An autoranging analog to digital conversion system is provided. The system may include a digitally programmable preamplifier for amplifying a difference between an analog input and an estimate of the analog input. The preamplifier may be coupled to an analog to digital converter for converting the preamplifier output to a digital signal. The system may also include digital domain predictor or estimation logic for determining an optimum gain and analog input estimate for a given analog input. Multiple signal input channels may be coupled to the analog to digital conversion system. The autoranging estimations may be performed on a sample by sample basis or a channel by channel basis. The conversion system may also include the use of a backup conversion path for use when the main conversion path overranges. The backup conversion path may utilize a dedicated backup converter. The backup conversion path may alternatively utilize the estimation converter to generate backup conversions or may utilize the main converter to generate backup conversions.

Analog to digital conversion circuitry including backup conversion circuitry

The disclosed invention takes advantage of the fact that the speech information and processing needed for successful animation lip-synching is actually much less than the information and processing which is needed for identifying individual words, as in the traditional speech recognition task, The disclosed embodiment utilizes linear prediction to obtain speech parameters which can be used to identify phonemes from a limited set corresponding to visually distinctive mouth positions. In the disclosed embodiment there is set forth an apparatus for producing lip-synching for a spoken sound track. Means are provided for storing, for each of a number of mouth positions, an unvoiced phonetic information representation associated with a mouth position. Means, responsive to samples of sound from the sound track, are provided for generating unvoiced phonetic information signals for the samples. Further means are provided for comparing the unvoiced phonetic information signals with the stored unvoiced phonetic information representations to determine which of the stored representations most closely matches the unvoiced phonetic information signals. The determined representations are then stored in time correspondence with the sound track.

Apparatus and method for lip-synching animation

An autoranging analog to digital conversion system is provided. The system may include a digitally programmable preamplifier for amplifying a difference between an analog input and an estimate of the analog input. The preamplifier may be coupled to an analog to digital converter for converting the preamplifier output to a digital signal. The system may also include digital domain predictor or estimation logic for determining an optimum gain and analog input estimate for a given analog input. Multiple signal input channels may be coupled to the analog to digital conversion system. The autoranging estimations may be performed on a sample by sample basis or a channel by channel basis.

Autoranging analog to digital conversion circuitry

A seismic data compression technique is disclosed which comprises sampling each individual seismic trace, operating upon a set number of samples to generate a predicted sample and quantizing the difference between the next sample and the predicted value of the sample, and transmitting the quantum number whereby the amount of information which need be transmitted is limited. In a preferred embodiment, a linear prediction differential pulse code modulation scheme is used to provide the predicted value, while an adaptive quantization scheme is used to quantize the error value to be transmitted, thus yielding further improvements in accuracy. A feedback loop can be applied to the decompression operation to limit quantization noise and further improve the fidelity of representation of the decompressed signals.

Linear prediction coding for compressing of seismic data

An improved method and means of determining reflection coefficients that characterize an electrical signal that obtains characteristics of an all-zero inverse lattice filter. The reflection coefficients are obtained by filtering the signal, sample the filtered signal, obtaining the elements of a correlation array from the samples, initializing values of arrays forward residuals, backward residuals, and cross correlation of residuals, combining array elements to obtain a first reflection coefficient, removing from the forward, backward and cross-correlation arrays the effect of the first reflection coefficient, calculating from the revised arrays a second coefficient, and repeating the calculations to the desired order. In a second embodiment of the present invention, samples are selected from the digitized signal and multiplied by a windowing function. The windowed samples are used to derive values of an autocorrelation array which eliminates the need for both forward and backward arrays as in the first embodiment of the invention.

Method and means of determining coefficients for linear predictive coding

Improved fidelity and reduced computational requirements are achieved in a linear predictive coding (LPC) system that utilizes multichannel signal processing and reduced sampling rates. The input analog signal is divided by filters into multiple, contiguous, substantially equal bandwidth signal components and each component is digitized and processed by a separate standard LPC transmit-receive system. Each transmit-receive system operates at a sampling rate that is equal to the normal sampling rate for the signal being processed divided by the number of channels or signal components used. The received signal components are filtered, converted to analog, and summed.

John E. Roberts

Papers

Piecewise linear predictive coding system