Chok Hang Yeung

ORCID: 0000-0003-2448-5965
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About
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Research Areas
  • Digital Holography and Microscopy
  • Cell Image Analysis Techniques
  • Image Processing Techniques and Applications
  • Photoacoustic and Ultrasonic Imaging
  • Wastewater Treatment and Nitrogen Removal
  • Domain Adaptation and Few-Shot Learning
  • Microbial Fuel Cells and Bioremediation
  • Image Enhancement Techniques
  • Advanced Neural Network Applications
  • Calcium Carbonate Crystallization and Inhibition
  • Herbal Medicine Research Studies
  • Water Quality Monitoring Technologies
  • Random lasers and scattering media
  • Geophysical and Geoelectrical Methods
  • Vitamin K Research Studies
  • Sesquiterpenes and Asteraceae Studies
  • Phytochemistry and Biological Activities
  • Microbial Community Ecology and Physiology
  • Advanced Optical Sensing Technologies
  • Industrial Vision Systems and Defect Detection
  • Constructed Wetlands for Wastewater Treatment
  • Advanced Image and Video Retrieval Techniques
  • Vitamin C and Antioxidants Research
  • Synthetic Aperture Radar (SAR) Applications and Techniques

University of Hong Kong
1976-2022

Hong Kong University of Science and Technology
2021-2022

Stanford University
2004-2012

Chinese University of Hong Kong
1976

Ammonia-oxidizing bacteria (AOB) have long been considered key to the removal of nitrogen in activated sludge bioreactors. Culture-independent molecular analyses established that AOB lineages bioreactors are dynamic, but underlying operational or environmental factors unclear. Furthermore, contribution ammonia-oxidizing archaea (AOA) has not studied. To this end, we investigated abundance AOA and as well correlations between dynamics parameters at a municipal wastewater treatment plant...

10.1111/j.1462-2920.2009.01958.x article EN Environmental Microbiology 2009-06-09

Abstract The observation and detection of the microplastic pollutants generated by industrial manufacturing require use precise optical systems. Digital holography is well suited for this task because its non-contact non-invasive features ability to generate information-rich holograms. However, traditional digital usually requires post-processing steps, which time-consuming may not achieve final object performance. In work, we develop a deep learning-based holographic classification method,...

10.1088/2515-7647/abf250 article EN cc-by Journal of Physics Photonics 2021-03-26

We devise an inline digital holographic imaging system equipped with a lightweight deep learning network, termed CompNet, and develop the transfer for classification analysis. It has compression block consisting of concatenated rectified linear unit (CReLU) activation to reduce channels, class-balanced cross-entropy loss training. The method is particularly suitable small imbalanced datasets, we apply it detection microplastics. Our results show good improvements both in feature extraction,...

10.1364/ao.403366 article EN Applied Optics 2020-09-16

Microplastic (MP) pollution poses severe environmental problems. Developing effective imaging tools for the identification and analysis of MPs is a critical step to curtail their proliferation. Digital holographic can record morphological refractive index information such small plastic fragments, yet due heterogeneous sampling environments variations in MP shapes, traditional supervised learning methods are limited use. In this work, we pioneer zero-shot method that combines images with...

10.1063/5.0093439 article EN cc-by APL Photonics 2022-06-15

A search in ancient Chinese medicinal literature and modern phytochemical reference indicates that the therapeutic value of Leonurus artemisia (I-mu ts'ao, motherwort) might reside a uterotonic principle present leaves. Leonurine (4-guanidino-n-butyl syringate) was isolated from fresh dry leaves artemisia. The effect leonurine demonstrated rat uterus vitro. Results this study suggest functional phytochemistry based on ethnobotanical experience could lead to development new effective drugs medicine.

10.1142/s0192415x76000470 article EN The American Journal of Chinese Medicine 1976-01-01

Micro-objects, such as microplastics and particulate pollution, need to be accurately observed detected by high-precision optical systems. Digital holography is a powerful tool detect microscopic objects. However, traditional digital requires additional image processing phase unwrapping, de-noising, refocusing, which costs lot of time does not have consistently better performance in micro-object detection. Here, we propose an intelligent holographic classifier, deep learning-based lensless...

10.1109/indin45582.2020.9442146 article EN 2022 IEEE 20th International Conference on Industrial Informatics (INDIN) 2020-07-20

An inline digital holography with deep learning is developed to detect microplastics automatically from the raw holograms, without any additional image processing and analysis.

10.1364/dh.2020.htu5b.1 article EN Imaging and Applied Optics Congress 2020-01-01

Microplastics, which are a major source of pollution in the ocean, need to be accurately detected and monitored. However, current detection approaches often require complex optical instrumentation long time for image processing. Furthermore, because difficulties particle sampling, it is hard collect dataset with sufficient images balanced distribution. Digital holography, non-destructive imaging method, suitable situ imaging. In this work, we propose novel digital holography microplastics...

10.1117/12.2575115 article EN 2020-10-10

Detecting and quantifying microplastic particles have become important problems in environmental monitoring recent years. In the natural environment, nanoplastic are often mixed with large pieces of plastic, microalgae, microorganisms, leaf fragments, etc., making them difficult to be distinguished. addition, microplastics themselves made different materials various shapes. As a result, conventional classification methods based mostly on morphological characteristics cannot accurately...

10.1117/12.2606532 article EN Twelfth International Conference on Information Optics and Photonics 2021-11-01

Underwater imaging is often affected by light scattering, which leads to a significant degradation in image quality and resolution. We propose digital holographic microscopy method with polarization multiplexing for underwater descattering. Our based on single laser source, so that the reference different states can interfere object at same time, required information be extracted frequency spectrum. Combined formation model, we achieve descattering one step. The experimental results...

10.1109/metrosea52177.2021.9611560 article EN 2021-10-04

Water scattering is a significant limiting factor for underwater imaging quality. It changes the transportation direction of original light path, causes attenuation intensity, and so on. In this work, we use synthetic polarizing camera to capture images with different polarization states reduce impact water in one step propagation model Stokes vector. addition, an untrained deep network designed complete image descattering processing. Compared methods based on learning or physical prior, it...

10.1117/12.2601098 article EN 2021-10-09

A zero-shot learning method with attribute embedding is developed for holographic image analysis and microplastics probing. Experimental results show its efficacy in identifying the unknown alleviating need manual dataset class annotation.

10.1364/dh.2022.w5a.41 article EN Digital Holography and 3-D Imaging 2022 2022-01-01

We propose a novel digital holographic microscope system with synthetic polarization. It can obtain the light intensity of different polarization states in single shot and achieve descattering underwater imaging through polarity calculation.

10.1364/dh.2021.dtu6h.6 article EN OSA Imaging and Applied Optics Congress 2021 (3D, COSI, DH, ISA, pcAOP) 2021-01-01
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