La Correlación Nolineal Dual en el Reconocimiento Óptico de Patrones (I): Principio y Realización Optoelectrónica Dual Nonlinear Correlation in Optical Pattern Recognition (I): Principle and Optoelectronic Implementation

Dual Nonlinear Correlation (DNC) is a general operation in optical pattern recognition where the nonlinear pre-processing introduced in the reference channel may differ from that introduced in the input channel. It involves a number of popular linear and nonlinear filtering methods and can be implemented by an optoelectronic two-step joint transform correlator (JTC). The eventual capabilities of the system depend on some experimental conditions such as quantization, greylevel dynamic range, saturation, and other technical characteristics of both the camera and the spatial light modulator used in the JTC. An overview of the pattern recognition techniques based on DNC is presented in this paper. Firstly, we focus our attention on the description of the principle, properties and optical implementation of the dual nonlinear correlation. The potential of DNC to achieve pattern recognition with adjustable sensitivity is presented in a second work (K. Chalasinska-Macukow et al.,” Dual Nonlinear Correlation in Optical Pattern Recognition II, Óptica Pura y Aplicada 38, núm. 2, 85-97, 2005).