Change detection (CD) is a critical task for monitoring the spatiotemporal evolution of the Earth’s surface. Recently, due to the advantages of reduced annotation cost and improved labeling efficiency, weakly supervised change detection (WSCD) has attracted increasing attention. However, existing WSCD methods encounter several critical challenges, including incomplete activation of class activation maps (CAMs), interference from noisy pseudo-labels during training, and instability in change recognition caused by illumination and environmental variations. To address these issues, we propose a prototype-aware learning and dual-view regularization network (PDRNet) for image-level WSCD. Specifically, to address the issue of incomplete activation caused by the tendency of CAM to focus excessively on locally discriminative regions, PDRNet devises a prototype-aware module (PAM), which captures stable category prototypes and refines CAM quality by reactivating hierarchical features. Furthermore, to mitigate the network’s sensitivity to noisy pseudo-labels, a dual-view regularization strategy (DRS) is designed to partition pseudo-labels into clean and noisy regions. Region-specific regularization is subsequently employed to improve the robustness of the model against noisy supervision. Finally, to enhance the capability of identifying changed regions, PDRNet constructs a wavelet-based change enhancement module (WCEM) to decompose bi-temporal features into multiple frequency bands. This facilitates the comprehensive utilization of low-frequency structural semantics and high-frequency texture details. Extensive experiments and analyses conducted on three publicly available CD datasets yield the superiority of PDRNet.

Semantic change detection (CD) not only helps pinpoint the locations where changes occur, but also identifies the specific types of changes in land cover and land use. Currently, the mainstream approach for semantic CD (SCD) decomposes the task into semantic segmentation (SS) and CD tasks. Although these methods have achieved good results, they do not consider the incentive effect of task correlation on the entire model. Given this issue, this article further elucidates the SCD task through the lens of multitask learning theory and proposes a semantic change detection network based on boundary detection and task interaction (BT-SCD). In BT-SCD, the boundary detection (BD) task is introduced to enhance the correlation between the SS task and the CD task in SCD, thereby promoting positive reinforcement between SS and CD tasks. Furthermore, to enhance the communication of information between the SS and CD tasks, the pixel-level interaction strategy and the logit-level interaction strategy are proposed. Finally, to fully capture the temporal change information of the bitemporal features and eliminate their temporal dependency, a bidirectional change feature extraction module is proposed. Extensive experimental results on three commonly used datasets and a nonagriculturalization dataset (NAFZ) show that our BT-SCD achieves state-of-the-art performance. The code is available at https://github.com/TangYJ1229/BT-SCD.

Change detection has consistently been a prominent direction in the field of remote sensing. As for high resolution remote sensing images (HRRSI), despite the notable achievements of change detection models, the majority of their impressive performance stems from their large scale architecture or computational requirements. To strike a balance between efficiency and efficacy, a lightweight change detection method based on transformer and feature interaction (LiFTNet) has been proposed. LiFTNet utilizes an efficient backbone, EfficientNet-B4, which is a lightweight network architecture. To fully utilize the information in features with limited model parameters, a multi scale feature interaction module (MSFI) is proposed to aggregate the shallow features and the deep features. As the network has a shallow depth, the semantic information contained in the features is incomplete. To enhance the extraction of semantic information with minimal increases in computational overhead, a lightweight semantic transformer is adopted in the model. A series of experiments indicate the superior performance of LiFTNet over other state-of-the-art (SOTA) methods, showing both efficiency and effectiveness.

Change detection is a prominent research direction in the field of remote sensing image processing. However, most current change detection methods focus solely on detecting changes without being able to differentiate the types of changes, such as “appear” or “disappear” of objects. Accurate detection of change types is of great significance in guiding decision-making processes. To address this issue, this article introduces the object fine-grained change detection (OFCD) task and proposes a method based on frequency decoupling interaction (FDINet). Specifically, in order to enhance the model’s ability to detect change types and improve its robustness to temporal information, a temporal exchange framework is designed. Additionally, to better capture spatial–temporal correlation in bi-temporal features, a wavelet interaction module (WIM) is proposed. This module utilizes wavelet transform for frequency decoupling, separating features into different components based on their frequency magnitudes. Then the module applies different interaction methods according to the characteristics of these frequency components. Finally, to aggregate complementary information from different-scale feature maps and enhance the representational capabilities of the extracted features, a feature aggregation and upsampling module (FAUM) is adopted. A series of experiments show the superiority of FDINet over most state-of-the-art methods, achieving good results on three different datasets.

In recent years, deep learning has demonstrated its transformative potential in the field of hyperspectral image (HSI) processing but is notoriously data-hungry. However, wanting to obtain a large number of labels is labor-intensive and time-consuming. To reduce the dependence of the model on the label samples while maintaining high detection accuracy, a hyperspectral image change detection algorithm based on active learning strategy (ALCD) is proposed. First, the active learning strategy is employed to select high-value labeled samples from the test set as additional training data, gradually enhancing the model’s detection performance. Second, the self-attention module MOAT is introduced to enable effective interaction of local information during the feature extraction process and enhance the network’s feature expression capability. Then, the feature interaction and the mixing block are used to blend the features of the bitemporal images, so that the feature distribution of the bitemporal images is more similar, which is conducive to subsequent feature extraction and classification. Experiments on two HIS datasets show that the proposed method can obtain better change detection results than the four comparison algorithms.

Erosion gullies are a prominent manifestation of soil erosion. And timely and accurate acquisition of relevant data about erosion gullies plays a crucial role in their management and control. Currently, there is a deficiency in automation within the majority of erosion gully detection methods. The post-classification comparison method using semantic segmentation techniques and the direct change detection method often struggle to ensure high accuracy. Therefore, a end to end change detection method based on deep supervised and feature interaction (DSFNet) is proposed for erosion gullies in this paper. To achieve accurate localization of erosion gully semantic information, DSFNet employs a deep supervision strategy to constrain the semantics of erosion gullies. Furthermore, in order to extract representative features related to erosion gullies and improve the detection accuracy of the model, a feature interaction and upsampling module (IUModule) is employed. Experimental results show that DSFNet exhibits better performance on erosion gully dataset.

With the development of remote sensing technology, high-resolution (HR) remote sensing optical images have gradually become the main source of change detection data. Albeit, the change detection for HR remote sensing images still faces challenges: 1) in complex scenes, a region contains a large amount of semantic information, which makes it difficult to accurately locate the boundaries between different semantics in the feature maps and 2) due to the inability to maintain consistent conditions such as light, weather, and other factors when acquiring bitemporal images, confounding factors such as the style of bitemporal data that are not related to change detection can cause detection difficulties. Therefore, a change detection method based on feature interaction and multitask learning (FMCD) is proposed in this article. To improve the ability to detect changes in complex scenes, FMCD models the context information of features through a multilevel feature interaction module, so as to obtain representative features, and to improve the sensitivity of the model to changes, the interaction between two temporal features is realized through the mix attention block (MAB). In addition, to eliminate the influence of weather and other factors, FMCD adopts a multitask learning strategy, takes domain adaptation as an auxiliary task, and maps the features of bitemporal images to the same space through the feature relationship adaptation module (FRAM) and feature distribution adaptation module (FDAM). Experiments on three datasets show that the proposed method is superior to other state-of-the-art methods.

1Change detection has always been a hot research area in the field of hyperspectral image (HSI) processing. However, in the current change detection methods, most of them need to train a large number of labeled data to extract representative features. In this paper, a hyperspectral change detection method based on multi-scale three-dimensional (3D) convolution autoencoder network (M3CAN) is proposed. Firstly, the multi-scale 3D convolution block is adopted in the autoencoder which can extract effective spectral-spatial joint features of HSIs. Then, the autoencoder is pre-trained to obtain the trained encoder as the feature extractor. Finally, the feature maps of the bi-temporal data are obtained by the encoder and then sent to the Softmax classifier to obtain the final change detection result. In this paper, unsupervised training of autoencoder is combined with supervised training of classifier. Therefore, only a small amount of data is needed to complete the training, which avoids the difficulty of requiring many labeled training data. Experiments show that the proposed method has good results on two datasets.

Transparent objects with unique visual properties often make depth cameras fail to scan their reflective and refractive surfaces. Recent studies on depth completion of transparent objects have leveraged a linear system based on the geometric constraints to predict the missing depth, which is hard to be employed in an end-to-end framework and achieve joint optimization. In this paper, we propose DepthGrasp - a deep learning approach for depth completion of transparent objects from a raw RGB-D image. More specifically, we use a generative adversarial network, which utilizes the generator to complete the depth maps by predicting the missing or inaccurate depth values, and use discriminator to guide the completed depth maps against the groundtruth. In the generator, we devise spectral residual blocks (SRB) with spectral normalization for network stability, and residual block to pass the attention map in order to capture the structure information and distinguish the geometric shape of transparent objects. In the discriminator, we use a patch-based convolutional network to adapt the data distributions of the predicted depth maps according to groundtruth. Extensive experiments conducted on ClearGrasp dataset show the effectiveness and generalization of the DepthGrasp for depth completion, and the deployed robotic picking system makes significant improvement on the performance of grasping on transparent objects.

Erasure coding is widely used in the distributed storage systems due to its significant storage efficiency compared with replication at the same fault tolerance level. However, erasure coding introduces high cross-rack traffic since (1) repairing a single failed data block needs to read other available blocks from multiple nodes and (2) updating a data block triggers parity updates for all parity blocks. In order to alleviate the impact of these traffic on the performance of erasure coding, many works concentrate on designing new transmission schemes to increase bandwidth utilization among multiple storage nodes but they don't actually reduce network traffic. With the emergence of programmable network devices, the concept of in-network computation has been proposed. The key idea is to offload compute operations onto intermediate network devices. Inspired by this idea, we propose XORInc, a framework that utilizes programmable network devices to XOR data flows from multiple storage nodes so that XORInc can effectively reduce network traffic (especially the cross-rack traffic) and eliminate network bottleneck. Under XORInc, we design two new transmission schemes, NetRepair and NetUpdate, to optimize the repair and update operations, respectively. We implement XORInc based on HDFS-RAID and SDN to simulate an in-network computation framework. Experiments on a local testbed show that NetRepair reduces the repair time to almost the same as the normal read time and reduces the network traffic by up to 41%, meanwhile, NetUpdate reduces the update time and traffic by up to 74% and 30%, respectively.

A divide and conquer deformable contour method is presented with an initial inside closed contour being divided into arbitrary segments, and these segments are allowed to deform separately preserving the segments' connectivity. A maximum area threshold, A/sub max/, is used to stop these outward contour segments' marching. Clear and blur contour points are then identified to partition the whole contour into clear and blur segments. A bi-directional searching method is then recursively applied to each blur segment including a search for contour-within-contour segment to reach a final close contour. Further improvements are provided by a model based searching algorithm. It is a two-step process with step 1 being a linked contour model matching operation where landmarks are extracted, and step 2 being a posteriori probability model matching and correction operation where large error segments are fine tuned to obtain the final results. The experiments include ultrasound images of pig heart, MRI brain images, MRI knee images having complex shapes with or without gaps, and inhomogeneous interior and contour region brightness distributions. These experiments have shown that the method has the capability of moving a contour into the neighboring region of the desired boundary by overcoming inhomogeneous interior, and by adapting each contour segment searching operation to different local difficulties, through a contour partition and repartition scheme in searching for a final solution.

A two-step model based approach to a contour extraction problem is developed to provide a solution to more challenging contour extraction problems of biomedical images. A biomedical contour image is initially processed by a deformable contour method to obtain a first order approximation of the contour. The two-step model includes a linked contour model and a posteriori probability model. Initially, the output contour from the deformable contour method is matched against the linked contour model for both model detection and corresponding landmark contour points identification. Segments obtained from these landmarks are matched for errors. Larger error are then passed on to a regionalized a posteriori probability model for further fine tuning to obtain a final result. Experiments on both MR brain images are most encouraging.