Ultrasonic observation apparatus, operation method of the same, and computer readable recording medium
An ultrasonic observation apparatus includes: a first conversion unit that converts an ultrasonic signal as a time domain signal reflected from a specimen into a frequency domain signal; a regression analysis unit that calculates a regression expression for the frequency domain signal; an attenuation correction coefficient calculation unit that calculates an attenuation correction coefficient which is obtained by dividing a difference between first-order coefficients in the regression expressions at two points having different reception depths by a difference between the reception depths at the two points; an attenuation correction processing unit that performs attenuation correction processing on the frequency domain signal based on the attenuation correction coefficient; a second conversion unit that converts the frequency domain signal after the attenuation correction processing, into a second time domain signal; and an image data generation unit that generates ultrasonic image data based on the second time domain signal.
1. An ultrasonic observation apparatus comprising:
a transmitting and receiving unit configured to transmit an ultrasonic signal, which is a time domain signal, to a specimen, and receive the ultrasonic signal reflected from the specimen;
a first conversion unit configured to convert the ultrasonic signal received by the transmitting and receiving unit into a frequency domain signal;
a regression analysis unit configured to calculate a regression expression for the frequency domain signal converted by the first conversion unit;
an attenuation correction coefficient calculation unit configured to calculate an attenuation correction coefficient which is obtained by dividing a difference between first-order coefficients in the regression expressions at two points having different reception depths by a difference between the reception depths at the two points;
an attenuation correction processing unit configured to perform attenuation correction processing on the frequency domain signal based on the attenuation correction coefficient calculated by the attenuation correction coefficient calculation unit;
a second conversion unit configured to convert the frequency domain signal, on which the attenuation correction processing has been performed by the attenuation correction processing unit, into a second time domain signal; and
an image data generation unit configured to generate B mode image data based on the second time domain signal.
2. The ultrasonic observation apparatus according to claim 1 , wherein the attenuation correction processing unit is configured to perform the attenuation correction processing on the frequency domain signal of a larger one of the reception depths at the two points used for calculating the attenuation correction coefficient, by applying the attenuation correction coefficient calculated based on the reception depths at the two points.
3. The ultrasonic observation apparatus according to claim 1 , further comprising a band limitation correction unit configured to perform correction to limit a frequency band to a given frequency band to thereby reduce contribution of a frequency component outside the given frequency band, after correction by the attenuation correction processing unit and before conversion by the second conversion unit or after conversion by the second conversion unit.
4. The ultrasonic observation apparatus according to claim 1 , wherein the image data generation unit is configured to generate the B mode image data based on amplitude information of the second time domain signal.
5. An operation method of an ultrasonic observation apparatus that transmits an ultrasonic signal, which is a time domain signal, to a specimen and receives the ultrasonic signal reflected from the specimen, the method comprising:
converting the received ultrasonic signal into a frequency domain signal by a first conversion unit;
calculating a regression expression for the frequency domain signal by a regression analysis unit;
calculating an attenuation correction coefficient by an attenuation correction coefficient calculation unit, the attenuation correction coefficient being obtained by dividing a difference between first-order coefficients in the regression expressions at two points having different reception depths by a difference between the reception depths at the two points;
performing attenuation correction processing on the frequency domain signal based on the attenuation correction coefficient, using an attenuation correction processing unit;
converting the frequency domain signal, on which the attenuation correction processing has been performed, into a second time domain signal, using a second conversion unit; and
generating B mode image data based on the second time domain signal, using an image data generation unit.
6. A non-transitory computer readable recording medium with an executable program stored thereon, the program instructing a processor to perform:
converting the received ultrasonic signal into a frequency domain signal by a first conversion unit;
calculating a regression expression for the frequency domain signal by a regression analysis unit;
calculating an attenuation correction coefficient by an attenuation correction coefficient calculation unit, the attenuation correction coefficient being obtained by dividing a difference between first-order coefficients in the regression expressions at two points having different reception depths by a difference between the reception depths at the two points;
performing attenuation correction processing on the frequency domain signal based on the attenuation correction coefficient, using an attenuation correction processing unit;
converting the frequency domain signal, on which the attenuation correction processing has been performed, into a second time domain signal, using a second conversion unit; and
generating B mode image data based on the second time domain signal, using an image data generation unit.