Signal processing apparatus for imaging scanner

Claim 1

An ultrasonic imaging scanner wherein a reflecting body in an ultrasonic propagation medium is scanned along a predetermined path or aperture by ultrasonic pulses to produce a processed image signal time function for high resolution imaging of said reflecting body with specified azimuthal resolved width, comprising in combination a. at least one ultrasonic sensing transducer whose width in the azimuthal direction is less than the specified azimuthal resolved width b. means for replication of said ultrasonic sensing transducer at a sequence of positions across said aperture, wherein the aperture length measured in units of the ultrasonic wavelength, must exceed the ratio of the maximum range of said reflecting body, to the specified azimuthal resolved width c. at least one ultrasonic radiation transducer d. means for successively pulsing said ultrasonic transducer wherein successive pulses have a determined phase relation to one another e. means for detection of a sequence of ultrasonic pulse signal time functions, back reflected from said reflecting body and incident at said replicated sequence of sensing transducer positions, wherein the phase of said reflected pulse functions is preserved by said detection means f. means for storage of said detected sequence of reflected ultrasonic pulse signal time functions in a doubly indexed memory array indexed by pulse transit time in one indexing dimension and by the sensing transducer position in the other indexing dimension g. means for reading back said stored signal time function values in transposed order as a sequence of sets indexed by pulse transit time, wherein each set of signal amplitudes is arranged in serial order according to the sensing transducer azimuthal position coordinate h. means for mathematical processing of said sequence of sets indexed by pulse transit time, by convolution calculation of said sequence of azimuthal position-dependent sets of reflected signal amplitudes with a prescribed filter function which is mathematically inverse to the filter function characterising a unit amplitude reflecting point return signal from said radiation transducer to said replicated sensing transducer positions in said ultrasonic propagation medium; said means including means for producing the fourier transform of the azimuthal position-dependent variation of each said set at each range corresponding to each pulse transit time, means for generating a fourier transform signal of said prescribed filter function at each range, means for forming the product function of said fourier transforms, and means for inverse fourier analysis of said product function at each range, said inverse fourier analysed function comprising said processed image signal time function for high resolution imaging.