Canadian Patents and Development Limited/societe Canadienne Des Brevets

Canadian Patents and Development Ltd. - Societe Canadienne Des Brevets

Marc Dufour

Paolo G Cielo

Mario Lamontagne

Ghislain Vaudreuil

An optical inspecting apparatus and the method thereof, including a series of optical units for rapidly acquiring the three-dimensional surface profile of a moving object. Each optical unit contains a multiple-beam light source to project a number of luminous spots on the object surface which are imaged through a properly oriented line-array camera. The surface position on both sides of the object, and thus the object thickness, is inferred at the position of each luminous spot from an analysis of their camera image. The projected luminous spots are preferably elliptically shaped and the line array elements are elongated in a direction perpendicular to their longitudinal axis in order to reduce speckle and other optical noise. The described optical configuration results in a superior performance in terms of spatial resolution and response speed.

Method and apparatus for monitoring the surface profile of a moving

The present disclosure describes an apparatus and a method for detecting the presence of flaws in a moving sheet of material. The apparatus comprises a light source for projecting a light beam; a beam shaping unit for shaping the light beam into a predetermined structured light pattern, and projecting the structured light pattern onto a portion of the surface of the sheet; an optical unit for collecting light emitted from the portion of the surface; and a light detecting unit for receiving the light collected by the optical unit and generating an electrical signal indicative of the intensity of the light generated from the portion of the surface. A signal processing unit is provided for filtering the electrical signal, the signal processing unit having predetermined characteristics specifically adapted to match an expected electrical signal corresponding to the predetermined structured light pattern. The present invention can be used in a transmission mode wherein the light beam is projected onto one side of the moving sheet and detected from the opposite side, or in a reflective mode wherein the light beam is projected onto and detected from the same side of the moving sheet.

Method and apparatus for detecting the presence of flaws in a moving

A method and apparatus for optically inspecting the geometry of a surface in an environment which is subject to the presence of external light noise perturbations. A beam of monochromatic light having a predetermined wavelength and a structured light pattern is projected onto the surface to thereby scatter the structured light beam and produce a scattered light beam which is thereafter separated into first and second scattered beam portions. The first scattered beam portion is passed through a first optical filter having a narrow bandwidth and a central wavelength corresponding substantially to the wavelength of the projected light, thereby providing a first optical output signal representative of the surface geometry and of external light noise perturbation. The second scattered beam portion is passed through a second optical filter having a narrow wavelength bandwidth and a central wavelength which is closely spaced from the predetermined wavelength of the projected light by a wavelength offset such as to reject the projected light wavelength, thereby providing a second optical output signal representative of substantially the same external light noise perturbation as that passing through the first optical filter. The first and second optical output signals are detected and converted into first and second electrical signals, respectively. The second electrical signal is then subtracted from the first electrical signal to provide a substantially noise-free electrical output signal representative of the surface geometry. The invention is particularly useful for active vision robot welding and enables arc light noise-free images to be obtained in real time.

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Montreal, Canada

Marc Dufour