Session Index

In this paper, we demonstrate design and operation principle of holographic waveguide by using holographic optical element (HOEs). The preliminary optical experiments have been performed to demonstrate our recursive inference. Then, we propose a novel optical scheme to increase FOV of a VHOE-based waveguide with 2D eye-box expansion.

 

We demonstrate fabrication of the photo-aligned liquid crystal cell using poly[1- [4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) azo-polymer and its application for writing a geometrical phase hologram (GPH).

 

In optical scanning holography (OSH), the interference fringe used for scanning the
object is generated by a two-pupil interferometer. However, this interference system is
sensitive to the environmental fluctuation. Here we proposed a new OSH technique without
interference to minimize environmental fluctuation.

 

To reduce the scanning time, a multifocal confocal microscopy system is designed and developed. By incorporating photopolymer (PQ-PMMA) based volume holographic optical element in the illumination path multifocal spots are generated. Uniformity of each focal spot is achieved by utilizing super Gaussian (SG) beam. Replacing pinhole-detector pair with CCD camera made the system design more simple.

 

High phase accuracy and fast response LCoS panel was applied for pattern recognition and depth sensing with a one-camera optical system. The various focusing distance of the near-infrared structured light can be generated by corresponding CGHs and captured by CCD camera. The captured images were sent to pre-trained model for pattern recognition and interpolation object distance from database. The predict distance error is less than +-2.10 cm in the range between 40 to 200 cm.

 

This paper mainly describes the generation of naked-eye 3D images with a well-designed digital optical phase conjugate system (DOPC). We compare the point light source reconstruction of a single-lens with the lens-array system, and then introduce the generation of the three-dimensional image with the proposed DOPC display.

  Preview abstract

Nowadays, hyperspectral imaging systems are costly and difficult to produce. Besides, the measurement is extremely time-consuming, which is not conducive to the rapidly changing scientific measurement. In this paper, we proposed a hyperspectral imaging system with reasonable production cost and fast measurement speed

  Preview abstract

A series of photopolymers based on the ethylene glycol phenyl ethyl arylate (EGPEA) monomers with varying initiator concentration and sample thickness is synthesized. The advantages of lowering the initiator concentration, including a rather short initiation time within few seconds and a sharp rising optical response, are demonstrated.

 

Airy beam light-sheet microscopy offer advantages in providing better optical sectioning capability, longer field of view, and deeper penetration depth. With the deconvolution method, contrast and resolution in images can be improved by removing out-of-focus noise. Here, we demonstrated Airy light-sheet microscopy and used the Richardson-Lucy deconvolution method to further improve the image quality.

 

In this paper, we present the feasibility of computer generated hologram (CGH) by Neural Network. In our method, CGH is done by autoencoder framework and the training dataset of the deep learning model is created by Iterative Fourier Transform Algorithm (IFTA). The method enables the non-iterative calculation of CGH for real-time applications.

 

Multiphoton excitation can reduce tissue scattering and get deeper image depth. With optogenetics, neural activity can be modulated to influence biological behavior. Precisely spatial and temporal control the shape of lights is important to observe the 3D distributed neural connection. In this study, we use a deep-learning based computer-generated holography to generate holograms with orders of magnitude faster and better accuracy. Furthermore, to improve axial resolution of the stimulated pattern, we introduce temporal focusing (TF) to get a better axial confinement. With all the applied technology, we can real-time and precisely stimulate drosophila brain in single-cell resolution.

 

We used generative adversarial networks (GAN) to help phase retrieval from interferometry. The established image is transformed from fringe pattern to phase map. They can be fitted by Zernike polynomial and reducing the calculating steps.

  Preview abstract

-

  Preview abstract

A profile measurement technique for specular surfaces is proposed. A fringe pattern is posited in front of the inspected surface. A virtual image of the fringe pattern is formed behind the metal surface. The virtual fringes are deformed by topography of the metal object. Thus, phase of the deformed fringes is desirable to retrieve the profile of the specular surface.

 

A method of temperature detection by means of fringe projection is presented. Only one-shot measurement is required. The full-field property makes it possible to inspect several objects at the same time.

 

-

  Preview abstract

Here we demonstrate highly conductive and transparent Aluminum Zinc Oxide (AZO) thin films combined with liquid crystal (LC) mater for application related to light intensity and phase modulation. Comparison between proposed device and conventional ITO based device is made.

 

An anti-reflection device formed by mesoporous silica materials is presented. Reflectance coefficients with large incident angles for various wavelengths is simulated as well.

 

The AR device with a holographic curved waveguide combiner is proposed. The device utilized the conjugated recording method to reduce the aberration caused by the curved reflection surfaces. Furthermore, the ghost noise can be avoided by arranging the dimension and position of the HOEs strategically.

 

We proposed a lensfree face recognition system with scattering encryption by means of an optical diffuser. The facial images were encrypted to be unrecognizable amid the imaging chain of a lensfree system. The encrypted intermediate images can be identified by the ResNet18, a neural network model. We experimentally implemented the system and achieve 100% accuracy subject to10 classes(subjects).

 

In this research, we analysis the measurement uncertainty of digital-grating moiré technique for the measurement of lens focal length. The results reveal that the technique can be applied for regular commercial spherical lenses with a measurement uncertainty less than 1.6 mm within a measurement distance of 2 m. The proposed methodology provides a valuable reference for related measurement techniques.

 

This research aims to integrate the two technologies of digital holography and fringe projection profilometry within the same system. The integrated system is capable of measuring the three-dimensional surface of the object. Utilizing the integrated system results in more complete three-dimensional surface information.

 

In this research, we propose an optical configuration to generate a heterodyne light source using a moving grating with constant speed. The results showed that the frequency of the heterodyne signal can be varied with the speed of grating and exhibited similar results of theoretical prediction.

  Preview abstract

The paper proposes a method for measuring small angle based on phase sensitive
total-internal-reflection heterodyne interferometry. When a half-wave plate, a quarter-wave
plate and an analyzer with proper azimuth angles are arranged in the tested arm of the
interferometer, the phase difference caused by total internal reflection of the interference
signal is greatly enhanced. The phase difference can be precisely measured with the
heterodyne interferometric technique, and the associated angle can be estimated. The
experimental results demonstrate the feasibility of this method.

 

In this study present a novel approach using deep learning-based active wavefront aberration correction for beam rotation holographic tomography to acquire three-dimensional image of native biological cell sample. As a result, the proposed algorithm is capable of accurately correct the background aberration and much faster than its original plain algorithm.

 

A novel 3D detection method was proposed by an incoherent holography based fringe projection profilometer. Compare with the conventional fringe projection profilometer, a high resolution quantitative profile can be realized by calculating without complicated adjustment before each detected procedure. The key point of the quantitative measurement is based on an absolute axis reconstruction by using incoherent holographic recording, which can obtain with the profilometer at the same time.

 

This research is a mosquito trap system, which is mainly divided into three parts. Firstly, 365nm UV light is used for visual induction. Secondly, the secondary element lampshade designed for this experiment is used to optimize the light distribution range, so as to be more suitable for attracting mosquitoes. Finally, the odor and CO2 concentration stimulated by UVA and photocatalyst are used to trap the sense of smell, and the trapping system is optimized by combining the above.

 

We proposed a method to calculating far-field wide-angle intensity distribution of diffractive objects using a modification of the Fraunhofer formula. By comparing with the Huygens-Fresnel formula, the proposed method is able to approximate the far-field wide-angle pattern of sub-micro diffractive objects with about 50% less time and the same accuracy.

 

A computer-generated hologram (CGH) comprising multiple CGHs of sliced images of a 3D object produced a volumetric image used to polymerize photosensitive resin. The method features high efficiency, high resolution, rapid fabrication, and good continuity.

 

This study provided a convenient technique for fabricating LC gratings with crystal/quasicrystal/kaleidoscopic patterns. The 2D patterns were generated with a collimated light to illuminate a high-precision mask with multiple apertures regularly distributed on a ring. The 2D LC gratings were electrically tunable and exhibited polarization-independent first-order diffraction.

  Preview abstract

A multi-beam splitter composed of a diffractive optical element ( DOE ) and a beam expander is proposed in the study. Through the optical simulation by ZEMAX and real optical experiments, it can be demonstrated that a laser beam can be split as four beams and their spot size and directions can be controlled by beam expander, in order to meet the requirement of laser printing system for integrated circuits.


 

This study set up the coaxial scanning fringe projection profilometry. And use the direct amplitude extraction method that is a faster way of image processing. Using curve fitting selection to increase the precision of profile reconstruction by choosing proportion correct images data.

 

The phase errors due to the inevitably noise of unstable ambient light, device flicker, or high surface reflectivity in captured fringes, which are non-ignorable in Fringe projection profilometry (FPP). In this paper, a deep learning-based noise detection and its reduction for 3D shape map is proposed. It enables to detect the noisy regions for inspection utilizing captured fringes by the camera. In order to reduce the measurement errors in noisy regions, the inpainting technique of interpolation is proposed. The experimental results demonstrate the method's efficient performance and efficiency without additional fringe reprojection and devices for 3D shape measurement.

 

We present a multimodal holographic microscopy combined digital holographic microscope and Raman spectroscopy to achieve the label-free cell imaging and diagnosis. The preliminary experimental demonstration shows the simultaneous measurement of neuroblastoma cell imaging and spectrum analysis to reveal the potential label-free biological applications.

 

YOLO (You Only Look Once) neural network uses deep learning for real-time multi-object recognition and detection. This study evaluates YOLO using mask detection for mask wearing mandates. The results show that YOLO is able to recognize people with and without masks in real time, and the accuracy is very high.

 

This research proposes an off-axis digital holographic microscopy (DHM) system, which is used to record digital holograms of living cells and obtain cell growth status from the reconstruction phase. This system records and measures cell changes over a long duration.

 

This study proposed a binocular HMD which consists of a planar acrylic waveguide and four HOEs. The diffractive efficiency of the HOEs was expected via coupled wave theory. The FOV for the system achieve to 17.7° in the horizontal direction and 5.3° in the vertical direction.

 

In this study, we demonstrated the heterodyne frequency with an moving grating at constant
speed. The modulated frequency of heterodyne signal was varied with the grating pitch changed. We
successfully showed that two frequencies of heterodyne signal can be obtained by the grating pitch of
0.833 μm and 1.667 μm, respectively.

  Preview abstract

In this paper, we developed an optical license plate automatic recognition system using the YOLO deep learning framework. During the training process, the license plate data set collected from the network database has a total of 1966 pictures, and then 393 pictures are randomly selected as the test set, the remaining images are used as the training set. then use LabelImg software to label and classify all images, and start training the YOLO neural network. finally, through experimental evaluation, it can be seen that the license plate recognition system proposed in this article, the highest mean Average Precision(mAP) is 90%.

 

We applied a high-resolution digital micromirror device (DMD) together with an imaging system at 405 nm to build a high-resolution hologram printer. Because only a small size of hologram fringes can be displayed on the DMD, the hologram data is separated to many tiles, and every time only a tile is projected to the photoresist for exposure. By stitching all the tiles, a large hologram can be produced.

 

-

  Preview abstract

Based on the previous study that presented an absolute optical rotary encoder (ORE) design with optical resolution of 15 bits by using a Dammann grating, this paper further improves the system with autofocusing for enhancing the optical signal retrieving.

 

Since the invention of microscope, microscope is inconvenient to be carried due to its heavy weight and bulky size. Therefore, we use Lensless Fourier Transform Digital Holographic Microscope system to combine with holographic optical components. It can make the setup smaller and portable, and it also has high resolution.

  Preview abstract

ABSTRACT:In this study, we propose a new counter beam light (CBL) capable of being equipped with 400W, 250W and 100W high pressured Sodium lamp respectively for CIE:88 2004 regulated tunnel road lighting design.
and the proposed light was simulated and its prototype was measured to get its beam pattern information to import into LiteStar 4D softwares for tunnel lighting analysis. The CBL fixture was designed as an optical reflector with three sectional curved finishing surfaces, which mission was to decrease optical glare and enhance object contrast, bringing more safety with drivers in tunnels than convention tunnel lights.

 

The proposed measurement based on total-internal reflection and the polarization interferometry can be used to measure the refractive index of lenses. By finding the relationship between the maximum phase difference and refractive index, the refractive index can be obtained. The system’s resolution is 1.6 × 10-3 RIU.

 

A rotation displacement measurement technique with high resolution for large range measurement is presented. The proposed technique is based on the birefringence effect and phase detection of polarization interferometry with a polarization camera. The experimental results show that the resolution can reach 0.003° with a 10° measurement range.

 

Design a group of two-lens system, and combine with the spatial light modulator (SLM), carry out the research of dynamic pattern enlargement and shrink. According to ynu ray tracing theory calculation, a pattern with 0.6~1.5 times of magnification can be obtained.



  Preview abstract

An LED Counter Beam Light (CBL) with a free surface secondary lens is proposed to enhance the safety and efficiency of tunnels. The secondary lens was designed and produced to be mounted on a 50 W white-light LED array to generate the targeted counter beam pattern, in order to meet the standards for enhanced tunnel road lighting of the CIE (Commission Internationale de l’Eclairage)—CIE 88:2004—in a trial tunnel lighting scheme.

 

In a scanning system, a laser beam moves linearly in one or two dimensions by using a galvanometer or scan mirrors. When using traditional lenses, the profile of the focused beam changes as the beam moves away from the optical axis. In this paper, a F-Theta telecentric lens for wavelength 355 nm is studied to create a flat field and the resulted image height is linearly proportional to the focal length and the scanning angle theta. The rays on the image plane of the proposed lens are parallel to the optical axis.

 

A zoom beam expander is designed for being applied in multi-beam splitter. By shifting the convex lenses in the beam expander, the directions and the spot size of the split beams can be changed. In consequence, a multi-beam splitter can become adjustable for fitting to optical systems with different specifications.

 

Deep learning are widely applied for automatic defect inspection in textile industry due to its versatility. In this research, we developed a compact convolutional neural network (CNN) architecture to position the defect in pixelwise level (segmentation) as well as find the type of abnormalities (classification) on the fabric surface. Proposed model was demonstrated to achieve 93.75% defect accuracy and average 72.92% anomaly classification.

 

We propose a novel dual-field digital holographic microscopy (DFDHM) technique and its miniaturization design for industry needs in future. The proposed technique shows a low noise for reconstruction images. DFDHM has the advantage of switching between bright-field and dark-field DHMs without the use of special optical components, and prevent the risk of damaging the samples.

 

The performance of automotive industrial lighting can be customized to the required applications through 3D LED lighting technology, which is still evolving while reducing costs. Potential for the future lies in the emerging 3D LED lighting technology. Prism array, known light shaping diffuser (the LSD), is integrated into an automobile taillights to provide security and traffic visibility ahead.

 

In this research, a set of spectrally resolved white-light interferometry is constructed to find out the group-refractive-index of beam-splitter. The measured intensity of the white-light interference spectra is analyzed. The phase difference is unwrapped from the interference intensity. This phase difference can be calculated to obtain the group-refractive-index of it.

  Preview abstract

This paper reports on the integration of a broadband light source with reflective optics
to enable white light confocal spectroscopy across a bandwidth of 400 nm to 1000 nm. All study
objectives were achieved, including the development of a scanning white light confocal
spectroscopy and the extraction of one- and two-dimensional spectral-imaging information from
single-point spectra via scanning. This paper focuses on the performance of the measurement
system used in the proposed spectroscopy, which comprises a graded reflectivity mirror.

 

The total market share of high-end eye protection product worth hundreds of billions, for instance, ski goggles which protect users from dust, snow and sun reflection usually cost NT$1000~NT$10000 a pair, but when defects occur during the production, it might cost severe safety issue resulting in danger. We proposed a novel defect detection framework based on image enhancement and deep learning, making the system efficient and precise, defect detection cost 5 sec for a single ski goggle sample with 100% accuracy and 5 sec for its defect recognition with a 96% accuracy.

  Preview abstract

In research,light-driving bug zapper is presented for well controlling the diseases brought by insects, such as mosquitos. In order to have device efficient to trap the insect pests in off-grid areas, pulse width modulated light emitting diodes (PWM-LED) combined with an solar power module are proposed and implemented. With specific PWM electric signals to drive the LED,The ability of catching insects or power efficiency can be enhanced. It is demonstrated that 40% of the electrical energy can be saved and the trapped mosquitos are about 250% increased when the PWM method is applied in bug zapper experiments.

 

With a properly designed null CGH, the mirror corresponding to the CGH can be fabricated and tested. By simulating and gaining understanding about the errors, fabricators can make better informed judgement calls on where to tighten the fabrication process or if a process requires a complete revision.

  Preview abstract

An optical system for measuring the depth distance of an object was proposed. This system can scan a region by obtaining the relationship curve between focus distance and motor step. The depth distance was acquired by determining whether the captured objects was in focus or not by discerning the sharpness of the object’s outline, with the motor step when the object was in focus. The optical path of the system was simple, and its volume was minimal.

 

This paper proposed an overlay measurement error calculation model caused by the pattern-center shift. Furthermore, the multiple-wavelength measurement methodology was used to verify that the overlay measurement error was linearly proportional to the pattern center shift. An asymmetric sidewall structure was set in the simulation showed a linear relationship between the overlay value of multiple-wavelength and the value of pattern center shift, and the R-square of the linear fitting curve was 0.9992.

 

In this paper, a flexibly compatible and wireless-based dynamic 3D acquisition and imaging for increasing mobility and scalability for many practical dynamic scenes in fringe projection profilometry is proposed. However, suffering from the spectrum overlapping and phase distortion artifacts for absolute phase retrieval, it generally yields a coarse phase map with low quality of depth ambiguity problems for dynamic 3D acquisition. We propose a deep learning framework for robust unambiguous depth measurement to ensure the stability of absolute retrieval phase in FPP. The practicality of the proposed deep-learning-based technology is verified by experiments without additional and compromising fringe modulation.

 

In this research, the wide-angle diffractive optical elements (DOEs) correct the distortion and intensity attenuation. The DOEs were designed using a combination method the Iterative Fourier Transform Algorithm (IFTA) with Stepwise quantization and the Large Error Reduction Algorithm (LERA) to optimize the diffraction image and output the phase diagram with the best image quality to make products. The wavelength light source actually illuminates the diffraction image and compares the simulation results and difference with the wafer structures and designed.

 

We demonstrate a 3D volumetric display system which utilizes two Fresnel Mirrors for displaying the 3D images at the exit aperture. The transverse and the longitudinal magnification were derived from the Fourier optics, and the imaging distance was confirmed by a MATLAB program for simulation of the optical dual-lens system.

 

We propose a digital-grating moiré technique for measuring the focal length of spherical lenses and mirrors. The feasibility of the method was experimentally demonstrated with percent errors less than 0.5%. The proposed method should have advantages of a simple setup, high stability, and high accuracy which has considerable potential in relevant application.

 

In this study, a misalignment measurement method was proposed which based on grating-type heterodyne interferometry. The misalignment between two transmission type grating can be obtained and approximated of 0.6 µm.

 

In this paper, we present our investigations on recording true-color holograms using photopolymer materials. The principle and experiments for recording and reconstructing colors of the 3D object based on the recording material and reconstruction light source characteristics are described. The results provide a prerequisite fund of knowledge for building up an electronic true-color holographic 3D display.

 

Optical elements fabricated by 3D printing shows fixed transmittance owing to the restriction of fabrication process. This research combines polymer dispersed liquid crystal (PDLC) with an element fabricated by photo-polymerization 3D printing, making the transmittance of the element tunable as the electric field applied increasingly.

 

We integrate the rainbow holographic technique and the depth-added computer-generated composite hologram (DA-CGHS) to produce a computer-generated rainbow hologram (CGRH). By the proposed method, high definition three-dimensional image can be reconstructed by using white light illumination.