Abstract: Method and apparatus for selectively increasing, decreasing or leaving unaffected the signal-to-noise ratio of portions of an analog transmission signal. As a result it is possible to increase the signal-to-noise ratio of some analog values, decrease the signal-to-noise ratio of other analog values, and leave the signal-to-noise ratio of the remaining values of a given analog signal, so as to better utilize a transmission channel according to the characteristics of the signal to be transmitted.

Abstract: The performance of speech coding in the presence of bit errors is improved. The quantized parameter bits are grouped into several categories according to their sensitivity to bit errors. More effective error correction codes are used to encode the most sensitive parameter bits, while less effective error correction codes are used to encode the less sensitive parameter bits. This method improves the efficiency of the error correction and improves the performance if the total bit rate is limited. The perceived quality of coded speech is improved. A smoothed spectral envelope is created in the frequency domain. The ratio between the actual spectral envelope and the smoothed spectral envelope is used to enhance the spectral envelope. This reduces distortion which is contained in the spectral envelope.

Abstract: The redundancy contained within the spectral amplitudes is reduced, and as a result the quantization of the spectral amplitudes is improved. The prediction of the spectral amplitudes of the current segment from the spectral amplitudes of the previous is adjusted to account for any change in the fundamental frequency between the two segments. The spectral amplitudes prediction residuals are divided into a fixed number of blocks each containing approximately the same number of elements. A prediction residual block average (PRBA) vector is formed; each element of the PRBA is equal to the average of the prediction residuals within one of the blocks. The PRBA vector is vector quantized, or it is transformed with a Discrete Cosine Transform (DCT) and scalar quantized. The perceived effect of bit errors is reduced by smoothing the voiced/unvoiced decisions. An estimate of the error rate is made by locally averaging the number of correctable bit errors within each segment.

Abstract: An apparatus for processing an image containing a plurality of original lines of pixels to generate one or more intermediate lines of pixels lying intermediate the original lines includes means for storing the original lines of pixels, means for estimating line shift velocities for pixels along the intermediate lines where the velocities are derived from surrounding pixels on the original lines, means for using the estimated line shift velocities to access the addressable memory and shift pixels from the original lines, means for generating the characteristics of pixels along the intermediate lines from the characteristics of the pixels shifted by the line shift velocities, and means for displaying or storing the generated characteristics of pixels along the intermediate lines.

Abstract: The pitch estimation method is improved. Sub-integer resolution pitch values are estimated in making the initial pitch estimate; the sub-integer pitch values are preferably estimated by interpolating intermediate variables between integer values. Pitch regions are used to reduce the amount of computation required in making the initial pitch estimate. Pitch-dependent resolution is used in making the initial pitch estimate, with higher resolution being used for smaller values of pitch. The accuracy of the voiced/unvoiced decision is improved by making the decision dependent on the energy of the current segment relative to the energy of recent prior segments; if the relative energy is low, the current segment favors an unvoiced decision; if high, it favors a voiced decision.

Abstract: Image quality is improved in high definition television using multi-scale representation of motion compensated residuals. The bandwidths of the subband filters vary with the frequency band and the total number of coefficients in the multi-scale-represented frames is equal to the number of values in the residual. Image initialization in the receivers is achieved using original image leakage, but the leakage factor is varied for different frequency subbands. To free up channel capacity at scene changes, a global (i.e., substantially frame-wide) decision is made as to whether to motion compensate a particular frame. To avoid the unattractive ghost of the previous scene persisting for a short time in a new scene, the motion estimator makes a decision on a block-by-block basis whether to use the original image or the residual. Chrominance resolution is improved by encoding all of the subbands of the chroma residuals, instead of just the low subbands.

Abstract: The pitch estimation method is improved. Sub-integer resolution pitch values are estimated in making the initial pitch estimate; the sub-integer pitch values are preferably estimated by interpolating intermediate variables between integer values. Pitch regions are used to reduce the amount of computation required in making the initial pitch estimate. Pitch-dependent resolution is used in making the initial pitch estimate, with higher resolution being used for smaller values of pitch. The accuracy of the voiced/unvoiced decision is improved by making the decision dependent on the energy of the current segment relative to the energy of recent prior segments; if the relative energy is low, the current segment favors an unvoiced decision; if high, it favors a voiced decision.

Abstract: The pitch estimation method is improved. Sub-integer resolution pitch values are estimated in making the initial pitch estimate; the sub-integer pitch values are preferably estimated by interpolating intermediate variables between integer values. Pitch regions are used to reduce the amount of computation required in making the initial pitch estimate. Pitch-dependent resolution is used in making the initial pitch estimate, with higher resolution being used for smaller values of pitch. The accuracy of the voiced/unvoiced decision is improved by making the decision dependent on the energy of the current segment relative to the energy of recent prior segments; if the relative energy is low, the current segment favors an unvoiced decision; if high, it favors a voiced decision.

Abstract: A new source distinguishing video system which exploits differences between video material originated from different video sources (such as from film or from a video camera). Method and apparatus exploits these different characteristics in an advanced receiver such that video quality can be significantly improved. The invention has a wide variety of applications including design of an improved NTSC system, an improved freeze-frame system, an extended definition television (EDTV) system and a high definition television (HDTV) system, for example.

Abstract: Continuously monitoring successive frames of a video signal and deciding, based on the similarity between the frames, whether to encode one of them with low or high information content, i.e., as a "low-resolution" frame or a "high-resolution" frame, and whether to encode the next transmitted frame as a low- resolution frame or as a high-resolution frame, and, when sending a high-resolution frame, determining whether to transmit an indication to re-display the past frame or to transmit an indication to display the high-resolution frame as a representation of the present frame. The compression method provides efficient compression of a video signal. A single future frame embodiment allows up to a doubling of the number of pixels transmitted through a channel. With multiple frame systems, even higher compression ratios are possible. Further improvements in compression ratios may be obtained by compressing the individual frames.

Abstract: A method for decoding National Television System Committee (NTSC) signals which exploits redundancies in film-to-NTSC transcoding, known as "3-2 pull-down". The decoding method estimates luma (Y) and chroma (C). The "3-2 pull-down" structure assigns three NTSC fields to one frame of a film frame pair, and two NTSC fields to the other film frame. Luma and chroma in different film frames are separated using different methods, and the separated signals are better than the separated signals achieved using conventional one dimensional and two dimensional NTSC decoding methods. The new method for separating luma and chroma from composite NTSC signals can be combined with an interlace-to-progressive method, which converts the decoded 3-2 NTSC signals to 2 film frames, and an upconversion procedure, to yield improved image quality.

Abstract: A class of methods and related technology for determining the phase of each harmonic from the fundamental frequency of voiced speech. Applications of this invention include, but are not limited to, speech coding, speech enhancement, and time scale modification of speech. Features of the invention include recreating phase signals from fundamental frequency and voiced/unvoiced information, and adding a random component to the recreated phase signal to improve the quality of the synthesized speech.

Abstract: A method and apparatus for reducing the amount of video information which is transmitted to a receiver, while still enabling the receiver to reconstruct a representation of the original video source material. In a preferred embodiment, a 60 frames per second progressively scanned video signal is transmitted at a 30 frames per second rate accompanied by decoding information. In short, every other frame is deleted and a respective nearest neighbor is selected to represent the deleted frame. This selection is represented by a digital selection information. Thus the transmitted frame information can be reconstructed into the original video source material after decoding with the digital selection information.

Abstract: Method and systems for combatting degradation in the transmission or storage of data signals especially useful in the field of motion picture or television signal transmission, such that an advanced receiver can decode that information to provide improved picture quality, while a standard receiver will display an image with minimally visible impairments. A data signal can be decomposed into a low frequency signal and a high frequency signal, and that the high frequency signal can then be modified by the application of a series of scaling factors over selected regions in response to local variance of data values in such regions. The low frequency signal and the modified high frequency signal are then combined and transmitted (or recorded) as a modulated facsimile of the data signal, together with the scaling factors.

Abstract: Methods and apparatus for motion estimation in motion picture processing are disclosed in which an initial velocity vector is selected as an estimation of the displacement of a region from a location in a first frame to a corresponding location in a second frame and the velocity estimate is then refined by minimizing an average value of the squared directional gradient residual over the region. A continuous signal representation is obtained from a set of image intensity samples over the region of interest and, from tThe U.S. government has rights in this invention pursuant to NSF Grant No. DC1-8407285.