Search results for "Optica"

Learning Flow-Based Feature Warping for Face Frontalization with Illumination Inconsistent Supervision

2020

Despite recent advances in deep learning-based face frontalization methods, photo-realistic and illumination preserving frontal face synthesis is still challenging due to large pose and illumination discrepancy during training. We propose a novel Flow-based Feature Warping Model (FFWM) which can learn to synthesize photo-realistic and illumination preserving frontal images with illumination inconsistent supervision. Specifically, an Illumination Preserving Module (IPM) is proposed to learn illumination preserving image synthesis from illumination inconsistent image pairs. IPM includes two pathways which collaborate to ensure the synthesized frontal images are illumination preserving and wit…

Target tracking with dynamically adaptive correlation

2016

Abstract A reliable algorithm for target tracking based on dynamically adaptive correlation filtering is presented. The algorithm is capable of tracking with high accuracy the location of a target in an input video sequence without using an offline training process. The target is selected at the beginning of the algorithm. Afterwards, a composite correlation filter optimized for distortion tolerant pattern recognition is designed to recognize the target in the next frame. The filter is dynamically adapted to each frame using information of current and past scene observations. Results obtained with the proposed algorithm in synthetic and real-life video sequences, are analyzed and compared w…

Extended Depth-of-Field 3-D Display and Visualization by Combination of Amplitude-Modulated Microlenses and Deconvolution Tools

2005

One of the main challenges in 3-D display and visualization is to overcome its limited depth of field. Such limitation is due to the fast deterioration of lateral resolution for out-of-focus object positions. Here we propose a new method to significantly extend the depth of field. The method is based on the combined benefits of a proper amplitude modulation of the microlenses, and the application of deconvolution tools. Numerical tests are presented to verify the theoretical analysis.

Depth sensing using coherence mapping

2010

A method for depth sensing based on sensing the visibility associated with the coherence function of a laser source is presented. The setup is based on an electronic speckle pattern interferometric (ESPI) setup, where the object depth is encoded into the amplitude of the interference pattern without the need for depth scanning. After performing phase-shifting method, the object three-dimensional (3-D) shape is reconstructed by means as a range image from the visibility of the image set of interferograms and where each gray level represents a given object depth. Experimental results validate the proposed approach for reflective diffuse objects at different measurement distances.

Novel constant current driver for ISFET/MEMFETs characterization

2001

Abstract In the present work a new constant current driver for ISFETs and MEMFETs sensors has been developed. The proposed circuit maintains the ISFET/MEMFET operation point at constant drain–source current and voltage. The combination of some programmable current sources and an appropriate selection of a simple precision resistor allow a good ISFET/MEMFET polarization. The use of operational amplifiers with low offset and drift are required to provide the buffering function needed by the sensor.

Optoelectronic Module with Integrated Transceiver and Mux-Demux for Optical Interconnect Applications

2019

The design, development and improvtableement in electronic devices and components have led to the further miniaturization of the system devices and their interconnecting interfaces. Hence, reducing the size of the transmitter (Tx) chips, receiver (Rx) chips and associated components play an important role in designing a reduced/small sized optoelectronic modules for optical interconnect applications. Some of the associated components include multiplexer, demultiplexer, clock and data recovery circuits (CDR), etc. Therefore, in this paper we present an optoelectronic module with integrated transceiver (Tx-Rx) and multiplexer-demultiplexer (mux-demux) with the aim of reducing the total area o…

Reconstruction Improvement in Integral Fourier Holography by Micro-Scanning Method

2015

Although integral holography has many promising advantages in the field of 3D imaging, the resolution of reconstructed holographic image is still limited by the insufficient information captured. To improve the reconstruction quality, an integral Fourier holographic imaging method based on micro-scanning of the micro-lens array is proposed in this paper. The micro-scanning of the micro-lens array can increase the sampling rate in spatial frequency domain and the information of the generated Fourier hologram, which will eventually eliminate the overlapping effect in the reconstructed 3D image. Experiments for different micro-scanning modes are carried out to verify the feasibility of the pro…

GPON as a contribution to the construction of Smart Cities

2019

Influence of the type of illumination on the measurement of the modulation transfer function in the living human eye: A theoretical study

1999

Abstract Applications such as refractive surgery demand an objective appraisal of the retinal image quality. The modulation transfer function (MTF) provides that information when measured directly. Moreover, the MTF obtained using a simple and objective method such as that described in this paper allows the neural contrast sensitivity function (CSF) to be obtained from the global CSF and the MTF. When calculating the MTF it must be borne in mind whether the applicable theory is coherent or incoherent. In the literature, the developed theory presents some approximations and incongruities. Also, it is interesting to note that the method of recording the MTF (short or long time of integration,…

Weighted nonlinear correlation for controlled discrimination capability

2002

We recently demonstrated the high discrimination capability as well as the high sensitivity to small intensity variations of the sliced orthogonal nonlinear generalized (SONG) correlation. This nonlinear correlation has a correlation matrix representation. Previous papers considered only the principal diagonal elements of the correlation matrix. We propose using the off-diagonal non-zero elements of the SONG correlation matrix in order to achieve variable discrimination performance and controlled detection adapted to the gray-scale variations. Moreover, we introduce negative coefficients in order to improve the discrimination properties of the SONG correlation. To control the degree of reco…