Method for the nondestructive examination of a test specimen by use of ultrasound

A method for the nondestructive examination of a test specimen by use of ultrasound, in which ultrasonic waves are coupled into the test specimen with ultrasonic transducers and ultrasonic waves which are reflected within the test specimen are received by ultrasonic transducers and converted into ultrasonic signals, wherein the ultrasonic signals are stored and subsequently divided into discrete signal information by use of a propagation time-based, phase-corrected superposition in the course of ultrasonic signal data processing, and wherein each discrete signal information is respectively assigned to a volume element within the test specimen, comprising the steps:

• determining an average noise level, to which are discrete signal information is subjected;
• determining voxels to which are respectively assigned discrete signal information of having an average signal level with a signal-to-noise ratio R, with 6 dB≤R;
• determining voxels which between respective pairs of voxels have a spatial distance A smaller than or equal a wavelength of ultrasonic waves coupled into the test specimen;
• combining the determined voxels into a voxel group;
• and
• evaluating the discrete signal information, of voxels of combined into a voxel group based on at least one of signal information contents of polarization, frequency, wave type and wave mode.