Abstract: An improved data acquisition system filter, optimized for the time domain and for use in a computed tomography scanner of the type using x-ray focal spot wobble, includes a filter time response F(t) which is a function of the waveform w(t) used to drive the focal spot from one position to the other.

Abstract: A system for and method of compensating for performance differences in a set of information channels is disclosed. The system and method model each channel as linear and characterizes the channel by an offset and a gain. The system includes memory for storing the offsets and gains associated with the N channels. The system further includes means for mathematically adjusting the output of each information channel by that channel's associated offset and gain. The system further includes filters for reducing the effect of random noise on the measurements of the offsets and gains by generating signals representative of time weighted averages of the offsets and gains.

Abstract: The disclosed ultrasound system processes ultrasound signals having centroid frequencies that decrease as a function of time. The system includes transducers for receiving the ultrasound signals and generating electrical signals representative thereof. The system further includes data samplers for sampling the electrical signals with a sampling frequency. A controller controls the sampling frequency so that it decreases according to a function of time and the centroid frequency.

Abstract: The invention is an autozeroing circuit for use in processing low level electrical charge signals by an integrating operational amplifier. The autozeroing circuit includes a switching circuit that periodically charges and discharges the integrating capacitor of the amplifier during set and reset phases of an operation cycle so that during the set phase of the cycle the input signal is integrated and processed by processing circuitry including an A/D converter, and during the reset phase the integrator is cleared.

Abstract: A variable pulse width precision pulse generator includes a constant current source for producing a number of different constant currents; a charge storage device whose voltage output is proportional to the charge stored; and gating means responsive to an input signal for controlling the time during which the constant current source charges the charge storage device to produce a ramp voltage; a first comparator responsive to the voltage ramp for detecting a first level of the ramp; a second comparator responsive to the voltage ramp for detecting a second level of the ramp; and logic means responsive to the comparators for providing a precision pulse during the presence of the input signal between the occurrence of the detection of the first and second levels of the ramp by the comparators.

Abstract: A data acquisition system is described for converting a plurality of analog information signals to a corresponding plurality of digital output signals each (a) having a dynamic range of n bits to match the dynamic range of the corresponding analog information signal, and (b) representative of the corresponding analog information signal during each of a plurality of time intervals. The system simultaneously converts each of the analog signals to an intermediate digital signal during each of the time intervals in accordance with a digitization code of m bits (where m is less than n) such that the digitization intervals of the code increase non-linearly so that the ratio of the noise level of the intermediate digital signal and the digitization interval of the code is substantially constant throughout the dynamic range of the analog signals. The intermediate digital signals are transformed to the corresponding digital output signals.

Abstract: A signal digitization system and method is disclosed which identifies a plurality of sets of spaced intervals of information; defines a strobing window within each spaced interval in one of the sets at a time; strobes the signal during the strobing window; integrates and holds the strobed signal; and digitizes the integrated signal.

Abstract: A digital signal filter circuit for convolving a sequence of at least n+(q+1) data samples with a kernel of n coefficients, where the coefficients have as an envelope a polynomial function of degree q, which extracts a first set of q+1 contiguous data samples, stores n-(q+1) intermediate data samples following the set of (q+1) contiguous data samples, extracts from the sequence of data samples a second set of (q+1) contiguous data samples that follow the intermediate data samples, linearly combines the data samples of the first and second sets with weighting values that are a function of the coefficients of the polynomials to obtain a linear combination of (q+2) sequential convolved samples with binomial coefficients, and recursively selects at least one of the convolved sample from the linear combination of (q+2) sequential convolved samples.

Abstract: A digital spatial filter system includes means for separating an image formed of a matrix of pixels into four regularly distributed interleaved subimages from alternate rows and columns of the matrix pixels; means for convolving each of the four subimages with two orthogonal unidimensioanal, vectors of a convolving kernel to produce four filtered subimages; and means for recombining said convolved four filtered subimages into the original image filtered.

Abstract: A radiology system for storing, processing, and displaying two-dimensional image data derived from an x-ray source. A visible x-ray image or sequence of images is scanned to produce a signal representing the intensity of the images, and this signal is encoded to provide a data compressed digital signal which is stored and processed to yield displayed images of enhanced quality in which image sequence and processing intervals may be in real-time. The encoded signal is of a format to reduce the amount of data stored in memory, and temporal and spatial averaging and variable length coding are employed for efficient image data processing. Apparatus is provided for defining a mask image, from which other image data is subtracted to yield an enhanced image. The system can include means for providing a control signal representing the level of radiation absorption by a body, and adjusting the intensity of x-ray radiation in accordance with the absorption level.

Abstract: An adaptive digitizer circuit for an information processing system includes an entropy filter responsive to an information signal V having a variable noise .sigma..sub.V that is a function of V, for providing a transform signal T, having a constant transform noise level .sigma..sub.T throughout its dynamic range; and an analog to digital converter in which the ratio .sigma..sub.T /.delta..sub.T of the noise level .sigma..sub.T of the transformed signal and the digitization interval .delta..sub.T is constant throughout the dynamic range of T.

Abstract: A radiology system for storing, processing, and displaying two-dimensional image data derived from an x-ray source. A visible x-ray image or sequence of images is scanned to produce a signal representing the intensity of the images, and this signal is encoded to provide a data compressed digital signal which is stored and processed to yield displayed images of enhanced quality in which image sequence and processing intervals may be in real-time. The encoded signal is of a format to reduce the amount of data stored in memory, and temporal and spatial averaging and variable length coding are employed for efficient image data processing. Apparatus is provided for defining a mask image, from which other image data is subtracted to yield an enhanced image. The system can include means for providing a control signal representing the level of radiation absorption by a body, and adjusting the intensity of x-ray radiation in accordance with the absorption level.