The ROC value of a test surface is measured with a single spectrally-controlled interferometric measurement using a reference source of known ROC. The test surface is placed at the confocal position of the reference surface and the light source is modulated so as to produce localized interference fringes at the location of the test surface. The interference fringes are then processed with conventional interferometric analysis tools to establish the exact position of the test surface in relation to the reference surface, thereby determining the distance between the test surface and the reference surface. The radius of curvature of the test surface is obtained simply by subtracting such distance from the known radius of curvature of the reference surface.

The ROC value of a test surface is measured with a single spectrally-controlled interferometric measurement using a reference source of known ROC. The test surface is placed at the confocal position of the reference surface and the light source is modulated so as to produce localized interference fringes at the location of the test surface. The interference fringes are then processed with conventional interferometric analysis tools to establish the exact position of the test surface in relation to the reference surface, thereby determining the distance between the test surface and the reference surface. The radius of curvature of the test surface is obtained simply by subtracting such distance from the known radius of curvature of the reference surface.

A system and method for determining eye surface contour using multifocal keratometry is disclosed. The system includes a light source, a light detector, a processor, a non-transitory machine-readable medium communicatively coupled to the processor, and instructions stored on the non-transitory machine-readable medium. The instructions, when loaded and executed by the processor, cause the processor to project a light, using the light source, onto a plurality of surfaces of an eye; create, using the light detector, an image of a plurality of reflections, each of the plurality of reflections created by reflecting the light off of one of the plurality of surfaces of the eye; determine that the plurality of reflections are in focus in the image; and calculate, based on the determination, a curvature of the plurality of surfaces of the eye based on the image.

A system and method for determining eye surface contour using multifocal keratometry is disclosed. The system includes a light source, a light detector, a processor, a non-transitory machine-readable medium communicatively coupled to the processor, and instructions stored on the non-transitory machine-readable medium. The instructions, when loaded and executed by the processor, cause the processor to project a light, using the light source, onto a plurality of surfaces of an eye; create, using the light detector, an image of a plurality of reflections, each of the plurality of reflections created by reflecting the light off of one of the plurality of surfaces of the eye; determine that the plurality of reflections are in focus in the image; and calculate, based on the determination, a curvature of the plurality of surfaces of the eye based on the image.

A device for detecting a two-dimensional morphology of a wafer substrate in real time. The device comprises: a first calculation module, a second calculation module and an analysis module, wherein the first calculation module calculates the curvature C.sub.X between any two points of incidence on the wafer substrate in an X direction of a substrate to be detected according to position signals of N light spots; the second calculation module calculates the curvature C.sub.Y at any one point of incidence on the wafer substrate in a moving direction, i.e. a Y direction, of the substrate to be detected according to the position signals of N light spots. The device can be adapted to a sapphire substrate on a graphite disc which rotates at a high speed.

A device for detecting a two-dimensional morphology of a wafer substrate in real time. The device comprises: a first calculation module, a second calculation module and an analysis module, wherein the first calculation module calculates the curvature C.sub.X between any two points of incidence on the wafer substrate in an X direction of a substrate to be detected according to position signals of N light spots; the second calculation module calculates the curvature C.sub.Y at any one point of incidence on the wafer substrate in a moving direction, i.e. a Y direction, of the substrate to be detected according to the position signals of N light spots. The device can be adapted to a sapphire substrate on a graphite disc which rotates at a high speed.

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 .sub.1 and .sub.2 such that .sub.1=.sub.B+.sub.B1 and .sub.2=.sub.B+.sub.B2, where .sub.B is the Bragg wavelength of the networks and where .sub.B1 and .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 .sub.B1 and .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 .sub.1 and .sub.2 such that .sub.1=.sub.B+.sub.B1 and .sub.2=.sub.B+.sub.B2, where .sub.B is the Bragg wavelength of the networks and where .sub.B1 and .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 .sub.B1 and .sub.B2 have substantially identical sensitivity to temperature and to deformations and substantially opposite sensitivity to curvature.

In regard to at least one of long separator sheets (12a, 12b), measurement is carried out to measure the amount of curl at an edge of the at least one of the long separator sheets (12a, 12b) while applying tension to the at least one of the long separator sheets (12a, 12b) in the lengthwise direction (MD) of the at least one of the long separator sheets (12a, 12b), the edge being parallel to the lengthwise direction (MD) of the at least one of the long separator sheets (12a, 12b). This makes it possible to provide a method of measuring the amount of curl in a separator, a slitting apparatus, and a curl amount measuring apparatus, each of which is capable of carrying out a highly accurate nondestructive measurement of the amount of curl without having to cut a sample from a long separator sheet.

In regard to at least one of long separator sheets (12a, 12b), measurement is carried out to measure the amount of curl at an edge of the at least one of the long separator sheets (12a, 12b) while applying tension to the at least one of the long separator sheets (12a, 12b) in the lengthwise direction (MD) of the at least one of the long separator sheets (12a, 12b), the edge being parallel to the lengthwise direction (MD) of the at least one of the long separator sheets (12a, 12b). This makes it possible to provide a method of measuring the amount of curl in a separator, a slitting apparatus, and a curl amount measuring apparatus, each of which is capable of carrying out a highly accurate nondestructive measurement of the amount of curl without having to cut a sample from a long separator sheet.