Creed F. Jones

Optimization of color conversion for face recognition

This paper concerns the conversion of color images to monochromatic form for the purpose of human face recognition. Many face recognition systems operate using monochromatic information alone even when color images are available. In such cases, simple color transformations are commonly used that are not optimal for the face recognition task. We present a framework for selecting the transformation from face imagery using one of three methods: Karhunen-Loève analysis, linear regression of color distribution, and a genetic algorithm. Experimental results are presented for both the well-known eigenface method and for extraction of Gabor-based face features to demonstrate the potential for improved overall system performance. Using a database of 280 images, our experiments using these methods resulted in performance improvements of approximately 4% to 14%.

Color face recognition by hypercomplex Gabor analysis

This paper explores the extraction of features from color imagery for recognition tasks, especially face recognition. The well-known Gabor filter, which is typically defined as a complex function, has been extended to the hypercomplex (quaternion) domain. Several proposed modes of this extension are discussed, and a preferred formulation is selected. To quantify the effectiveness of this novel filter for color-based feature extraction, an elastic graph implementation for human face recognition has been extended to color images, and performance of the corresponding monochromatic and color recognition systems have been compared. Our experiments have shown an improvement of 3% to 17% in recognition accuracy over the analysis of monochromatic images using complex Gabor filters

EXPERIMENTAL INVESTIGATION OF RADIO FREQUENCY IDENTIFICATION RANGE FOR INTRAOCULAR IMPLANTS

Application of RFID technology to intraocular instrumentation requires an understanding of the reliability of propagation through optical tissues and fluids. In this study, the working distance for passive RFID operation is measured in a simulated intraocular environment using porcine eyes. Results are obtained in three common RFID ranges: low frequency, high frequency and ultra-high frequency. Several media were tested to assess the possible impact of intraocular materials. Variations in the possible working distance were observed for certain media, but the data suggest that reliable RFID operation for intraocular sensors is possible at a range of 2-4 cm.