Valtion Teknillinen Tutkimuskeskus

Rautaruukki Oy

Focalspec Oy

Other

Teknologian Tutkimuskeskus Vtt

Spectra-physics Visiontech Oy

Helmee Imaging Oy

Sr-instruments Oy

Heimo Keranen

Jouko Malinen

Heikki Saari

Karri Niemelä

Mikko Juuti

Pasi Pietarinen

Tapani Alajarvi

Petri Lehtonen

Veli Vali

Mika Christophliemk

Iiro Hietanen

Seppo Pyorret

A measuring apparatus is provided for inspecting a seal of an item. The measuring apparatus includes a radiation source for providing radiation for illuminating the seal of the item, a detector for receiving radiation from the item for generating a corresponding detected signal, and a processing arrangement for processing the detected signal to generate an output signal indicative of a state of the seal. The radiation source is arranged to focus the radiation into a plurality of focal points at the seal of the item, wherein the focal points are mutually spatially spaced apart. Moreover, the detector is arranged to image one or more of the focal points and to be selectively sensitive to an intensity of radiation received from the one or more focal points to generate a detected signal.

Apparatus and method for inspecting seals of items

In the measuring device and measuring method, confocal measuring principle is utilized. A certain component of an optical measurement signal is, from the point of view of both illumination and imaging, in focus only at one point on the virtual measuring surface. In the measuring device, the surface to be measured always hits a common focus point of the illumination and imaging, whereby a reflection is generated. The reflected optical signal is directed to a detector belonging to the imaging unit, where one picture element of the detector corresponds to a certain focus point, respectively. The optical efficiency received by each picture element is indicated. The light reflecting from the intersection of the virtual measuring surface and the surface of the object produces an intensity maximum for the detector. This maximum point is indicated and converted in the imaging unit () into the height of the surface of the object.

Method and measuring device for measuring the distance of a surface, thickness and optical properties of an object

An arrangement for optically measuring the surface of an optionally glossy target object, includes: a diffusive, semi-transparent illumination structure defining a hollow surface shape configured to surround the target object at least partially, the surface being further provided with at least two apertures, a number of light sources optically coupled to the diffusive illumination structure for illuminating the target object via the surface of the illumination structure, at least two imaging devices, each configured to image the target object via an aperture, and a control entity configured to instruct the number of light sources to form a sequence of predetermined illumination patterns illuminating the target object, to instruct the at least two imaging devices to obtain an image of the target object relative to each illumination pattern, and to derive, through the utilization of the patterns utilized and images obtained, a predetermined surface-related property of the target object.

Arrangement for optical measurements and related method

The invention relates to a system and a method for optical measurement of a target, wherein the target is illuminated, either actively illuminated, reflecting ambient light, or self illuminating, and a measurement radiation beam received from the target or through it is detected. The measurement system has optical fibers for guiding radiation from/to target positions. Radiation of several target positions is simultaneously filtered by a Fabry-Perot interferometer and detected by a row detector, for example.

System and method for optical measurement of a target at multiple positions

A method and apparatus for determining the topography or optical properties of a moving surface of a subject are disclosed. Taking images of the moving surface at different moment in time by aiming different illuminations at the subject. Taking images of a reference area located near the moving surface synchronously with the images of the moving surface, in such a way that, in each image of the reference area, illumination of substantially the same type is aimed at the reference area, wherein the images created of the reference area are used to position image areas corresponding to the same area of the subject in the images of the moving surface.

Method and apparatus for determining the topography and optical properties of a moving surface

An optical radiation processing unit directs different wavelengths of the optical radiation emitted by an optical source to an object being measured from a direction that differs from the normal of a surface being measured so that the different wavelengths focus on different heights in the direction of the normal of the surface. A possible polarizer polarizes the reflected radiation in a direction perpendicular to the normal of the surface. The optical radiation processing unit directs to a detector polarized optical radiation that received from the object. The signal processing unit determines on the basis of a signal provided by the detector from the detected radiation the wavelength on which radiation is the highest, and determines the location of the surface by the determined wavelength. When measuring an object from both sides, the thickness of the object being measured is determinable using the locations of the surfaces.

Determining surface and thickness

A method for finding holes, and other related defects and measuring characteristics of sheets of industrial material. Optical detections systems are constantly plagued by intense ambient light and challenged in accuracy. The invention exhibits a defect detection method and apparatus that is resistant to intense ambient light and is capable of inspecting sheets of material () continuously, without integration of long periods. In the invention, synchronous detection between the optical transmitters and receivers is utilized. The invention is applicable for inspecting and measuring materials like paper, metal, rubber, plastic, aluminum foil, copper foil, film, coated metal sheet or any other sheet-like material that could run on a production line. The invention is also applicable for finding special defects like holes, pinholes, scratches, spots, cracks, edge faults, streaks, surface faults or any other conceivable defects.

Synchronous optical measurement and inspection method and means

A calibration method especially for calibrating a reflection spectrometric gauge, such as an oil film gauge. In the method, calibration is conducted by measuring the gauge response by means of a calibration unit and a solid, stable permanent sample (37) provided on it as a calibration sample. A change that simulates a certain substance concentration is generated by the stable permanent sample (37) in the reflection spectrum, and the gauge response is calibrated on the basis thereof. In the invention, the gauge response is calibrated by using at least two calibration samples (37, 39) having different absorption responses, said two calibration samples being said permanent sample (37) and a second calibration sample (39). For calibration, roughness compensation is performed, in which the gauge response is corrected on the basis of the measurement of the optical response of the surface to be measured and the known data on roughness dependence.

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Oulu, Finland

Heimo Keranen