On the generation of airborne multi-frequency ultrasonic images with biomimetic sonar head

Airborne ultrasonic frequency images are used in many areas, e.g. medicine and industry, for change detection and fault detection. Airborne images are difficult to obtain or manage, mainly because of the high absorption and attenuation by air. This work presents new results in this field, i.e. airborne ultrasonic images at various ultrasonic frequencies: 120, 200, 225 and 300 kHz. The size of the images is 40 by 40 elements, with gray intensity level on 8 bits. The images are generated by a biomimetic sonar head, called ROVIBAT-05 (ROmanian VIrtual BAT). For each ultrasonic frequency, a pair of two images is generated, from the left and right sides. Later, the airborne multi-frequency ultrasonic images, in a single or combined paradigm of image fusion, enhance the performances of the detection and classification processes, of the targets, in navigation processes of mobile vehicles.