Patent ID: 8425419

Claim:
An ultrasonic diagnostic apparatus comprising: an ultrasonic probe; a transmitting and receiving unit which transmits a voltage to the ultrasonic probe to cause the ultrasonic probe to transmit an ultrasonic beam and to receive an echo from a subject with the ultrasonic probe; a signal processing unit which acquires ultrasonic image data on the subject from an output signal of the transmitting and receiving unit; a subject recognition unit which sets a plurality of image areas in an image of the subject in the ultrasonic image data acquired by the signal processing unit, calculates a spatial variance value and a first spatial average value of a luminance value of the ultrasonic image data, and a second spatial average value of noise data for each of the image areas, and recognizes whether each of the image areas is a part of the image of the subject based on the spatial variance value, the first spatial average value, and the second spatial average value; and an optimum voltage computing unit that calculates a sensitivity, which is a difference between the first spatial average value and the second spatial average value, in the image area recognized as the subject by the subject recognition unit, and limits the transmission voltage to the ultrasonic probe based on the sensitivity and a preset threshold value; and a shape change detection unit which detects a change in shape of the subject from temporally-consecutive image data in the ultrasonic image data; wherein the optimum voltage computing unit calculates the sensitivity for each of the image areas recognized by the subject recognition unit when the shape change detection unit detects a change in shape of the subject, and limits the transmission voltage to the ultrasonic probe based on the sensitivity and the preset threshold value.