An optical fiber curvature sensor. Two networks (R1, R2) with periodic longitudinal modulation of the refractive index of the optical fiber core are inscribed in the fiber (F) one behind the other or one on top of the other. The networks are configured to respectively reflect wavelengths λ.sub.1 and λ.sub.2 such that λ.sub.1=λ.sub.B+Δλ.sub.B1 and λ.sub.2=λ.sub.B+Δλ.sub.B2, where λ.sub.B is the Bragg wavelength of the networks and where λ.sub.B1 and λ.sub.B2 are shifts sensitive to the temperature, to deformations and to the curvature of the optical fiber. The two networks are defined so that the quantities Δλ.sub.B1 and Δλ.sub.B2 have substantially identical sensitivity to temperature and to deformations and substantially opposite sensitivity to curvature.

An optical fiber curvature sensor. Two networks (R1, R2) with periodic longitudinal modulation of the refractive index of the optical fiber core are inscribed in the fiber (F) one behind the other or one on top of the other. The networks are configured to respectively reflect wavelengths λ.sub.1 and λ.sub.2 such that λ.sub.1=λ.sub.B+Δλ.sub.B1 and λ.sub.2=λ.sub.B+Δλ.sub.B2, where λ.sub.B is the Bragg wavelength of the networks and where λ.sub.B1 and λ.sub.B2 are shifts sensitive to the temperature, to deformations and to the curvature of the optical fiber. The two networks are defined so that the quantities Δλ.sub.B1 and Δλ.sub.B2 have substantially identical sensitivity to temperature and to deformations and substantially opposite sensitivity to curvature.

This invention provides a system and a method for supporting the operation of subsea installations for 3D reconstruction of flexible pipes (1) during a direct vertical connection operation, comprising the steps of painting the flexible pipe (1) with a specific regular pattern, and performing a 3D reconstruction of the points sampled on the flexible pipe (1) to obtain the radius of curvature of the flexible pipe (1), in which the 3D reconstruction comprises the steps of: capturing images of the flexible pipe (1) during the direct vertical connection operation; sending the captured images to a dedicated computer (4); and processing the captured images, generating information on the radius of curvature, wherein the method initially comprises at least one of the following steps: painting the bend restrictor (6) with a specific regular pattern; painting straps (71) for buoys (7) with a specific regular pattern; and painting straps (71) for the arch bend, in the event of second-end direct vertical connection.

A device and method are described having/using at least a first radiation source and a second source of radiation, at least one measurement or detection device as well as at least one evaluation system with the first radiation source and second radiation source either oriented towards a top or bottom side of the optically effective object, or together oriented towards the top or bottom of the optically effective object, whereby at least the first radiation source emits reflective radiation towards the optically effective object and/or excitation radiation emitted for the stimulation of luminescence radiation in the material of the optically effective object and/or in the coating material of the optically effective object, and whereby the second radiation source at least emits radiation that penetrates through the optically effective object.

A method for inspection of a target object, the method including irradiating a reference surface having a non-flat reference profile with radiation; determining reference response data based on detected radiation having interacted with the reference surface; irradiating a target object with radiation, the target object including a target surface having a non-flat target profile corresponding to the reference profile; determining inspection response data based on detected radiation having interacted with the target object; and determining at least one parameter of the target object based on the reference response data and the inspection response data. An alternative method; a control system for controlling an emitter system and a detector system; and an inspection system including a control system, an emitter system and a detector system, are also provided.

Disclosed are a method and an apparatus for inspection of workpieces and products having curved and, in particular, spherical surfaces. The method is based on scanning inspected objects with a narrow probing beam of electromagnetic radiation and concurrently measuring the radiation scattered on the surface. The method and apparatus improve the detectability of features and imperfections on inspected surfaces by providing invariable parameters and conditions of scanning, robust mechanical stability of scanning systems, high positioning accuracy of the probing electromagnetic beam and efficient collection of the scattered radiation. The apparatus allows surface defect classification, determining defect dimensions and convenient automation of inspection.

Disclosed are a method and an apparatus for inspection of workpieces and products having curved and, in particular, spherical surfaces. The method is based on scanning inspected objects with a narrow probing beam of electromagnetic radiation and concurrently measuring the radiation scattered on the surface. The method and apparatus improve the detectability of features and imperfections on inspected surfaces by providing invariable parameters and conditions of scanning, robust mechanical stability of scanning systems, high positioning accuracy of the probing electromagnetic beam and efficient collection of the scattered radiation. The apparatus allows surface defect classification, determining defect dimensions and convenient automation of inspection.

Systems and methods for measuring a curvature radius of a sample. The methods comprise: emitting a light beam from a laser source in a direction towards a beam expander; expanding a size of the light beam emitted from the laser source to create a broad laser beam; reflecting the broad laser beam off of a curved surface of the sample; creating a plurality of non-parallel laser beams by passing the reflected broad laser beam through a grating mask or a biprism; using the plurality of non-parallel laser beams to create an interference pattern at a camera image sensor; capturing a first image by the camera image sensor; and processing the first image by an image processing device to determine the curvature radius of the sample.

Systems and methods for measuring a curvature radius of a sample. The methods comprise: emitting a light beam from a laser source in a direction towards a beam expander; expanding a size of the light beam emitted from the laser source to create a broad laser beam; reflecting the broad laser beam off of a curved surface of the sample; creating a plurality of non-parallel laser beams by passing the reflected broad laser beam through a grating mask or a biprism; using the plurality of non-parallel laser beams to create an interference pattern at a camera image sensor; capturing a first image by the camera image sensor; and processing the first image by an image processing device to determine the curvature radius of the sample.

A physical parameter estimating method, a physical parameter estimating device, and electronic apparatus are disclosed. The method includes: reading a Newton's rings fringe pattern obtained by performing an interferometric measurement on a unit to be measured; downsampling the Newton's rings fringe pattern to obtain a downsampled Newton's rings fringe pattern; calculating a magnitude spectrum of an intensity distribution signal of at least one first-direction pixel set in the downsampled Newton's rings fringe pattern under each fractional Fourier transform (FRFT) order in a searching range of FRFT orders, the first-direction direction pixel set including a line of pixels in a first direction, the first direction being one of a row direction and a column direction of the downsampled Newton's rings fringe pattern; determining a matched order of the intensity distribution signal according to the calculated magnitude spectrums; and estimating a physical parameter involved in the interferometric measurement according to at least the matched order. Therefore, physical parameters of the unit to be measured can be estimated with high accuracy even in presence of noise and obstacles in the fringe pattern.