Abstract: A method performed by a network node. The method includes determining to transmit a first reference signal. The method also includes determining whether a second reference signal should be transmitted. The method also includes transmitting the first reference signal using a first precoder. The method also includes transmitting the second reference signal as a result of determining that the second reference signal should be transmitted. The second reference signal is transmitted using a second precoder that is complementary to the first precoder such that the second reference signal occupies a first part of a channel not occupied by the first reference signal.

Abstract: A method and apparatus for image classification includes a first embodiment, in which halftone detection is performed based on the size of a boundary set between a class of light pixels and a class of dark pixels, and further based upon image information contained within each single image plane (i.e within one color plane). This embodiment of the invention is based upon the distinctive property of images that halftone areas within the image have larger boundary sets than non-halftone areas within the image. A second, equally preferred embodiment of the invention provides a cross color difference correlation technique that is used to detect halftone pixels.