Image analysis – Histogram processing – For setting a threshold
Patent
1991-09-19
1994-12-27
Moore, David K.
Image analysis
Histogram processing
For setting a threshold
327 72, 327 91, G06K 938, H03K 5153, H03K 700
Patent
active
053772822
ABSTRACT:
An optical imaging surface inspection system and method are provided. The system comprises an illumination source for illuminating an image pattern on a surface to be inspected, a video camera for detecting a portion of the light reflected from the surface and outputting an analog video signal, a dynamic thresholding circuit for converting the analog video signal into a digital representation of the image pattern, and means to compare a known accurate digital representation of the image pattern to the digital representation provided by the dynamic thresholding circuit. The method includes the steps of illuminating the surface, scanning the surface with the video camera, separating the video signal into a black level signal component and a white level signal component, detecting successive peak levels in the white level signal component and outputting a corresponding variable peak voltage. A variable threshold voltage is determined by selecting a percentage of the variable peak voltage. This variable threshold voltage is then compared with a delayed portion of the analog video signal to provide the digital representation of an image pattern on the surface being inspected.
REFERENCES:
patent: 4230265 (1980-10-01), Casaly
patent: 4247873 (1981-01-01), Decuyper
patent: 4251837 (1981-02-01), Janeway, III
patent: 4442544 (1984-04-01), Moreland et al.
patent: 4446486 (1984-05-01), Itoh
patent: 4453268 (1984-06-01), Britt
patent: 4468704 (1984-08-01), Stoffel et al.
patent: 4539600 (1985-09-01), Takahashi et al.
patent: 4566125 (1986-01-01), Clunn
patent: 4593325 (1986-06-01), Kannapell et al.
patent: 4626922 (1986-12-01), Saitoh
patent: 4644410 (1987-02-01), Schlichtig
patent: 4691239 (1987-09-01), Nelson et al.
patent: 4731862 (1988-03-01), Tsuda et al.
patent: 4766332 (1988-08-01), Pelgrom et al.
patent: 4794647 (1988-12-01), Forgues et al.
patent: 4856075 (1989-08-01), Smith
patent: 4876605 (1989-10-01), Ishikawa et al.
patent: 4908875 (1990-03-01), Assael et al.
patent: 4998122 (1991-03-01), Kanno et al.
Klepp, "Dynamic Video Thresholding", IBM Tech Discl., vol. 22, No. 3 pp. 1031-1033, (Aug. 1979).
Wilson, "Thresholding of Video Signals" IBM Tech. Discl., vol. 16, No. 12, pp. 4021-4022 (May 1974).
Penny, "Dynamic Threshold Setting Circuit", IBM Tech Discl. Bull. vol. 18, No. 6 pp. 1962-1965 (Nov. 1975).
IBM Technical Disclosure Bulletin, vol. 24, No. 1B, pp. 847-848 Jun. 1981.
IBM Technical Disclosure Bulletin, vol. 24, No. 2, pp. 1209-1211 Jul. 1981.
Fellows Todd C.
Rittenhouse Norman E.
Yablonsky Peter J.
Cammarata Michael R.
International Business Machines - Corporation
Moore David K.
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