Ultrasonic distance measuring system without blind area

In short range ultrasonic measurement systems, the blind area of the measurement limit the application of the low cost ultrasonic transducers. In a double transducer measurement system, when impulses are loaded to transmitter with reflection and refraction of sonic, the receiver nearby will receive echoes immediately, which will leads to a period of time that can't be measured. If an object is near the transducer, the receiver gets stronger echoes reflection from the object than reflection and refraction from the transmitter. By distinguishing the amplitude of echo waves in blind area, we figured out the distance between the object and the transducer.