Title:
【発明の名称】ムラ検査方法および装置
Document Type and Number:
Japanese Patent JP3366802
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To determine the unevenness of gray pattern quantitatively by deter mining a blurred image of gray pattern and a power spectral distribution in a partial region thereof, adding the power spectrums in a specified spatial frequency region thereof and comparing the sum with a threshold value. SOLUTION: An image processor 54 executes a software through a CPU 66 to perform various operations. At first, a CCD camera 49 picks up the image of shadow mask SM of an object for which the unevenness is inspected at a position shorter by a specified length than the focal length thus inputting a blurred image. A plurality of square processing regions are then clipped from the image and two-dimensional Fourier transform is performed for each region thus calculating a power spectrum. Subsequently, the power spectrum values are added in a specified frequency region for each region to obtain a sum of power spectrums. Furthermore, a maximum sum is determined for each region and compared with a predetermined threshold thus deciding whether the mask SM is acceptable or not. According to the method, acceptability of the mask SM can be determined quantitatively.
Inventors:
Kunio Ueda
Application Number:
JP5843096A
Publication Date:
January 14, 2003
Filing Date:
February 20, 1996
Export Citation:
Assignee:
Dainippon Screen Mfg. Co., Ltd.
International Classes:
G01N21/59; G01M11/00; G01N21/956; H01J9/42; (IPC1-7): G01M11/00; G01N21/956
Domestic Patent References:
| JP5312542A | ||||
| JP6229736A | ||||
| JP6308046A | ||||
| JP727714A |
Attorney, Agent or Firm:
Takao Igarashi (3 outside)