Implementation of Zoom FFT in Ultrasonic Blood Flow Analysis

Published on Nov 06, 2015


An adequate blood flow supply is necessary for all organs of the body. Analysis of the blood flow finds its importance in the diagnoses of diseases. There are many techniques for analyzing the blood flow. These techniques are not affordable by the poor people because of their high expense. So we have implemented a technique called Zoom-FFT. This technique is simple and affordable to detect the blood clots and other diseases.

Human with his potential tries to get whichever is unexplored, explored, and till now we are managing and succeeding using some technical ways. In the same way this is one of the explorations made for scanning the intra details of some specific objects using ultrasound named SONOGRAPHY, which is used as an alternative to x-ray photography. In this paper, the method to zoom the image or the scanned data-using zoom FFT has been discussed.

It also explains the algorithm to get ZOOM FFT and how it can be obtained via simulation. Real time experimentation and its applications, with basics of ultrasound scanning are also explained. Here a specific application will be dealt i.e., ultrasonic blood flow analyzer using ZOOM FFT.

Blood flow analysis is done by passing a high frequency ultrasonic wave in the blood vessels through a transducer (transmitter) .The reflected signal; from the receiver transducer has a different frequency due to the Doppler principle. This signal is passed to a DSP processor to find the frequency spectrum. Because of the high frequency of the ultrasonic wave, the resolution of the frequency spectrum output will not be good.

herefore we go for advanced Zoom FFT technique, wherein a very small frequency change due to the clot formation can be obtained with a good resolution. It can be used to locate the initial presence of a blood clot. All of these tasks must be achieved with a single DSP chip in order for the system to be both cost-effective and power
efficient and thus widely accepted.

This paper proposes:

1.Study of Bio-medical signal processing

2.Mixing down the input signal to the base band frequency using Hilbert Transform

3. Finding the down sampling using the decimation process

4.Obtaining the spectrum output using fast Fourier transform

5.Simulation is done by Matlab/C.

6.TMS320C5X/6X DSP processor does real time implementation.

Steps involved:

" Sound generation: The ultrasonic sound is generated using the piezoelectric transducer

" Number of transducer may vary from 1 to many.

" Narrow beam of wave is to be feed in.

" Continuous mode of operation with no timed switching is applied in real time to measure Frequency and Amplitude

" Doppler shift analysis for frequency content is to be done.

" Creation of image - to plot in 2 Dimension.

" Display using color differentiation.


In an Ultrasonic blood flow analysis, a beam of ultrasonic energy is directed through a blood vessel at a shallow angle and its transit time is then measured.. More common are the ultrasonic analyzers based on the Doppler principle. An oscillator, operating at a frequency of several Mega Hertz, excites a piezoelectric transducer. This transducer is coupled to the wall of an exposed blood vessel and sends an ultrasonic beam with a frequency F into the flowing blood. A small part of the transmitted energy is scattered back and is received by a second transducer arranged opposite the first one.