Development of bottle recognition system using acoustic Fourier transform

✍ Scribed by Tadashi Honda; Iwaki Akiyama; Masato Nakajima

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 845 KB
• Volume: 83
• Category: Article
• ISSN: 1042-0967
• DOI: 10.1002/(sici)1520-6440(200007)83:7<42::aid-ecjc5>3.0.co;2-x

✦ Synopsis

In this paper, with a view to automatic selection of bottles in empty bottle recycling, an object recognition system based on the acoustic wave as an acquisition medium of the object information is described. The unique features of this system are: (1) the method can be used for optically transparent objects such as glass bottles, and (2) it can flexibly cope with shift and rotation of the objects. First, the acoustic Fourier transform (AFT) carrying out the Fourier transform of the object information by acoustic waves is presented. In this system, the power spectrum of the object information can be obtained instantaneously at the focal plane of the acoustic wave and the positional invariance of the object is automatically realized. Further, the rotational invariance of the object can also be realized easily by applying the polar coordinate transform to the power spectrum of the object and by considering the rotation as a shift in the rotating direction. For the recognition of the object, a three-layered neural network is used in which the input is the power spectrum with the positional and rotational invariance processes described above. By computer simulation, the design parameters of the experimental system are determined so that a simple experimental system is fabricated. The effectiveness of the present method is verified by the recognition experiments of 10 types of bottle objects specifically carried out for this verification.