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Digital Processor for Data Compaction and Image Enhancement of Echographical Signals

IP.com Disclosure Number: IPCOM000083094D
Original Publication Date: 1975-Mar-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 5 page(s) / 85K

Publishing Venue

IBM

Related People

Chow, CK: AUTHOR [+2]

Abstract

It is known, that an organ such as the human heart, may be examined using ultrasonic energy. Typically, a cross-sectional view of the organ is obtained by emitting ultrasonic impulses to various parts of the organ, and by receiving and processing the reflected signals. One of the major difficulties in attempting computer application to process ultrasonic signals, resides in the mismatch in data rates; the diagnostic ultrasound is typically in the megahertz range, while the computer input rate is of the kilohertz range.

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Digital Processor for Data Compaction and Image Enhancement of Echographical Signals

It is known, that an organ such as the human heart, may be examined using ultrasonic energy. Typically, a cross-sectional view of the organ is obtained by emitting ultrasonic impulses to various parts of the organ, and by receiving and processing the reflected signals. One of the major difficulties in attempting computer application to process ultrasonic signals, resides in the mismatch in data rates; the diagnostic ultrasound is typically in the megahertz range, while the computer input rate is of the kilohertz range.

In order to obviate this mismatch, an arrangement is provided to compact the analog, high-frequency ultrasonic signals to provide computer usable digital data, to thereby improve the signal-to-noise ratio of the echo signals, and enhance the image quality. The apparatus is described in the context of reconstructing heart cross-sections with slow-probe manipulation, although its use is not necessarily limited to such applications.

Fig. 1 shows a block diagram of the complete diagnostic ultrasound system. As is understood by those skilled in the art, clock generator 1 provides pulses at a repetition rate of typically 1KHz to pulse generator 3. Pulse generator 3, in turn, provides high-amplitude pulses to drive ultrasonic transducer 5. Ultrasonic waves of a frequency commonly 2MHz propagate toward the organ, such as the heart shown in Fig. 1.

Reflected ultrasonic impulses are picked up by transducer 5 and received by amplifier 7, where they are amplified with a time-gain compensation to equalize for smaller signals received from deeper locations. Envelope detector 9 detects the envelope of the reflected ultrasonic signals, and A/D converter 11 acts to digitize this information for digital processor 13.

As can be seen, digital processor 13 acts as the interface between detector 9 and digital computer 15. A/D converter 17 acts to convert the X and Y coordinates of the transducer location on the heart, as well as the transducer angle, and the electrocardiographic signal from the heart to receiver 19.

The data rate of the ultrasonic signal is quite high. Assuming that 256, generally denoted by symbol M, time samples are taken on each ultrasonic return signal with 8 bits or 1 byte for each sample, the data rate is 256 K bytes per second. If the examination lasts, for example, 5 minutes, the total storage capacity required amounts to 76.8M bytes. Typically available magnetic tape or disks cannot handle this amount of data at this speed. Moreover, since the transducer is slowly manipulated (by human hand), the received signal contains considerable redundancy, and there is no technical need to store all of the received signals.

Digital processor 13 functions to first compact and enhance the ultrasonic signals before transmitting them to computer 15. Fig. 2 shows a block diagram detailing digital processor 13, shown in Fig. 1. The N-counter 21...