Measurement of Tire Tread Depth with Image Triangulation

Tires bear the grip and friction force between a vehicle and the ground. Worn tires will result in slippage, a longer braking distance, and even flat tires, which could eventually result in a driving accident. Therefore, governments, including Taiwan, have formulated standards stipulating the appropriate tire pressure and depth of tire treads. The tire tread depth used to be determined using manual contact measurement. This study created a non-contact measurement prototype system which applying machine vision to measure tread depth that uses image triangulation to reduce the manpower expense and improve the convenience of measurement. Based on the Epipolar plane, this system obtains the distance between the tire treads and camera lens, consequently, the depth image of the tire tread was constructed. Along with the normal direction of groove of the tire's main tread on the depth images, obtaining the correct depth data using the majority decision voting strategy. Consequently, the tread depth was measured. In addition, this system produced an application (APP) which allows a user to obtain and record the tire tread depth on their Android smart phone.