Proc. SPIE. 6027, ICO20: Optical Information Processing
KEYWORDS: Digital signal processing, 3D image reconstruction, Digital watermarking, Transform theory, Signal processing, Near field diffraction, Electronic filtering, Signal detection, Filtering (signal processing), 3D image processing
In this paper, we present a new approach for digital audio watermarking scheme in three-dimensional (3-D) space. The architecture of 3-D digital audio watermark insertion is on the basis of virtual optics imaging system (VOIS), which relies on the propagation of virtual light wave through discrete Fresnel diffraction (DFD). The embedding strategy of a watermark with a methodology of the VOIS is analyzed in detail under the framework of Fourier optics. In order to test the robustness against signal processing, we carried out several detection experiments. Common audio signal manipulations like adding noise, filtering and data compression are used. Simulation results have shown a good agreement to theoretical predictions.
In order to implement 3-D imaging of objects with large height discontinuities and/or surface isolation, we present a novel 3-D imaging system based on temporal sequential fringe projector to provide multi-resolution 3-D reconstruction. To recover the range data of such a surface, an enhanced scheme for temporal phase unwrapping procedure is proposed. We also describe methods for extracting the color texture corresponding to a range image. Experimental results are given to illustrate the validity of our proposed method.
A three-dimensional (3D) profilometry based on a dual-acousto-optic fringe projection is reported in this paper. The fringe projector is able to generate fringe patterns with different optical sensitivities and therefore can handle the object surface with complex geometry and topology. It is also qualified for video-rate 3-D profilometry of arbitrary shape objects. By using two acousto-optic deflectors (AODs), the projector can generate a time-series, frequency-varying fringe patterns by use of the AO interaction effect. The two AODs are driven by the radio frequency (RF) signal with the same frequency. Changing the RF frequency leads to the change of the period of fringe patterns and, therefore, different sensitivities. In practice, the changing rate of sesitivity is limited by the frame rate of the detector, e.g. CCD, so it makes a dynamic 3-D profilometry possible. Experimentally, we project a sequence of spatial frequency-varying fringe patterns onto the test object surface. Then, a CCD camera simultaneously acquires the phase-modulated fringe patterns accordingly. With a sequence of phase measurement in a progression of fringe periods, an enhanced scheme for phase unwrapping algorithm is implemented in a recursive manner. The object surface with complex geometry and topology can be reconstructed in this way. Experimental results are also given to validate this approach.
Proc. SPIE. 5642, Information Optics and Photonics Technology
KEYWORDS: Digital signal processing, Image encryption, Optical signal processing, Data modeling, Image processing, Telecommunications, Signal processing, Multimedia, Computer security, Network security
In this paper, we present an approach of real-time implementation of multimedia data security based on virtual-optics with the aid of a parallel digital signal processor (DSP). In order to partially compensate the parallelism of optical processing lost by digital implementation, we make full use of parallel hardware architecture and parallel computation structure of the TMS320C6701 DSP, leading to a high-efficiency operation. This approach makes it possible for the virtual-optics imaging methodology (VOIM) to be realized in real-time applications in embedded systems for multimedia data security. Experiments with multimedia data are performed to validate the proposed method, and parameter-sensitivities are quantitatively analyzed and illustrated.
A virtual-optical based encryption model with the aid of public key infrastructure (PKI) is presented in this paper. The proposed model employs a hybrid architecture in which our previously published encryption method based on virtual-optics scheme (VOS) can be used to encipher and decipher data while an asymmetric algorithm, for example RSA, is applied for enciphering and deciphering the session key(s). The whole information security model is run under the framework of international standard ITU-T X.509 PKI, which is on basis of public-key cryptography and digital signatures. This PKI-based VOS security approach has additional features like confidentiality, authentication, and integrity for the purpose of data encryption under the environment of network. Numerical experiments prove the effectiveness of the method. The security of proposed model is briefly analyzed by examining some possible attacks from the viewpoint of a cryptanalysis.