Optical image encryption based on polarization encoding by liquid crystal spatial light modulators

This work describes a polarization-encoding scheme with cascaded liquid crystal spatial light modulators for two-dimensional exclusive OR logic encryption. The transfer characteristic of the encryption system is analysed to determine suitable polarization modulation for optical realization. Performance is compared across systems that use various displays, including twisted nematic, supertwisted nematic and homogeneously parallel aligned nematic liquid crystal devices. Experiments show that binary image encryption/decryption is accomplished with fair image quality by choosing the orientation of the polarization and modulation conditions. Both simulated and experimental results are presented and discussed.

[1]  B. Javidi.  Securing Information with Optical Technologies , 1997 .

[2]  Bahram Javidi,et al.  Optical pattern recognition for validation and security verification , 1994 .

[3]  G. Unnikrishnan,et al.  A polarization encoded optical encryption system using ferroelectric spatial light modulator , 2000 .

[4]  B Javidi,et al.  Optical image encryption based on input plane and Fourier plane random encoding. , 1995, Optics letters.

[5]  O Matoba,et al.  Secure optical memory system with polarization encryption. , 2001, Applied optics.

[6]  Kehar Singh,et al.  Optical encryption using quadratic phase systems , 2001 .

[7]  D A Gregory,et al.  Real-time liquid crystal TV XOR- and XNOR-gate binary image subtraction technique. , 1987, Applied optics.

[8]  Eun-Soo Kim,et al.  Optical image encryption based on XOR operations , 1999 .

[9]  Y Li,et al.  Security and encryption optical systems based on a correlator with significant output images. , 2000, Applied optics.

[10]  J. Glückstad,et al.  A phase-based optical encryption system with polarisation encoding , 2000 .

[11]  P C Mogensen,et al.  Phase-only optical encryption. , 2000, Optics letters.

[12]  Mohammad A. Karim,et al.  High-security optical integrated stream ciphers , 1999 .

[13]  Chris Chatwin,et al.  Random phase encoding for optical security , 1996 .

[14]  James D. Brasher,et al.  Optical recognition of phase-encrypted biometrics , 1998 .

[15]  Bahram Javidi,et al.  Polarization encoding for optical security systems , 2000 .

[16]  J. Davis,et al.  Two-dimensional polarization encoding with a phase-only liquid-crystal spatial light modulator. , 2000, Applied optics.

[17]  K Takizawa,et al.  Optical parallel logic gate using a Pockels readout optical modulator and twisted nematic liquid-crystal cells. , 1989, Optics letters.