Process and apparatus for applying noise reducer elements to tyres for vehicle wheels

A process for applying noise reducer elements to tyres, wherein each noise reducer element comprises an anchoring surface coated with an adhesive layer, comprising:

• illuminating said anchoring surface coated with said adhesive layer with a reference radiation;
• and
• detecting a radiation emitted by the anchoring surface illuminated by the reference radiation and, as a function of said emitted radiation,
• determining a digital image representative of the anchoring surface coated with said adhesive layer, each pixel of the digital image being associated with a respective brightness value representative of the amount of adhesive present in an area of said anchoring surface corresponding to said each pixel,
• calculating as a function of the brightness values at least one first parameter representative of the overall distribution of said adhesive layer on the anchoring surface,
• performing a comparison between a value of said at least one first parameter and at least one reference value representative of a correct distribution of said adhesive layer on the anchoring surface,
• based on said comparison, applying on the radially inner surface of a tyre or direct along a discard path one or more noise reducer elements.