Wei Ji

Dr. Wei Ji

National University of Singapore, Singapore, Central Singapore, Singapore
orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 June 2022
Verified
Conference Paper
Closed access
CGChuan Guo
Chuan Guo
SZShihao Zou
Shihao Zou
XZXinxin Zuo
Xinxin Zuo
SWSen Wang
Sen Wang
Wei JiWei Ji
Wei Ji
LCLi Cheng
Li Cheng
Automated generation of 3D human motions from text is a challenging problem. The generated motions are expected to be sufficiently diverse to explore the text-grounded motion space, and more importantly, accurately depicting the content in prescribed text descriptions. Here we tackle this problem with a two-stage approach: text2length sampling and text2motion generation. Text2length involves sampling from the learned distribution function of motion lengths conditioned on the input text. This is followed by our text2motion module using temporal variational autoen-coder to synthesize a diverse set of human motions of the sampled lengths. Instead of directly engaging with pose sequences, we propose motion snippet code as our internal motion representation, which captures local semantic motion contexts and is empirically shown to facilitate the generation of plausible motions faithful to the input text. Moreover, a large-scale dataset of scripted 3D Human motions, HumanML3D, is constructed, consisting of 14,616 motion clips and 44,970 text descriptions.

1 October 2019
Verified
Conference Paper
Closed access
YPYongri Piao
Yongri Piao
Wei JiWei Ji
Wei Ji
JLJingjing Li
Jingjing Li
MZMiao Zhang
Miao Zhang
HLHuchuan Lu
Huchuan Lu

12 April 2024 in Machine Intelligence Research
Verified
Journal Article
Open access
PDF file
Wei JiWei Ji
Wei Ji
JLJingjing Li
Jingjing Li
QBQi Bi
Qi Bi
TLTingwei Liu
Tingwei Liu
WLWenbo Li
Wenbo Li
LCLi Cheng
Li Cheng
Recently, Meta AI Research approaches a general, promptable segment anything model (SAM) pre-trained on an unprecedentedly large segmentation dataset (SA-1B). Without a doubt, the emergence of SAM will yield significant benefits for a wide array of practical image segmentation applications. In this study, we conduct a series of intriguing investigations into the performance of SAM across various applications, particularly in the fields of natural images, agriculture, manufacturing, remote sensing and healthcare. We analyze and discuss the benefits and limitations of SAM, while also presenting an outlook on its future development in segmentation tasks. By doing so, we aim to give a comprehensive understanding of SAM’s practical applications. This work is expected to provide insights that facilitate future research activities toward generic segmentation. Source code is publicly available at https://github.com/LiuTingWed/SAM-Not-Perfect .

1 June 2021
Verified
Conference Paper
Closed access
Wei JiWei Ji
Wei Ji
JLJingjing Li
Jingjing Li
SYShuang Yu
Shuang Yu
MZMiao Zhang
Miao Zhang
YPYongri Piao
Yongri Piao
LCLi Cheng
Li Cheng
Complex backgrounds and similar appearances between objects and their surroundings are generally recognized as challenging scenarios in Salient Object Detection (SOD). This naturally leads to the incorporation of depth information in addition to the conventional RGB image as input, known as RGB-D SOD or depth-aware SOD. Meanwhile, this emerging line of research has been considerably hindered by the noise and ambiguity that prevail in raw depth images. To address the aforementioned issues, we propose a Depth Calibration and Fusion (DCF) framework that contains two novel components: 1) a learning strategy to calibrate the latent bias in the original depth maps towards boosting the SOD performance; 2) a simple yet effective cross reference module to fuse features from both RGB and depth modalities. Extensive empirical experiments demonstrate that the proposed approach achieves superior performance against 27 state-of-the-art methods. Moreover, our depth calibration strategy alone can work as a preprocessing step; empirically it results in noticeable improvements when being applied to existing cutting-edge RGB-D SOD models. Source code is available at https://github.com/jiwei0921/DCF.

4 December 2020
Verified
Book Chapter
Closed access
PDF file
Wei JiWei Ji
Wei Ji
JLJingjing Li
Jingjing Li
MZMiao Zhang
Miao Zhang
YPYongri Piao
Yongri Piao
HLHuchuan Lu
Huchuan Lu

1 June 2021
Verified
Conference Paper
Closed access
Wei JiWei Ji
Wei Ji
SYShuang Yu
Shuang Yu
JWJunde Wu
Junde Wu
KMKai Ma
Kai Ma
CBCheng Bian
Cheng Bian
YZYefeng Zheng
Yefeng Zheng
In medical image analysis, it is typical to collect multiple annotations, each from a different clinical expert or rater, in the expectation that possible diagnostic errors could be mitigated. Meanwhile, from the computer vision practitioner viewpoint, it has been a common practice to adopt the ground-truth labels obtained via either the majority-vote or simply one annotation from a preferred rater. This process, however, tends to overlook the rich information of agreement or disagreement ingrained in the raw multi-rater annotations. To address this issue, we propose to explicitly model the multi-rater (dis-)agreement, dubbed MRNet, which has two main contributions. First, an expertise-aware inferring module or EIM is devised to embed the expertise level of individual raters as prior knowledge, to form high-level semantic features. Second, our approach is capable of reconstructing multi-rater gradings from coarse predictions, with the multi-rater (dis-)agreement cues being further exploited to improve the segmentation performance. To our knowledge, our work is the first in producing calibrated predictions under different expertise levels for medical image segmentation. Extensive empirical experiments are conducted across five medical segmentation tasks of diverse imaging modalities. In these experiments, superior performance of our MRNet is observed comparing to the state-of-the-arts, indicating the effectiveness and applicability of our MRNet toward a wide range of medical segmentation tasks. Source code is publicly available.