Apparatus and methods are described, for detecting the surface topography of a portion of a curved surface of an object. A beam of light is directed toward the surface from a broad angle of incidence with respect to an optical axis of a camera. Light reflected from the surface is received by the camera, via a narrow-angle aperture. One or more darkened regions in the received light are detected, and the surface topography of portion of the surface is detected at least partially in response to the detected darkened regions. Other applications are also described.

A method for optically checking by interferometry the thickness of an object (2) being machined comprises a phase of direct checking wherein the spectrum of the result of interference between primary reflected radiations (R1) generated by reflection of incident radiations (I) on an external surface (16) and secondary reflected radiations (R2) generated by reflection on an internal surface of discontinuity (17) of the object is analyzed, and a preliminary phase wherein information relative to the variation of a virtual thickness (D) delimited and defined by a reference surface (18) and the external surface of the object, indicative of thickness variations of the object being machined. In the preliminary phase, the processing is based on the analysis of the spectrum of the result of interference between primary reflected radiations and reference reflected radiations (Rref) generated by the reflection of the incident radiations on the reference surface, that defines the length of a reference optical path. An apparatus that implements such method for optically checking includes an optical probe (6) that receives and detects the primary, secondary and reference reflected radiations, and a spectrometer (5) that analyzes the spectrum of the result of interference.

Apparatus and methods are described for performing structure measurement on a tear film of an eye of a subject. At least a portion of a surface of the tear film is illuminated using a broadband light source. A spectrum of light of the broadband light that is reflected from at least one point of the tear film is measured, using a spectrometer. Color information for a plurality of points of the tear film is obtained, by imaging a field of view of the tear film using a color camera. Using a processing unit, data from the color camera and data from the spectrometer that are indicative of characteristics of the tear film are received, and based upon a combination of the data received from the color camera and the data received from the spectrometer, an output is generated that is indicative of a structure of the tear film.

Apparatus and methods are described for performing structure measurement on a tear film of an eye of a subject. At least a portion of a surface of the tear film is illuminated using a broadband light source. A spectrum of light of the broadband light that is reflected from at least one point of the tear film is measured, using a spectrometer. Color information for a plurality of points of the tear film is obtained, by imaging a field of view of the tear film using a color camera. Using a processing unit, data from the color camera and data from the spectrometer that are indicative of characteristics of the tear film are received, and based upon a combination of the data received from the color camera and the data received from the spectrometer, an output is generated that is indicative of a structure of the tear film.

A device for the interferometric measuring of an object, including a radiation source for generating an output beam, at least one beam splitter, as well as at least one detector, with the beam splitter being arranged in the radiation path of the output beam such that the output beam is split into at least one measuring beam and one reference beam, and the device is embodied to interfere the reference beam on the detector with an interference beam to form an optic interference. The device has an open optic resonator, which is arranged in the radiation path of the device such that the measuring beam enters the open optic resonator and the interference beam emitted from the open optic resonator is interfered with a reference beam on the detector to form an optic interference. The invention further relates to a method for the interferometric measuring of an object.

A distance measuring device measures a distance to a target object with high accuracy by reducing stray light in a probe tip end section.

In the distance measuring device, the probe tip end section has an optical path switching element that switches an optical path of measurement light incident from the optical element, at a tip end of the probe tip end section. A material of at least a part of the probe tip end section provided at a position opposite to a fifth surface absorbs the measurement light.