The principle of a true acoustic gray scale standard is presented and experimentally applied to the Scanning Acoustic Microscope (SAM). The implementation is based on the impedance matching property of a quarter wave impedance transformer through which precise changes in reflection coefficient may be produced in a single material. The performance of the first implementation designed for 375 MHz operation is described and the implications of its use are discussed in detail. The application of the principle to diagnostic ultrasound is also treated.
MarmorM. F.WichramasingheH. K.LemonsR. A., Acoustic microscopy of the human retina and pigment epithelium, Investigative Opthamology and Vis. Science16 (7), 66–666 (July 1977).
2.
KossoffG.GarrettW. J.CarpenterD. A.TellionJr.DoddM. J., Principles and classification of soft tissues by gray scale echography, Ultrasound in Medicine and Biology2 (2), 89–105 (1976).
3.
KakA. C.GryF. J., Acoustic Impedance Profiling: An Analytical and Physical Model Study, in Ultrasonic Tissue Characterization, LinzerM., ed. National Bureau of Standards Special Publication 453, pp. 231–251 (U. S. Government Printing Office, Washington, D. C.1976).
WegleinR. D.WilsonR. G., Image resolution of the scanning acoustic microscope, Appl. Phys. Lett. 31, (12), 793–795 (1977).
6.
AuldB., Acoustic Fields and Waves in Solids, Vol. 1, Chap. 6, (John Wiley & Sons, New York1973). (in particular, problems 11 and 12).
7.
WegleinR. D., Acoustic properties of sputtered glass at microwave frequencies, Appl. Phys. Lett. 29, (5) 277–279, (1976).
8.
GerardH. M.OttoO. W.WegleinR. D., Development of a Broadband Reflective Array 10,000 to 1 Pulse Compression Filter, 1974 Ultrasonics Symposium Proceedings, IEEE Cat. No. 74, CHO 896-ISU, pp. 197–201.
9.
AtalarA.QuateC. F.WickramasingheH. K., Phase imaging in reflection with the acoustic microscope, Appl. Phys. Lett. 31, (12), 791–793 (1977).
10.
WegleinR. D.WilsonR. G., Characteristic Material Signatures in the Acoustic Microscope, Electronic Letters, 14, (12), 352–354 (1978).
