Optical method and device for detecting surface and structural defects of a travelling hot product
AssigneeSiemens Vai Metals Technologies GmbH
InventorJean-Luc Legoupil
Life of this patent
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Abstract
An optical method and device for detecting surface and structural defects of a traveling hot product, such as flat metal products during hot rolling, is disclosed. The optical method includes using images of the product from a camera and formed for one part by light for which the wavelength is in the infrared region and for another part by light for which the wavelength is in the visible spectrum. Detection of the images is provided by several linear sensors, each of them being associated with the detection of one image, each located in a different focal plane associated with each wavelength range so as to obtain superposable images. The light forming a portion of the images is sent onto the surface of the traveling product.
Claims17
An optical method which detects defects of a hot traveling product having a temperature typically within the range of 600-1000° C. during hot-rolling, the method simultaneously detecting defects located on a surface and under the surface of the hot traveling product by the formation and processing of images of the hot traveling product, the images formed by a first portion from light emitted by the hot traveling product itself and for which the wavelength is in the infrared region and by a second portion from light reflected by the product and for which the wavelength is in the visible spectrum, the detection of the lights being provided by a plurality of linear sensors, each of the linear sensors being associated with the detection of an image, the method comprising:
- providing linear sensors collectively arranged relative to an objective of a camera, with each of the linear sensors being located in a different focal plane associated with a wavelength range in order to obtain superposable images;
- moving the linear sensors relative to the objective depending upon the wavelength of light forming an image to be recorded, each of the linear sensors being movable to a multiplicity of positions relative to the objective;
- and
- providing a defect detection signal obtained from the linear sensors.
An optical device which detects the defects of a hot traveling product having a temperature typically within the range of 600-1000° C., the optical device including:
- a forming unit which forms images of the hot traveling product, the forming unit comprising a camera and an objective;
- a plurality of linear sensors arranged relative to the objective and which detect the formed images, each of the linear sensors being sensitive to respective different spectrums of light sent by the camera using the objective;
- each of the linear sensors being located in a different focal plane and being moveable relative to the objective to a multiplicity of positions within that plane depending upon a wavelength of light forming the image;
- and
- an image processor which processes the detected images of the hot traveling product, the processing comprising analyzing images formed by a first portion from light for which the wavelength spectrum is located in the infrared region, and by a second portion from light for which the wavelength spectrum is located in the visible region.
Dependencies are inferred from the claim text.