Device and method for detecting angle of rotation from normal position of image

Patent metadata

Field	Value
Publication number	US-9514526-B2
Application number	US-201114005913-A
Country	US
Kind code	B2
Filing date	Nov 9, 2011
Priority date	Mar 25, 2011
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

An evaluation value indicative of the extent of lines in each direction is calculated for a pre-processed image in which 0s are filled in and extended in the lateral direction of the inputted image and which has been reduced ⅛th in the longitudinal direction. To obtain the angle of rotation of an image from the change in the evaluation value obtained while the angle relative to the lateral direction of the pre-processed image is modified in small steps, a parallel line is drawn for each direction, a projection is taken, and the sum of squares serves as the evaluation value of the direction. The direction having the highest evaluation value serves as the obtained direction of rotation from the normal position. The projection of each direction references the point of intersection between the parallel line drawn for each direction and the coordinate line of the horizontal axis.

First claim

The invention claimed is:

1. A device for detecting a rotation angle from a normal position of an image, the device comprising:
an electron microscope configured to generate an original photographed image of an inspection object;
a computing device coupled to the electron microscope,
wherein the computing device is configured to:
based on one of the original photographed image and the original photographed image having been subjected to predetermined preprocessing used as an input image, generate a plurality of equally-spaced virtual parallel lines that extend at each angle of a plurality of angles,
at each angle that the plurality of equally-spaced virtual parallel lines extend, of the plurality of angles, generate an evaluation value based on reference points of each of the equally-spaced virtual parallel lines, the reference points are points of intersection of each of the equally-spaced virtual parallel lines and horizontal axis lines of the input image, or the reference points are points of intersection of each of the equally-spaced virtual parallel lines and vertical axis lines of the input image;
generate evaluation value data based on the evaluation value of the equally-spaced virtual parallel lines extending at each of the plurality of angles wherein a distance between each of the equally-spaced virtual parallel lines, in a direction that is perpendicular to the equally-spaced virtual parallel lines, differs depending on the angle; and
detect a desired angle of the plurality of predetermined discrete angles based on the evaluation value data.

2. The device for detecting a rotation angle from a normal position of an image according to claim 1 , wherein the predetermined preprocessing includes processing in which the original photographed image is reduced in a predetermined direction.

3. The device for detecting a rotation angle from normal position of an image according to claim 1 , wherein the predetermined preprocessing includes processing in which the original photographed image is copied to generate an image expanded by a predetermined length along a predetermined one of the coordinate axes.

4. The device for detecting a rotation angle from normal position of an image according to claim 1 , wherein the plurality of desired discrete angles are determined based on a size of one of the original photographed image and the original photographed image having been subjected to predetermined preprocessing.

5. The device for detecting a rotation angle from normal position of an image according to claim 1 ,
wherein each of the equally-spaced virtual parallel lines extend from another horizontal line, which is parallel to the horizontal lines of the input image, and each of the equally-spaced virtual parallel lines are spaced apart by one pixel.

Assignees

• Taguchi Jun'Ichi
• Ikeda Mitsuji
• Abe Yuichi
• Kitazawa Masahiro
• Hitachi High Tech Corp

Inventors

• Taguchi Jun'Ichi
• Ikeda Mitsuji
• Abe Yuichi
• Kitazawa Masahiro

Classifications

• G06T7/0004 Primary

  Industrial image inspection · CPC title

• G06V10/243 Primary

  by compensating for image skew or non-uniform image deformations · CPC title

• G06K9/3275

  Physics · mapped topic