Patent ID: 8388536

Claim:
An ultrasonic imaging apparatus comprising: a transmitter configured to transmit, to a test subject, a first chirp signal with a frequency that increases monotonically with time, the first chirp signal produced as a convolution of a first pulse signal with a first coding signal, and pulse compression is performed according to the first coding signal, and a second chirp signal with a frequency that decreases monotonically with time, the second chirp signal produced as a convolution of a second pulse signal with a second coding signal, and pulse compression is performed according to the second coding signal; a receiver configured to receive, from the test subject, a first reception signal resulting from the first chirp signal and a second reception signal resulting from the second chirp signal; a decoder that includes: a first decode filter based on the first coding signal, a second decode filter based on the second coding signal, and the decoder being configured to convolve the first reception signal with the first decode filter to output a first convolution signal, and to convolve the second reception signal with the second decode filter to output a second convolution signal; and a subtractor that performs subtraction processing in order to determine a difference between the first convolution signal and the second convolution signal.