Search Results for author: Lok Ming Lui

Found 27 papers, 2 papers with code

QIS : Interactive Segmentation via Quasi-Conformal Mappings

no code implementations22 Feb 2024 Han Zhang, Daoping Zhang, Lok Ming Lui

In this paper, we propose the quasi-conformal interactive segmentation (QIS) model, which incorporates user input in the form of positive and negative clicks.

Image Segmentation Interactive Segmentation +2

Enhancing Facial Classification and Recognition using 3D Facial Models and Deep Learning

no code implementations8 Dec 2023 Houting Li, Mengxuan Dong, Lok Ming Lui

Accurate analysis and classification of facial attributes are essential in various applications, from human-computer interaction to security systems.

Classification Gender Classification

Deformation-Invariant Neural Network and Its Applications in Distorted Image Restoration and Analysis

no code implementations4 Oct 2023 Han Zhang, Qiguang Chen, Lok Ming Lui

The QCTN is a deep neural network that outputs a quasiconformal map, which can be used to transform a geometrically distorted image into an improved version that is closer to the distribution of natural or good images.

Image Classification Image Restoration +1

Fast MRI Reconstruction via Edge Attention

1 code implementation22 Apr 2023 Hanhui Yang, Juncheng Li, Lok Ming Lui, Shihui Ying, Jun Shi, Tieyong Zeng

To solve this problem, we propose a lightweight and accurate Edge Attention MRI Reconstruction Network (EAMRI) to reconstruct images with edge guidance.

MRI Reconstruction

Topology-Preserving Segmentation Network

no code implementations7 Oct 2022 Han Zhang, Lok Ming Lui

Comparing to the segmentation framework based on pixel-wise classification, deformation-based segmentation models that warp a template to enclose the regions are more convenient to enforce geometric constraints.

Image Segmentation Medical Image Segmentation +2

Automatic Landmark Detection and Registration of Brain Cortical Surfaces via Quasi-Conformal Geometry and Convolutional Neural Networks

no code implementations15 Aug 2022 Yuchen Guo, Qiguang Chen, Gary P. T. Choi, Lok Ming Lui

In this work, we propose a novel framework for the automatic landmark detection and registration of brain cortical surfaces using quasi-conformal geometry and convolutional neural networks.

Topology-Preserving Segmentation Network: A Deep Learning Segmentation Framework for Connected Component

no code implementations27 Feb 2022 Han Zhang, Lok Ming Lui

TPSN is a deformation-based model that yields a deformation map through a UNet, which takes the medical image and a template mask as inputs.

Image Segmentation Medical Image Segmentation +2

A unifying framework for $n$-dimensional quasi-conformal mappings

no code implementations20 Oct 2021 Daoping Zhang, Gary P. T. Choi, Jianping Zhang, Lok Ming Lui

With the advancement of computer technology, there is a surge of interest in effective mapping methods for objects in higher-dimensional spaces.

Image Registration Medical Image Registration

A Deep Learning Framework for Diffeomorphic Mapping Problems via Quasi-conformal Geometry applied to Imaging

no code implementations20 Oct 2021 Qiguang Chen, Zhiwen Li, Lok Ming Lui

Existing methods to solve the mapping problems are often inefficient and can sometimes get trapped in local minima.

Image Registration

Topology-Preserving 3D Image Segmentation Based On Hyperelastic Regularization

no code implementations31 Mar 2021 Daoping Zhang, Lok Ming Lui

In this paper, we propose a novel 3D topology-preserving registration-based segmentation model with the hyperelastic regularization, which can handle both 2D and 3D images.

Image Segmentation Segmentation +1

Harmonic Beltrami Signature: A Novel 2D Shape Representation for Object Classification

no code implementations30 Mar 2021 Chenran Lin, Lok Ming Lui

The proposed signature is based on the harmonic extension of the conformal welding map of a unit circle and its Beltrami coefficient.

General Classification Translation

Quasiconformal model with CNN features for large deformation image registration

no code implementations30 Oct 2020 Ho Law, Gary P. T. Choi, Ka Chun Lam, Lok Ming Lui

In this paper, we develop a novel method for large deformation image registration by a fusion of quasiconformal theory and convolutional neural network (CNN).

BIG-bench Machine Learning Image Registration

Decomposition of Longitudinal Deformations via Beltrami Descriptors

1 code implementation6 Aug 2020 Ho Law, Lok Ming Lui, Chun Yin Siu

To decompose the longitudinal deformation, we propose to carry out the low rank and sparse decomposition of the Beltrami descriptor.

Modal Uncertainty Estimation via Discrete Latent Representation

no code implementations25 Jul 2020 Di Qiu, Lok Ming Lui

We motivate our use of discrete latent space through the multi-modal posterior collapse problem in current conditional generative models, then develop the theoretical background, and extensively validate our method on both synthetic and realistic tasks.

Shape analysis via inconsistent surface registration

no code implementations3 Mar 2020 Gary P. T. Choi, Di Qiu, Lok Ming Lui

In this work, we develop a framework for shape analysis using inconsistent surface mapping.

Tooth morphometry using quasi-conformal theory

no code implementations7 Jan 2019 Gary P. T. Choi, Hei Long Chan, Robin Yong, Sarbin Ranjitkar, Alan Brook, Grant Townsend, Ke Chen, Lok Ming Lui

We deploy our framework on a dataset of human premolars to analyze the tooth shape variation among genders and ancestries.

General Classification

Subsampled Turbulence Removal Network

no code implementations12 Jul 2018 Wai Ho Chak, Chun Pong Lau, Lok Ming Lui

Instead of requiring a massive training sample size in deep networks, we purpose a training strategy that is based on a new data augmentation method to model turbulence from a relatively small dataset.

Data Augmentation

Variational models for joint subsampling and reconstruction of turbulence-degraded images

no code implementations8 Dec 2017 Chun Pong Lau, Yu Hin Lai, Lok Ming Lui

The energy consists of a fidelity term measuring the discrepancy between the extracted image and the subsampled frames, as well as regularization terms on the extracted image and the subsample.

Image retargeting via Beltrami representation

no code implementations11 Oct 2017 Chun Pong Lau, Chun Pang Yung, Lok Ming Lui

In this paper, we propose a simple and yet effective method to resize an image, which preserves the geometry of the important content, using the Beltrami representation.

Image Retargeting

Restoration of Atmospheric Turbulence-distorted Images via RPCA and Quasiconformal Maps

no code implementations11 Apr 2017 Chun Pong Lau, Yu Hin Lai, Lok Ming Lui

The subsampled image sequence is then stabilized by applying the Robust Principal Component Analysis (RPCA) on the deformation fields between image frames and warping the image frames by a quasiconformal map associated with the low-rank part of the deformation matrix.

Efficient Feature-based Image Registration by Mapping Sparsified Surfaces

no code implementations20 May 2016 Chun Pang Yung, Gary P. T. Choi, Ke Chen, Lok Ming Lui

For each high resolution image or video frame, we compute an optimal coarse triangulation which captures the important features of the image.

Image Registration

TEMPO: Feature-Endowed Teichmüller Extremal Mappings of Point Clouds

no code implementations20 Nov 2015 Ting Wei Meng, Gary Pui-Tung Choi, Lok Ming Lui

Based on the discrete analogue, we propose a novel method called TEMPO for computing Teichm\"{u}ller extremal mappings between feature-endowed point clouds.

General Classification

Spherical Conformal Parameterization of Genus-0 Point Clouds for Meshing

no code implementations30 Aug 2015 Gary Pui-Tung Choi, Kin Tat Ho, Lok Ming Lui

In this paper, we extend a state-of-the-art spherical conformal parameterization algorithm for genus-0 closed meshes to the case of point clouds, using an improved approximation of the Laplace-Beltrami operator on data points.

Fast Disk Conformal Parameterization of Simply-connected Open Surfaces

no code implementations29 Aug 2014 Pui Tung Choi, Lok Ming Lui

Surface parameterizations have been widely used in computer graphics and geometry processing.

Surface Registration by Optimization in Constrained Diffeomorphism Space

no code implementations CVPR 2014 Wei Zeng, Lok Ming Lui, Xianfeng GU

The physically plausible constraints, in terms of feature landmarks and deformation types, define subspaces in the Beltrami coefficient space.

QCMC: Quasi-conformal Parameterizations for Multiply-connected domains

no code implementations26 Mar 2014 Kin Tat Ho, Lok Ming Lui

QCMC computes a quasi-conformal map from a multiply-connected domain $S$ onto a punctured disk $D_S$ associated with a given Beltrami differential.

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