A method and apparatus for determining the size and shape to which a finished lens used to make an eyeglass lens is to be cut. Coordinates which define the outer perimeter of a lens are determined by illuminating either an eyeglass frame or a lens. An image of the shadow of the frame or lens is captured by an imaging device. A first linear polarizing filter is positioned optically between a light source and the membrane. A second linear polarizing filter, oriented at 180.degree. from the first filter, is placed optically between the membrane and the camera. Thus, the first and second polarizing filters allow a high definition image to be attained for substantially transparent plastic. A general purpose computer: (1) identifies the edges of the image so as to define the perimeter; (2) orients the image by identifying an orientation line placed upon a lens, if the image is of a lens which is not within a frame; and (3) measures the distance between lenses if an eyeglass frame is being measured. If an eyeglass frame is being measured, then a depth gauge indicator is used to measure the depth of a groove in the frame into which a lens is recessed when mounted in the eyeglass frame. Once the coordinates of the lens are determined, they may be verified by comparison with the frames or lens from which they were derived. Further, the coordinates of the outer perimeter of the edged lens may be determined to verify the accuracy of the operation.
On a monitor (52) there is displayed a synthesized image (G4) in which an image (G1) of a subject lens showing a refractive power distribution, an image (G2) of a lens frame, and an eyepoint mark image (G3) are superimposed based on the refractive power distribution data of the subject lens by a lens meter (100), on the frame shape data of the lens frame by a frame shape measurement apparatus (200), and on the eyepoint data by an eyepoint measurement apparatus (300).
A length measure apparatus and the method for measuring transform an image from a lens set into a digital contrast image via a central processing unit. The CPU has multiple standard lines that are previously set therein. Multiple movement controllers control a movement of a selected standard line from the CPU relative to the digital contrast image. A movement value is output when the selected standard line flushes with a profile of the contrast image. The measure value is shown on a monitor when the CPU contrasts the movement of the selected standard line.
A method of verifying at least one centering characteristic of an ophthalmic lens provided with markings and mounted on a frame, the method includes: a) positioning the ophthalmic lens on a support placed facing a pattern filter; b) using a diffuse light source to illuminate the ophthalmic lens through the pattern filter; c) using a digital camera to pick up the light transmitted by the ophthalmic lens; d) processing the signal output by the digital camera to determine the positions of the markings of the ophthalmic lens in a stationary frame of reference; e) determining the position of the support in the stationary frame of reference; and f) deducing the value of the centering characteristic from the known position of the support and from the positions of the permanent markings of the ophthalmic lens.
Device (100) for automatically detecting various characteristics of an ophthalmic lens (10), the device includes a support (110) adapted to receive the lens. The support is displaceable in translation along two mutually perpendicular axes, and include elements for forming a positioning image on first acquisition and analysis elements.
A method for filtering undesired light reflections in a structured light measurement system during the inspection of shiny metal prismatic objects having uncoated prismatic surfaces, such as turbine blades, using polarized light.
