The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 25, 1989
Filed:
Nov. 12, 1987
Steven C Leavitt, Hampstead, NH (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A medical Doppler ultrasound imaging system with improved filtering to separate blood flow information from clutter due to heart wall and vessel motion. In combination with a clutter rejection filter and velocity determination system as in the prior art, a velocity sample rejection system implements a velocity-dependent (i.e., frequency-dependent) threshold for rejecting velocity values, or samples, based on too weak echoes. That is, the acceptance/rejection threshold is a function of frequency. Optimally, the shape of the velocity-dependent thresholding function closely matches that of the attenuation transfer function of the clutter rejection filter. Thuys, for low velocity samples (corresponding to low Doppler frequency shifts), the rejection threshold is substantially lower than it is for high velocity samples. The rejection level increases monotonically as the signal deviates from the I.F.