Method and system for calculating a height map of a surface of an object from an image stack in scanning optical 2.5D profiling of the surface by an optical system, a focal plane is scanned at different height positions with respect to the object surface. An image is captured at each height position of the focal plane to form the image stack. The scanning of the focal plane comprises long range sensing and short range sensing a displacement of the focal plane for sensing low and high spatial frequency components. The height position of the focal plane is estimated by combining the low and high spatial frequency components. A height position of each image in the image stack is calculated, based on the estimated height position of each respective focal plane. The images of the image stack are interpolated to equidistant height positions for obtaining a corrected image stack.

A system and method for metrology and profilometry using a light field generator are disclosed. For this purpose, a system such as an optical analysis system scans a sample using light, and detects light reflected off a sample in various ways. The system operates different operational modes including a backscatter intensity, a triangulation, and an interferometric mode. For this purpose, the optical analysis system includes one or more optical angle modulation systems, such as surface acoustic wave (SAW) modulators, that emit light, a sample holder, and a scanning system that scans the one or more SAW modulators relative to the sample holder. The system performs tomographic reconstructions of information generated by the scans to create 3D maps/volume datasets of the sample.

A motion compensation system for a shearography apparatus includes: an adjustable first fold mirror to reflect laser radiation to a receiving aperture of the shearography apparatus during separate pulse periods at corresponding angles of reflection; and corresponding second fold mirrors to reflect the laser radiation from a target surface to the first fold mirror during the respective pulse periods. The shearography apparatus moves with respect to the target surface between the separate pulse periods. The angles of reflection make the laser radiation reflected from the target surface via the respective second fold mirrors appear to the receiving aperture as if the shearography apparatus is stationary with respect to the target surface. In another system, the second fold mirrors are replaced by an adjustable second fold mirror to reflect the laser radiation from the target surface to the first fold mirror during the pulse periods at corresponding second angles of reflection.

An apparatus and a method for measuring blood flow of vessels are provided. The apparatus includes a light source, a light splitting module, a reference arm module, a sample arm module, a probing module, and a control system. The sample arm module includes a scanning unit and an optical-path shifting device. A probe light is obtained from the light splitting module, and a central line of a main light of the probe light extends through a rotation axis of the scanning unit. The probe light is reflected by the scanning unit to the optical-path shifting device. When the optical-path shifting device is rotated between a first position and a second position respectively, the probe light scans a vessel in fundus to obtain a first phase shift signal and a second phase shift signal blood flow rates and total blood flow of all the vessels near an optic disc are determined.

Provided is an optical measurement device configured so that a high-accuracy three-dimensional image can be obtained. An emission angle of a ray of light is changed in such a manner that the rotation frequencies of two motors configured to rotatably drive a first optical path changing unit and a second optical path changing unit is controlled. The ray of light is emitted to a front three-dimensional region, and reflected light is obtained. Then, calculation is made by a computer, and in this manner, three-dimensional data on a measurement target object is obtained. The amount (vibration amount) of axial backlash or play of a rotary mechanism, such as a motor shaft, along which the ray of light is emitted is measured in real time, and such a backlash or play amount is subtracted from a three-dimensional image obtained by the computer. Consequently, a high-accuracy three-dimensional image is obtained.

Interferometric measurement signals are detected by a single optical interferometric interrogator for a length of a sensing light guide and an interferometric measurement data set corresponding to the interferometric measurement signals is generated. The interferometric measurement data set is transformed into a spectral domain to produce a transformed interferometric measurement data set. The transformed interferometric measurement data set is compared to a baseline interferometric data set to identify a time-varying signal corresponding to a time-varying disturbance. The baseline interferometric data set is representative of the sensing light guide not being subjected to the time-varying disturbance. A compensating signal is determined from the time-varying signal and used to compensate at least a portion of the interferometric measurement data set for the time-varying disturbance as part of producing a measurement of the parameter.

Method and system for calculating a height map of a surface of an object from an image stack in scanning optical 2.5D profiling of the surface by an optical system, a focal plane is scanned at different height positions with respect to the object surface. An image is captured at each height position of the focal plane to form the image stack. The scanning of the focal plane comprises long range sensing and short range sensing a displacement of the focal plane for sensing low and high spatial frequency components. The height position of the focal plane is estimated by combining the low and high spatial frequency components. A height position of each image in the image stack is calculated, based on the estimated height position of each respective focal plane. The images of the image stack are interpolated to equidistant height positions for obtaining a corrected image stack.

An optical interrogation system, e.g., an OFDR-based system, measures local changes of index of refraction of a sensing light guide subjected to a time-varying disturbance. Interferometric measurement signals detected for a length of the sensing light guide are transformed into the spectral domain. A time varying signal is determined from the transformed interferometric measurement data set. A compensating signal is determined from the time varying signal which is used to compensate the interferometric measurement data set for the time-varying disturbance. The compensation technique may be applied along the length of the light guide.

An apparatus and a method for measuring blood flow of vessels are provided. A light source, a light splitting module, a reference arm module, a sample arm module, a probing module, and a control system are arranged; the sample arm module includes a scanning unit and an optical-path shifting device; a probe light is obtained from the light splitting module, and a main light of the probe light is on a rotating shaft of the scanning unit; the probe light is reflected by the scanning unit to the optical-path shifting device, when the optical-path shifting device is in a first position and in a second position respectively, the probe light scans a vessel in fundus to obtain a first phase shift signal and a second phase shift signal blood flow rates and total blood flow of all the vessels near an optic disc are determined.

Disclosed are in-line apparatuses, systems and methods for measuring a physical characteristic of a constant supply of an ophthalmic device, the apparatuses including: an interferometer; an automatic alignment system that positions the interferometer or ophthalmic device; and a central processing unit in communication with the automatic alignment system and receiving measurements from the interferometer. The in-line apparatus measures the desired physical dimensions of the ophthalmic device in real time. In-line systems, apparatuses and methods for measuring a physical characteristic of an ophthalmic device can include: a camera imaging an actual position of a feature of the ophthalmic device; a vibration resistant interferometer projecting a surface measurement beam having a wavelength that transmits through a beam splitter onto the ophthalmic device; and an automatic alignment system positioning the interferometer and the camera.