Diffracto, Ltd.

Donald A Clarke

Timothy R Pryor

Nicholas Liptay-Wagner

Rodger L Reynolds

Omer L Hageniers

Walter J Pastorius

Roland Renaud

Blaine Richards

A method for creating a retroreflective image of a surface (or transparent medium) is provided where the retroreflective image is produced by illuminating an area of the surface with light which is reflected therefrom to a retroreflector which returns this light to the surface area. At the surface area, the retroreflected light is then reflected again and imaged to thus form the retroreflected image. In one embodiment, a broad light source is used to image a secondary image of the surface. In another embodiment, the light field produced by the surface is larger than the retroreflective element or group of elements which are then moved. In still another embodiment, a single retroreflective element is used together with a divergent light source.

Methods and apparatus for retroreflective surface inspection and

This invention relates to an electro-optical technique which senses form type and other defects on surfaces such as sheet metal or plastic panels. Method and apparatus are disclosed for allowing the inspection of the entire surface of interest from a single point of view while reducing the complexity of defects' optical signatures to simplify their subsequent analysis.

Surface inspection using retro-reflective light field

Methods for improving and calibrating a retroreflection defects determination system are disclosed. The retroreflection system includes a light source which directs light to an area of a surface such that the light is reflected therefrom, a retroreflective member positioned such that the reflected light from the surface area impinges thereon and is thus returned to the surface area and re-reflected therefrom and an imaging device whereby the re-reflected light is imaged as a retroreflection image and scanned for intensity variations. In the identifying method, the retroreflective member of the system has a divergence angle, and the imaging step is repeated after the divergence angle has been appropriately changed. According to the calibrating methods, a first retroreflection image of a system is obtained. Then, one of the test conditions of the system is changed or the test surface is changed. The subsequent retroreflection image is then compared to the first in order to calibrate the system. A method for returning or calibrating the system to a previous condition is also disclosed. According to this method, a stored reference is displayed alternately and in quick succession on a visual display with a current image so that differences therebetween appear as a flicker. Then, the flickers are reduced by adjusting variables of the system and hence to return the system to the previous condition.

A method of determining physical characteristics of a surface. Light or other electromagnetic radiation is directed onto a first portion of a surface and the reflected radiation is received such as by a photodiode. The radiation is also directed onto at least two further portions of the surface and located on either side of the proximate to the first portion. The radiation reflected by the further portions is also received. The radiation reflected from the first portion is compared with the radiation reflected from the two further portions. The radiation and comparison steps are repeated and the comparisons are used to determine a physical characteristic of the surface, such as the presence of one or more flaws. In another embodiment, light or other electromagnetic radiation is used to determine object dimension, such as bore dimension.

Method and apparatus for determining physical characteristics of objects

This invention relates to electro-optical sensing of form type and other defects on surfaces such as sheet metal or plastic panels. Method and apparatus are disclosed for detection and quantification of defects such as dents, creases, low spots, flat spots, etc. which are a result of the manufacturing, material handling and assembly process. Surfaces of interest are generally those of automobile body panels, (e.g. hoods, fenders), refrigerator panels, furniture panels, and aircraft panels. Similar applications exist to dies and other formed metallic or plastic parts. Both automatic and human visual methods and apparatus are disclosed. The disclosed invention is also effective on paint defects such as orange peel encountered in automotive and other applications. Assemblies of panels, such as car bodies may also be inspected using the invention, and both fixed and moving (e.g. robotic) sensor versions are disclosed.

Panel surface flaw inspection

The invention concerns optical non-destructive test of materials using surface distortions detected by light which is reflected from the surface, retroreflected back to the surface and thence to form an image containing a greatly enhanced view of local deformation. In addition, the method is usable for determining surface characteristics of membranes and the like which can be influenced by sound and other wave energy from tested members and other sources and objects.

Non destructive testing and other applications using retroreflective

Disclosed are improvements in the surface inspection method and apparatus invention of our copending application 'Panel Surface Flaw Inspection', Ser. No. 579,971, U.S. Pat. No. 4,629,319, which has now come to be described as 'DiffractoSight'. Particularly disclosed are semi and full automatic techniques for quantifying and locating localized surface distortions. Applications for determination of scratches, paint finish defects and other surface problems are also described. The primary area of application is to cosmetic defects on automobile bodies, appliances, and furniture, and the dies, molds and models and other surfaces used in their manufacture.

Diffractosight improvements

A method an apparatus are provided for inspecting the surface of objects such as panels for automobile vehicles wherein the surface of the object is sprayed with an oil mist or the like to increase the reflectivity thereof. The surface is then illuminated with light so that the light image reflected therefrom is formed on a light detector such as a photodiode array. The output of the light detector is analyzed to determine surface features of the object such as 'dings' and dents therein.

Surface reflectivity detector with oil mist reflectivity enhancement

This invention relates to new and useful electro-optical methods and apparatus using photodetector arrays for measurement of parts and other objects in industrial environments. Several particularly useful optical embodiments are illustrated together with desirable electronic circuitry for improving the accuracy of practical systems of this type.

Photodetector array based optical measurement systems

A method of determining physical characteristics of a surface. Light or other electromagnetic radiation is directed onto a first portion of a surface and the reflected radiation is received such as by a photodiode. The radiation is also directed onto at least two further portions of the surface and located on either side of and proximate to the first portion. The radiation reflected by the further portions is also received. The radiation reflected from the first portion is compared with the radiation reflected from the two further portions. The radiation and comparison steps are repeated and the comparisons are used to determine a physical characteristic of the surface, such as the presence of one or more flaws. In another embodiment, light or other electromagnetic radiation is used to determine object dimension, such as bore dimension.

Method and apparatus for determining dimensional information concerning an object. A ring of light is directed onto an object surface such that at least a portion of the ring of light is incident upon the object surface. An image is formed of the incident light reflected from the surface. The width or position of the image is determined. The location of the surface is determined from the image width or position, and dimensional information about the object is determined from the surface location.

Method and apparatus for determining dimensional information concerning

A method and apparatus are provided for analyzing the light pattern produced on a photodetector array. The signal produced by the array is filtered with a low pass filter and the output of the filter is differentiated to obtain either the first or second derivative of the filtered signal for one or more points in the pattern. The zero crossing of the differentiated signal is detected and the zero crossing point is timed relative to a further point, e.g., the start of the scan of the array, so as to obtain an output related to the position of the corresponding point or points in the pattern.

New photodetector array based optical measurement systems

A method and apparatus is disclosed for determining physical characteristics, such as defects, in the outer surface of an elongate object, wherein the object to be inspected passes through an aperture of a mirror surface which is a conical surface of revolution. Light directed onto the mirror surface in an axial direction is reflected by the object surface, imaged, and analyzed to determine a physical characteristic of the object surface.

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Windsor, Canada

Donald A Clarke