Showing papers by "Javier Garcia published in 2015"
TL;DR: A novel algorithm for high-resolution quantitative phase imaging in a new concept of lensless holographic microscope based on single-shot multi-wavelength illumination and a novel and fast iterative phase retrieval algorithm are reported on.
Abstract: We report on a novel algorithm for high-resolution quantitative phase imaging in a new concept of lensless holographic microscope based on single-shot multi-wavelength illumination. This new microscope layout, reported by Noom et al. along the past year and named by us as MISHELF (initials incoming from Multi-Illumination Single-Holographic-Exposure Lensless Fresnel) microscopy, rises from the simultaneous illumination and recording of multiple diffraction patterns in the Fresnel domain. In combination with a novel and fast iterative phase retrieval algorithm, MISHELF microscopy is capable of high-resolution (micron range) phase-retrieved (twin image elimination) biological imaging of dynamic events. In this contribution, MISHELF microscopy is demonstrated through qualitative concept description, algorithm implementation, and experimental validation using both a synthetic object (resolution test target) and a biological sample (swine sperm sample) for the case of three (RGB) illumination wavelengths. The proposed method becomes in an alternative instrument improving the capabilities of existing lensless microscopes.
48 citations
24 Mar 2015
TL;DR: This optical sensing technology is demonstrated to have the ability to monitor three additional biomedical indicators, breathing, blood oximetry, and blood coagulation, as well as its ability to simultaneously monitor indicators that were previously only monitored separately.
Abstract: An optical approach to the extraction and separation of remote vibration sources has recently been proposed. The technique has previously been applied successfully to biomedical measurements including pulse pressure, heart rate, blood glucose and alcohol concentrations, and intraocular pressure. In this paper, we review this optical sensing technology and demonstrate its ability to monitor three additional biomedical indicators, breathing, blood oximetry, and blood coagulation, as well as its ability to simultaneously monitor indicators that were previously only monitored separately. The proposed compact and potentially low-cost biomedical sensor can be highly beneficial given the global healthcare challenges, especially in the developing countries.
38 citations
TL;DR: In this paper, a method for resolution enhancement of a diffraction limited optical system based on the capture of a set of low-resolution images is proposed, which is obtained after projection of an ensemble of unknown speckle patterns on top of the high resolution object that is to be imaged.
Abstract: We propose a method for resolution enhancement of a diffraction limited optical system based on the capture of a set of low resolution images. These images are obtained after projection of an ensemble of unknown speckle patterns on top of the high resolution object that is to be imaged. Each speckle pattern is generated by the same thin (and unknown) diffuser, but illuminated with a slightly different wavelength. From the ensemble of low resolution images, we obtain a system of equations that can be solved in an iterative manner that enables reconstruction of the high resolution object. As a result, we also achieve the projected high resolution speckle patterns used for the encoding.
16 citations
TL;DR: The first steps of a device suitable for detection of broken and cracked bones are presented based on temporal tracking of back reflected secondary speckle patterns generated when illuminating the limb with a laser and while applying periodic pressure stimulation via a loud speaker.
Abstract: We present the first steps of a device suitable for detection of broken and cracked bones. The approach is based on temporal tracking of back reflected secondary speckle patterns generated when illuminating the limb with a laser and while applying periodic pressure stimulation via a loud speaker. Preliminary experiments are included showing the validity of the proposed device for detection of damaged bones.
15 citations
TL;DR: Preliminary experimental results involving analysis of red blood cells being either healthy or infected with malaria parasites, validated the potential benefit of the proposed numerical approach.
8 citations
TL;DR: This manuscript introduces the connection between the physiological muscle tremor and the lactate blood levels and proposes an optical non-contact approach to estimate the concentration level of this parameter.
Abstract: The ability to measure the blood lactate level in a non-invasive, non-contact manner is very appealing to the sports industry as well as the home care field. That is mainly because this substance level is an imperative parameter in the course of devolving a personal workout programs. Moreover, the blood lactate level is also a pivotal means in estimation of muscles' performance capability. In this manuscript we propose an optical non-contact approach to estimate the concentration level of this parameter. Firstly, we introduce the connection between the physiological muscle tremor and the lactate blood levels. Secondly, we suggest a photonic optical method to estimate the physiological tremor. Lastly, we present the results of tests conducted to establish proof of concept to this connection.
3 citations
22 Jun 2015
TL;DR: In this paper, the authors presented a low cost, extremely simple, and highly stable scheme to update a standard microscope into a holographic microscope, which is based on a common-path interferometric configuration which is adapted into a conventional microscope with some specific constraints to allow holographic recording.
Abstract: In this contribution we present a low cost, extremely simple, and highly stable scheme to update a standard microscope into a holographic microscope. The proposed architecture is named as SMIM (incoming from the initials of spatially-multiplexed interferometric microscopy) and it is based on a common-path interferometric configuration which is adapted into a conventional microscope with some specific constraints to allow holographic recording. The main layout modifications are three: i) the use of a coherent light source instead of the broadband one included in the microscope, ii) the insertion of a properly placed one-dimensional diffraction grating needed for the holographic recording, and iii) the use of spatial multiplexing at the input plane to allow reference beam transmission in a common light-path with the imaging branch. As consequence of the input plane spatial multiplexing, the field of view provided by the used microscope objective is reduced in comparison with the field of view reported by the same objective lens in conventional white light illumination mode. However, complex amplitude distribution of the inspected sample is retrieved after off-axis holographic recording and conventional digital image processing of the recorded hologram. The proposed update is experimentally validated in a standard upright microscope by using coherent illumination incoming from a commercial grade laser diode, by inserting a one-dimensional precision Ronchi ruling grating in the microscope embodiment, and by dividing the input plane into the spatially multiplexed areas. Experimental results are provided for the different microscope objectives included in the Olympus microscope showing calibration (USAF resolution test) as well as biological (red blood cells and sperm cells) images containing complex (amplitude and phase) information.