Accession Number : ADA302286

Title :   A study of Ultrasonic Wavefront Distortion Compensation.

Descriptive Note : Annual rept. 1 Sep 94-31 Aug 95,

Corporate Author : PENNSYLVANIA UNIV PHILADELPHIA

Personal Author(s) : Zhu, Qing

PDF Url : ADA302286

Report Date : SEP 1995

Pagination or Media Count : 80

Abstract : The requirement for higher ultrasound resolution needed for early detection of breast tumors is to compensate distorted ultrasonic wavefronts. We have found that two types of algorithms are necessary to fully deaberrate ultrasonic waves in breast. One is a global algorithm for isotropic scattering, an example of which is time delay correction (TDC). In the last year we found that applying (TDC) type algorithms to Zn vitro breast data suppressed scattered energy and folded it into the target image, increasing contrast resolution by 10-15 (113. Recently, we have discovered that amplitude compression in addition to phase deaberration (App.A), is akin to inverse filter, improves contrast resolution to 10 d13 more than that of TDC type algorithms, and 5 (113 more than that of backpropagation and phase deaberration. Preliminary studies also show that diverse images obtained from different spatial locations of a large 2-D aperture are likely to provide the identification information of true targets vs. image artifacts. Once the real targets are identified, nonlinear deconvolution techniques and interference cancellation techniques are applicable to reconstruct the refractive artifact-free scene or to cancel image artifacts. The initial results are encouraging.

Descriptors :   *SPATIAL DISTRIBUTION, *SCATTERING, *ULTRASONICS, *DISTORTION, *WAVEFRONTS, *MAMMARY GLANDS, *BREAST CANCER, COMPRESSION, ALGORITHMS, TIME INTERVALS, POSITION(LOCATION), CONTRAST, GLOBAL, ACOUSTIC WAVES, RESOLUTION, NEOPLASMS, TARGETS, HIGH RESOLUTION, IDENTIFICATION, ISOTROPISM, IMAGES, INTERFERENCE, DELAY, INVERSION, FILTERS, ARTIFACTS, COMPENSATION, AMPLITUDE, CANCELLATION, CORRECTIONS.

Subject Categories : Medicine and Medical Research
      Laminates and Composite Materials
      Test Facilities, Equipment and Methods
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE