Time gain compensation for ultrasonic medical imaging systems
AssigneeElscint Ltd.
InventorsDan Inbar, Moshe Delevy
Life of this patent
Estimating the term…
Abstract
Time gain compensation is provided on an automatic basis by storing an amplification gain function for an amplifier operating on the received signals and automatically varying the function until the intensity versus time functions of the received signal is substantially flat.
Claims12
An ultrasonic imaging method including time gain compensation (TGC) to correct received ultrasonic echoes for attenuation due to distance traversed by ultrasonic signals and echoes, said method for use with ultrasonic imaging system having transmitting and receiving means for transmitting the ultrasonic signals and receiving means for transmitting the ultrasonic signals and receiving the ultrasonic echoes, said receiving means having gain varying means, said method comprising determining attenuation characteristics of a body being examined, said determining step comprising the steps of:
- (a) transmitting beams of ultrasonic signals into said body, the direction of transmittal being a depth direction;
- (b) receiving echoes back from the interior of the body;
- (c) locating the source of the echoes;
- (d) amplifying the received echoes;
- (e) measuring the intensity of the amplified received echoes;
- (f) converting the measured intensity into pixel values according to the echo source location whereby the location of the pixel value in the image corresponds to the echoe source location in the body being examined;
- (g) selecting pixels along ultrasonic beams extending in the depth direction;
- (h) dividing said scanned depth into a plurality of segments;
- (i) using rows of the selected pixels to obtain average pixel values per segment in the depth direction;
- (j) said average pixel values providing intensity versus depth values for use in determining an intensity versus depth function extending along the scanned depth of the body;
- (k) fitting an intensity versus depth function curve over each of said plurality segments;
- (l) the slopes of said curves being the determined attenuation characteristics of the body;
- and
- the step of using the determined attenuation to vary the gain of the receiving means.
An ultrasonic imaging method including time gain compensation (TGC) to correct received ultrasonic echoes for attenuation due to distance traversed by ultrasonic signals and echoes, said method for use with ultrasonic imaging systems having transmitting and receiving means for transmitting the ultrasonic signals and receiving the ultrasonic echoes, said receiving means having gain varying means, said method comprising determining attenuation characteristics of a body being examined, said determining step comprising the steps of:
- (a) transmitting beams of ultrasonic signals into said body, the direction of transmittal being a depth direction;
- (b) receiving echoes back from the interior of the body;
- (c) locating the source of the echoes;
- (d) amplifying the received echoes;
- (e) measuring the intensity of the amplified received echoes;
- (f) converting the measured intensity into pixel values according to the echo source location whereby the location of the pixel value in the image corresponds to the echo source location in the body being examined;
- (g) selecting pixels along ultrasonic beams extending in the depth direction;
- (h) dividing said scanned depth into a plurality of segments;
- (i) using rows of the selected pixels to obtain average pixel values per segment in the depth direction;
- (j) said average pixel values providing intensity versus depth values for use in determining an intensity versus depth function extending along the scanned depth of the body;
- (k) fitting an intensity versus depth function line over each of said plurality of segments;
- (l) the slope of each of said lines being one of the determined attenuation characteristics;
- providing a predetermined gain function to control the amplification of the received echoes to provide echoes having intensities independent of the distance between the transducer and the source of the echo;
- and
- automatically varying the gain function as a function of the determined attenuation characteristics.
Dependencies are inferred from the claim text.