Title:
DEFECT DETECTING DEVICE
Document Type and Number:
Japanese Patent JPS6365583
Kind Code:
A
Abstract:
PURPOSE:To reduce a quantizing error and to detect a defect with high accuracy by providing a shift quantity detecting circuit, correcting a shift quantity whenever two pieces of images correspond to each other, and also, executing a calculation up to a decimal part. CONSTITUTION:An image input is obtained as the value of '0' or '1' by allowing it to pass through a binarization circuit 16. If a variation occurs in a position of (X0, Y0) of one image, whether the same variation is occurred in the position of coordinates (X0+dx, Y0+dy) to which shift quantities (dx), (dy) are added, in the other image or not is detected. Unless the same variation is occurred within (k) picture elements centering around its position [(k) picture elements have the smallest size that are decided to be a defect], its position is written as a defect in a memory device B6. If the same variation is detected within the range of + or -1 picture element, the correction of the shift quantity is executed. The shift quantity is derived by collecting 16 pieces of photographed coordinate values of coordinates in which two pieces of images correspond to each other, and averaging them, and at the time of correcting the shift quantity, 16 pieces of the latest data are used, and by deriving this value up to a decimal part, the accuracy is raised.
Inventors:
NAKAJIMA KEIJI
SAKAGAMI YOSHIKAZU
SAKAGAMI YOSHIKAZU
Application Number:
JP21038386A
Publication Date:
March 24, 1988
Filing Date:
September 05, 1986
Export Citation:
Assignee:
MITSUBISHI ELECTRIC CORP
International Classes:
G01N21/88; G06T7/00; (IPC1-7): G01N21/88; G06F15/70
Attorney, Agent or Firm:
Kenichi Hayase