INVITE SPEAKERS
Wei Wang
Heriot-Watt University, UK
Speech Title: Towards Polarization
Sensitive Machine Vision: Stokes Correlations for
Diagnostics of Random Polarization
Abstract: In system
engineering, machine vision has been used to extract
information from an image on an automated basis for
applications such as automatic inspection and robot and
process guidance in industry, for security monitoring
and vehicle guidance. It has been recognized that the
polarization and coherence properties of light have
significant influence on the image formation. With the
recent progress in device technology for highresolution
polarization cameras and liquid-crystal-based spatial
polarization modulators, the field of machine vision and
application has been growing at a fast pace and an
increasing interest has been attracted for new
applications such as biomedical diagnosis, remote
sensing, and mineralogy.
In this talk, we will review our recent work on the
Stokes-correlation-based technology with its application
to machine vision. With the aid of the ensemble-average
van Cittert-Zernike theorem for the propagation of
polarcoherence, we investigated the autocorrelation
functions and power spectra of the Stokes parameters to
highlight the dependence of the polarization-related
scale-size distributions. A generalized concept of the
Stokes ensembleaverage coherence areas has been
introduced to deal with the polarization-related average
areas associated with polarization speckle. Noting the
fact that the Stokes parameters cannot be measured at an
ideal point, we also made investigation of the means and
variances of the integrated Stokes parameters in
polarization speckle after introduction of four
parameters, i.e., the numbers of degrees of freedom for
the Stokes detection. Furthermore, a new scheme of
interferometry referred to as the Stokes Vector
Interferometry has been proposed as an extension of
intensity interferometry by taking the vector nature of
the electromagnetic field into account. Through the
cross-covariance computations for the fluctuating Stokes
parameters, the squared moduli of the generalized Stokes
parameters are reconstructed for the first time.
Biodata: Wei Wang received his BSc and DSc in Physics from University of Science and Technology of China, in 1997 and 2001, respectively, and his PhD with summa cum laude in Optics from the University of Electro-Communications, Japan, in 2006. He was a Japanese Government (MONBUKAGAKUSHO) Scholar from 2002 to 2003, Research Fellow of Japan Society for the Promotion of Science (JSPS) from 2003 to 2006, and COE (Center of Excellence) Post-Doctoral Research Fellow from April of 2006. Recently, he took up a lectureship in Department of Mechanical Engineering at Heriot-Watt University, Edinburgh, UK. Dr. Wang's research interests are around statistical optics, optical information processing, imaging science and their applications to optical metrology and sensing. He has published over 60 papers in journals and conference proceedings, and was awarded the best science paper award of the Japan Society for Applied Physics in March 2007 (its highest research award of Optical Society of Japan). He is a member of the SPIE, OSA, and JSAP.
Chau-Jern Cheng
National Taiwan Normal University, Taiwan
Speech Title: Deep Learning-enabled Holographic Tomography
Abstract: This talk
will describes a systematic approach of deep
learning-enabled holographic tomography for biological
cells processing, analysis, and diagnosis through
three-dimensional (3-D) cell refractive index (RI)
model. The deep learning-assisted technique is applied
to execute the system calibration of the holographic
tomography before cell processing, analysis, and
diagnosis. Deep learning also perform effective
segmentation of 3-D RI cell morphology for the different
cellular states under normal, autophagy, and apoptosis.
For heuristic example, we show a label-free possibility
of 3-D cell RI model for neuroblastoma cell death
identification. The biophysical parameters of 3-D RI
cell morphology are analyzed and selected for
learning-based classification to identify cell death
pathways. The results show that the proposed approach
achieve high hit rate in identifying cell morphology and
cell death states through optimized biophysical
parameters.
Biodata: Chau-Jern Cheng received his PhD degree in Electro-Optical Engineering from the National Chiao-Tung University, Taiwan, in 1994. From 1994 to 2007, Prof. Chau-Jern Cheng was invited to be the faculty of St. John’s & St. Mary’s University, Feng-Chia University, and National Taipei University of Technology. Prof. Cheng is currently the Distinguished Professor of Institute of Electro-Optical Engineering, National Taiwan Normal University. Prof. Cheng served as the Topical/Guest Editor of Applied Optics (OPTICA), Chinese Optics Letters (CLP & OPTICA) etc.. His research interests include information optics & photonics, optical metrology, digital holography, computer-generated holography, 3-D imaging & display, artificial intelligence (AI)/deep learning (DL) and related fields.
Wenqi He
Shenzhen University, Shenzhen, China
Speech Title: Recent Works on the
GROUND GLASS: From Encrypting to Imaging
Abstract: Almost three
decades ago, the ground glass was used to encrypt 2D
information by adopting a conventional 4f architecture,
namely the Double Random Phase Encoding, the milestone
work in optical encryption. In the past ten years, we
published a series of works to analysis the security
flaws of those optical encryption schemes. About 5 years
ago, we realized that the cryptanalysis is the same
thing with the IMAGING through a ground glass. From
then, we are mostly focusing on the imaging things,
mainly using the speckle auto-correlation algorithm, the
PSF-based technique or even the deep learning strategy.
A crucial issue there is the limited FOV. We’ve made
some progresses on it. In a recent work we even realized
the customization of the FOV in a scattering imaging
system. More recently, we find back the
security/encryption application referring to the ground
glass, a high-security level storage method for
traditional digital secret key.
Biodata: Associate Prof. Dr. HE works at the College of Physics and Optoelectronic Engineering of Shenzhen University, China. He received his BS in optoelectronic information engineering from South China Normal University in 2007, an MS in physical electronics, and a Ph.D. in optical engineering from Shenzhen University in 2010 and 2012. Dr. He’s research interests include computational optical imaging, metrology, and machine vision. He has authored more than 50 papers in peer-reviewed professional journals.
Yoshio Hayasaki
Utsunomiya University, Japan
Speech Title: Holographic
Femtosecond Laser Processing Enhanced with Optical
Interferometry
Abstract: A shaped beam
is effective for increasing the processing throughput in
laser grooving of silicon wafers, laser scribing of
indium tin oxide films, and thin-film solar, and laser
cleaving of glass substrates, because an ordinary
Gaussian beam gives undesired melting of the material
due to thermal conduction, called the heat-affected
zone, occurs around the processed area if the intensity
at both ends of the Gaussian profile is below the
ablation threshold of the substrate material. Also, the
center peak intensity of the Gaussian beam may cause
serious damage to the substrate. To obtain the desired
depth of the processed structure in the above material
laser processing, optimal processing parameters should
be explored according to the target material. A complex
set of parameters is usually explored experimentally.
The post-processing with scanning electron microscopy
and atomic force microscopy is used to optimize the set
of parameters based on a high-resolution image of the
processed structure. The post-processing is iteratively
performed until the desired structure is obtained.
Accordingly, significant time and production costs are
required. To overcome these issues, in-process
monitoring of the depth of the processed structure in
laser drilling of silicon with picosecond pulses has
been demonstrated. In our research, optical
interferometric methods based on a hand-made
swept-source optical coherence tomography (SS-OCT)
system and a commercially available white-light
interferometry (WLI) are employed. The advantage of
SS-OCT is the ability to perform non-mechanical depth
scanning (A-scan). Accordingly, it is possible to
perform laser processing while simultaneously measuring
the depth of the processed structure. The advantage of
WLI is no lateral beam scanning although it needs the
axial beam scanning. They can be used depending on the
purposes and the target structures. The in-process
monitoring of processed structures is applied to
holographic femtosecond laser processing based on a
computer-generated hologram (CGH) displayed on a
liquid-crystal spatial light modulator (LC-SLM).
Biodata: Yoshio Hayasaki received his PhD degree in Applied Physics from The University of Tsukuba, Japan in 1993. From 1993, Prof. Yoshio Hayasaki was invited to be the faculty of Photodynamic Research Center, RIKEN, Japan, The University of Tokushima, Japan, and Utsunomiya University, Japan. Prof. Hayasaki’s research areas are Applied optics/Quantum optical engineering / Applied optics/Quantum optical engineering / Science and Engineering / Inorganic industrial materials.
Rong Su
Shanghai Institute of Optics and Fine Mechanics, Chinese
Academy of Science, China
Speech Title: Fourier Optics
Models for 3D Image Formation in Interference Microscopy
Abstract: Interference
microscopy is a three-dimensional (3D) imaging technique
that provides quantitative analysis of industrial and
biomedical specimens. Although the major components of
the 3D imaging theory for interference microscopy have
been developed and documented, the use of the 3D imaging
theory in the modelling, design, development and
improvement of 3D interferometric imaging methods is
advancing slowly, mainly due to the difficulty of
understanding the 3D theory, inconsistencies in the
previous derivations, and the missing links between
scattering and imaging processes, between the 2D and 3D
imaging theories, and among different approximations in
the context of interference microscopy. Advance in
understanding the 3D image formation in interference
microscopy is introduced in this talk, providing a
significant physical insight into the instrument
response of objects with complex geometries, underpins
the development of virtual optical instrument for
surface metrology, and paves the way for new instrument
designs.
Biodata: Prof. Rong Su is currently with Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences. He received BSc from Sun Yat-sen University, and MSc in photonics and PhD in optical metrology from KTH Royal Institute of Technology in Sweden. Between 2015 and 2021 he worked at the National Physical Laboratory and University of Nottingham in the UK. He has had a long-term commitment to ultra-precision optical surface topography measuring instruments and technology, focusing on the basic theory of interferometric imaging and scattering, algorithm, calibration, industrial applications and corresponding international standards. He has published 40+ peer-reviewed journal papers and 2 book chapters, and had ten-year research and management experience in EU and UK projects. His research outcomes have been adopted by world-leading optical instrument manufacturers. In 2021, he was awarded a fellowship from the Chinese Academy of Sciences and since then has secured more than 20-million funding for research. He is an editor of Light: Advanced Manufacturing and Nanomanufacturing and Metrology, a program committee member of SPIE, ASPE and EOSAM conferences, an observer of the National Professional Standardization Committee, a member of the Professional Committee of Measuring Instruments of the Chinese Society of Measurement.
Percival Almoro
University of the Philippines Diliman, Philippines
Speech Title: Multiple-plane Phase
Retrieval using Nature-Inspired Algorithm
Abstract: In conventional
iterative phase retrieval with an initial guess phase,
the lack of intensity variation can result in stagnation
artifacts. Here, an algorithm based on insect behavior
that naturally determines optimum solution is explored
for multiple-plane phase retrieval. The effectiveness of
the technique is investigated in terms of rate and
quality of reconstructions.
Biodata: Dr. Percival
Flavier Almoro is a professor at the National Institute
of Physics, University of the Philippines Diliman. He
researched on holograms, phase retrieval, and optical
metrology during his postdoc fellowship stints at the
University of Utsunomiya, Japan in 2014, Risoe National
Laboratory, Denmark in 2008-2009, and at the University
of Stuttgart, Germany in 2006.
A current focus of his research is on the development of
novel algorithms for enhanced phase retrieval. Stemming
from object-related and detector sampling issues, lack
of intensity variation in the measurements may lead to
the problems of slow convergence and poor
reconstruction. Assessment of these physical issues is
critical and further development of more robust
algorithmic strategies is being actively pursued.
Peng Gao
Xidian Univeristy, China
Speech Title: Quantitative phase
contrast tomography (QPCT)
Abstract: Optical
three-dimensional (3D) microscopy is one of the
indispensable common basic technologies in many frontier
fields and has essential scientific and practical
values. In this talk, quantitative phase contrast
tomography (QPCT) for observing 3D subcellular
organelles inside transparent samples (for instance
biological cells) will be presented. QPCT was performed
by switching LEDs distributed on a ring to generate
oblique illuminations at different angles and carrying
out quantitative phase contrast imaging for each
illumination with a ultra-fast spatial light modulator
(SLM). A 3D tomographic phase map of transparent samples
can be reconstructed from the phase-shifted phase
contrast images obtained at different illumination
angles. We demonstrated QPCT with 3D imaging of 200-nm
polystyrene microspheres (PMs) and sub-organelles inside
COS7 cells. The results reveal that QPCT has a high
spatiotemporal resolution, low speckle noise, and
thence, it has a great potential to be applied to
industrial testing and life science research.
Biodata: Prof. Dr. Peng Gao, studied Physics and received his Ph.D. at the Xi’an Institute of Optics and Precision Mechanics (XIOPM), CAS, in 2011. He was a “Humboldt Fellow” in University Stuttgart (2012-2014) and Marie-Curie Fellow (IEF) in KIT (2014-2018). He is currently a PI at Xidian University. His group focuses on developing quantitative phase microscopy and super-resolution optical microscopy techniques for biology. So far, he has authored over 100 peer-reviewed papers published in journals, including Nat. Photonics, Adv. Opt. Photon. Some of his publications were highlighted by tens of international media, such as Science Daily, Physics News, and so on. He is currently one of the associate editors of Optics and Laser Technology (OLT) and Frontiers in Physics.
Qian Kemao
Nanyang Technological University, Singapore
Speech Title: Tab
Biodata: Dr Qian Kemao is an Associate Professor in the School of Computer Science and Engineering (SCSE) at Nanyang Technological University (NTU). He graduated from University of Science and Technology of China (USTC), where he got his BE, ME and PhD degrees. His research interests include optical metrology, image processing, parallel computing, and computer vision.
Max Liebmann
HoloEye Company Berlin, Germany
Speech Title: LCOS SLMs as
Versatile Tools for Optical Imaging and Metrology
Abstract: Over the past
decades, Spatial Light Modulators (SLM) have proven
themselves to be a powerful device in many applications
like microscopy, telecommunication, digital holography
and more.
Among SLM technologies, Liquid Crystal on Silicon (LCoS)
enables dynamic shaping of light fields in terms of
amplitude, phase, or polarization. Being able to
individually control these parameters, opens for new
ideas on possible use cases. The broad field of machine
vision systems is one of them.
In fact, considering already established practices, LCoS
SLMs can offer solutions and improvements for many
aspects of such systems: First, dynamic, and structured
illumination. Second, imaging through scattered media,
and ghost imaging. Third, optimization of data
processing speed via optical computing.
In this regard, utilizing the versatility of LCoS SLMs,
one might just overcome most of the challenges of
machine vision.
Biodata: Max Liebmann
received the B.E. degree in physical science from the
college of technology Wildau (Germany) in 2017.
He pursued with a M.E. degree in photonics from the
colleges of technology Wildau and Brandenburg (Germany)
in 2020.
During his study he worked as a Research Assistant at
the Max-Born-Institute for Nonlinear Optics and Short
Pulse Spectroscopy (Berlin, Germany). His investigations
on generation and spectral characterization of optical
vortices drove his interest into spatial light
modulation.
Since 2020, he has been with HOLOEYE Photonics AG
(Berlin, Germany) where he currently holds the position
as an application manager. From there he was able to
extend his research on applications for liquid-crystal
on silicon display technology.
Caojin Yuan
Nanjing Normal University, China
Speech Title: The Light Field
Modulation Techniques and Their Applications in
Information Security
Abstract: Orbital angular
momentum (OAM) holography which has attracted wide
attentions from researchers in high-security encryption
field. In this presentation, besides reviewing the
traditional OAM holography, newly developed OAM
holography techniques and their applications will be
introduced. The modulated parameters including the moiré
phase plate, the topological charge (TC) number, the
moiré constant, the azimuthal displacement factor, the
sub-region space location and the displacement amount on
the structure of the moiré phase plate can be used as
encoding and decoding keys in OAM holography. The
feasibility of the proposed schemes with the above
parameters are verified by numerical simulations and
experiments. The advantage is of higher design freedom
and security compared to the existed previously proposed
orbital angular momentum multiplexed holography
techniques. The flexibility of the moiré phase plate
promotes the encrypted channel diversity and shows a new
perspective.
Biodata: Caojin Yuan received her Ph.D in Optical engineering from Nankai University in 2008. She is a professor in the school of Physics and Technology at Nanjing Normal University. She serves as the dean of Optoelectronic information Science and Engineering Department. Her current research interests include: quantitative phase imaging and optical information encryption.
Xiang Peng
Shenzhen University, China
Speech Title: Making Range and
Shape Scanning more Smart
Abstract: In this talk we
focus on a topic of 3D scanning of complex shapes with a
mobile device. When scanning an object with a handheld
3D scanner, we must deal with two key issues: sensor
tracking and re-localization in order to provide a good
initial guess, for the registration of multi-view range
images, with use of the ICP strategy. We shall discuss
the technical route of sensor tracking based on an
unsupervised learning approach, following by a route of
re-localization with help of fast point feature
histogram (FPFH). Furthermore, we propose a
learning-based approach to construct feature descriptor
on the set of point clouds, which shows a promising
potential for making the handheld 3D scanning more
smart.
Biodata: Xiang Peng received his B.S., M.S., and Ph.D. from Tianjin University in 1981, 1984, and 1989, respectively, all in Optical Engineering. From July 1985 to July 1986, he is a visiting scholar at the Department of Electrical and Electronic Engineering, University of Huston, TX, USA. From August 1990 to June 1992, Dr. Peng was awarded a fellowship by Alexander von Humboldt Foundation, Germany. He worked with Institute of Applied Optics (ITO) at University of Stuttgart as an Alexander von Humboldt Fellow. Prof. Peng’s current research interests include Optical Imaging, Metrology, and Optical Security. Prof. Peng has numerous publications in refereed journals and was awarded more than 20 inventions wherein ten of patents have been transferred to ESUN Co. Ltd.. He also serves as Director of Engineering Laboratory for 3D imaging and modeling of Shenzhen Government and Principal Scientist at the ESUN Co. Ltd. Prof. Peng’s research activities have been supported by Natural Science Foundation of China (NSFC), Sino-German Center for Research Promotion (SGCRP), and Industrial Sectors.
Jun Ma
Nanjing University of Science and Technology, China
Speech Title: Interferometric
Absolute Testing Method Based on Tilted Wave
Illuminations
Abstract: The
high-precision surface of the optical elements is an
important guarantee for the overall performance of the
optical system, and its implementation requires multiple
iterations between fabrication and testing. Fizeau
interferometry is commonly utilized in optical workshops
as a testing technique, but the reference surface and
system errors limit the ability to improve accuracy
further. Therefore, interferometric absolute testing
methods are required to eliminate these effects.
Traditional absolute testing methods suffer from
adjustment-induced errors such as translation and
rotation operations to the flat, which will break the
stability and introduce additional measurement errors,
especially for large aperture interferometry. Different
from those, this study focuses on the modulation of
light source rather than the cavity and provides more
conditions based on the manipulation of the light
source. Specifically, a unique light source array is
designed to generate four tilted wave illuminations,
which can realize the micro-translation between the two
coherent wavefronts. Besides, simultaneous collection of
four interferograms in a single frame is realized with a
novel design for the imaging optics. Combined with the
traditional conjugate differential absolute testing
wavefront reconstruction algorithm, high-accuracy and
repeatability absolute surface results can be obtained.
The proposed method avoids adjustments to the cavity and
provides a novel approach for interferometric absolute
testing.
Biodata: Dr. Jun Ma is a professor in the school of Electronic and Optical Engineering at Nanjing University of Science and Technology. He received his B.E. in 2005, and Ph.D. in 2011 at the same university. His research interests includes optical interferometry, digital holography, and imaging optics. Currently, he is a Changjiang Junior Scholar awarded by the Ministry of Education of the People’s republic of China. Since 2022, he serves as the deputy dean of the school.