David Carmona, Juan Manuel Trujillo, Sabato Ceruso, Oscar Casanova
In this work we present a novel application in the field of shoulder-surfing prevention by using a light-field display consisting of a multilayered structure of LC screens. By controlling the directionally displayed content, we can discriminate between authorized and unauthorized observers. Optimizations regarding different parameters were assessed, i.e, number of unauthorized/authorized observers, quality and complexity of the contents, and physical limitations. Tests were made in simulations and a real model implementation.
Sergio Bonaque. Industrial Metrology Using Wavefront Technology La Laguna, España, 2019 / March 2019
Sergio Bonaque
Wavefront metrology is a key step in the manufacturing of high performance optical components and systems. We present a new wavefront sensor based in a deterministic approach for the propagation of light fields, able to recover the wavefront with the same resolution of the camera used from two intensity images recorded at two different planes…
Juan Manuel Trujillo, Oscar Casanova, Sergio Bonaque, Jan Gaudestad, José Manuel Rodríguez-Ramos
In this work we present a novel wave front phase sensing technique developed by Wooptix. This new wave front phase sensor uses only standard imaging sensor, and does not need any specialized optical hardware to sample the optical field. In addition, the wave front phase recovery is zonal, thus, the obtained wave front phase map provides as much height data points…
Jose Manuel Ramos Rodrigues, Juan Manuel Trujillo
We present a new wafer metrology technique called Wave Front Phase Imaging (WFPI) for high speed measurement of wafer warpage and nanotopography. This is accomplished by acquiring a single image snapshot using that provides depth data for every single pixel. The number of topography data points for the entire wafer will be proportional to the number of pixels in the image sensor.
Dailos Guerra, Lara Díaz, Juan Manuel Trujillo, Jose Manuel Rodríguez-Ramos
Most of the methods used today for the alignment of segmented mirrors are based on Shack-Hartman wavefront sensors. Other proposed methods are based on curvature sensors. These can be used to cross-check the measurements given by the primary method. We investigate a different approach which employs convolutional neural networks.
David Carmona, Juan Manuel Trujillo, Lara Díaz, Daniel Walo, Ángela Hernández, Juan J. Fernández, Óscar Casanova, Óscar Gómez, José Manuel Rodríguez-Ramos
In this work we have presented a brief insight into the capabilities of multilayer displays as to selectively display information in relation to the observers. We labeled the views of a light-field as blocked and non-blocked, and then a predefined text was assigned accordingly, modifying it to achieve a privacy criterion in the blocked case.
Sergio Bonaque, Oscar Casanova, Juan Manuel Trujillo, J.J. Fernández Valdivia, A. Hernández-Delgado, David Carmona
Optical organic materials, or optical plastics, are raising interest in recent decades thanks to advances in manufacturing processes. It is already common for these materials to be in optical systems, for example in the field of medicine or computer science.
David Carmona, Juan Manuel Trujillo, Sergio Bonaque, Óscar Gómez, José Manuel Rodríguez-Ramos
Context. Increasing the area on the sky over which atmospheric turbulences can be corrected is a matter of wide interest in astrophysics, especially when a new generation of extremely large telescopes (ELT) is to come in the near future. Aims. In this study we tested if a method for visual representation in three-dimensional displays, the weighted nonnegative tensor factorization (WNTF)…
David Carmona, Juan Manuel Trujillo, Sergio Bonaque, Ángela Hernández, José M Rodríguez-Ramos
Tensor display is an option in glasses-free three-dimensional (3-D) display technology. An initial solution has to be set to decompose the light-field information to be represented by the system. We have analyzed the impact of the initial guess on the multiplicative update rules in terms of peak signal-to-noise ratio, and proposed a method based on depth map estimation from an input light field.
Óscar Gómez, José G. Marichal, Juan Manuel Trujillo, David Carmona, José Manuel Rodríguez-Ramos
The discrete Radon transform, DRT, calculates, with linearithmic complexity, the sum of pixels through a set of discrete lines covering all possible slopes and intercepts in an image. In 2006, a method was proposed to compute the inverse DRT that remains exact and fast, in spite of being iterative. In this work the DRT pair is used to propose a Ridgelet and a Curvelet transform that perform focus measurement of an image.