Ultrasound images are created by first emitting ultrasound waves into the body and then interpreting the intensity of the reflected echoes from the interface between the tissue layers. The return time of the wave tells the depth of the reflecting surface.

Real-time distance ultrasonic reflection

The time it takes for the transmitted pulse to reflect back is used to calculate the distance of the probe's reflective boundary.

This is achieved by using a probe that contacts the body through a water-based gel.

The collected data is then processed within the scanner and displayed as a black and white image, commonly referred to as grayscale.

How ultrasound image is formed

The probe contains a large number of emitters aligned along its length. Typically, up to five of these emissions simultaneously produce short-pulsed ultrasound waves, which propagate in a narrow column away from the probe. The transmitter then acts as a receiver and records the intensity of the reflected sound.
The process repeats in the order of the length of the probe. The time used for returning the echo is used to determine the distance from the probe, and the distance is calculated assuming that the sound has a constant velocity (1540 m/s). This is calculated by the range equation.

The echo intensity returned from any point is represented by the brightness of that point on the screen.