Ultrasonic imaging apparatus and ultrasonic imaging method

Patent metadata

Field	Value
Publication number	US-9645118-B2
Application number	US-40972309-A
Country	US
Kind code	B2
Filing date	Mar 24, 2009
Priority date	Mar 31, 2008
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

An ultrasonic imaging apparatus in which ultrasonic tomographic images can be obtained without repeating ultrasonic transmission/reception at many times while sequentially changing the direction of the ultrasonic beam. The ultrasonic imaging apparatus includes: a transmitting and receiving unit for processing reception signals outputted from ultrasonic transducers; a sampling unit for generating a reception signal matrix representing ultrasonic echoes from sampling points on a section of the object; a conversion matrix calculating unit for calculating a conversion matrix representing weighting information when ultrasonic echoes from plural locations on the section are synthesized; an inverse matrix calculating unit for calculating an inverse matrix of the conversion matrix; and a sound source information calculating unit for calculating a product of the inverse matrix and the reception signal matrix to obtain a sound source signal matrix representing information on reflective sound sources within the object, and generating an image signal.

First claim

The invention claimed is:

1. An ultrasonic imaging apparatus comprising:
a transmitter configured to supply at least one drive signal to at least one ultrasonic transducer to transmit ultrasonic waves to an object to be inspected;
a receiver configured to process reception signals outputted from plural ultrasonic transducers receiving ultrasonic echoes from the object; and
a central processing unit comprising:
a sampling unit configured to sample the reception signals processed by said receiver to generate a reception signal matrix representing reception signals obtained by receiving ultrasonic echoes from plural sampling points on a section of the object with respect to said plural ultrasonic transducers and depths of the plural sampling points;
a conversion matrix calculating unit configured to calculate a conversion matrix representing weighting information when ultrasonic echoes from the plural sampling points are synthesized to cause reception signals of said plural ultrasonic transducers, said conversion matrix being calculated in consideration of a width of each of said plural ultrasonic transducers such that each of said plural ultrasonic transducers receives the ultrasonic echoes at the same time from sampling points within a region surrounded by circular arcs having the same radius around center points which are located in a reception area from one end to the other end of said ultrasonic transducer;
an inverse matrix calculating unit configured to calculate an inverse matrix of the conversion matrix calculated by said conversion matrix calculating unit; and
a sound source information calculating unit configured to calculate a product of the inverse matrix calculated by said inverse matrix calculating unit and the reception signal matrix generated by said sampling unit to obtain a sound source signal matrix representing information on reflective sound sources at the plural sampling points within the object, and generate an image signal representing an ultrasonic image within the object, based on the sound source signal matrix.

2. The ultrasonic imaging apparatus according to claim 1 , wherein said receiver includes plural anti-aliasing filters configured to perform filter processing to prevent aliasing in sampling the reception signals, respectively.

3. The ultrasonic imaging apparatus according to claim 1 , wherein said sampling unit is configured to sample reception signals obtained based on ultrasonic echoes received by said plural ultrasonic transducers at plural time points.

4. The ultrasonic imaging apparatus according to claim 1 , wherein said conversion matrix calculating unit is configured to calculate the conversion matrix when ultrasonic echoes from plural sampling points two-dimensionally arranged on the section of the object are synthesized.

5. The ultrasonic imaging apparatus according to claim 1 , wherein the central processing unit further comprises:
a weighting processing unit configured to weight plural elements included in the conversion matrix calculated by said conversion matrix calculating unit, based on acoustic field estimation;
wherein said inverse matrix calculating unit is configured to calculate the inverse matrix of the conversion matrix weighted by said weighting processing unit.

6. The ultrasonic imaging apparatus according to claim 1 , wherein:
said receiver includes plural quadrature detectors configured to perform quadrature detection processing on the reception signals to obtain real parts and imaginary parts of the reception signals;
said sampling unit includes a first sampling unit configured to sample the real parts of the reception signals to generate a first reception signal matrix representing real parts of the reception signals obtained by receiving the ultrasonic echoes from the plural sampling points on the section of the object, and a second sampling unit configured to sample the imaginary parts of the reception signals to generate a second reception signal matrix representing imaginary parts of the reception signals obtained by receiving the ultrasonic echoes from the plural sampling points on the section of the object;
said sound source information calculating unit includes a first sound source information calculating unit configured to calculate a product of the inverse matrix calculated by said inverse matrix calculating unit and the first reception signal matrix generated by said first sampling unit to obtain a first sound source signal matrix representing information on the reflective sound sources within the object, and a second sound source information calculating unit configured to calculate a product of the inverse matrix calculated by said inverse matrix calculating unit and the second reception signal matrix generated by said second sampling unit to obtain a second sound source signal matrix representing information on the reflective sound sources within the object; and
the central processing unit further comprises an amplitude computing unit configured to obtain amplitudes of sound source signals based on real parts of the sound source signals included in the first sound source signal matrix and imaginary parts of the sound source signals included in the second sound source signal matrix, and generate an image signal representing an ultrasonic image within the object, based on the amplitudes of the sound source signals.

7. The ultrasonic imaging apparatus according to claim 1 , wherein said sound source information calculating unit is configured to calculate a product of the inverse matrix calculated by said inverse matrix calculating unit and the reception signal matrix generated by said sampling unit with respect to each region formed by dividing the section of the object into plural regions.

8. The ultrasonic imaging apparatus according to claim 1 , wherein said transmitter is configured to supply drive signals to the plural ultrasonic transducers, respectively, so as to form transmission focuses on sectional regions sequentially selected within the object; and
said sound source information calculating unit is configured to calculate a product of the inverse matrix calculated by said inverse matrix calculating unit and the reception signal matrix generated by said sampling unit with respect to the sequentially selected sectional regions.

9. The ultrasonic imaging apparatus according to claim 1 , wherein said conversion matrix calculating unit is configured to calculate the conversion matrix on an assumption that a reception signal outputted from respective one of said ultrasonic transducers receiving an ultrasonic echo from a sampling point at a first distance from said ultrasonic transducer includes a signal component caused by an ultrasonic echo multiple-reflected between said ultrasonic transducer and another sampling point at a second distance that is one third of the first distance from said ultrasonic transducer.

10. The ultrasonic imaging apparatus according to claim 1 , wherein said sampling unit is configured to raise a sampling frequency of the reception signals processed by said receiver, and said sound source information calculating unit is configured to generate an image signal representing an enlarged ultrasonic image based on the sound source signal matrix representing the reception signals sampled with the raised sampling frequency.

11. The ultrasonic imaging apparatus according to claim 1 , wherein said sound source information calculating unit is configured to repeatedly calculate products of the inverse matrix calculated by said inverse matrix calculating unit and the reception signal matrix generated by said sampling unit with respect to selected sectional regions, and thereby, generate an image signal repre

Assignees

• Kondo Yuji
• Fujifilm Corp

Inventors

• Kondo Yuji

Classifications

• A61B8/5215

  involving processing of medical diagnostic data · CPC title

• G01N2291/044

  Internal reflections (echoes), e.g. on walls or defects · CPC title

• G01N2291/106

  one or more transducer arrays · CPC title

• G01S7/52025

  for pulse systems (G01S7/52034 takes precedence) · CPC title

• A61B8/14

  Echo-tomography · CPC title