Ultrasonic diagnosis apparatus including simple digital scan converter

• US 5,902,244 A
• Filed: 12/22/1997
• Issued: 05/11/1999
• Est. Priority Date: 02/05/1997
• Status: Expired due to Term

• Current Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Osawa, Atsushi, Kodaira, Yoshihiro, Kobayashi, Hideyuki, Gondo, Masahiko
• Primary Examiner(s): Jaworski, Francis J.
• Assistant Examiner(s): Imam, Ali M.
• Application Number:
  US08/995,647
• Time in Patent Office: 505 Days
• Field of Search: 600/444, 600/445, 600/447, 600/448, 600/437, 600/462, 368/113, 73/597, 73/626
• US Class Current: 600/447
• CPC Class Codes: G01S 15/8997 using synthetic aperture techniques
• CPC Class Codes: G01S 7/52044 Scan converters
• CPC Class Codes: G01S 7/52046 Techniques for image enhancement involving transmitter or receiver image enhancement by image data processing G06T5/00

Abstract

An ultrasonic diagnosis apparatus comprises a probe having a plurality of transducers for performing transmission/reception of ultrasonic waves; a selection circuit for sequentially selecting the transducers for performing transmission/reception of ultrasonic waves; and an A/D converter for converting a reception waveform signal from the transducer selected by the selection circuit into a digital waveform signal. The apparatus also includes a memory for storing the digital waveform signal converted by the A/D converter in correspondence with the selected transducer; and a read control circuit having a wavefront locus address generator for generating a wavefront locus data corresponding to time-of-flight data between each point in an ultrasonic scanning region and respective transducers to synthesize a wavefront converging on a point in the ultrasonic scanning region (including points which are not located on lines normal to the radiating surfaces of the transducers). The apparatus also includes an output unit for outputting the wavefront locus data to the memory as a read address in order to read waveform samples along the wavefront; and a synthesis circuit for synthesizing the waveform samples read from the memory by a read address from the read control circuit.

Claims

1. An ultrasonic diagnosis apparatus comprising:

a probe having a plurality of transducers for performing transmission and reception of ultrasonic waves, the transducers including radiating surfaces;

a selection means for sequentially selecting said transducers for performing transmission and reception of the ultrasonic waves;

an A/D converter for converting a reception waveform signal from said transducer selected by said selection means into a digital waveform signal;

a waveform memory for storing said digital waveform signal;

a read control means having a wavefront locus generator for generating wavefront locus data corresponding to time-of-flight data between each point in an ultrasonic scanning region and respective transducers to synthesize a wavefront converging on one or more points in the ultrasonic scanning region, including points which are not located normal to the radiating surfaces of said transducers, the read control means further having an output unit for outputting the wavefront locus data to the waveform memory as read addresses in order to read waveform samples along the wavefront; and

a synthesis means for synthesizing the waveform samples read from the waveform memory by the read addresses from said read control means.

2. The ultrasonic diagnosis apparatus according to claim 1, wherein said read control means further comprises a pixel address generator for generating pixel addresses representing pixel positions at which each point of said ultrasonic scanning region is displayed, and

said output unit outputs said read addresses on the basis of said pixel addresses and said wavefront locus data.

3. The ultrasonic diagnosis apparatus according to claim 2, wherein said output unit is a look-up table, and said pixel addresses and said wavefront locus data are assigned to upper and lower addresses of said look-up table, respectively.

4. The ultrasonic diagnosis apparatus according to claim 3, wherein said output unit comprises a plurality of said look-up tables which can be selected depending on said ultrasonic scanning region or the type of probe employed.

5. The ultrasonic diagnosis apparatus according to claim 1, further comprising:

a factor memory for storing factor information corresponding to said waveform samples read from said waveform memory, said factor information including a phase correction factor corresponding to time-of-flight data between each point in the scanning region and a respective transducer, and an interpolation factor corresponding to each pixel of a display image;

a multiplication process means for multiplying the waveform samples read from said waveform memory and corresponding factors read from said factor memory; and

an arithmetic synthesis operation means for performing an arithmetic synthesis operation to a plurality of data processed by said multiplication process means,

wherein said read control means selects factor information of said phase correction factor from said factor memory in an electronic scanning operation, and selects factor information of said interpolation factor from said factor memory in a mechanical radial scanning operation.

6. An ultrasonic diagnosis apparatus comprising:

a transducer group obtained by arranging transducers for transmitting and receiving ultrasonic waves in the form of an array;

an electronic scanning means for selecting a specific transducer from said transducer group for transmission and reception to perform an electronic scanning operation;

a mechanical scanning means for performing a mechanical radial scanning operation for said transducers for transmitting and receiving the ultrasonic waves;

a switching means for performing a switching operation between a reception waveform signal in the electronic scanning operation and a reception waveform signal in the mechanical radial scanning operation;

an A/D converter means for converting the reception waveform signal obtained by the electronic scanning operation or the mechanical scanning operation into digital waveform data;

a waveform memory for storing said digital waveform data in a time-sequential manner;

a waveform sample read means for reading digital waveform samples read from said waveform memory in correspondence with pixels of display images in respective scanning operations;

a factor memory for storing factor information corresponding to the waveform samples read from said waveform memory;

a multiplication process means for multiplying the waveform sample read from said waveform memory and corresponding factors read from said factor memory;

an arithmetic synthesis operation means for performing an arithmetic synthesis operation to a plurality of data processed by said multiplication process means; and

a read control means for selecting factor information of a phase correction factor corresponding to time-of-flight data between each point in a scanning region and respective transducers from said factor memory in an electronic scanning operation, and selecting factor information of an interpolation factor corresponding to each pixel of a display image from said factor memory.

7. An apparatus for receiving reflected ultrasonic waves from a scanning region and converting the reflected waves into data representing intensities of pixels of an output device, the apparatus comprising:

a first probe including an array of ultrasonic transducers, each transducer being adapted to transmit an incident ultrasonic wave into the scanning region along a respective ray and receive a predetermined number of samples of the reflected ultrasonic wave of the incident ultrasonic wave along the respective ray from the scanning region, each transducer also receiving other reflected waves corresponding to samples along other respective rays;

a multiplexing and demultiplexing device coupled to the transducer array and configured such that the transducers transmit the incident ultrasonic waves in a predetermined sequence and receive the samples in a predetermined sequence;

a memory unit adapted to store the samples and the other reflected waves corresponding to samples along other respective rays corresponding to a first spacial coordinate system of the scanning region, the memory unit being adapted to write according to write addresses and retrieve according to read addresses;

a locus addressing unit adapted to produce first portions of intermediate read addresses corresponding to respective wavefront loci, each wavefront locus representing at least one of;

(i) a sample from one of the transducers and the other reflected waves corresponding to samples along other respective rays, and (ii) an interpolated sample not located on a ray and other reflected waves corresponding to the interpolated sample which would be received from other respective rays;

a pixel addressing unit adapted to produce second portions of the intermediate read addresses corresponding to the pixels of the output device; and

an address conversion unit adapted to receive the intermediate read addresses and convert them into the read addresses such that the waveform loci are converted into a second spacial coordinate system corresponding to the pixel location of the output device when they are read from the memory.

8. The apparatus of claim 7, wherein the address conversion unit is a look-up-table.

9. The apparatus of claim 7, further including a plurality of probes having different output characteristics, the address conversion unit including a plurality of look-up-tables, each look-up-table being adapted to correspond to and be selectable for use with one or more of the plurality of probes.

10. The apparatus of claim 7, wherein the first coordinate system is a polar coordinate system and the second coordinate system is a Cartesian coordinate system.

11. The apparatus of claim 7, further including an A/D converter, the reflected waves being analog and converted by the A/D converter for storing in the memory unit.

12. The apparatus of claim 7, further including a summing unit adapted to receive each waveform locus and sum the sample and other reflected waves corresponding to the sample received from the other rays to produce an intensity for a particular pixel of the output device.

13. The apparatus of claim 7, further including a summing unit adapted to receive each waveform locus and sum the interpolated sample and other reflected waves corresponding to the interpolated sample to produce an intensity for a particular pixel of the output device.