Silicon infrared diffuser for wireless communication.
We show what we believe to be a novel way to use silicon in infrared radio communication as a suitable material for the realization of optical diffusers in the range of 850-1600 nm. A crystalline silicon wafer is made porous by means of electrochemical etching. The porous silicon produced is optically characterized, and measurements report a high reflectance in the band of interest. We also study the angular distribution of diffused radiation by the porous silicon surface at different angles of incident radiation. Measurements show that radiation diffuses in a quasi-Lambertian manner, confirming the good performance of this material as an incident radiation diffuser.
Pattern recognition by quantization of modulated function to complexes of a quadrupole in matched filtering
An improved matched filtering method for pattern recognition is proposed. In this method, functions modulated by the matched filter are quantized to the complexes of a quadrupole in the frequency domain. It is shown that shaper autocorrelation and much more suppressed cross-correlation signals can be obtained over those achieved by ordinary matched filters. It is also demonstrated that video-rate correlation processing with an 256×256 input image size can be performed on a regular personal computer using the proposed method even when the reference pattern is switched for every input image.
On-axis joint transform correlation based on a four-level power spectrum.
We propose a method to obtain a single centered correlation with use of a joint transform correlator. We analyze the required setup to carry out the whole process optically, and we also present experimental results.