News

2016 has been a fruitful year for MCL. Some members graduated with impressive research work and began a new chapter of life. Some new students joined the MCL family and explored the joy of research. MCL members have made great efforts on their research and published quality research papers on top journals and conferences.

Wish all MCL members a happy new year.

Image credits: Photo 1: “Happy New Year” by maf04, used under CC BY-SA 2.0 / Resized with white padding on the borders; Photo 2: “New Years 2017” by maf04, used under CC BY-SA 2.0 / Resized with black padding on the borders.

Congratulations to Shangwen Li for passing his defense on December 1, 2016. His Ph.D. thesis is entitled “Multimodal Image Retrieval and Object Classification Using Deep Learning Features”.

Abstract of thesis:

Computer vision has achieved a major breakthrough in recent years with the advancement of deep learning based methods. However, its performance is still yet to be claimed as robust for practical applications, and more advanced methods on top of deep learning architecture are needed. This work targets at using deep learning features to tackle two major computer vision problems: Multimodal Image Retrieval and Object Classification.

Multimodal Image Retrieval (MIR) aims at building the alignment between the visual and textual modalities, thus reduce the well-known “semantic gap” in image retrieval problem. As the most widely existing textual information of images, tag plays an important semantic role in MIR framework. However, treating all tags in an image as equally important may result in misalignment between visual and textual domains, leading to bad retrieval performance. To address this problem and build a robust retrieval system, we propose an MIR framework that embeds tag importance as the textual feature. In the first part, we propose an MIR system, called Multimodal Image Retrieval with Tag Importance Prediction (MIR/TIP), to embed the automatically predicted object tag importance in image retrieval. To achieve this goal, a discounted probability metric is first presented to measure the object tag importance from human sentence descriptions. Using this as ground truth, a structured object tag importance prediction model is proposed. The proposed model integrates visual, semantic, and context cues to achieve robust object tag importance prediction performance. Our experimental results demonstrate that, by embedding the predicted object tag importance, significant performance gain can be obtained in terms of [...]

Thanksgiving luncheon, which has always been a tradition of MCL, was held on December 3, 2016. More than 30 MCL members and their families attended the luncheon. The atmosphere was joyful and we enjoyed the food and conversation with each other. “It has been a long time that I haven’t tasted good Chinese food since I arrived in LA. I would like to thank Professor Kuo for treating us to such a good luncheon,” said Professor Xin Zhou. “The atmosphere is so joyful. I enjoyed the casual chats with others,” said Anubhuti.

Though most of the MCL members are international students and did not get to spend Thanksgiving with their families. We were so happy to celebrate Thanksgiving with other MCL members as a big family.

MCL members, Yuzhuo Ren and Wenchao Zheng presented their papers at Asian Conference on Computer Vision (ACCV) 2016.

Yuzhuo’s presented paper is entitled “a coarse-to-fine indoor layout estimation (CFILE) method”. Here is an abstract of the paper:

Existing solutions to indoor layout estimation problem largely rely on hand-craft features and vanishing lines, and they often fail in highly cluttered indoor rooms. The proposed coarse-to-fine indoor layout estimation (CFILE) method consists of two stages: 1) coarse layout estimation; and 2) fine layout localization. In the first stage, we adopt a fully convolutional neural network (FCN) to obtain a coarse-scale room layout estimate that is close to the ground truth globally. The proposed FCN considers combines the layout contour property and the surface property so as to provide a robust estimate in the presence of cluttered objects. In the second stage, we formulate an optimization framework that enforces several constraints such as layout contour straightness, surface smoothness and geometric constraints for layout detail refinement. Our proposed system offers the state-of-the-art performance on two commonly used benchmark datasets.

Wenchao’s paper is entitled “Object Boundary Guided Semantic Segmentation”. Here is a brief summary of the paper:

Recent development in fully-convolutional neural network (FCN) has enabled accurate pixel-level in semantic segmentation. However, segmentation details are lost since the object boundary information is not exploited. Our proposed object boundary guided FCN (OBG-FCN) is able to integrate the distinct properties of object shape and class features elegantly in a fully convolutional way with a designed masking architecture. We show that the end-to-end trainable OBG-FCN system offers great improvement in optimizing the target semantic segmentation quality.

Congratulations to Yuzhuo and Wenchao for their quality research work!

The MCL joined a collaborative project to build a large-scale subjective video quality database. The database was proposed to boost a major breakthrough in video coding and processing. On one hand, revolutionary ideas rather than fine-tuning patches are highly expected to accommodate increasing video traffic. On the other hand, PSNR has been the dominant distortion metric for many years, but it has also been criticized for not correlating well with perceptual quality. With this database, perceptual coding is promising to lead to numerous R&D opportunities and revolutionary research with machine learning tools.

The database consists of 200 raw sequences with a duration of 5 seconds, encoded by H.264/AVC with fixed QP as bit rate control method. They are available in 5 resolutions from 3840×2160 to 540×360. Around 1000 students participated in the subjective test and it took around 7000 hours to get sufficient samples about 3 JND points. The database will be freely available for downloading for scientific purposes.

The projected was supported by 4 major multimedia companies, Netflix, Huawei, MediaTek, and Samsung. Meanwhile, 6 universities at Shenzhen joined the project, Shenzhen Institutes of Advanced Technology (Chinese Academy of Science), Shenzhen University, Graduate School at Shenzhen (Tsinghua University), Peking University Shenzhen Graduate School, The Chinese University of Hong Kong (Shenzhen), City University of Hong Kong.

We would like to give special thanks to the participating companies, institutes and universities.