Research On Tyre Non-destructive Inspection Based On Digital Holography

Separation and blister are two main kinds of tyre's interior defects which can be hardly detected by traditional techniques except non-destructive laser holographic inspection. Laser holographic inspection using holofilm plate is not suitable for the modern industry detecting because of the low efficiency. Digital holography using CCD instead of holographic plate implements holographic recording,storage and reconstruction in computer and achieve extensive application.Based on theoretic analysis,computer simulation and the corresponding experiment research,this paper gives some analysis about the theory of digital holography and its application in the tyre inspection. The main work is as the followings:1. Simulate the whole holographic progress in computer, including simulating ideal digital holograms, reconstructing them using Fresnel transform, and reconstructing 3D-object images based on the reconstructed phrase.2. Double exposure hologram and elimination of zero-order diffraction spot are analyzed and simulated. It is also performed in holographic experiment using Michelson's interferometer and the results match well with the ideal ones.3. New optical system is designed aimed at the low reflection index of object,and tyre deformations are detected successfully using phrase difference holography inspection. Parameters in experiment are analyzed and the whole optical system is calculated at the same time.4. To get a larger field of view,optical system is improved. It is proved that range of the system have reached 138.1mm×112.4mm and calculating an image of 1300×1024 pixel cost only 62ms. So the holography non-destructive system have achieve basic requirements and can be used in industry detection.