Abstract: An image, having N dimensions, is partitioned into a set of bounded arbitrarily shaped regions. This partitioning is achieved through the use of arbitrarily shaped N-1 dimensional surfaces which pass through the boundaries of the image. The arbitrarily shaped regions are represented in the leaf nodes of a binary tree and the arbitrarily shaped surfaces, which are used to partition the image, are represented in the non-leaf nodes of the tree. In a preferred embodiment, arbitrarily oriented lines passing through the image boundaries are employed to partition a two-dimensional image into a set of convex regions. The convex regions are represented in the leaf nodes of a binary tree and the arbitrarily oriented lines, which are used to partition the image, are represented in the non-leaf nodes of the tree. Furthermore, the arbitrarily oriented lines are selected through the use of a Hough transform and the image is partitioned, along the selected lines, in a recursive manner as the binary tree is developed.

Abstract: In an automated directory assistance system, the telephone number of the calling party is used to determine whether or not the outgoing "spoken" message will include the area code of the sought-after number.

Abstract: In order to mitigate against the multiplicative noise effects caused by known non-linearities in a trellis coded data transmission system, a signal constellation is formed by starting with a base constellation whose number of signal points and whose geometry are selected in accordance with conventional criteria and then warping that constellation by adjusting the positions of its signal points in accordance with a warp function which is the inverse of the known component of the non-linear characteristic of the transmission system. Because the constellation warping is deterministic, it is possible for the receiver to "unwarp" the received signal points prior to applying them to the Viterbi decoder.

Abstract: A multilevel coded modulation scheme trellis encodes a portion of the input data and the resulting encoded stream is used to identify a particular one of a predetermined number of subsets of symbols of a predetermined signal constellation. The remaining input data is coded using a Reed-Solomon (RS) code whose output is used to select for transmission a particular symbol from the identified subset. In applications in which phase hits or other channel phenomena may cause the received signal points to be phase-rotated versions of the signal points that were transmitted, differential encoding is included in the overall coded modulation scheme. In different embodiments, the differential encoding/decoding and RS encoding/decoding are in different orders. In one such embodiment, overlapped multilevel codes are used to preserve the advantages afforded by taking a multilevel coding approach.

Abstract: Viterbi decoder performance in a data communication system using 2N-dimensional channel symbols N>1 can be further enhanced by an interleaving technique which uses a distributed trellis encoder in combination with a signal point interleaver.

Abstract: A quantization parameter for use in encoding a region of an image is developed from a) a categorization of the region into one of a predetermined plurality of perceptual noise sensitivity (PNS) classes, b) a level of psycho-visual quality that can be achieved for the encoded version of the image, the level being selected from among a plurality of predetermined levels, and c) a prestored empirically derived model of the relationship between the PNS classes, the psycho-visual quality levels and the values of the quantization parameter. PNS indicates the amount of noise that would be tolerable to a viewer of the region, i.e., the perceptual sensitivity of the region to noise. Some characteristics on which PNS classes may be based are: spatial activity, speed of motion, brightness of the region, importance of the region in a particular context, the presence of edges within the region and the texture of the region, e.g., from "flat" to "highly textured".

Abstract: A new receiver structure is disclosed for a full-duplex modem in which a fractionally spaced equalizer, which is normally present to mitigate the effects of linear impairments present on a communication channel, also performs echo cancellation. Specifically, an additional echo signal is formed in the full-duplex modem and added to a received signal, which includes an echo signal, thereby forming a composite signal. This composite signal is then applied to the fractionally spaced equalizer for equalization, which mitigates the echo signal.

Abstract: An enhanced "800" service translates an Automatic Number Identification (ANI) of a calling party into a customer data base key defined by the called party. The customer data base key is then provided by the enhanced "800" service to the called party in place of the ANI information.

Abstract: In a system where a signal constellation is used for data communications, signal points in the signal constellation are selected to represent incoming data. The signal points, thus selected, are transmitted through a channel. The signal constellation is divided into a plurality of regions each including an equal number of signal points. A coding scheme is employed to ensure that signal points within any one region are selected equiprobably, and the probability of selecting any signal point in one region is different from that in another region.

Abstract: Digital signals, such as digitized television signals, are subjected to a source coding step in which a class of "most important" data elements represents a proportionately greater amount of the information to be communicated than the rest of the data elements. This is followed by a constellation mapping step which is carried out in such a way that those data elements have a lower probability of being erroneously detected at the receiver than the others. The constellation mapping step uses coded modulation in order to provide enhanced noise immunity for the "most important" data element class.

Abstract: Coefficient drift, in fractionally-spaced equalizers, is constrained by combining a received data signal with a cyclostationary signal of the same symbol rate as the received data signal.

Abstract: Written material is read at low cost by a computer-based system which is designed to receive via a telephone line a facsimile of the written material submitted by a system user. Once the facsimile is received, the system performs an optical character recognition (OCR) process thereon. The text thus identified by the OCR process is converted to intelligent speech using a speech synthesizer. The synthesized speech is communicated back to the system user either over the already established telephone connection or in a subsequent call.

Abstract: A rational rate generator circuit is disclosed where the output signal frequency, f.sub.o, is rationally related to the input signal frequency, f.sub.i, by: f.sub.o =f.sub.i (P/Q). This rational rate generator is capable of a high-resolution output, where the resolution is only limited by the value of the integers P and Q, with P<Q.

Abstract: A personal computer having an associated telephone is provided with a note-taking facility integrated therewithin. The operation of the note-taking facility is automatically initiated by the computer in response to the entering into a telephone transaction by the user. Specifically, the user is prompted when the telephone transaction is entered into for an indication as to whether notes are to be taken during that transaction. If the user gives an affirmative such indication, the facility immediately adapts itself to begin to receive the notes and present them on the computer display. An association is maintained between the notes taken during an individual telephone transaction and the party with whom the user was engaged during the transaction and the notes associated with a party are automatically retrieved and displayed for the user when a subsequent telephone transaction with that party is entered into.

Abstract: Interleavers used in fading channel applications can be matched to a particular trellis or block code being used. This matching can occur even in a particular transmission scheme such as TDMA. Matching both the interleaver and the code increases the separation between interdependent signal points and provides an improvement in error performance, without an increase in time delay over known interleaver design.

Abstract: In a telephone local loop transmission arrangement, data is communicated from the customer premises to the central office utilizing a multidimensional, passband signal illustratively at 480 kb/s. Specifically, the transmitted signal is encoded in a trellis code and the received signal is processed by a circuitry that implements decision feedback equalization in combination with trellis decoding.

Abstract: In a wireless local area network, predetermined interference-detection sequences of signal points, known at both the transmitter and receiver, are transmitted over a plurality of hopping frequencies along with a sequence of data signal points taken from a modulated code exhibiting built-in diversity. In the receiver, the extent to which there are errors in the received interference-detection signal points is used as a mechanism for identifying the likely occurrence of strong interference. If there are no, or few, errors, decoding proceeds normally. However, if the number of errors is above a predetermined threshold, it is assumed that the transmitted signal was subjected to significant interference and an erasure is declared. This is used as "side" information by the decoder to improve its ability to accurately recover data in the presence of interference.

Abstract: In a multiplier for binary numbers represented in two's complement notation, the need to perform sign-bit extension in order to combine the partial products is avoided by representing the value represented by the sign bits of all the partial products as a two's complement number in its own right. The bits of that number, rather than the original sign bits, are then used in the partial product addition. Since (as with all two's complement numbers) all the bits of the sign-bit-value word are guaranteed to have positive significance (except for the left-most one), the digits of the partial products can then be direcly added without the need for sign bit extension.