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The instantaneous frequency of a chirp-like signal varies with time. The sampling density of a signal should preferably correspond to its local bandwidth. The paper discusses the level-crossing sampling principle, which provides the capability for performing such an analog-to-digital conversion. The properties of level-crossing sampling are considered. As(More)
An application of the Karhunen-Loeve transformation (principal component analysis) to the extraction of the signal corresponding to small breathing displacements of the human chest is illustrated by the example of the ultrabandwidth impulse reflected from a simple human target. The reduction in the dimensions of the original signals from 256 to 5 is shown(More)
This paper considers the possibility to employ the first principal component (Kahrunen-Loeve transform) to reveal the law of reflected signal phase modulation. The processing of modeled and real signals representing ultrawideband impulses reflected from a simple target and from a model imitating human breath was taken as an example. It is experimentally(More)
—This paper combines the results of our previous experiments concerning acquisition of the images of the human palm in infrared and visible light, the extraction of features from images as well as our current results on biometric data hashing with the advanced biohashing algorithm. We first describe the properties of the complex 2D matched filtering for(More)
In pattern recognition systems it is usually necessary to detect different image details, like edges, lines, corners, blobs, etc. For this purpose a bank of special filters, matching each individual detail can be used. As the details usually are oriented in different directions and have different scales, the image processing leads to many convolution(More)
In this paper, the use of the palm vein pattern for biometrics is discussed. To obtain pictures of blood vessels, two methods of infrared imaging -- reflection and transmission are investigated. Basic image processing methods for extraction of vein structure are discussed. Complex matched filtering result provides matching intensity vectors that are used to(More)