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To overcome the adverse effects of noise and shadow regions on target detection in side-scan sonar images, more precisely, it is difficult to accurately detect targets, a target detection technology based on a multi-region optimal selection strategy of spectral clustering combined with the entropy weight method is proposed in this study. First, the cluster numbers for spectral clustering are set in advance based on prior knowledge, and the pixels of the sonar image are clustered into several different regions. Second, the invariable features of translation, rotation and scaling up that each region is extracted and used to construct the feature criterion matrix for the multiple regions. Last, the entropy weight method is used to calculate the weights of each feature and the comprehensive weighted score of each region for this feature criterion matrix to obtain the final target region. Experimental results show that the proposed method can effectively overcome the adverse effects of noise and shadow regions in side-scan sonar images, but also achieve the selection of optimal target region among multiple regions after image clustering, thus verifying the feasibility and effectiveness of the proposed method in this study.

Heatmap-based cattle pose estimation methods suffer from high network complexity and low detection speed. Addressing the issue of cattle pose estimation for complex scenarios without heatmaps, an end-to-end, lightweight cattle pose estimation network utilizing a reparameterized network and an attention mechanism is proposed to improve the overall network performance. The EfficientRepBiPAN (Efficient Representation Bi-Directional Progressive Attention Network) module, incorporated into the neck network, adeptly captures target features across various scales while also mitigating model redundancy. Moreover, a 3D parameterless SimAM (Similarity-based Attention Mechanism) attention mechanism is introduced into the backbone to capture richer directional and positional feature information. We constructed 6846 images to evaluate the performance of the model. The experimental results demonstrate that the proposed network outperforms the baseline method with a 4.3% increase in average accuracy at OKS = 0.5 on the test set. The proposed network reduces the number of floating-point computations by 1.0 G and the number of parameters by 0.16 M. Through comparative evaluations with heatmap and regression-based models such as HRNet, HigherHRNet, DEKR, DEKRv2, and YOLOv5-pose, our method improves AP0.5 by at least 0.4%, reduces the number of parameters by at least 0.4%, and decreases the amount of computation by at least 1.0 GFLOPs, achieving a harmonious balance between accuracy and efficiency. This method can serve as a theoretical reference for estimating cattle poses in various livestock industries. [ABSTRACT FROM AUTHOR]

In response to the need for smaller and lighter power supply equipment, there has been a push towards higher power density in current power electronic converters. This development aligns well with the requirements of photovoltaic grid‐connected inverters. Among various passive filters utilized in these inverters, the LCL filter stands out as a popular choice. Nevertheless, it should be noted that traditional LCL filters have limited core utilization and exhibit significant redundancy. In view of the above problems, this paper proposes a magnetic integrated passive filter based on ripple transfer technology and carries out volume optimization design. Compared to the conventional LCL filter, the magnetic integrated passive filter offers a reduction in size and weight while preserving its capability to ripples attenuate. Finally, a laboratory prototype with a rated power of 2 kW is built to verify the effectiveness of the proposed magnetic integrated passive filter. [ABSTRACT FROM AUTHOR]

High-order transverse-mode lasers have important potential application value in many fields. To address the current issue of the limited controllability of modes in high-order transverse-mode lasers, we have designed a self-matching photonic lantern (SMPL). The SMPL is formed by introducing a few-mode fiber into the input fiber array of the traditional photonic lantern. The parameters of the few-mode fiber match those of the tapered few-mode port of the SMPL; thus, it can transmit high-order modes in a closed loop. The designed SMPL exhibits dual-band multiplexing characteristics at 980/1550 nm, manifesting specifically as high-order mode selectivity excitation at 980 nm and mode preservation at 1550 nm. These characteristics have been validated through simulation and preliminary experiments. The SMPL is designed for constructing all few-mode fiber ring cavity lasers, enabling the pumping of the 980 nm fundamental mode to high-order modes and the transmission of multiple high-order transverse-mode lasers at 1550 nm in a closed loop. The proposed SMPL extends the configuration and functionality of the photonic lantern family, offering a flexible and effective approach to facilitate the generation of multiple high-order transverse-mode lasers. The SMPL combined with fiber laser systems could effectively broaden communication channels and enhance communication bandwidth. It also holds significant value in optical sensing, high-resolution imaging, laser micro-processing, and other fields. [ABSTRACT FROM AUTHOR]

Inert passivation can significantly enhance the upconversion intensity of lanthanide ion doped nanocrystals, especially in the heavily doped cases. In this paper, we revealed that, besides the well-known enhancement of intensity, the inert shell can also influence the upconversion color of Er3+/Yb3+ heavily doped nanocrystals in two opposite directions. The mechanisms of the effects of inert shell passivation are discussed based on the spectroscopic observations. The quantum yields of upconversion nanocrystals were estimated for the core-only and core–shell nanocrystals. This work provides guidelines for designing upconversion nanomaterials with bright emission and desired color and thus can further help them to be applied in multichannel imaging, display devices, and phototherapy. [ABSTRACT FROM AUTHOR]