摘要:
This invention employs an ultrasound apparatus with a phased transducer having transmit and receive array systems to form an electronically scanned ultrasonic "pencil" beam (25) from crossed flat acoustic beams. The flat transmit beams and flat receive apertures are shaped by the arrays with size of individual elements on the order of the wavelength of a generated carrier frequency in a human body. The separation of array functions in the transmission and reception modes reducess the side lobe level and improves the noise performance. A fast method of acquisition of two dimensional images is described. This method uses a property of a dynamic focused and scanned flat acoustic beam together with the ability to shape flat synthetic receive apertures from digitized and memorized amplitude information. The same fast method of three dimensional image reconstruction is suggested, which uses an unfocused acoustic beam generated by a single transducer element together with the ability to form flat synthetic receive apertures in memory.
摘要:
A present invention shows some schemes of a cross transducer with one transmit and one receive array for the three dimensional image acquisition. Designs of the cross transducer with and without a central shared element are described. Conditions for an extension of a frequency range and the method of an extended frequency range for use of the cross transducer are suggested. A new method of image formation allowed by the above is also presented.
摘要:
The present invention consists of a method for a fast acquisition of two dimensional images by the use of synthetic transmit and receive apertures formed in the schematics with cross transducers and can be used for the reconstruction of three dimensional images. The method of a fast two dimensional image acquisition preserves the flat beam generation and irradiation of the sector of an investigated part of a human body by a single transmit array. Simultaneously, a switching of transmit (or receive) arrays and irradiation of the same sector of a human body by different transmit arrays with a consequent fine shifting and summation of the received and digitized information in the region of interest provides an additional focusing of the transmit (or receive) beam along the coordinate parallel to the flat beam plane. The schematics of transducers for the realization of this method are described. The suggested method works with digital beamformer schematics, when echo signals from every individual element of the receive arrays are amplified, digitized and stored in memory.
摘要:
New apodization functions providing an effective rejection of side lobe amplitude level within wide range of beam steering angles are described in this invention. A central amplitude apodization function (13) reduces amplitudes for the central section of transmit and receive array individual elements. A time apodization function (14) changes a duration of transmit pulses. A duration of transmit pulses is short for central section of transmit array and increases for outlying transmit individual elements. A frequency apodization function (15) changes frequency of transmit pulses for different transmit individual elements. The use of new apodization function allows realization of portable acoustic scanners. Some versions of a portable acoustic scanner design and a version with time compression of echo signals are described.