Correction information generation apparatus, and correction information generation method for correcting image of rotating inspection target

1. A correction information generation apparatus comprising:

an image sensor configured to acquire a plurality of images along a rotating direction of an inspection target at predetermined time intervals; and

a processor configured to:

extract position change information representing a change in an on-image position of a pixel including a predetermined feature value or a predetermined pixel value of the acquired images along a time lapse;

generate information on correspondence between the position of the pixel in each of the images and an angle of rotation of the inspection target from the position change information;

replace each of the plurality of images acquired at the predetermined time intervals with pixel information representing the position of the pixel including the predetermined feature value or the pixel including the predetermined pixel value, and arrange resulting images acquired by the replacement in a direction of a temporal axis, to generate a rotation angle information image as first information of the information on the correspondence; and

generate a superimposed image in which trajectories of the pixel including the predetermined feature value or of the pixel including the predetermined pixel value in the rotation angle information image are superimposed on one another, with predetermined pixel positions being coincident with one another, calculate an average point from a plurality of curves of the superimposed trajectories of the pixel including the predetermined feature value or of the pixel including the predetermined pixel value, to generate a correction curve, and calculate, from the generated correction curve, a correction table, as second information of the information on the correspondence.

2. The correction information generation apparatus according to claim 1 ,

wherein the feature value is a value representing an edge in each of the images.

3. The correction information generation apparatus according to claim 1 ,

wherein the superimposed image is an image formed by extracting the plurality of images including the pixel value in every predetermined cycle and superimposing the images on one another.

4. The correction information generation apparatus according to claim 1 ,

wherein the image sensor comprises a linear sensor, and the images are each a linear image.

5. A correction information generation method for correcting an image of a rotating inspection target, the method comprising:

acquiring a plurality of images along a rotating direction of the inspection target at predetermined time intervals;

extracting position change information representing a change in an on-image position of a pixel including a predetermined feature value or a predetermined pixel value of the acquired images along a time lapse;

generating information on correspondence between the position of the pixel in each of the images and an angle of rotation of the inspection target from the position change information;

replacing each of the plurality of images acquired at the predetermined time intervals with pixel information representing the position of the pixel including the predetermined feature value or the pixel including the predetermined pixel value, and arranging resulting images acquired by the replacement in a direction of a temporal axis, to generate a rotation angle information image as first information of the information on the correspondence; and

generating a superimposed image in which trajectories of the pixel including the predetermined feature value or of the pixel including the predetermined pixel value in the rotation angle information image are superimposed on one another, with predetermined pixel positions being coincident with one another, calculating an average point from a plurality of curves of the superimposed trajectories of the pixel including the predetermined feature value or of the pixel including the predetermined pixel value, to generate a correction curve, and calculating, from the generated correction curve, a correction table, as second information of the information on the correspondence.

6. The correction information generation apparatus according to claim 1 ,

wherein the processor is configured to correct an image of the rotating inspection target based on the first information and the second information of the information on the correspondence.

7. The correction information generation method according to claim 5 , further comprising:

correcting an image of the rotating inspection target based on the first information and the second information of the information on the correspondence.