Scene Adaptive Sparse Transformer for Event-based Object Detection

While recent Transformer-based approaches have shown impressive performances on event-based object detection tasks, their high computational costs still diminish the low power consumption advantage of event cameras. Image-based works attempt to reduce these costs by introducing sparse Transformers. However, they display inadequate sparsity and adaptability when applied to event-based object detection, since these approaches cannot balance the fine granularity of token-level sparsification and the efficiency of window-based Transformers, leading to reduced performance and efficiency. Furthermore, they lack scene-specific sparsity optimization, resulting in information loss and a lower recall rate. To overcome these limitations, we propose the Scene Adaptive Sparse Transformer (SAST). SAST enables window-token co-sparsification, significantly enhancing fault tolerance and reducing computational overhead. Leveraging the innovative scoring and selection modules, along with the Masked Sparse Window Self-Attention, SAST showcases remarkable scene-aware adaptability: It focuses only on important objects and dynamically optimizes sparsity level according to scene complexity, maintaining a remarkable balance between performance and computational cost. The evaluation results show that SAST outperforms all other dense and sparse networks in both performance and efficiency on two large-scale event-based object detection datasets (1Mpx and Gen1). Code: https://github.com/Peterande/SAS

Observation of the TeV gamma-ray source MGRO J1908+06 with ARGO-YBJ

The extended gamma ray source MGRO J1908+06, discovered by the Milagro air shower detector in 2007, has been observed for about 4 years by the ARGO-YBJ experiment at TeV energies, with a statistical significance of 6.2 standard deviations. The peak of the signal is found at a position consistent with the pulsar PSR J1907+0602. Parametrizing the source shape with a two-dimensional Gauss function we estimate an extension \sigma = 0.49 \pm 0.22 degrees, consistent with a previous measurement by the Cherenkov Array H.E.S.S.. The observed energy spectrum is dN/dE = 6.1 \pm 1.4 \times 10^-13 (E/4 TeV)^{-2.54 \pm 0.36} photons cm^-2 s^-1 TeV^-1, in the energy range 1-20 TeV. The measured gamma ray flux is consistent with the results of the Milagro detector, but is 2-3 times larger than the flux previously derived by H.E.S.S. at energies of a few TeV. The continuity of the Milagro and ARGO-YBJ observations and the stable excess rate observed by ARGO-YBJ along 4 years of data taking support the identification of MGRO J1908+06 as the steady powerful TeV pulsar wind nebula of PSR J1907+0602, with an integrated luminosity above 1 TeV about 1.8 times the Crab Nebula luminosity.Comment: 6 pages, accepted for pubblication by ApJ. Replaced to correct the author lis

Event-assisted Low-Light Video Object Segmentation

In the realm of video object segmentation (VOS), the challenge of operating under low-light conditions persists, resulting in notably degraded image quality and compromised accuracy when comparing query and memory frames for similarity computation. Event cameras, characterized by their high dynamic range and ability to capture motion information of objects, offer promise in enhancing object visibility and aiding VOS methods under such low-light conditions. This paper introduces a pioneering framework tailored for low-light VOS, leveraging event camera data to elevate segmentation accuracy. Our approach hinges on two pivotal components: the Adaptive Cross-Modal Fusion (ACMF) module, aimed at extracting pertinent features while fusing image and event modalities to mitigate noise interference, and the Event-Guided Memory Matching (EGMM) module, designed to rectify the issue of inaccurate matching prevalent in low-light settings. Additionally, we present the creation of a synthetic LLE-DAVIS dataset and the curation of a real-world LLE-VOS dataset, encompassing frames and events. Experimental evaluations corroborate the efficacy of our method across both datasets, affirming its effectiveness in low-light scenarios.Comment: CVPR 202

Morphological study of the superficial palmar arch and its significance in clinical operation

Background: The superficial palmar arch is a crucial blood supply to the palm. However, it exhibits significant variations, posing challenges in surgical procedures. Gaining a comprehensive understanding of the relationship between differenttypes, physiological indices, and the clinical significance of the superficial palmar arch will enhance the accuracy of diagnosing and treating patients. Materials and methods: In this study, we dissected a total of 72 specimens, comprising 39 males and 33 females. We observed the type, length, and diameter of the superficial palmar arch and analysed its correlation with the disease. Additionally, we conducted Doppler ultrasound measurements on 20 healthy volunteers (10 males and 10 females) and 18 patients with superficial palmar arch injury (10 males and 8 females) to assess the classification, diameter, intimal thickness, and blood flow velocity of the superficial palmar arch. We collected information on 9 male patients with finger fractures and observed the classification of the superficial palmar arch, fracture healing time, and basic function recovery time. Lastly, we analysed rare variant specimens encountered during the anatomy process. Results: In the exploration of human anatomy, there were 4 types of superficial palmar arch: ulnar artery arch type in 17 cases (23.61%), radial ulnar artery type in 46 cases (63.89%), ulnar artery without arch type in 6 cases (8.33%), and 3cases (4.17%) of double arch type of radial and ulnar artery. One case of nonarched type was found in an imaging examination (5%). In one elderly male specimen, the hand’s superficial palmar arch artery was tortuous and dilated. In addition, there was a positive correlation between the diameter and length of the superficial palmar arch (except the second common palmar digital artery in women), among which the ulnar artery and the third common palmar digital artery had the strongest correlation. Compared to healthy volunteers, patients with ulnar injury in the radial-ulnar artery type exhibited a decrease in the diameter and blood flow velocity of the ulnar artery, as well as the second and thirdcommon palmar digital arteries. No such change was observed in patients with radial injury. Additionally, patients with ulnar injury in other types of radial-ulnar artery also experienced a decrease in the diameter and blood flow velocity of the ulnar artery. Finger fracture patients with ulnar artery with arch and ulnar artery without arch had shorter fracture healing time and basic function recovery time compared to those with radial-ulnar artery type. Conclusions: This study investigated the relationship between the classification, physiological index, and clinical significance of the superficial palmar arch at all levels. The results demonstrated that when the superficial palmar arch is damaged, it is important to consider both the classification and the site of damage, because this potentially results in improved therapeutic outcomes. These findings provide a basis for future clinical research