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Chen A.,State Key Laboratory of Modern Optical Instrumentation | Yuan F.,State Key Laboratory of Modern Optical Instrumentation | Liu J.,State Key Laboratory of Modern Optical Instrumentation | Liu S.,State Key Laboratory of Modern Optical Instrumentation | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

In this paper, an overlapped sub-block gray-level average method for contrast enhancement is presented. The digital image correction of uneven illumination under microscope transmittance is a problem in image processing, also sometimes the image in the dark place need to correct the uneven problem. A new correction method was proposed based on the mask method and sub-blocks gray-level average method because Traditional mask method and background fitting method are restricted due to application scenarios, and the corrected image brightness is low by using background fitting method, so it has some limitations of the application. In this paper, we introduce a new method called AOSCE for image contrast enhancement. The image is divided into many sub-blocks which are overlapped, calculate the average gray-level of the whole image as M and the calculate the average gray-level of each one as mi, next for each block it can get d = mi - m, each block minus d to get a new image, and then get the minimum gray-level of each block into a matrix DD to get the background, and use bilinearity to get the same scale of the image. over fitting the image in matlab in order to get smoother image, then minus the background to get the contrast enhancement image. © 2016 SPIE.


Lu C.,State Key Laboratory of Modern Optical Instrumentation | Lu C.,Zhejiang University | Liu X.,Zhejiang University | Li Y.,East China University of Science and Technology | And 4 more authors.
ACS Applied Materials and Interfaces | Year: 2015

The design and engineering of multifunctional nanostructures with multiple components and synergistic properties are in urgent demand for variety of acceptable biosensing platforms, enabling users to fulfill multiple tasks in a single nanosystem. Herein, we report using an asymmetric hematite-silica hybrid of Janus γ-Fe2O3/SiO2 nanoparticles (JFSNs) as a multifunctional biosensing platform for sensitive colorimetric detection of H2O2 and glucose. It was demonstrated that JFSNs exhibit an intrinsic peroxidase-like catalytic activity. Compared with natural enzyme, JFSNs nanoenzymes could be used over a wider range of pH and temperatures and were more stable over time. Importantly, besides its excellent catalytic activity, the asymmetric properties of the Janus nanoparticle enable it to form the multiple functional utilities for various biosensing applications, including the ease of surface modification without deactivation of catalytic activity and recoverable use by magnetic separation. Thus, we utilized JFSNs with glucose oxidase (GOx) immobilization for glucose-sensitive colorimetric detection, which exhibited both catalytic activity of glucose oxidase and peroxidase with high selectivity and acceptable reproducibility. By combining these two analysis systems into Janus particles, an all-in-one and reusable sensor for blood glucose was formed and has the capability for determination of glucose in complex samples such as serum. These results suggest that such Janus nanosystems have the potential to construct robust nanoarchitecture with multiple functionalities for various biosensing applications. © 2015 American Chemical Society.


Peng Y.-F.,State Key Laboratory of Modern Optical Instrumentation | Li H.-F.,State Key Laboratory of Modern Optical Instrumentation | Zhong Q.,State Key Laboratory of Modern Optical Instrumentation | Xia X.-X.,State Key Laboratory of Modern Optical Instrumentation | Liu X.,State Key Laboratory of Modern Optical Instrumentation
Optical Engineering | Year: 2013

A scalable system to achieve large-sized light field three-dimensional display using multi-projectors and directional diffuser is presented. The system mainly employs an array of mini-projectors projecting images onto a special cylindrical directional diffuser screen. The principle of light field reconstruction, configuration of multi-projectors style, and characteristics of directional diffuser are explicitly analyzed, respectively. A prototype of a piece of equipment in mini-cinema class is proposed, with 100 mini-projectors and a special cylindrical directional diffuser performing different diffuse angles in horizontal and vertical directions. Bright and large-sized three-dimensional images displayed by the system can be observed at different horizontal viewing positions around the cylindrical display area with stereo parallax and motion parallax.


Dong W.,State Key Laboratory of Modern Optical Instrumentation | Feng H.,State Key Laboratory of Modern Optical Instrumentation | Xu Z.,State Key Laboratory of Modern Optical Instrumentation | Li Q.,State Key Laboratory of Modern Optical Instrumentation
Optics Communications | Year: 2012

In this paper, we present a method for single image blind deconvolution. To improve its ill-posedness, we formulate the problem under Bayesian probabilistic framework and use a prior named Fields of Experts (FoE) which is learnt from natural images to regularize the latent image. Furthermore, due to the sparse distribution of the point spread function (PSF), we adopt a Student-t prior to regularize it. An improved alternating minimization (AM) approach is proposed to solve the resulted optimization problem. Experiments on both synthetic and real world blurred images show that the proposed method can achieve results of high quality. © 2012 Elsevier B.V. All rights reserved.


Chen J.,State Key Laboratory of Modern Optical Instrumentation | Feng H.,State Key Laboratory of Modern Optical Instrumentation | Pan K.,State Key Laboratory of Modern Optical Instrumentation | Xu Z.,State Key Laboratory of Modern Optical Instrumentation | Li Q.,State Key Laboratory of Modern Optical Instrumentation
Optik | Year: 2014

An optimization method for registration and mosaicking of remote sensing images has been proposed. More than four pairs of control points extracted by scale invariant feature transform (SIFT) detector have been used to obtain the projective transformation relation between the reference image and text image. A method based on gradient information of the region has been proposed to assign the weighted value to the feature points. The weighted value reflects the importance of the area, which can change the result of optimization. The combination method of seam cutting and feathering technique is used to stitch two overlapped images. Our experiment shows that the alignment error of interest area is smaller than that of normal area. If the weighted parameter is given proper value, the alignment error of interest area can reduced to less than one pixel. © 2013 Elsevier GmbH.


Winston Wang Z.,State Key Laboratory of Modern Optical Instrumentation | Ronnier Luo M.,State Key Laboratory of Modern Optical Instrumentation | Ronnier Luo M.,University of Leeds
Coloration Technology | Year: 2016

Diffuse coarseness (graininess) and glint impression (sparkle) are two aspects of visual perception for special-effect materials, including car finishes, etc. Previous work has shown that these two attributes become apparent when illuminated under two distinct illumination conditions: diffuse and unidirectional illumination respectively. The effect of glint impression has significant dependency on the viewing geometry. In this work, three psychophysical experiments were carried out, including diffuse coarseness assessment, glint impression assessment, and finding dimensions of glint space. In the experiments, one geometry for diffuse coarseness and three geometries for glint impression were designed. The three viewing geometries were designed according to a commercial device, BYK-mac, so that the results were used to test the reliability of instrumental measurements. Based on the conclusions drawn from the psychophysical experiments, a further investigation on glint space was conducted using the multidimensional scaling technique. From the visual results, two dimensions, corresponding to two attributes, were extracted and were validated by the instrumental results. Bidirectional reflectance distribution function data were also adopted from another commercial device, Imaging Sphere from Radiant Vision Systems Inc., USA (originally RadiantZemax Inc.), to predict glint impression. Some promising results were obtained. © 2016 Society of Dyers and Colourists.

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