Mark J. Bentum

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Gradient information is used in volume rendering to classify and color samples along a ray. In this paper we present an analysis of the theoretically ideal gradient estimator and compare it to some commonly used gradient estimators. A new method is presented to calculate the gradient at arbitrary sample positions, using the derivative of the interpolation(More)
—A novel optical beamformer concept is introduced that can be used for seamless control of the reception angle in broadband wireless receivers employing a large phased array antenna (PAA). The core of this beamformer is an optical beam-forming network (OBFN), using ring resonator-based broadband delays, and coherent optical combining. The electro-optical(More)
—We present a novel device-free stationary person detection and ranging method, that is applicable to ultra-wide bandwidth (UWB) networks. The method utilizes a fixed UWB infrastructure and does not require a training database of template waveforms. Instead, the method capitalizes on the fact that a human presence induces small low-frequency variations that(More)
—The Low Frequency Array (LOFAR) is the largest telescope in the world operating at a frequency range from 30 to 240 MHz. LOFAR is the first radio telescope of its size which uses phased array principles to detect radio signals. More than 10,000 antennas are installed in the field. The antennas are grouped in 44 stations. The maximal distance between the(More)