The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 20, 1991
Filed:
Jun. 11, 1990
David B Chang, Tustin, CA (US);
James E Drummond, Oceanside, CA (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
An infrared holographic defect detector (10) comprises a far infrared pulsed coherent source (14) of infrared radiation which provides infrared radiation. The radiation is directed at a generally non-reflective surface (12), for example, a surface of an automobile body having a matt grey pre-coat thereon. A semi-transparent mirror (15) is placed in the path of the radiation to provide a reference beam (17) therefrom. An infrared detector (18) and a charge-coupled device (20) receives the radiation reflected from the surface and the reference signal. A comparator (22) compares the received reflected information and the reference signal and, preferably, information from a source (24) which defines a desired surface configuration in order to derive a quantitative measurement of the surface. A monitor (26) visually displays the quantitative mesurement and location of any dents in the surface. To avoid a requirement that sequential automobile doors containing the surface of investigation be three-dimensionally aligned to within microns of reference points, a detector of the reflected radiation can be translated and rotated. A number of sensed images of the surface are taken, one at each of the different positions of the detector. For each image a measure of its correlation with the standard image is made.