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The fabrication and characterization of an optical fiber refractometer based on Lossy Mode Resonances (LMR) is presented. TiO2/ poly (sodium 4-styrenesulfonate) coatings deposited on side-polished D-shaped optical fibers are used as LMR supporting coatings. LMRs are sensitive to the external medium refractive index and D-shaped optical fibers enable the observation of TE and TM LMR polarizations. These refractometers based on TE and TM LMR showed an average sensitivity of 2737 nm/RIU and 2893 nm/RIU respectively for a surrounding medium refractive index (SMRI) range from 1.35 to 1.41.

In recent years, the demands on three-dimensional (3-D) measurement systems have been getting higher, es- pecially concerning their speed. The use of a 3-D array projector enables measurement frame rates of up to the 100-kHz range. Our contribution introduces a new purpose-built setup that projects aperiodic sinusoidal fringes. We explain the 3-D measurement principle and the basic design of a 3-D array projector and describe the method how the desired aperiodic sinusoidal fringes are generated. We verify the consistency between specified and projected patterns and point out the results of the setups’s characterization, e.g., of its high-speed capability. Furthermore, first 3-D shape measurements at a projection frame rate of 3 kHz resulting in a 3-D frame rate of

Saccadic eyes are important human behaviors and have important applications in commercial and security fields. In this paper, we focus on saccadic eyes recognition from 3-D shape data acquired from a 3-D near infrared sensor. Two salient features, normal vectors of meshes and curvatures of surfaces, are extracted. The distributions of normal vectors and curvatures are computed to represent eye states. The support vector machine (SVM) is applied to classify eyes states into saccadic and non-saccadic eyes states. To verify the proposed method, we performed three groups of experiments using different strategies for samples selected from 300 3-D data, and present experimental results that demonstrate the effectiveness and robustness of the proposed algorithm.

This paper presents a real-time 3-D, or 4-D, shape measurement technique that can reach the speed limit of a digital fringe projection system without significantly increasing the system cost. Instead of generating sinusoidal fringe patterns by a computer directly, they are produced by defocusing binary structured patterns. By this means, with a relatively inexpensive camera, the 3-D shape measurement system can double the previously maximum achievable speed, and reaches the refreshing rate of a digital-light-processing (DLP) projector: 120 Hz.

A shape measurement method combining the fibre-optic interferometric fringe projection method and effective numerical spatial phase unwrapping method is proposed in this paper. Simplicity of the system arrangement determining low set-up cost is the main advantage of the presented approach. The paper presents a detailed theoretical method description. It is based on a specially worked out procedure of an automated analysis of the fringe patterns obtained by the Fourier transform and phase unwrapping based on the Mathematica software procedures. Experimental results of the measurements made for a real object show usefulness and efficiency of the proposed method.

In this paper, an integrated system based on a phase-shift laser scanning for measuring shape and a imaging spectrograph for measuring color is described. The system is designed for acquisition of large areas, such as chapels or frescoed walls. The phase-shift laser range-finder provides accurate distance measurement, up to 10 meters, pointing at most target surfaces through the measurement of the phase shift. The acquisition of a complete object is performed point by point by a 2D scanning. The imaging spectrograph measures the spectrum of the light coming from on a narrow rectangular region having width and height equal to the image of the entrance slit projected on the object plane. A complete 2D image is acquired by scanning the region in the direction perpendicular to the slit height. The merging of these multiple acquisitions yields the complete spectral and spatial description of the color of the object.

We present an implementation of high-sensitivity optical chemsensors based on FBGs UV-inscribed in D-shape and multimode fibres and sensitized by HF-etching treatment, demonstrating a capability of detecting chemical concentration changes as small as < 0.5%.

Surface contamination of insulators in high voltage transmission and distribution systems may lead to troublesome flashovers which interrupt service. Insulator contamination may be monitored using direct measurement of equivalent salt deposit density (ESDD), which directly relates to the flashover voltage. A fiber-optic evanescent- coupling fiber-optic ESDD monitor is presented. The use of a piece of D-shape E-core fiber as sensor head can provide a sensitive and large area ESDD monitoring system. We have demonstrated the use of D-shape fiber in monitoring ESDD on insulator surfaces. A simple process has been developed to precisely etch the D-fiber. The polarimetric and evanescent loss sensors have been investigated. The evanescent loss sensor is particularly suitable for in-situ ESDD monitoring in power transmission lines and substations.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A method based on differential geometry is presented for quantitatively measuring facial (or body) surfaces and the amount of change produced in them by facial surgery. Facial shape is described mathematically in terms of 8 fundamental surface types. Changes produced in the shape of the face are described in terms of changes in these constituent surfaces. The method is illustrated using examples of faces changed by reconstructive surgery and its relationship to clinical observation explained.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper presents parallel computable contour based feature strings for two dimensional shape recognition. Parallel techniques are used for contour extraction and for computation of normalized contour based features independent of scale and rotation. The EREW PRAM architecture is considered, but the technique can be adapted to other parallel architectures. Illustrated examples are presented.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.