A distance calculation device includes a first light source and a second light source that emit detection light from positions different from each other and that apply the detection light to at least one of eyeballs of a subject; an imaging unit that captures an image of the eyeball of the subject to which the detection light is applied; a position calculator that, based on the image of the eyeball of the subject that is captured by the imaging unit, calculates each of a position of a first cornea reflection center according to the detection light from the first light source and a position of a second cornea reflection center according to the detection light from the second light source; a center-center distance calculator that calculates a center-center distance between the position of the first cornea reflection center and the second cornea reflection center; and an object distance calculator.

A system and method of characterizing through-focus visual performance of an IOL using metrics based on an area under the modulation transfer function for different spatial frequencies at different defocus positions of the IOL. Also disclosed is a system and method of characterizing through-focus visual performance of an IOL using a metric based on an area under a cross-correlation coefficient for an image of a target acquired by the IOL at different defocus positions of the IOL.

An apparatus for inspecting lenses includes an inspection system including an open cuvette, a communicatively coupled CT measurement device, and a user interface communicatively coupled to the inspection system. According to one embodiment, the lens inspection system provides a single instrument for inspecting the quality of a lens, thereby minimizing the transference of the lens from one inspection component to another.

The spatial structure of an optical element is determined. The optical element has a first optically active surface and a second optically active surface. The optical element is arranged in a holding device. The position of a point (P) on the first optically active surface and the position of a point (P′) on the second optically active surface are referenced in a coordinate system fixed to the holding device. The topography of the first optically active surface is determined in a coordinate system referenced to the holding device by the position of point (P) and the spatial structure of the optical element is calculated from the topography of the first optically active surface and from a data set as to the topography of the second optically active surface. The data set is referenced to the fixed coordinate system of the holding device by the position of point (P′).

A semiconductor device may include a semiconductor wafer, and a reference circuit carried by the semiconductor wafer. The reference circuit may include optical DUTs, a first set of photodetectors coupled to outputs of the optical DUTs, an optical splitter coupled to inputs of the optical DUTs, and a second set of photodetectors coupled to the optical splitter. The optical splitter is to be coupled to an optical source and configured to transmit a reference optical signal to the first set of photodetectors via the optical DUTs and the second set of photodetectors.

A method includes receiving, into a measurement tool, a substrate having a material feature, wherein the material feature is formed on the substrate according to a design feature. The method further includes applying a source signal on the material feature by using a source in the measurement tool having a tool setting parameter, collecting a response signal from the material feature by using a detector in the measurement tool to obtain measurement data, and with a computer connected to the measurement tool, calculating a simulated response signal from the design feature using the tool setting parameter. The method further includes, with the computer, in response to determining that a difference between the collected response signal and the simulated response signal exceeds a predetermined value, causing the measurement tool to re-measure the material feature.

Embodiments of the invention provide a method of determining one or more characteristics of a target object, comprising recording one or more diffraction patterns at a detector, wherein each diffraction pattern is formed by a target object scattering incident radiation, determining a phase map for at least a region of the target object based on the one or more diffraction patterns, and determining a refractive property of the target object based on the phase map.

Provided are a lens power measurement device and a lens power measurement method whereby lens power measurement results of a contact lens can be displayed in a manner which is easy to view, while maintaining fully satisfactory precision of the lens power measurement results. From lens power distribution information determined based on optical property measurement information of a contact lens, correction target information including positive and negative abnormal peaks on both sides of a lens central axis in a lens central area is selected. Lens power distribution measurement results are then obtained by applying substitution using a correction function that smoothes out the abnormal peaks to the selected correction target information to smooth the lens power measurement values.

The thick lens calibration method enables better calibration of complex camera devices such as devices with thick lens systems. The thick lens calibration method includes a two step process of calibrating using the distance between a second nodal point and an image sensor, and calibrating using the distance between the first and second nodal point.

An apparatus and a method for optical measurement of an internal contour of a spectacle frame are disclosed. The apparatus contains an optical unit, which is configured to capture light reflected from an illuminated section of the inner contour of the spectacle frame. The optical unit is insertable into the inner contour of the spectacle frame and, when inserted as intended, is rotatable relative to the spectacle frame. The optical unit contains at least one light source, an objective, and at least one optical sensor, wherein the light source is configured to generate a light section, wherein at least one section of the inner contour is illuminable by the light section, wherein the objective is configured to image the illuminated section of the inner contour onto the optical sensor, and wherein the optical sensor is configured to capture the light reflected by the illuminated section of the inner contour.