Modeling LED street lighting.

LED luminaires may deliver precise illumination patterns to control light pollution, comfort, visibility, and light utilization efficiency. Here, we provide simple equations to determine how the light distributes in the streets. In particular, we model the illuminance spatial distribution as a function of Cartesian coordinates on a floor, road, or street. The equations show explicit dependence on the luminary position (pole height and arm length), luminary angle (fixture tilt), and the angular intensity profile (radiation pattern) of the LED luminary. To achieve this, we propose two mathematical representations to model the sophisticated intensity profiles of LED luminaries. Furthermore, we model the light utilization efficiency, illumination uniformity, and veiling luminance of glare due to one or several LED streetlamps.

Digital holographic interferometer using simultaneously three lasers and a single monochrome sensor for 3D displacement measurements.

The use of digital holographic interferometry for 3D measurements using simultaneously three illumination directions was demonstrated by Saucedo et al. (Optics Express 14(4) 2006). The technique records two consecutive images where each one contains three holograms in it, e.g., one before the deformation and one after the deformation. A short coherence length laser must be used to obtain the simultaneous 3D information from the same laser source. In this manuscript we present an extension of this technique now illuminating simultaneously with three different lasers at 458, 532 and 633 nm, and using only one high resolution monochrome CMOS sensor. This new configuration gives the opportunity to use long coherence length lasers allowing the measurement of large object areas. A series of digital holographic interferograms are recorded and the information corresponding to each laser is isolated in the Fourier spectral domain where the corresponding phase difference is calculated. Experimental results render the orthogonal displacement components u, v and w during a simple load deformation.

Endoscopic pulsed digital holography for 3D measurements.

A rigid endoscope and three different object illumination source positions are used in pulsed digital holography to measure the three orthogonal displacement components from hidden areas of a harmonically vibrating metallic cylinder. In order to obtain simultaneous 3D information from the optical set up, it is necessary to match the optical paths of each of the reference object beam pairs, but to incoherently mismatch the three reference object beam pairs, such that three pulsed digital holograms are incoherently recorded within a single frame of the CCD sensor. The phase difference is obtained using the Fourier method and by subtracting two digital holograms captured for two different object positions.

Simultaneous two-dimensional endoscopic pulsed digital holography for evaluation of dynamic displacements.

An endoscope is used in pulsed digital holography to simultaneously evaluate in-plane and out- of-plane transient and harmonic displacements on a flat metallic plate. The plate is illuminated from two different directions. The optical path for each illumination direction is matched to its corresponding reference beam, but also in such a way that each object-reference beam pair optical path is mismatched such that they are incoherent and can be stored in a single CCD frame. As is typical in these types of interferometric arrangement, two digital holograms are needed to compare two different states of the plate. Each hologram is Fourier transformed and due to the incoherence introduced, two separate spectra are readily identified, each belonging to an object-reference beam pair. On comparing by subtraction the phase obtained from the two pulsed digital holograms, it is possible to gather quantitative in-plane and out-of- plane results from transient and harmonic displacements.