Title:
THRESHOLD DECIDING DEVICE
Document Type and Number:
Japanese Patent JPS6367684
Kind Code:
A
Abstract:
PURPOSE:To isolate and detect a target spot from a two-dimensional electrically floating image by deciding a threshold based on a distribution in response to a concentration distribution about the background out of a concentration and frequency distribution about an entire image. CONSTITUTION:A concentration D0 giving the peak of a histogram about the entire image is considered the peak concentration only of the background, and the distribution lower than the concentration D0 is considered similar to the distribution only of the background. Consequently a feature amount DELTAD expressing the expansion of the distribution on the low concentration side is obtained, from which the distribution expansion of the background on the high concentration side is estimated, and a concentration that almost all the background is less than a fixed concentration is decided a threshold to detect the spot. Practically, the threshold is assumed DT=D0+n.DELTAD. It is obtained in such a way that the distribution feature amount DELTAD is multiplied by a constant (n), 1.4, for instance, and added with the most frequent concentration value D0.
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Inventors:
TSUNEMITSU KAZUKO
FUNO TAKAKAZU
YABUSAKI YUKIO
SUZUKI RYUICHI
FUNO TAKAKAZU
YABUSAKI YUKIO
SUZUKI RYUICHI
Application Number:
JP21156586A
Publication Date:
March 26, 1988
Filing Date:
September 10, 1986
Export Citation:
Assignee:
HITACHI LTD
International Classes:
G01N27/26; G06T1/00; G01N27/447; (IPC1-7): G01N27/26; G06F15/64
Attorney, Agent or Firm:
Katsuo Ogawa