Directivity of the source at 1000 Hz in the case of a rigid object of width l_obj equal to 15 cm, 30 cm, and 50 cm located at a distance z_obj = 15 cm. (a) sketch of the microphone positions on a semicircle in the ZX plan; (b) directivity plots obtained from the direct computation with the rigid masking object; (c) directivity plots obtained from the velocity fields identified by iPTF with the rigid masking object without any pressure points taken in the shadow of the object; (d) directivity plots obtained from the velocity fields identified by iPTF with or without the rigid masking object with pressure points also taken in the shadow of the object.