Ultrasonic pulse-echo apparatus

Claim 2

An ultrasonic pulse-echo apparatus comprising: (a) transducer means which transmits an ultrasonic beam into a multilayered object to be examined and converts ultrasonic pulses reflected at interfaces between the layers within the object into a first image signal; (b) X-Y type display means which is intensity-modulated by a second image signal for displaying an image within the object; (c) a signal processing means which amplifies the first image signal by a given amplification degree to produce the second image signal which comprises: a timing circuit which transfers to said transducer means a timing control signal for determining transmitting and receiving timings of the ultrasonic pulses, transfers to the display means a scanning synchronizing signal to synchronize the scannings of X- and Y-axes with the transmitting/receiving timing of the ultrasonic pulses, and produces a first pulse with a period corresponding to the X-axis scanning of the display means and the timing of the ultrasonic pulse transmission, and a second pulse corresponding to the timing of the Y-axis scanning of the display means; a gain controlled amplifier which receives the first image signal and produces the second image signal, and a control means which integrates control data corresponding to the second image signal to keep uniform an average brightness of an image displayed on the display means, accumulates the result of the integration at the timing corresponding to the second pulse and provides the accumulated result as a control signal for the succeeding frame or field to said gain controlled amplifier of which the given amplification degree is determined by the control signal.

Claim 3

An ultrasonic pulse-echo apparatus according to claim 1, wherein the control signal fed by said control means includes information which is the cumulated integration result for the preceding frame or field and the information of the preceding frame or field controls the brightness of the next frame or field.

Claim 4

An ultrasonic pulse-echo apparatus according to claim 1, wherein the control signal fed by said control means include information which is the cumulated integration result for the plural preceding frames or fields and the formation of the plural preceding frames or fields and the information of the plural preceding frames or fields controls the brightness of the next frame or field.

Claim 5

An ultrasonic pulse-echo apparatus according to claim 1, wherein, in order to obtain the integration result with respect to an area which is formed by dividing the same frame or the same field into N section in a X-axis scanning direction, said control means accumulates at the second timing corresponding to a second pulse a difference between first data which is an accumulation of the ith integration result at the timing of a first gate pulse synchronized with the first pulse and the second data which is an accomulate of the (i+1)th integration result at the timing of the second gate pulse subsequently occurring after the first gate pulse, and the cumulative result is used as the control signal, where 0≦i+1≦N, i=1, 2, 3 . . .

Claim 6

An ultrasonic pulse-echo apparatus according to claim 1, 2 or 3, wherein the integration timing of said control data in said control means is carried out at the timing of the first pulse.

Claim 7

An ultrasonic pulse-echo apparatus according to claim 1, 2 or 3, wherein the integration of said control data in said control means is carried out at the timing of the second pulse.

Claim 8

An ultrasonic pulse-echo apparatus according to claim 1, 2, 3 or 4, wherein, in said control means, an average value of the integration result of said control data is accumulated in order to obtain said cumulative result.

Claim 9

An ultrasonic pulse-echo apparatus according to claim 1, 2, 3 or 4 wherein, in said control means, a maximum value of the integration result of said control data is accumulated in order to obtain said cumulative result.

Claim 10

An ultrasonic pulse-echo apparatus according to claim 1, 2, 3 or 4, wherein said gain controlled amplifier comprises: a voltage controlled amplifier of which the transfer function is changed in accordance with a DC level of said control signal; and a dynamic range adjustment circuit connected in series to said voltage controlled amplifier to change a graduation of an image displayed by said display means, said dynamic range adjustment circuit being responsive to only an analog signal input with a larger level than a given threshold level.

Claim 11

An ultrasonic pulse-echo apparatus according to claim 1, 2, 3 or 4, wherein said transducer means includes a logarithmic amplifier for converting an attenuation of the ultrasonic echo pulse with respect to time into a linear function; and wherein said control means includes a saw-tooth generator which integrates said cumulative result for each period of the first pulse to provide the integration result as said control signal, in order to execute a sensitivity time control for said first image signal which is damped in a linear function manner.

Claim 12

An ultrasonic pulse-echo apparatus according to claim 7, wherein said control means comprises: an integrator for integrating said control data at the timing of the first pulse; a subtractor for providing a difference signal between the integration result of the integrator and a reference voltage serving as a control target for defining the brightness of an image displayed by said display means; an adder for providing a sum signal of the difference signal and the preceding frame or field information having been accumulated up to that time with respect to the preceding frame or field; a first memory into which the sum signal is loaded by a first load pulse in synchronism with the second pulse and the contents stored provides said cumulative result; and a second memory into which the contents of said first memory immediately before its contents is updated by the first load pulse is loaded by a second load pulse produced prior to the first load pulse, and the contents stored provides said preceding frame or field information.

Claim 13

An ultrasonic pulse-echo apparatus according to claim 8, wherein said control means comprises: an integrator for integrating said control data at the timing of the first pulse; a subtractor for providing a difference signal between the integration result of the integrator and a reference voltage serving as a control target for defining the brightness of an image displayed by said display means; an adder for providing a sum signal of the difference signal and the preceding frame or field information having been accumulated up to that time with respect to the preceding frame or field; a first memory into which the sum signal is loaded by a first load pulse in synchronism with the second pulse and the contents stored provides said cumulative result; and a second memory into which the contents of said first memory immediately before its contents is updatated by the first load pulse is loaded by a second load pulse produced prior to the first load pulse, and the contents stored provides said preceding frame or field information; and a maximum value detector which detects the maximum value signal from said integration results of said integrator and supplies the maximum value signal to said subtractor, said detector effecting said detecting operation for each frame or field at the timing of a third load pulse following the first load pulse.

Claim 14

An ultrasonic pulse-echo apparatus according to claim 4, wherein said control means comprising: first means for composing said first data which includes a first integrator for integrating said control data at the timing of the first gate pulse: a second adder for adding the first integration result from said first integrator to a first preceding information accumulated up to that time with respect to the ith frame or field, thereby to provide a first addition result: a third memory to which the first addition result is loaded in response to a fourth load pulse subsequently occurring after the first gate pulse, the contents stored providing the first data: a fourth memory to which the contents of said third memory just before its content is updated by the fourth load pulse is loaded by a fifth load pulse occurring preceding to the fourth load pulse, the contents stored providing the first preceding information; second means for composing said second data which includes a second integrator for integrating the control data at the timing of the second gate pulse: a third adder for adding a second integration result from said second integrator to the preceding information accumulated up to that time with respect to the i+1th frame or field, thereby to provide a second addition result; a fifth memory to which the second addition result is loaded by a sixth load pulse occurring following the second gate pulse, the contents stored providing the second data: and a sixth memory to which the contents of said fifth memory before its content is updated by the sixth load pulse is loaded by the 7th load pulse occurring preceding to the sixth load pulse, the contents stored providing the second preceding information; third means for composing said control signal which includes a subtractor for providing a difference signal between said first data and the second data: an adder for providing a sum signal of the difference signal and preceding frame or frame information accumulated up to that time with respect to the preceding frame or field; a first memory to which the sum signal is stored by the first load pulse in synchronism with the second pulse, the contents stored providing the cumulative result: and a second memory to which the contents of said first memory just before its contents is updated by the 10th pulse is loaded by the second load pulse occurring preceding to the first load pulse, the contents of stored providing the preceding frame or field information.