Automotive tire defect characterization with a portable digital holographic camera with an extended field of view

Detection of tire defects is of prime importance for the on-road safety of vehicles. Hence, a quick non-invasive mechanism is required for frequent testing of tires in service as well as for quality checks of newly manufactured tires in the automotive industry. We propose a methodology based on the principle of double-exposure digital holographic interferometry, implemented with a portable digital holographic camera for successful detection and dimension measurement of tire defects. To implement the principle, mechanical load is applied to a tire to produce interferometric fringes by comparing the normal and stressed states of the tire surface. The defects in the tire sample are identified from discontinuities in the interferometric fringes. Quantitative analysis of the displacement of the fringes gives the dimensions of the defects. Some experimental results are presented, validated by a vernier caliper.