Method for determining adhesion of foreign matter on green tire

A method for determining the adhesion of a foreign matter which is a determining method for determining whether a foreign matter is adhered on an outer surface of a green tire which outer surface is formed by spirally winding a rubber strip, comprising:

• a raw data acquiring step in which an examination surface of the outer surface of the green tire is scanned in the circumferential direction with a two-dimensional displacement sensor, and a raw three-dimensional data D0 of the examination surface is created,
• an averaging processing step in which by averaging processing distance data z in the raw three-dimensional data D0, processed three-dimensional data D1 are obtained,
• an imaging step in which distance data z in the processed three-dimensional data D1 are each binarized at a threshold, and an image is created, and
• a determining step in which, based on the data about the created image, whether a foreign matter is adhered is determined,
• wherein
• in the raw data acquiring step,
• the green tire is rotated about an axis thereof, and
• the two-dimensional displacement sensor irradiates the examination surface of the rotating green tire with a sensor light which is linear and elongate in X direction perpendicular to the circumferential direction, thereby,
• the raw three-dimensional data D0 made up of position data x in the X direction, position data y in the circumferential direction, and the distance data z from the two-dimensional displacement sensor to the examination surface,
• are created, and
• in the averaging processing step,
• with respect to the raw three-dimensional data D0,
• for each of the distance data z, the averaging process is made over a range having a width Wx in the X direction and a width Wy in the circumferential direction, thereby, processed three-dimensional data D1 are obtained,
• wherein
• each of the width Wx and the width Wy is larger than a spiral pitch of the rubber strip and is smaller than the width of the rubber strip.