Person: Martínez Antón, Juan Carlos
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First Name
Juan Carlos
Last Name
Martínez Antón
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Óptica y Optometría
Department
Óptica
Area
Optica
Identifiers
7 results
Search Results
Now showing 1 - 7 of 7
Item Wavefront measurement by solving the irradiance transport equation for multifocal systems(Optical Engineering, 2001) Quiroga Mellado, Juan Antonio; Gómez Pedrero, José Antonio; Martínez Antón, Juan CarlosA method for sensing wavefronts is presented. The method is based on the resolution of the irradiance transport equation, which relates the irradiance distribution and the shape of the wavefront of a light beam propagating along a given direction. The method presents no restrictions in the locations of the measurement planes and incorporates an improved procedure to geometrically correct the acquired images to take into account the effect of ray deflection in the propagation of the irradiance distributions. With the proposed technique, we measure the wavefront at the exit pupil of a progressive addition lens and find good agreement with an alternative deflectometric method.Item Optical method for the surface topographic characterization of Fresnel lenses(Optical Fabrication, Testing and Metrology IV, 2011) Martínez Antón, Juan Carlos; Gómez Pedrero, José Antonio; Alonso Fernández, José; Quiroga Mellado, Juan AntonioFresnel lenses and other faceted or micro-optic devices are increasingly used in multiple applications like solar light concentrators and illumination devices. As applications are more exigent this characterization is of increasing importance. We present a technique to characterize the surface topography of optical surfaces. It is especially well adapted to Fresnel lenses where abrupt surface slopes are usually difficult to handle in conventional techniques. The method is based on a new photometric strategy able to codify the height information in terms of optical absorption in a liquid. A detailed topographic map is simple to acquire by capturing images of the surface. Some experimental results are presented. A single pixel height resolution of similar to 0.1 mu m is achieved for a height range of similar to 50 mu m. A surface slope analysis is also made achieving a resolution of similar to +/- 0.15 degrees.Item Classification of surface structures on fine metallic wires(Applied Surface Science, 2001) Bernabeu Martínez, Eusebio; Sánchez Brea, Luis Miguel; Siegmann, Philip; Martínez Antón, Juan Carlos; Gómez Pedrero, José Antonio; Wilkening, Günter; Koenders, Ludger; Müller, Franz; Hildebrand, M.; Hermann, HartiIn this report a classification of the main surface structures found on fine metallic wires is carried out (between ∼20 and 500 μm in diameter). For this, we have analyzed a series of wires of different metallic materials, diameters and production environments by scanning electron microscopy, atomic force microscopy, and confocal microscopy. A description and the images of the structures is given and, in addition, a nomenclature to be used by manufacturers, customers and researches is proposed. With this information the surface quality of fine metallic wires may be improved in a fabrication level. One of the objectives of this catalogue of defects is to serve as a basis for measuring the quality of the surface of the wires during the production process and the development of a measuring device for that purpose.Item In-line detection and evaluation of surface defects on thin metallic wires(Optical Measurement Systems for Industrial Inspection II: Applications in Production Engineering, 2001) Martínez Antón, Juan Carlos; Siegmann, Philip; Sánchez Brea, Luis Miguel; Gómez Pedrero, José Antonio; Canabal Boutureira, Héctor Alfonso; Bernabéu Martínez, Eusebio; Hoefling, Roland; Jueptner, Werner P. O.; Kujawinska, MalgorzataWe have developed a prototype for in-line detection of surface defects in metallic wires, specially for scratches. A simple geometrical relationship between surface topography and conical reflection, permits to correlate the defects with intensity patterns in a simple way. The presented apparatus consists basically in a grating-divided laser beam incident on angular equidistant points. A CCD and an associated optics capture the information of the whole wire perimeter at once. Analytic rudiments are provided in agreement with the experimental results.Item Recent advances in automatic demodulation of single fringe patterns(Fringe 2005, 2006) Quiroga Mellado, Juan Antonio; Crespo Vázquez, Daniel; Gómez Pedrero, José Antonio; Martínez Antón, Juan CarlosItem Structured light-based NDT techniques of interest in the aerospace industry(Insight, 2003) Quiroga Mellado, Juan Antonio; Martínez Antón, Juan Carlos; Gómez Pedrero, José AntonioStructured light techniques (Moiré, projected fringes and other pattern projection techniques) have been used for many years in the aerospace and other industries for external defect location and characterization, 3D shape, deformation measurements and the like. The application of digital image processing methods to the images generated by these techniques has made possible the realization of fast and automatic systems for quantitative NDT measurements. This work is divided in two parts. First, the principal approaches to structured light-based NDT are reviewed, presenting the basis, performance characteristics as well as their expected ranges and resolutions. The second part concentrates on the digital image processing techniques of interest in the field of structured light-based NDT. As the images produced by these techniques are often in the form of phase-modulated fringe patterns, the branch of image processing that deal with this kind of images is denominated fringe pattern processing. Among the many existing fringe pattern processing techniques, the paper will concentrate on the phase-shifting methods (spatial and temporal) and the regularization and natural demodulation methods. It will be shown how when acquisition time is not critical, and several phase-shifted images can be acquired, phase-shifting techniques are well-suited for phase demodulation. Related with these techniques is the so-called phase unwrapping problem that will be discussed. Finally, fringe pattern processing techniques are discussed which can be applied in cases when acquisition time or the optical set-up only allows the use of one fringe pattern. In this case the problem of demodulating the phase is ill-posed from a mathematical point of view and special techniques as regularization and the so-called natural demodulation are needed.Item Topographic optical profilometry by absorption in liquids(Optics Express, 2012) Quiroga Mellado, Juan Antonio; Martínez Antón, Juan Carlos; Alonso Fernández, José; Gómez Pedrero, José AntonioOptical absorbance within a liquid is used as a photometric probe to measure the topography of optical surfaces relative to a reference. The liquid fills the gap between the reference surface and the measuring surface. By comparing two transmission images at different wavelengths we can profile the height distribution in a simple and reliable way. The presented method handles steep surface slopes (<90 degrees) without difficulty. It adapts well to any field of view and height range (peak to valley). A height resolution in the order of the nanometer may be achieved and the height range can be tailored by adapting the concentration of water soluble dyes. It is especially appropriate for 3D profiling of transparent complex optical surfaces, like those found in micro-optic arrays and for Fresnel, aspheric or free-form lenses, which are very difficult to measure by other optical methods. We show some experimental results to validate its capabilities as a metrological tool and handling of steep surface slopes.