Title:
【発明の名称】透過照明を用いたパターン位置検出方法およびその装置
Document Type and Number:
Japanese Patent JP2997306
Kind Code:
B2
Abstract:
PURPOSE:To set the optimum threshold value according to the state of patterns with high producibility by setting the prescribed inspection area to obtain the frequency distribution of the brightness for each picture element in an inspection area and deciding the threshold value based on the relation between the darkest section and the next darkest one. CONSTITUTION:The prescribed inspection area is set against the gradation picture stored in a frame memory 12, and each picture element in it is read out by an address counter 13 to obtain the frequency distribution of the brightness in a histogram preparation part 14. Plural selectors classifying the brightness and a counter counting the number of picture elements corresponding to it are provided, and the frequency distribution is obtained in the histogram preparation part 14. Plural mountain parts appear in this. The threshold value is set on the frequency in a change point detection part 17, and the brightness of the intersected point with the threshold value is obtained about the darkest section and the next darkest one. The median value of this brightness is taken as the threshold value. The processing emphasizing the contrast of the picture against the gradation picture is performed while utilizing this threshold value.
Inventors:
Masayuki Hattori
Okamoto Shinji
Nagao Hamada
Okamoto Shinji
Nagao Hamada
Application Number:
JP24535090A
Publication Date:
January 11, 2000
Filing Date:
September 14, 1990
Export Citation:
Assignee:
MATSUSHITA ELECTRIC WORKS,LTD.
International Classes:
G01B11/24; G06T1/00; G06T7/00; (IPC1-7): G06T1/00; G01B11/24; G06T7/00
Attorney, Agent or Firm:
Keisei Nishikawa (1 person outside)