Tire defect detection method

摘要

Provided is a tire defect detection method capable of accurately detecting a thinly extending convex defect of a tire surface. Prior to the start of Step S1, two-dimensional images including a slit light image are successively obtained in advance. In Step S1, a slit light image is extracted from data of a plurality of shot two-dimensional images. In Step S2, an eccentricity component which is deviation resulting from eccentricity is eliminated from the extracted slit light image. In Step S3, a feature quantity is calculated based on the light image from which the eccentricity component is eliminated, and in Step S4, a thinly extending convex defect is detected based on the calculated feature quantity.

主权项

1. A tire defect detection method for detecting a convex defect in a contact area of a tire comprising tread pattern elements, comprising:
a shooting step of successively shooting two-dimensional images of an area of the tire including a region irradiated with slit light by irradiating a tire tread with the slit light so that a longitudinal direction thereof becomes parallel to a width direction of the tire, while rotating the tire about a predetermined axis; an extraction step of removing, from among light images of the slit light appearing in respective shot two-dimensional images, a light image other than linear light images which are light images of the contact area of the tire and extracting the linear light images; an eliminating step of eliminating an influence of displacement of the contact area resulting from the rotation of the tire, from the two-dimensional images including the extracted linear light images; a calculation step of calculating a difference between a position of the linear light image in each of the two-dimensional images from which the influence of displacement is eliminated and an average position of linear light images in all two-dimensional images from which the influence of displacement is eliminated as a feature quantity for each of the two-dimensional images; and a detection step of comparing a calculated feature quantity for each of the two-dimensional images and a predetermined threshold, and in a case where the feature quantity is larger than the predetermined threshold, determining that the tire has some defect.