Acoustical Holography

1 The Scope of the Symposium.- Definitions.- Generalized Principles of Holography.- Sound Recording.- Liquid Surface Deformation.- Scanning or Sampling Technique.- Mechanical Scanning.- Electronic Scanning.- Laser Beam Scanning.- Effect of Scanning on Hologram Reconstruction.- Direct Visualization of Sound Field by Bragg Diffraction of Light.- General Remarks.- References.- 2 A Survey of Ultrasonic Image Detection Methods.- Photographic and Chemical Methods.- Thermal Techniques.- Optical and Mechanical Methods.- Electronic Methods.- Conclusions.- References.- 3 The Liquid-Gas Interface as a Recording Medium for Acoustical Holography.- The Wave Equation.- The Boundary Conditions.- The Surface Deformation.- The Surface Under Plane Wave Excitation.- General Surface Excitations.- Conclusion.- References.- 4 A Comparison of Acoustical Holography Methods.- Acoustical Holography Employing a Liquid Surface.- Experimental Arrangement.- Analysis.- Two-step Holography Using a Liquid Surface.- Real-time Holography With a Liquid Surface.- Ultrasonic Holography Using a Scanned Hologram Method.- Construction of the Hologram.- Reconstruction of the Image.- Holograms and Reconstructions.- Conclusions.- Acknowledgments.- References.- 5 Acoustic Holographic Techniques for Nondestructive Testing.- Experiments.- The Acoustical Hologram.- Acoustical Hologram Recorder.- Visible Image Formation from the Acoustical Hologram.- Some Acoustical Holograms and Images.- Theoretical Analysis and Discussion of Some Properties of Acoustical Holograms.- General Theory.- Effects of Sampling the Acoustical Hologram.- Properties of the Image Formed by an Acoustical Hologram.- Potential Uses of Acoustical Holographic Techniques in Nondestructive Testing.- References.- 6 Application of Fourier Transforms in Assessing the Performance of an Ultrasonic Holography System.- A Criterion for the Maximum Frequency in a Hologram.- Analysis of the Effect of Scanning System on Recorded Information.- Analysis in the Fourier Transform Domain.- Practical Applications.- Summary.- References.- 7 Biomedical Prospects for Ultrasound Holography.- References.- Appendix. Ultrasound Holography and Visual Reconstruction.- Conclusions.- Acknowledgments.- References.- 8 Acoustical Holographic Model of Cetacean Echo-Location.- References.- 9 The Generation of Sound.- Sound Generation.- Sound Generation in a Gas.- Sound Generation in a Liquid.- Sound Generation in a Solid.- Detection of Sound.- References.- 10 Acoustical Imaging by Diffracted Light-Two-Dimensional Interaction.- Plane Wave Interaction Formalism.- Acoustical Imaging.- References.- 11 Acoustical Transparencies for Optical Imaging and Ultrasonic Diffraction.- Acoustical Transparencies.- Transparencies as Diffracting Screens.- Transparent Plates as Band-Pass Spatial Filters.- Transparent Plates for Velocity Measurement.- Conclusion.- References.- 12 Digital Image Formation from Detected Holographic Data.- Optical Image Reconstruction From Nonoptical Data.- Production of a Photographic Transparency.- Sources of Image Degradation.- Advantages of Optical Image Reconstruction.- Digital Image Reconstruction.- General Procedure.- The Required Digital Operations.- The Fast Fourier Transform.- Effects of Quantization, Sampling, and Scan Nonuniformities.- Quantization.- Sampling.- Scan Nonuniformities.- Experimental Results.- Summary and Conclusions.- References.- 13 Phase Distortions Due to Nonlinear Effects in an Acoustic Field.- Formulation of the Problem.- The Interaction Terms.- Description of Interference Pattern.- The Second-Order Induced Field.- Phase Distortion in Wavefront.- Conclusion.- References.- 14 The Relative Importance of Phase and Amplitude in Acoustical Holography.- Experiments.- General Instrumentation.- Reconstruction Technique.- First Experiments with the Letter "R".- The Three Point-source Experiments.- Elimination of the Conjugate Images.- The Phase and Amplitude of an Object Wave.- Qualitative Mathematical Explanation.- A Point Object.- An Extended Object.- Qualitative Physical Explanation.- Conventional and "Phase-only" Hologram Fringe Patterns.- The Hologram as a Spatial Frequency Carrier.- Effect on Image Resolution.- Concluding Remarks.- Acknowledgments.- References.- 15 Acoustical Holograms and Optical Reconstruction.- Matrix Representation of Holographic Systems.- Scalar Sound Waves.- Matrix of a Lens.- Matrix of a Diffraction Grating.- Matrix of a Zone-Plate.- Matrix of Gabor's Hologram.- Construction of Acoustical Holograms.- Experimental Arrangement.- Acoustical Hologram.- Optical Reconstruction of Images.- Reconstruction Condition.- Reconstruction of Virtual and Conjugate Images.- Experimental Results.- Effect of Scanning Lines on the Reconstructed Images.- Scanning Lines as a Diffraction Grating.- Effect of Scanning Lines on the Reconstructed Images.- Improvement of Reconstructed Images.- Effects of Hologram Construction Condition on the Reconstructed Images.- Effect of Light Intensity Level on the Reconstructed Images.- Effect of Limited Scanning Plane on Reconstructed Images.- Effect of Frequency of Sound Wave on Reconstructed Images.- Some Properties of Acoustical Holograms.- Detection of Objects in a Turbid and Turbulent Medium.- Three-Dimensional Information Storage in Acoustical Holograms.- Acknowledgment.- References.- 16 Ultrasonic Holography via the Ultrasonic Camera.- Acknowledgments.- References.- 17 Acoustical Filtering with Holographically Matched Spatial Filters.- Extending Spatial Filtering to Acoustic Waves.- Preliminary Experiments.- Results.- General Remarks.- References.- 18 Summary and Directions for Future Progress.- 19 Supplementary Bibliography.