Ultrasonic imaging apparatus

An ultrasonic imaging apparatus for obtaining a tomogram image of an object having a surface to be diagnosed on a monitor, comprising:

• electroacoustic transducers emitting ultrasonic waves in a line along the surface of the object, and for detecting the ultrasonic waves reflected from the object as reflected waves, and for converting the reflected waves into electric signals as detection signals having a phase and a detection frequency;
• phasing means operatively connected to the electroacoustic transducers for receiving the detection signals, for delaying the detection signals for a delay period as delayed detection signals responsive to a distance between the electroacoustic transducers and the object, and for phasing the delayed detection signals for a phase period to match the phase of the detection signals as phased detection signals having a phased frequency;
• phase detection means operatively connected to the electroacoustic transducers and the phasing means for detecting an error of phase between a reference signal and one of the detection signals output from the electroacoustic transducers and the phased detection signals output from the phasing means, and for correcting the delay period previously set in the phasing means responsive to the error;
• reference signal generating means operatively connected to the phase detection means for generating the reference signal having a reference frequency the same as one of the detection and phased frequencies;
• and
• adding means operatively connected to the phasing means for adding the phased detection signals phased by the phasing means as an added detection signal;
• and
• the phase detection means comprising a calculation unit for calculating a mutual-relation value between the one of the detection and phased detection signals and the reference signal, and an error detection unit for detecting the error responsive to the mutual-relation value.