reconstruction algorithm
Optical diffraction neural networks assisted computational ghost imaging through dynamic scattering media
Li, Yue-Gang, Zheng, Ze, Wang, Jun-jie, He, Ming, Fan, Jianping, Xiao, Tailong, Zeng, Guihua
Ghost imaging leverages a single-pixel detector with no spatial resolution to acquire object echo intensity signals, which are correlated with illumination patterns to reconstruct an image. This architecture inherently mitigates scattering interference between the object and the detector but sensitive to scattering between the light source and the object. To address this challenge, we propose an optical diffraction neural networks (ODNNs) assisted ghost imaging method for imaging through dynamic scattering media. In our scheme, a set of fixed ODNNs, trained on simulated datasets, is incorporated into the experimental optical path to actively correct random distortions induced by dynamic scattering media. Experimental validation using rotating single-layer and double-layer ground glass confirms the feasibility and effectiveness of our approach. Furthermore, our scheme can also be combined with physics-prior-based reconstruction algorithms, enabling high-quality imaging under undersampled conditions. This work demonstrates a novel strategy for imaging through dynamic scattering media, which can be extended to other imaging systems.
- North America > United States > Oklahoma > Beaver County (0.05)
- Asia > China > Shanghai > Shanghai (0.05)
- Asia > China > Anhui Province > Hefei (0.04)
- Asia > China > Beijing > Beijing (0.04)
- North America > United States > Illinois > Cook County > Chicago (0.04)
- Europe > Spain > Catalonia > Barcelona Province > Barcelona (0.04)
Hierarchical Spatial-Frequency Aggregation for Spectral Deconvolution Imaging
Lv, Tao, Zhou, Daoming, Huang, Chenglong, Zi, Chongde, Chen, Linsen, Cao, Xun
Abstract--Computational spectral imaging (CSI) achieves real-time hyperspectral imaging through co-designed optics and algorithms, but typical CSI methods suffer from a bulky footprint and limited fidelity. Therefore, Spectral Deconvolution imaging (SDI) methods based on PSF engineering have been proposed to achieve high-fidelity compact CSI design recently. However, the composite convolution-integration operations of SDI render the normal-equation coefficient matrix scene-dependent, which hampers the efficient exploitation of imaging priors and poses challenges for accurate reconstruction. T o tackle the inherent data-dependent operators in SDI, we introduce a Hierarchical Spatial-Spectral Aggregation Unfolding Framework (HSF AUF). By decomposing subproblems and projecting them into the frequency domain, HSF AUF transforms nonlinear processes into linear mappings, thereby enabling efficient solutions. Furthermore, to integrate spatial-spectral priors during iterative refinement, we propose a Spatial-Frequency Aggregation Transformer (SF A T), which explicitly aggregates information across spatial and frequency domains. By integrating SF A T into HSF AUF, we develop a Transformer-based deep unfolding method, Hierarchical Spatial-Frequency Aggregation Unfolding Transformer (HSF AUT), to solve the inverse problem of SDI. Systematic simulated and real experiments show that HSF AUT surpasses SOT A methods with cheaper memory and computational costs, while exhibiting optimal performance on different SDI systems. Hyperspectral images (HSIs) capture high-resolution spectra at each spatial location, providing a spectral representation that reveals the rich characteristics of various components and materials, offering a high-dimensional visual capability beyond human vision. Thus, HSIs have found widespread applications in fields such as medical diagnosis [1], remote sensing [2], [3], agricultural inspection [4], and machine vision [5]. However, early hyperspectral imaging techniques were constrained by 2D sensor, requiring spatial or spectral scanning that sacrificed temporal resolution for spectral resolution, restricting their use in dynamic scenes. To overcome these challenges, computational spectral imaging (CSI) [6] integrates optics, electronics, and algorithms to enhance imaging capabilities [7], [8], [9].
- North America > United States > Texas > Travis County > Austin (0.14)
- Asia > China > Jiangsu Province > Nanjing (0.05)
- Asia > China > Beijing > Beijing (0.04)
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- Health & Medicine > Diagnostic Medicine (0.66)
- Education > Educational Setting > Higher Education (0.46)
- Information Technology > Sensing and Signal Processing > Image Processing (1.00)
- Information Technology > Artificial Intelligence > Vision (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning (0.93)
- Information Technology > Artificial Intelligence > Machine Learning > Neural Networks > Deep Learning (0.66)
Stochastic Poisson Surface Reconstruction with One Solve using Geometric Gaussian Processes
Holalkere, Sidhanth, Bindel, David S., Sellán, Silvia, Terenin, Alexander
Poisson Surface Reconstruction is a widely-used algorithm for reconstructing a surface from an oriented point cloud. To facilitate applications where only partial surface information is available, or scanning is performed sequentially, a recent line of work proposes to incorporate uncertainty into the reconstructed surface via Gaussian process models. The resulting algorithms first perform Gaussian process interpolation, then solve a set of volumetric partial differential equations globally in space, resulting in a computationally expensive two-stage procedure. In this work, we apply recently-developed techniques from geometric Gaussian processes to combine interpolation and surface reconstruction into a single stage, requiring only one linear solve per sample. The resulting reconstructed surface samples can be queried locally in space, without the use of problem-dependent volumetric meshes or grids. These capabilities enable one to (a) perform probabilistic collision detection locally around the region of interest, (b) perform ray casting without evaluating points not on the ray's trajectory, and (c) perform next-view planning on a per-slice basis. They also improve reconstruction quality, by not requiring one to approximate kernel matrix inverses with diagonal matrices as part of intermediate computations. Results show that our approach provides a cleaner, more-principled, and more-flexible stochastic surface reconstruction pipeline.
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
- Asia (0.04)
Using 3D reconstruction from image motion to predict total leaf area in dwarf tomato plants
Usenko, Dmitrii, Helman, David, Giladi, Chen
Accurate estimation of total leaf area (TLA) is essential for assessing plant growth, photosynthetic activity, and transpiration but remains a challenge for bushy plants like dwarf tomatoes. Traditional destructive methods and imaging-based techniques often fall short due to labor intensity, plant damage, or the inability to capture complex canopies. This study evaluated a non-destructive method combining sequential 3D reconstructions from RGB images and machine learning to estimate TLA for three dwarf tomato cultivars-- Mohamed, Hahms Gelbe Topftomate, and Red Robin--grown under controlled greenhouse conditions. Two experiments, conducted in spring-summer and autumn-winter, included 73 plants, yielding 418 TLA measurements using an "onion" approach, where layers of leaves were sequentially removed and scanned. High-resolution videos were recorded from multiple angles for each plant, and 500 frames were extracted per plant for 3D reconstruction. Point clouds were created and processed, four reconstruction algorithms (Alpha Shape, Marching Cubes, Poisson's, and Ball Pivoting) were tested, and meshes were evaluated using seven regression models: Multivariable Linear Regression (MLR), Lasso Regression (Lasso), Ridge Regression (Ridge-Reg), Elastic Net Regression (ENR), Random Forest (RF), extreme gradient boosting (XGBoost), and Multilayer Perceptron (MLP). The Alpha Shape reconstruction (α = 3) combined with XGBoost yielded the best performance, achieving an R of 0.80 and MAE of 489 cm These findings demonstrate the robustness of our approach across variable environmental conditions and canopy structures. This scalable, automated TLA estimation method is particularly suited for urban farming and precision agriculture, offering practical implications for automated pruning, improved resource efficiency, and sustainable food production. Keywords: Total leaf area, dwarf tomato, point cloud, mesh reconstruction, machine learning, precision agriculture 1. Introduction Total leaf area (TLA) is a comprehensive metric describing the plant's growth and functioning. It is a primary metric that describes the plant's photosynthetic activity and transpiration capacity. Normalized by the plant's surface area, TLA may provide information on the canopy structure, which is crucial for understanding the plant's energy and resource efficiency. For example, reduced TLA is a sign of stress (Dong et al., 2019), while excessive biomass, indicated by a higher TLA, signifies lower water use efficiency (Glenn et al., 2006). Farmers often use pruning to reduce TLA in commercial crops to increase crop productivity (Budiarto et al., 2023). However, measuring and finding the optimum TLA of the crop are challenging tasks.
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- Europe > Switzerland > Basel-City > Basel (0.04)
- Europe > Netherlands > North Holland > Amsterdam (0.04)
- Asia > Middle East > Israel > Southern District > Ashdod (0.04)
- Research Report > New Finding (0.48)
- Research Report > Experimental Study (0.46)
The Marginal Importance of Distortions and Alignment in CASSI systems
Paillet, Léo, Rouxel, Antoine, Carfantan, Hervé, Lacroix, Simon, Monmayrant, Antoine
This paper introduces a differentiable ray-tracing based model that incorporates aberrations and distortions to render realistic coded hyperspectral acquisitions using Coded-Aperture Spectral Snapshot Imagers (CASSI). CASSI systems can now be optimized in order to fulfill simultaneously several optical design constraints as well as processing constraints. Four comparable CASSI systems with varying degree of optical aberrations have been designed and modeled. The resulting rendered hyperspectral acquisitions from each of these systems are combined with five state-of-the-art hyperspectral cube reconstruction processes. These reconstruction processes encompass a mapping function created from each system's propagation model to account for distortions and aberrations during the reconstruction process. Our analyses show that if properly modeled, the effects of geometric distortions of the system and misalignments of the dispersive elements have a marginal impact on the overall quality of the reconstructed hyperspectral data cubes. Therefore, relaxing traditional constraints on measurement conformity and fidelity to the scene enables the development of novel imaging instruments, guided by performance metrics applied to the design or the processing of acquisitions. By providing a complete framework for design, simulation and evaluation, this work contributes to the optimization and exploration of new CASSI systems, and more generally to the computational imaging community.
ThinTact:Thin Vision-Based Tactile Sensor by Lensless Imaging
Xu, Jing, Chen, Weihang, Qian, Hongyu, Wu, Dan, Chen, Rui
Vision-based tactile sensors have drawn increasing interest in the robotics community. However, traditional lens-based designs impose minimum thickness constraints on these sensors, limiting their applicability in space-restricted settings. In this paper, we propose ThinTact, a novel lensless vision-based tactile sensor with a sensing field of over 200 mm2 and a thickness of less than 10 mm.ThinTact utilizes the mask-based lensless imaging technique to map the contact information to CMOS signals. To ensure real-time tactile sensing, we propose a real-time lensless reconstruction algorithm that leverages a frequency-spatial-domain joint filter based on discrete cosine transform (DCT). This algorithm achieves computation significantly faster than existing optimization-based methods. Additionally, to improve the sensing quality, we develop a mask optimization method based on the generic algorithm and the corresponding system matrix calibration algorithm.We evaluate the performance of our proposed lensless reconstruction and tactile sensing through qualitative and quantitative experiments. Furthermore, we demonstrate ThinTact's practical applicability in diverse applications, including texture recognition and contact-rich object manipulation. The paper will appear in the IEEE Transactions on Robotics: https://ieeexplore.ieee.org/document/10842357. Video: https://youtu.be/YrOO9BDMAHo
- Information Technology > Sensing and Signal Processing (1.00)
- Information Technology > Artificial Intelligence > Robots > Manipulation (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Optimization (0.66)
- Information Technology > Artificial Intelligence > Machine Learning > Neural Networks > Deep Learning (0.46)
PALMS: Parallel Adaptive Lasso with Multi-directional Signals for Latent Networks Reconstruction
Networks are commonly existing in our world, which characterize the interactions between different items in many fields, such as the social networks between people and the trading networks between companies. With the deepening of research into various complex dynamic systems, network data and network-based dynamic processes have increasingly become focal points of academic inquiry. From the perspective of empirical analysis, the network structures commonly influence the changes and evolution of the world profoundly (Dhar et al., 2014), like transportation networks between cities, supply chain networks for international trades, and competition relationships in an evolutionary ultimatum game. Many scholars regard the known network structures as a treatment, focusing on whether existing network connections exert an influence on other variables, which is commonly referred to as network effects identification. Examples include the impact of transportation networks on economic development (Bramoullé et al., 2009) and the influence of social networks on U.S. election outcomes (Herzog, 2021; Kleinnijenhuis and De Nooy, 2013).
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- Asia > China > Fujian Province > Xiamen (0.04)
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
Multi-frequency Electrical Impedance Tomography Reconstruction with Multi-Branch Attention Image Prior
Fang, Hao, Liu, Zhe, Feng, Yi, Qiu, Zhen, Bagnaninchi, Pierre, Yang, Yunjie
Multi-frequency Electrical Impedance Tomography (mfEIT) is a promising biomedical imaging technique that estimates tissue conductivities across different frequencies. Current state-of-the-art (SOTA) algorithms, which rely on supervised learning and Multiple Measurement Vectors (MMV), require extensive training data, making them time-consuming, costly, and less practical for widespread applications. Moreover, the dependency on training data in supervised MMV methods can introduce erroneous conductivity contrasts across frequencies, posing significant concerns in biomedical applications. To address these challenges, we propose a novel unsupervised learning approach based on Multi-Branch Attention Image Prior (MAIP) for mfEIT reconstruction. Our method employs a carefully designed Multi-Branch Attention Network (MBA-Net) to represent multiple frequency-dependent conductivity images and simultaneously reconstructs mfEIT images by iteratively updating its parameters. By leveraging the implicit regularization capability of the MBA-Net, our algorithm can capture significant inter- and intra-frequency correlations, enabling robust mfEIT reconstruction without the need for training data. Through simulation and real-world experiments, our approach demonstrates performance comparable to, or better than, SOTA algorithms while exhibiting superior generalization capability. These results suggest that the MAIP-based method can be used to improve the reliability and applicability of mfEIT in various settings.
- North America > United States > New York > Westchester County > New Rochelle (0.04)
- Europe > Austria > Styria > Graz (0.04)
Near-Isotropic Sub-{\AA}ngstrom 3D Resolution Phase Contrast Imaging Achieved by End-to-End Ptychographic Electron Tomography
You, Shengboy, Romanov, Andrey, Pelz, Philipp
Three-dimensional atomic resolution imaging using transmission electron microscopes is a unique capability that requires challenging experiments. Linear electron tomography methods are limited by the missing wedge effect, requiring a high tilt range. Multislice ptychography can achieve deep sub-{\AA}ngstrom resolution in the transverse direction, but the depth resolution is limited to 2 to 3 nanometers. In this paper, we propose and demonstrate an end-to-end approach to reconstructing the electrostatic potential volume of the sample directly from the 4D-STEM datasets. End-to-end multi-slice ptychographic tomography recovers several slices at each tomography tilt angle and compensates for the missing wedge effect. The algorithm is initially tested in simulation with a Pt@$\mathrm{Al_2O_3}$ core-shell nanoparticle, where both heavy and light atoms are recovered in 3D from an unaligned 4D-STEM tilt series with a restricted tilt range of 90 degrees. We also demonstrate the algorithm experimentally, recovering a Te nanoparticle with sub-{\AA}ngstrom resolution.
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- Europe > Germany > Bavaria > Middle Franconia > Nuremberg (0.04)
- Asia > Middle East > Jordan (0.04)
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