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Huiling Li

Publications and source records attributed to Huiling Li.

8 recordsLinked to original sources
arXiv2026

FreqAdapt: Frequency-Adaptive Processing for RAW Object Detection

Existing object detection methods predominantly utilize sRGB inputs, which are compressed from RAW sensor data using Image Signal Processors (ISP) originally designed for visualization purposes. Compared to RGB images, RAW images possess favorable noise characteristics and richer information representation, which are crucial for object detection, particularly under challenging conditions such as adverse weather or low-light environments. In this paper, we propose FreqAdapt, a lightweight module for adaptive RAW data enhancement in the frequency domain. Unlike traditional spatial domain processing methods, FreqAdapt innovatively maps ISP operations to the Fourier frequency domain and performs domain separation based on the physical properties of ISP operations, ensuring each operation is performed in its most suitable domain. Meanwhile, through an adaptive frequency domain encoder that jointly analyzes amplitude spectrum, phase spectrum, and RAW image features, we provide global context for ISP parameter prediction and employ a learnable fusion mechanism to achieve adaptive feature enhancement. Extensive experiments on multiple datasets with diverse lighting and weather conditions demonstrate that FreqAdapt achieves state-of-the-art performance while maintaining lightweight efficiency and good physical interpretability. Furthermore, our module can be seamlessly incorporated into existing object detection frameworks, providing a novel solution for visual perception tasks in the RAW domain.

cs.CV↗
arXiv2026

Disk-Resident Graph ANN Search: An Experimental Evaluation

As data volumes grow while memory capacity remains limited, disk-resident graph-based approximate nearest neighbor (ANN) methods have become a practical alternative to memory-resident designs, shifting the bottleneck from computation to disk I/O. However, since their technical designs diverge widely across storage, layout, and execution paradigms, a systematic understanding of their fundamental performance trade-offs remains elusive. This paper presents a comprehensive experimental study of disk-resident graph-based ANN methods. First, we decompose such systems into five key technical components, i.e., storage strategy, disk layout, cache management, query execution, and update mechanism, and build a unified taxonomy of existing designs across these components. Second, we conduct fine-grained evaluations of representative strategies for each technical component to analyze the trade-offs in throughput, recall, and resource utilization. Third, we perform comprehensive end-to-end experiments and parameter-sensitivity analyses to evaluate overall system performance under diverse configurations. Fourth, our study reveals several non-obvious findings: (1) vector dimensionality fundamentally reshapes component effectiveness, necessitating dimension-aware design; (2) existing layout strategies exhibit surprisingly low I/O utilization (less than or equal to 15%); (3) page size critically affects feasibility and efficiency, with smaller pages preferred when layouts are carefully optimized; and (4) update strategies present clear workload-dependent trade-offs between in-place and out-of-place designs. Based on these findings, we derive practical guidelines for system design and configuration, and outline promising directions for future research.

cs.DB↗
arXiv2025

Multiplexed SiPM Readout of Plastic Scintillating Fiber Detector for Muon Tomography

Muon tomography is a non-destructive imaging technique that uses cosmic-ray muons to probe dense materials. Bar scintillator and scintillating fiber detectors equipped with one-dimensional SiPM arrays offer compact, high-resolution solutions, but large-area implementations require effective reduction of readout channels while preserving detector performance. To address this challenge, we present a novel multiplexing scheme based on a diode-based symmetric charge division circuit combined with a position-encoding algorithm, enabling up to $N_{\textrm{SiPM}}^{\textrm{max}}=C^{2}_{N_{\textrm{ele}}}$ SiPM channels to be read out using only ${N_{\textrm{ele}}}$ electronic channels. Circuit simulations confirm the feasibility of the multiplexing design and guide the choice of appropriate diodes to preserve SiPM signal integrity. The approach was validated using a SciFi detector module comprising 21 SiPM channels multiplexed into 7 electronic channels. Electronic tests show that this multiplexing circuit exhibits low crosstalk between electronic channels, and preserves linearity over a dynamic range from $\sim$10 to 122 photoelectrons. Cosmic-ray measurements further show that the multiplexed SciFi detector achieves a detection efficiency above 95\% and a spatial resolution of about 0.65~mm, with only minor degradation compared to the direct (per SiPM channel) readout. These results verify that the proposed method provides a scalable and cost-effective readout solution for large-area muon tomography systems and is applicable to other scintillator-based detectors employing similar one-dimensional SiPM array readout.

physics.ins-det↗
arXiv2025

Performance evaluation of compact plastic scintillating fiber modules for muon tomography applications

Muon tomography is a non-destructive imaging technique that exploits cosmic-ray muons from multiple directions. Its performance critically depends on the stability, active-area coverage, and spatial resolution of position-sensitive detectors. In this work, we report on the development of four compact scintillating fiber modules, each 100 cm long and composed of two staggered layers of 1 mm diameter fibers. The fibers are read out at one end by one-dimensional silicon photomultiplier arrays with a 2 mm pitch, coupled to Citiroc 1A-based front-end electronics. The modules were characterized with cosmic-ray muons, yielding a detection efficiency above 97% and a mean spatial resolution of about 0.56 mm, with uniform response over different distances from the readout end. An imaging test of a lead block was also performed, and the reconstructed results are consistent with the blocks profile. These results demonstrate the suitability of this detector design for compact and large-area systems in muon tomography applications.

physics.ins-det↗
arXiv2025

BAMG: A Block-Aware Monotonic Graph Index for Disk-Based Approximate Nearest Neighbor Search

Approximate Nearest Neighbor Search (ANNS) over high-dimensional vectors is a foundational problem in databases, where disk I/O often emerges as the dominant performance bottleneck at scale. To accelerate search, graph-based indexes rely on proximity graph, where nodes represent vectors and edges guide the traversal toward the target. However, existing graph indexing solutions for disk-based ANNS typically either optimize the storage layout for a given graph or construct the graph independently of the storage layout, thus overlooking their interaction. In this paper, we bridge this gap by proposing the Block-aware Monotonic Relative Neighborhood Graph (BMRNG), theoretically guaranteeing the existence of I/O monotonic search paths. The core idea is to align the graph topology with the data placement by jointly considering both geometric distance and storage layout for edge selection. To address the scalability challenge of BMRNG construction, we further develop a practical and efficient variant, the Block-Aware Monotonic Graph (BAMG), which can be constructed in linear time from a monotonic graph considering the storage layout. BAMG integrates block-aware edge pruning with a decoupled storage design that separates raw vectors from the graph index, thereby maximizing block utilization and minimizing redundant disk reads. Additionally, we design a multi-layer navigation graph for adaptive and efficient query entry, along with a block-first search algorithm that prioritizes intra-block traversal to fully exploit each disk I/O operation. Extensive experiments on real-world datasets show that BAMG can outperform state-of-the-art methods in search performance.

cs.DB↗
arXiv2023

Towards a muon scattering tomography system for both low-Z and high-Z materials

Muon scattering tomography (MST) is a non-destructive technique to image various materials by utilizing cosmic ray muons as probes. A typical MST system with a two-fold track detectors is particularly effective in detecting high-$Z$ materials (e.g. nuclear materials), but difficult to recognize low-$Z$ materials (e.g. explosive materials). In this work, we present a concept of MST system to discriminate both low-$Z$ and high-$Z$ materials by extra measuring momentum of low-energy muons with a Cherenkov detector. A toy Monte Carlo simulation to describe detector responses and multiple scatterings of a muon tracking through materials is developed for statistical tests. Based on momentum-dependent track reconstruction and image reconstruction algorithm, we evaluate separation powers of different materials in the system. The results show that momentum measurement of low-energy muons and accurate track reconstruction can improve separation power of low-$Z$ materials significantly. This may enable the MST system to detect both low-$Z$ and high-$Z$ materials with cosmic ray muons in the whole energy range.

physics.ins-det↗
arXiv2023

Characterization of silicon photomultipliers for their application in muon scattering tomography

Muon scattering tomography is a non-destructive technique used to image different materials by utilizing natural cosmic ray muons. Typically it requires position-sensitive detectors with a sub-millimeter resolution to effectively distinguish high-$Z$ materials in a compact system. The plastic scintillating fiber detector is a feasible candidate and is currently being designed with one-dimensional silicon photomultiplier (SiPM) readout. In this work, we constructed experimental setups to characterize three different SiPMs from the NDL, SensL, and HPK manufacturers for optimal performance of the scintillating fiber detector. The breakdown voltage, temperature compensation factor, dark noise, and photodetection efficiency of each SiPM are evaluated and summarized. Among the SiPMs tested, the HPK SiPM demonstrated the lowest dark count rate and crosstalk probability while exhibiting the best photodetection efficiency response at the emission wavelengths of the scintillating fibers. This makes the HPK SiPM particularly well-suited to meet the requirements of the detector and serves as a reference for further customization of the one-dimensional SiPM array.

physics.ins-det↗