-net. In order to improve the result of small image processing, we use not only the commonly used bilinear interpolation method, but also try several other image interpolation methods. After trained and tested by PedCut2013_Segmentation dataset, the result shows that the UA-net can produce nice saliency map of pedestrians, and different interpolation methods have different quality evaluated by evaluation methods. After testing by UAV’s collected images, the saliency map can also be nice SOD results. These results show that UA-net is an applicable SOD structure for UAV to carry out the pedestrian recognition task.

A pooling-based feature pyramid network for salient object detection

Weakly supervised salient object detection (WSOD) methods endeavor to boost sparse labels to get more salient cues in various ways. Among them, an effective approach is using pseudo labels from multiple unsupervised self-learning methods, but inaccurate and inconsistent pseudo labels could ultimately lead to detection performance degradation. To tackle this problem, we develop a new multi-source WSOD framework, WBNet, that can effectively utilize pseudo-background (non-salient region) labels combined with scribble labels to obtain more accurate salient features. We first design a comprehensive salient pseudo-mask generator from multiple self-learning features. Then, we pioneer the exploration of generating salient pseudo-labels via point-prompted and box-prompted Segment Anything Models (SAM). Then, WBNet leverages a pixel-level Feature Aggregation Module (FAM), a mask-level Transformer-decoder (TFD), and an auxiliary Boundary Prediction Module (EPM) with a hybrid loss function to handle complex saliency detection tasks. Comprehensively evaluated with state-of-the-art methods on five widely used datasets, the proposed method significantly improves saliency detection performance. The code and results are publicly available at https://github.com/yiwangtz/WBNet.

Salient object detection (SOD) has achieved remarkable performance in well‐illuminated scenarios. However, in inevitable low‐light environments, SOD faces inherent challenges such as insufficient illumination, noise interference, and contrast degradation, which severely compromise the perceptual accuracy of visual models. To address these issues, we propose a novel Edge‐Guided Dual‐Stream Collaborative Network (EGDSNet), which enhances the integrity of salient objects through multi‐level feature interaction between edge detection and segmentation branches. Specifically, EGDSNet adopts a dual‐branch architecture: the edge detection branch integrates a Local Context Refinement (LCR) module and a Cross‐Modal Edge Refinement (CER) module to suppress noise while reinforcing boundary responses of targets. The segmentation branch employs a Global Feature Fusion (GFF) module and an Edge‐Guided Feature Enhancement (EFE) module to achieve complementary integration of global semantics and local details. The two branches interact via an edge‐guided attention mechanism, enabling saliency predictions to maintain structural integrity while attaining precise boundary localization. Additionally, the Residual Channel Attention (RCA) module is leveraged to further suppress noise and extract structural details from low‐level features. Comprehensive experiments on the LLI and SOD‐LL datasets demonstrate that our model outperforms state‐of‐the‐art methods in both quantitative metrics and qualitative visualizations, validating its superiority in low‐light SOD tasks.

We propose 3D salient object detection and segmented point cloud gridding methods to accelerate the real object-based full-color holographic system. The feasibility of the proposed methods is confirmed by experiments.

Due to the rapid development of deep learning, salient object detection has achieved promising results in recent years. However, how to construct a powerful saliency detection network to generate saliency maps with completely highlighted salient objects and effectively suppressed background noise still remains an open and challenging problem. In this paper, we propose a novel trifurcated cascaded refinement network (TCRNet) to explore multi-level feature fusion and global information representation. Specifically, all the side-output features from the backbone network are divided into three branches (i.e., global information, deep information and shallow information) according to feature similarities, and then the global contexts, semantic knowledge and fined details respectively generated by the three branches are integrated in a cascaded refinement way. This refinement strategy aims to guide the feature learning of important regions and suppress background noises. Moreover, we propose a cross-level feature fusion (CFF) module to fuse multi-level similar features within a same branch by exploring their interrelationship, thus capturing the important semantic information and structure details. To this end, the complementarity of similar features is utilized to refine feature at each level by sharing an encoded spatial weight map. Besides, we design a context-aware feature learning (CFL) module to capture global contexts in a single layer by taking account of both single-feature representation and multi-feature interaction, thus providing important location information of salient objects. Extensive experiments on five benchmarks are conducted to demonstrate that the proposed network TCRNet performs favorably against 20 state-of-the-art salient object detection methods on five benchmark datasets, indicating the effectiveness and superiority of our method.