Showing papers by "Javier Garcia published in 2013"
TL;DR: The presented preliminary results validate the proposed optical sensor as a potentially useful device for measuring alcohol in blood stream with subjects that can be car drivers inspected by police authorities or medically monitored patients.
29 citations
TL;DR: The proposed lensless object scanning holography method is extended to the cases of two-dimensional (2D) mirror-like and 1D diffuse-based objects and the experimental results show an impressive image quality improvement over a factor of 3 in FOV, SNR, and resolution.
Abstract: Recently proposed lensless object scanning holography (LOSH) [Opt. Express20, 9382 (2012)] is a fully lensless method capable of improving the image quality in digital Fourier holography applied to one-dimensional (1D) reflective objects and it involves a very simplified experimental setup. LOSH is based on the recording and digital postprocessing of a set of digital lensless Fourier transform holograms, which finally results in a synthetic image with improved resolution, field-of-view (FOV), signal-to-noise ratio (SNR), and depth of field. In this paper, LOSH is extended to the cases of two-dimensional (2D) mirror-like and 1D diffuse-based objects. For 2D mirror-like objects, the experimental results show an impressive image quality improvement over a factor of 3 in FOV, SNR, and resolution, as good as that obtained for the 1D case but in two dimensions. For 1D diffuse-based objects, in general the speckle affects the image resolution, which will not be only a function of the aperture size. In this case, increasing the aperture produces a decrease of the speckle size. Moreover, due to the overlapping of speckles between successive images, different types of digital processing can be applied to obtain the final synthetic image: fully incoherent, fully coherent, and partially coherent. The last, arising from the incoherent sum of several independent sets of coherently added images, provides the best improvement in the resolution. Experimental results for both types of objects are presented.
12 citations
TL;DR: A super-resolving approach for detecting an axially moving target that is based upon a time-multiplexing concept and that overcomes the diffraction limit set by the optics of an imaging camera by a priori knowledge of the high-resolution background in front of which the target is moving.
Abstract: In this paper we present a super-resolving approach for detecting an axially moving target that is based upon a time-multiplexing concept and that overcomes the diffraction limit set by the optics of an imaging camera by a priori knowledge of the high-resolution background in front of which the target is moving. As the movement trajectory is axial, the approach can be applied to targets that are approaching or moving away from the camera. By recording a set of low-resolution images at different target axial positions, the super-resolving algorithm weights each image by demultiplexing them using the high-resolution background image and provides a super-resolved image of the target. Theoretical analyses as well as simulations and preliminary experimental validation are presented to validate the proposed approach.
6 citations
13 May 2013
TL;DR: In this article, a lensless SESRIM (L-SES-RIM) was proposed to achieve one-dimensional super resolved imaging in digital holographic microscopy, which uses red-green-blue (RGB) multiplexing for illuminating the sample having different propagation angles for each one of the three illumination wavelengths.
Abstract: Single Exposure Super Resolved Interferometric Microscopy (SESRIM) has been recently proposed as a way to achieve
one dimensional super resolved imaging in digital holographic microscopy. SESRIM uses Red-Green-Blue (RGB)
multiplexing for illuminating the sample having different propagation angles for each one of the three illumination
wavelengths and it has been experimentally validated considering color (A. Calabuig, V. Mico, J. Garcia, Z. Zalevsky,
and C. Ferreira, “Single-exposure super-resolved interferometric microscopy by red–green–blue multiplexing,” Opt.
Lett. 36, 885-887, 2011) and monochrome (A. Calabuig, J. Garcia, C. Ferreira, Z. Zalevsky, and V. Mico, “Resolution
improvement by single-exposure superresolved interferometric microscopy with a monochrome sensor,” J. Opt. Soc.
Am. A 28, 2346-2358, 2011) digital sensors for holographic recording. In this contribution, we will first review some of
the characteristics of the previously reported SESRIM approaches and second, we will present preliminary results for the
extension of SESRIM to the field of lensless holographic microscopy. Experimental results are reported validating this
new kind of superresolution imaging method named as lensless SESRIM (L-SESRIM).
3 citations
TL;DR: A novel type of model incorporating a special remote life signals sensing optical system on top of a controllable robotic platform to use the developed robotic system for search and rescue mission such as saving survivals from a fire.
Abstract: We present a novel type of model incorporating a special remote life signals sensing optical system on top of a controllable robotic platform. The remote sensing system consists of a laser and a camera. By properly adapting our optics and by applying a proper image processing algorithm we can sense within the field of view, illuminated by the laser and imaged by the camera, the heartbeats and the blood pulse pressure of subjects (even several simultaneously). The task is to use the developed robotic system for search and rescue mission such as saving survivals from a fire.
3 citations
09 Apr 2013
TL;DR: In this article, a multipoint speckle imaging based on the correlation statistics of speckles was proposed for deformation measurement, where a camera is used to capture images at a desired frame rate, a collimated laser and a diffractive optical element.
Abstract: In this contribution we propose a new technique for deformation measurement based upon a multipoint speckle imaging using the correlation statistics of speckle patterns. The system is capable of interferometric accuracy, although it relies on self-interference, shown as speckle patterns on the detector plane. Therefore, most of the constraints imposed by interferometric setups no longer apply. A camera is used to capture images at the desired frame rate, a collimated laser and a diffractive optical element, achieving a high number of inspection points opens the possibility for analyzing simultaneously a plurality of inspected points. Proper adjustment of the optical parameters (aperture size and shape) can deal with the measurements at different locations of the object’s surface with no crosstalk between the outputs for each inspected point. The data from the different inspected locations can be analyzed separately or integrated to provide a global surface change in shape. The system has two major advantages. On one hand, it uses few hardware elements, making the system easily portable and compact. On the other hand the system needs a laser source with relatively low degree of coherence, as interference is done on the tested surface itself and no external coherent reference is needed. The system can be packed in a compact enclosure and it can operate at an arbitrary distance from the inspected object, limited only by intensity available on the detector and sensor’s sensitivity. The system can work at frame rate allowed by the camera in the selected region of interest.
2 citations
TL;DR: In this article, a decoding mask is computed and used to obtain super-resolution digital holograms and eliminate the twin image and DC from a digital hologram, which is also applicable for other optical methods.
Abstract: Metal nanoparticles are used for different applications in holographic configurations. The metal nanoparticles are placed
close to an object and encode it by a time varying random mask. A decoding mask is computed and used to obtain super-resolution digital hologram and eliminate the twin image and DC from a digital hologram. The method is also shown to be applicable for other optical methods.
1 citations
21 Apr 2013
TL;DR: In this article, a method for eliminating the unwanted terms in an on axis hologram is presented, where free randomly distributed nanoparticles are used to encode and later on to decode/separate the desired term from the unwanted aberrations.
Abstract: A method for eliminating the unwanted terms in an on axis hologram is presented. Free randomly distributed nanoparticles are used to encode and later on to decode/separate the desired term from the unwanted aberrations.
1 citations
13 May 2013
TL;DR: In this article, a lensless object scanning Holography (LOSH) method for diffuse-based objects has been proposed, which is based on the recording and digital post-processing of a set of digital lensless Fourier transform holograms which finally results in a synthetic image with improved resolution, field of view (FOV), signal-to-noise ratio (SNR), and depth of field (DOF).
Abstract: Recently proposed, Lensless Object Scanning Holography (LOSH) is a fully lensless method, capable of improving
image quality in digital Fourier holography applied to reflective objects, and involving a very simplified experimental
setup. LOSH is based on the recording and digital post-processing of a set of digital lensless Fourier transform
holograms which finally results in a synthetic image with improved resolution, field of view (FOV), signal-to-noise ratio
(SNR), and depth of field (DOF). In this paper, LOSH is expanded to the case of diffuse-based objects. Now, the speckle
can affect the resolution and it will not be a function of only the size of the aperture. The fact of increasing the aperture
can produce the decrease of the size of the speckle. Moreover, there is an overlapping of speckles of the successive
images. Different kinds of digital processing can be applied to obtain the final synthetic image. Among them, partial
coherent processing, arising from the incoherent sum of several sets of images coherently added, provides the best
improvement in the resolution and also in the SNR due to partial averaging of the speckles. Experimental results for a
diffuse object are presented for different kinds of digital processing.
1 citations
TL;DR: This work enables precise measurement (with nanometer accuracy) of the propagation of electronic stimulation waves within the culture, which could be useful for studying re-entrant arrhythmias, when the electrical signal travels in a circle, instead of propagating in a linear fashion.
Abstract: Cardiovascular disease is America’s number one killer, accounting for more than 41% of deaths each year.1 Furthermore, 61 million Americans have some form of the condition, including heart disease, stroke, high blood pressure, congestive heart failure, congenital heart defects, and hardening of the arteries. Early detection of abnormality is the key to treating cardiovascular disease and reducing the death toll. However, some conditions, such as myocardial ischemia (reduced blood supply to the heart), can be difficult to establish in the early stages, which is when treatment is most effective. Cardiac ischemia is currently diagnosed by measuring electrical signals from the heart, or by using ultrasound waves to analyze heart contractions.2, 3 Our study aims to understand the contraction behavior of cardiac myocytes (muscle cells) in their simplest form: in a culture. We propose a robust way to test the influence of certain substances on the rate and magnitude of those contractions. Our work enables precise measurement (with nanometer accuracy) of the propagation of electronic stimulation waves within the culture. Such capability could be useful for studying re-entrant arrhythmias, when the electrical signal travels in a circle, instead of propagating in a linear fashion. Reentrant arrhythmias can be detected on the pericardium (outer wall) of the heart. We propose a very simple configuration to assess the statistics of cell contractions by measuring their physical contraction and expansion following illumination and analysis of the resulting secondary speckle patterns.4–7 Our system provides an ‘instant snapshot’ of the sample, enabling the study of numerous cells, and obtains statistics of their contractions. We illuminate the culture with a laser, while a camera positioned at a given distance from the culture collects the Figure 1. Results from measuring simultaneous contractions of muscle cells without using an imaging lens.