Lipu Zhou

ORCID: 0000-0003-2148-393X
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Research Areas
  • Robotics and Sensor-Based Localization
  • Advanced Vision and Imaging
  • Optical measurement and interference techniques
  • 3D Surveying and Cultural Heritage
  • Advanced Image and Video Retrieval Techniques
  • Remote Sensing and LiDAR Applications
  • Thin-Film Transistor Technologies
  • Organic Electronics and Photovoltaics
  • Image and Object Detection Techniques
  • Advanced Neural Network Applications
  • Autonomous Vehicle Technology and Safety
  • Spectroscopy Techniques in Biomedical and Chemical Research
  • Brain Tumor Detection and Classification
  • Image Processing Techniques and Applications
  • Advanced Optical Sensing Technologies
  • Computational Geometry and Mesh Generation
  • Augmented Reality Applications
  • Indoor and Outdoor Localization Technologies
  • Advanced Optical Network Technologies
  • Surface Roughness and Optical Measurements
  • Surface Modification and Superhydrophobicity
  • Organic Light-Emitting Diodes Research
  • Block Copolymer Self-Assembly
  • Video Surveillance and Tracking Methods
  • Advanced Image Processing Techniques

Beihang University
2024-2025

Meizu (China)
2022-2023

Magic Leap (United States)
2020-2021

Carnegie Mellon University
2018-2020

Tsinghua University
1999-2017

Baidu (China)
2015

Pennsylvania State University
2002-2006

Princeton University
1997

We have fabricated organic thin-film transistor (OTFT)-driven active matrix liquid crystal displays on flexible polymeric substrates. These small 16×16 pixel polymer-dispersed arrays addressed by pentacene layer OTFTs. The were using a low-temperature process (<110 °C) polyethylene naphthalate film and are operated as reflective displays.

10.1063/1.1448659 article EN Applied Physics Letters 2002-02-11

We report on parasitic contact effects in organic thin film transistors (OTFTs) fabricated with pentacene films. The influence the OTFT performance of source and drain metal device design was investigated. Top (TC) bottom (BC) gated transmission line model (gated-TLM) test structures were used to extract combined resistance as a function gate voltage swing drain-source for OTFTs gold contacts. For comparison BC palladium contacts studied. Differences bias dependence TC indicate that charge...

10.1063/1.2215132 article EN Journal of Applied Physics 2006-07-15

In this paper, we address the problem of extrinsic calibration a camera and 3D Light Detection Ranging (LiDAR) sensor using checkerboard. Unlike previous works which require at least three checkerboard poses, our algorithm reduces minimal number poses to one by combining line plane correspondences. Besides, prove that parallel planar targets with boundaries provide same constraints in algorithm. This allows us place close LiDAR so laser points better approximate target boundary without loss...

10.1109/iros.2018.8593660 article EN 2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 2018-10-01

We report on organic thin-film transistors fabricated using the small-molecule semiconductor naphthacene as active layer material with device performance suitable for several large-area or low-cost electronics applications. investigated thin films deposited by thermal evaporation onto amorphous substrates held near room temperature. Using atomic-force microscopy and x-ray diffraction we find consist of a high density submicron-sized grains surprisingly degree molecular order. Thin-film...

10.1063/1.1471378 article EN Applied Physics Letters 2002-04-22

This paper presents a new algorithm to automatically solve algebra word problems.Our solves problem via analyzing hypothesis space containing all possible equation systems generated by assigning the numbers in into set of system templates extracted from training data.To obtain robust decision surface, we train log-linear model make margin between correct assignments and false ones as large possible.This results quadratic programming (QP) which can be efficiently solved.Experimental show that...

10.18653/v1/d15-1096 article EN cc-by Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing 2015-01-01

Planes ubiquitously exist in the indoor environment. This letter presents a real-time and low-drift LiDAR SLAM system using planes as landmark for Our algorithm includes three components: localization, local mapping global mapping. The localization component performs registration, instead of scan-to-scan registration adopted state-of-the-art odometry (LOAM) framework that yields lower fidelity poses. optimizes poses keyframes within sliding window parameters observed by these keyframes....

10.1109/lra.2021.3092274 article EN IEEE Robotics and Automation Letters 2021-06-28

We use grazing incidence x-ray scattering to study the molecular structure and morphology of thin (70 ML) crystalline films 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on Au(111) surfaces as a function film thickness, substrate temperature, growth rate. Although first two PTCDA monolayers grow in layer-by-layer fashion, evolution beyond second monolayer depends strongly upon conditions resulting low-temperature [i.e., nonequilibrium (NEQ)] high-temperature [equilibrium (EQ)]...

10.1103/physrevb.56.3046 article EN Physical review. B, Condensed matter 1997-08-01

In this paper, we present a new minimal solution for the extrinsic calibration of 2D light detection and ranging (LIDAR) sensor perspective camera. This problem is formulated as registering three planes corresponding coplanar lines. All existing algorithms solve by its geometric structure in original or dual 3D space. contrast, our algorithm directly exploits algebraic polynomial system to resolve problem. more abstract, however, provides broadly applicable method other problems that need...

10.1109/jsen.2013.2284789 article EN IEEE Sensors Journal 2013-10-07

Real-time traffic sign detection and recognition are essential challenging tasks for intelligent vehicle. The previous works mainly focus on detecting recognizing based images captured by onboard camera. Visual features of such as color, shape, appearance, however, often sensitive to illumination condition, angle view, etc. Except camera, LIDAR also provides important alternative sign. fusion complementary data acquired from both sensors can improve the robustness algorithm, especially when...

10.1109/itsc.2014.6957752 article EN 2014-10-01

In this paper, we propose a novel robust algorithm for the extrinsic calibration of camera and lidar. This utilizes checkerboard as object. Since interaction between estimation errors plane parameters obtained from images downgrades quality results, new geometric constraint is presented to decouple rotation translation so reduce effect such an interaction. Weights that represent uncertainty unit normal vector are introduced totally evaluate each pair image lidar scan. Furthermore, analyze...

10.1109/ivs.2012.6232233 article EN IEEE Intelligent Vehicles Symposium 2012-06-01

This paper introduces a real-time dense planar LiDAR SLAM system, named π-LSAM, for the indoor environment. The widely used odometry and mapping (LOAM) framework [1] does not include bundle adjustment (BA) generates low fidelity tracking pose. seeks to overcome these drawbacks Specifically, we use plane as landmark, introduce (PA) our back-end jointly optimize planes keyframe poses. We present π-factor significantly reduce computational complexity of PA. In addition, an efficient loop...

10.1109/icra48506.2021.9561933 article EN 2021-05-30

Planes, lines, and cylinders widely exist in man-made environments. This letter introduces a LiDAR simultaneous localization mapping (SLAM) system using those three types of landmarks. Our algorithm has components including local mapping, global localization. The jointly adjust planes, with poses to minimize the point-to-model cost, which is referred as plane-line-cylinder adjustment (PLCA). We prove that, some preprocessing, PLCA independent number points captured from landmarks, makes...

10.1109/lra.2022.3180116 article EN IEEE Robotics and Automation Letters 2022-06-03

This paper introduces an efficient direct visual odometry (VO) algorithm using points and lines. Pixels on lines are generally adopted in methods. However, the original photometric error is only defined for points. It seems difficult to extend it In previous works, collinear constraints either ignored [1] or introduce heavy computational load into resulting optimization system [2]. extends We prove that 3D of a 2D line determined by inverse depths endpoints line, derive closed-form solution...

10.1109/icra46639.2022.9812133 article EN 2022 International Conference on Robotics and Automation (ICRA) 2022-05-23

In this letter, we present a direct visual odometry (VO) using points and lines. Direct methods generally choose pixels with sufficient gradients to minimize the photometric error for status estimation. Pixels on lines are involved in process. But collinear constraint among these ignored, which may result less accurate depth This letter introduces into state-of-the-art DSO (J. EngelI et al., 2018) overcome problem. The 3D lines, poses within sliding window jointly optimized. Points only...

10.1109/lra.2021.3097052 article EN IEEE Robotics and Automation Letters 2021-07-28

In order to constrain the evolutionary state of red supergiant Betelgeuse, we have produced a suite models with ZAMS masses from 15 25 Msun in intervals 1 including effects rotation. The were computed stellar code MESA. For non-rotating find results that are similar other work. It is somewhat difficult agree within sigma observed values R, Teff and L, but modestly easy 3 uncertainty. Incorporating nominal rotational velocity, ~15 km/s, yields significantly different, challenging,...

10.1093/mnras/stw2893 article EN Monthly Notices of the Royal Astronomical Society 2016-11-08

This paper presents an efficient algorithm for the least-squares problem using point-to-plane cost, which aims to jointly optimize depth sensor poses and plane parameters 3D reconstruction. We call this Planar Bundle Adjustment (PBA), due similarity between original (BA) in visual As planes ubiquitously exist man-made environment, they are generally used as landmarks SLAM algorithms various sensors. PBA is important reduce drift improve quality of map. However, directly adopting...

10.1109/ismar50242.2020.00035 article EN 2020-11-01

Voxel-based methods have achieved state-of-the-art performance for 3D object detection in autonomous driving. However, their significant computational and memory costs pose a challenge application to resource-constrained vehicles. One reason this high resource consumption is the presence of large number redundant background points Lidar point clouds, resulting spatial redundancy both voxel BEV map representations. To address issue, we propose an adaptive inference framework called Ada3D,...

10.1109/iccv51070.2023.01625 article EN 2021 IEEE/CVF International Conference on Computer Vision (ICCV) 2023-10-01

We present a novel unsupervised learning framework for single view depth estimation using monocular videos. It is well known in 3D vision that enlarging the baseline can increase accuracy, and jointly optimizing set of camera poses landmarks essential. In previous frameworks, only part photometric geometric constraints within sequence are used as supervisory signals. This may result short overfitting. Besides, works generally estimate low resolution from impute image. The then interpolated...

10.48550/arxiv.1812.03368 preprint EN other-oa arXiv (Cornell University) 2018-01-01

Road curb detection and tracking is essential for the autonomous driving of intelligent vehicles on highways urban roads. In this paper, we present a fast robust road algorithm using 3D lidar data Integral Laser Points (ILP) features. Range intensity decomposed into elevation projected ground plane. First, left right curbs are detected each scan line range segment Then, points determined data. The ILP features proposed to speed up both procedures. Finally, parabola model RANSAC used fit...

10.1109/scis-isis.2012.6505310 article EN 2012-11-01

In this paper, we propose a new extrinsic calibration algorithm for camera and 2D LIght Detection And Ranging sensor (LIDAR). N plane-line correspondences are used to establish geometric constraints computing the parameters. The existing algorithms that use same either require ≥ 5 or focus on minimal solution = 3. contrast, proposed is effective all This made possible by decoupling initial estimation of rotation from translation imposing orthonormal computation rotation. When matrix...

10.1088/0957-0233/25/6/065107 article EN Measurement Science and Technology 2014-05-12

Reliable detection and recognition of planar objects including traffic sign, street road surface in dynamic cluttered natural scenes are a big challenge for self-driving cars. In this paper, we propose comprehensive method object recognition. First, the data association LIDAR camera is set up to acquire colorized laser scans, which simultaneously contain both color geometrical information. Second, combine three spaces RGB, HSV, CIE L*a*b* with reflectivity as an aggregation-based feature...

10.1109/tits.2017.2723902 article EN IEEE Transactions on Intelligent Transportation Systems 2017-08-21

This letter presents a self-supervised framework for learning depth from monocular videos. In particular, the main contributions of this include: (1) We present windowed bundle adjustment to train network. Compared most previous works that only consider constraints consecutive frames, our increases camera baseline and introduces more avoid overfitting. (2) extend widely used U-Net architecture by applying Spatial Pyramid Net (SPN) Super Resolution (SRN). The SPN fuses information an image...

10.1109/lra.2020.2976301 article EN IEEE Robotics and Automation Letters 2020-02-26

In this paper, we address the problem of pose estimation from N 2D/3D point correspondences, known as Perspective-n-Point (PnP) problem. Although many solutions have been proposed, it is hard to optimize both computational complexity and accuracy at same time. propose an accurate simultaneously efficient solution PnP Previous algorithms generally involve two sets unknowns including depth each pixel camera. Our formulation does not pixel. By introducing some intermediate variables, leads a...

10.1109/iros40897.2019.8968482 article EN 2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 2019-11-01

This paper proposes a novel algorithm to solve the pose estimation problem from 2D/3D line correspondences, known as Perspective-n-Line (PnL) problem. It is widely that minimizing geometric distance generally results in more accurate than an algebraic distance. However, rational form of reprojection yields complicated cost function, which makes solving first-order optimality conditions infeasible. Furthermore, iterative algorithms based on are time-consuming for large-scale In contrast...

10.1609/aaai.v33i01.33019307 article EN Proceedings of the AAAI Conference on Artificial Intelligence 2019-07-17
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