The physical meaning of the visualization method by sending several probing ultrasonic waves with a flat front into the object in comparison with the method of digital focusing of the aperture is described. The results of experimental studies on the reconstruction of tomograms by these imaging methods from ultrasound data recorded during the testing of metal samples with reflectors are presented. It is shown that the method of plane waves will allow to obtain images, not only when the interelement delays of the probing pulses provide generation of real waves with a flat front, but also with delays giving a virtual wave front that physically do not exist. Coherent summation of images obtained at several angles of inclination of the wave front forms a tomogram that is not significantly inferior in quality to the tomogram reconstructed by Total Focusing Method. But the time required to collect ultrasound data is several times less, which is important for practical applications, in particular, for high-speed automated testing.