Particle shape recognition by using digital holography

摘要

3D object recognition is now an increasing interest in the optical information processing. In this paper, a method of 3D particle shape recognition by using in-line digital holography and optical correlation techniques is presented. The complex amplitude distribution generated by particle field at any plane located in the Fresnel diffraction region is recorded directly by CCD. The original field is then reconstructed numerically by wavelet transform. The scale parameter of the wavelet family, a, is related to the distance between the particle hologram and the plane of observation. The whole information of particle field can be obtained by changing the value of a. Holographic information of the 3D reference object can also be gained by the same method, and act as complex filter. Correlation techniques are then applied to recognizing the particle shape, and experimental results are also given.