Sydney M Karp

US Patent:

52495787, Oct 5, 1993

Filed:

Sep 15, 1992

Appl. No.:

7/945313

Inventors:

Sydney M. Karp - Reading MA
Raymond A. Beaudin - Windham NH

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

A61B 800

US Classification:

12866101

Abstract:

An asymmetric finite impulse response digital filter, typically used in an ultrasound imaging system, includes forward and reverse sections. In the forward section, a group of input data samples is multiplied by a set of filter coefficients in a forward order to provide first intermediate results. The first intermediate results are summed to provide a first output sample. In the reverse section, the group of input data samples is multiplied by the set of coefficients in a reverse order as compared with the forward section to provide second intermediate results. The second intermediate results are summed to provide a second output sample. The process is repeated to provide multiple first and second output samples. A signal estimation unit estimates a characteristic of the input data samples, such as the frequency of a Doppler ultrasound signal, based on the first and second output samples. The filter provides twice as many output samples as prior art filters for a given set of input data samples.

US Patent:

51522926, Oct 6, 1992

Filed:

Dec 20, 1990

Appl. No.:

7/633718

Inventors:

Sydney Karp - Somerville MA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

A61B 800

US Classification:

12866108

Abstract:

An adaptive flash rejection filter for a color flow imaging apparatus uses a flash strength identifier to make an initial determination of flash content. The identifier assigns a flash strength to each signal portion of a scan line according to a velocity component and a magnitude component of that signal portion. The number of flash strengths in a line which fall into a designated flash range are accumulated to arrive at an approximate measure of flash content. A filter arrangement uses the accumulated flash content to determine a proper flash rejection level for a line. An entire line of flash strengths and velocity measurements are stored in a line memory, which serves to delay those signals while the proper flash rejection level is being determined. The filter arrangement then receives the flash strengths and the velocity components, and inhibits an output of a velocity component if its corresponding flash strength exceeds the assigned flash rejection level. This serves to reject velocity components containing flash and prevent their processing by the color flow display circuitry.

US Patent:

55158528, May 14, 1996

Filed:

Jun 6, 1994

Appl. No.:

8/254100

Inventors:

Sydney M. Karp - Reading MA
Jerome F. Witt - Andover MA
Raymond A. Beaudin - Andover MA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

A61B 800
A61B 806

US Classification:

12866007

Abstract:

An ultrasound imaging system where a location in the image has associated with it an amplitude and a velocity derived from a doppler shift assigns a detection strength to each location. Detection strength is a mapping from each possible combination of the amplitude and velocity into a scalar value that represents the likelihood that the velocity is not an artifact of the noise in the environment. The detection strength values are spatially filtered and then used to determine whether to accept or reject the measured velocity. A more optimistic filtering strategy for the measured velocity is now possible, and cooperates with a filtered detection strength to trim away suspicious regions in the image. The filtered detection strength signal can be used to compensate for unwanted side effects of other filtering done during the processing of the measured parameters. When the number of input bits exceeds the address space of a ROM filtering digital representations of measured parameters, the input values can be bifurcated into MSB's and LSB's, with the MSB's applied to the ROM as the address.