Method of and apparatus for scanning objects by means of ultrasound echography
AssigneeU.S. Philips Corporation
InventorJean-Marie Nicolas
Life of this patent
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Abstract
A method and device of scanning objects by means of ultrasound echography by repeated transmission of ultrasound signals and the reception of the ultrasound echoes includes the following operations: (a) storing an echographic line in a memory; (b) determining the ratio of the power spectra for two distinct observation depths, including correction for the effects of the diffraction; (c) storing in a memory and/or displaying the frequency-dependency of the scatter function of the object examined; (d) repeating the proceding operations for two other observation depths which correspond to resepctive boundaries of homogeneous zones, and for other echographic lines.
Claims8
A method of scanning an object by means of ultrasound echography which comprises the step of:
- (a) repeatedly transmitting ultrasound energy into an object;
- (b) receiving echoes from the object which correspond to reflections of the energy from obstacles at a plurality of separate observation depths in the object;
- (c) storing in a memory, signals which correspond to the echoes along an echographic line;
- (d) calculating a power spectrum for a pair of the stored signals which correspond to echoes received from separate observation depths in the object;
- (e) correcting the power spectra for effects of ultrasound diffraction;
- and
- (f) calculating and producing a signal which represents a ratio of the two power spectra.
A device for scanning objects by ultrasound echography comprising:
- ultrasound transmitting means for repeatedly transmitting ultrasound energy into an object;
- receiving means for receiving echoes of the ultrasound energy which are reflected by obstacles at a plurality of observation depths in the object and for producing electrical signals corresponding thereto;
- first memory means for storing signals from the receiving means which correspond to echoes along an echographic line in the object;
- means for receiving stored signals from the first memory means and which calculate a power spectra for a pair of signals which correspond to echoes from a first observation depth and a second observation depth in the object;
- correction means for correcting the calculated power spectra for the effects of ultrasound diffraction;
- arithmetic means for calculating an output function, T from said corrected spectra using the formula ##EQU8## wherein a.sub.1 and b.sub.1 are the values of a coeffeicient a and an exponent b in a general formula U(f)=Af.sup.b of a scatter function for the object being scanned and wherein a.sub.2 and b.sub.2 are the values of said coefficient and exponent in said general function for a reference object in which the frequency-dependency of said scatter function is known and .epsilon. is a ratio of the two observation depths;
- a logarithmic amplifier which acts on the output function T of the arithmetic means;
- and means for calculating a frequency dependent scatter function from an output of said logarithmic amplifier.
Dependencies are inferred from the claim text.