473 research outputs found
Latent Degradation Representation Constraint for Single Image Deraining
Since rain streaks show a variety of shapes and directions, learning the
degradation representation is extremely challenging for single image deraining.
Existing methods are mainly targeted at designing complicated modules to
implicitly learn latent degradation representation from coupled rainy images.
This way, it is hard to decouple the content-independent degradation
representation due to the lack of explicit constraint, resulting in over- or
under-enhancement problems. To tackle this issue, we propose a novel Latent
Degradation Representation Constraint Network (LDRCNet) that consists of
Direction-Aware Encoder (DAEncoder), UNet Deraining Network, and Multi-Scale
Interaction Block (MSIBlock). Specifically, the DAEncoder is proposed to
adaptively extract latent degradation representation by using the deformable
convolutions to exploit the direction consistency of rain streaks. Next, a
constraint loss is introduced to explicitly constraint the degradation
representation learning during training. Last, we propose an MSIBlock to fuse
with the learned degradation representation and decoder features of the
deraining network for adaptive information interaction, which enables the
deraining network to remove various complicated rainy patterns and reconstruct
image details. Experimental results on synthetic and real datasets demonstrate
that our method achieves new state-of-the-art performance
Assessing the Impacts of Species Composition on the Accuracy of Mapping Chlorophyll Content in Heterogeneous Ecosystems
Chlorophyll is an essential vegetation pigment influencing plant photosynthesis rate and growth conditions. Remote sensing images have been widely used for mapping vegetation chlorophyll content in different ecosystems (e.g., farmlands, forests, grasslands, and wetlands) for evaluating vegetation growth status and productivity of these ecosystems. Compared to farmlands and forests that are more homogeneous in terms of species composition, grasslands and wetlands are more heterogeneous with highly mixed species (e.g., various grass, forb, and shrub species). Different species contribute differently to the ecosystem services, thus, monitoring species-specific chlorophyll content is critical for better understanding their growth status, evaluating ecosystem functions, and supporting ecosystem management (e.g., control invasive species). However, previous studies in mapping chlorophyll content in heterogeneous ecosystems have rarely estimated species-specific chlorophyll content, which was partially due to the limited spatial resolution of remote sensing images commonly used in the past few decades for recognizing different species. In addition, many previous studies have used one universal model built with data of all species for mapping chlorophyll of the entire study area, which did not fully consider the impacts of species composition on the accuracy of chlorophyll estimation (i.e., establishing species-specific chlorophyll estimation models may generate higher accuracy). In this study, helicopter-acquired high-spatial resolution hyperspectral images were acquired for species classification and species-specific chlorophyll content estimation. Four estimation models, including a universal linear regression (LR) model (i.e., built with data of all species), species-specific LR models (i.e., built with data of each species, respectively), a universal random forest regression (RFR) model, and species-specific RFR models, were compared to determine their performance in mapping chlorophyll and to evaluate the impacts of species composition. The results show that species-specific models performed better than the universal models, especially for species with fewer samples in the dataset. The best performed species-specific models were then used to generate species-specific chlorophyll content maps using the species classification results. Impacts of species composition on the retrieval of chlorophyll content were further assessed to support future chlorophyll mapping in heterogeneous ecosystems and ecosystem management
Dual-Path Coupled Image Deraining Network via Spatial-Frequency Interaction
Transformers have recently emerged as a significant force in the field of
image deraining. Existing image deraining methods utilize extensive research on
self-attention. Though showcasing impressive results, they tend to neglect
critical frequency information, as self-attention is generally less adept at
capturing high-frequency details. To overcome this shortcoming, we have
developed an innovative Dual-Path Coupled Deraining Network (DPCNet) that
integrates information from both spatial and frequency domains through Spatial
Feature Extraction Block (SFEBlock) and Frequency Feature Extraction Block
(FFEBlock). We have further introduced an effective Adaptive Fusion Module
(AFM) for the dual-path feature aggregation. Extensive experiments on six
public deraining benchmarks and downstream vision tasks have demonstrated that
our proposed method not only outperforms the existing state-of-the-art
deraining method but also achieves visually pleasuring results with excellent
robustness on downstream vision tasks
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