Image forming method using ultrasound and aberration correction method

Patent metadata

Field	Value
Publication number	US-9689974-B2
Application number	US-93753509-A
Country	US
Kind code	B2
Filing date	Apr 3, 2009
Priority date	Apr 14, 2008
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

An ultrasound image forming method comprises a first step of receiving a first signal reflected from the object, a second step of obtaining an aberration correction value based on the first signal thus received, a third step of receiving a second signal reflected from the object when a second ultrasound corrected based on the aberration correction value is transmitted to the object, and a fourth step of forming an image from the aberration correction value and the second signal. The center frequency of the second ultrasound is between 0.5 MHz and 20 MHz, the center frequency of the first ultrasound is between 3/16 and 9/20 of the center frequency of the second ultrasound. By this method, an accurate aberration correction value can be obtained and an ultrasound imaging with high resolution can be achieved even if aberrations are large and difficult to correct.

First claim

The invention claimed is:

1. An image forming method for forming an image using an ultrasound signal processing apparatus to form an image using ultrasound reflected from an object when ultrasound is transmitted to the object by an ultrasound probe, where the ultrasound signal processing apparatus comprises a signal processor, the method comprising:
a first step of the ultrasound probe receiving a first reflected wave reflected from the object when first ultrasound is transmitted to the object, and generating a first signal therefrom, the first reflected wave being a reflection of a first ultrasound having a first center frequency;
a second step of the signal processor obtaining an aberration correction value based on the first signal;
a third step of the ultrasound probe receiving a second reflected wave reflected from the object when second ultrasound corrected based on the aberration correction value is transmitted to the object, and generating a second signal therefrom, the second reflected wave being a reflection of second ultrasound having a second center frequency, wherein the second center frequency is not lower than 0.5 MHz and not higher than 20 MHz, and wherein the first center frequency is not lower than 3/16 and not higher than 9/20 of the second center frequency; and
a fourth step of the signal processor forming an image from the aberration correction value and from the second signal obtained by transmitting, by the ultrasound probe, the second ultrasound which has been corrected based on the aberration correction value,
wherein the first center frequency is determined in such a way that the value E defined by the following formula (1) with respect to a beam pattern formed by the second ultrasound corrected using the aberration correction value falls within a predetermined range:

E
=

∑

(

I
⁡

(
x
)

-

P
T

)

⁢

i
⁡

(
x
)

⁢

j
⁡

(
x
)

⁢
Δ
⁢

⁢

x
/

∑

(

I
⁡

(
x
)

-

P
T

)

⁢

i
⁡

(
x
)

⁢
Δ
⁢

⁢
x

⁢

⁢

i
⁡

(
x
)

=

{

1
⁢

:

⁢

⁢

I
⁡

(
x
)

>

P
T

0
⁢

:

⁢

⁢
other
⁢

⁢
than
⁢

⁢
above

Assignees

• Someda Yasuhiro
• Nagae Kenichi
• Oikawa Katsuya
• Saito Keishi
• Takai Yasuyoshi
• Taki Hirofumi
• Sato Toru
• Canon Kk

Inventors

• Someda Yasuhiro
• Nagae Kenichi
• Oikawa Katsuya
• Saito Keishi
• Takai Yasuyoshi
• Taki Hirofumi
• Sato Toru

Classifications

• G01S15/8952

  using discrete, multiple frequencies · CPC title

• G01S7/52049 Primary

  using correction of medium-induced phase aberration · CPC title