An increasing number of people within the UK are overweight or even clinically obese. A recent report concluded that 60% of men and 40% of women are overweight. More worryingly, 20% of men and 25% of women are clinically obese. This is a threefold increase in last 20 years and presents severe difficulties in ultrasound imaging of a section of the population that carries an increasing risk of health problems.  The principal problem in ultrasound imaging is the rapid attenuation of the signal as it passes through the body. Another 10cm of intervening tissue might reduce the ultrasound echo by several thousand times. This is usually countered by using a lower frequency at the expense of significant loss of image quality. Just the fact that the organ to be viewed is deeper leads to further loss of definition as the ultrasound beam spreads with range.  Improving long range images is an issue that QinetiQ has addressed in sonar where the problem is to reliably identify objects in the sea or on the sea bed at increasing ranges. Medical diagnostic ultrasound has many parallels with sonar and defence technology offers a new solution to imaging large patients.  The QinetiQ solution is a system that uses wideband pulses to penetrate deeper and a novel processing solution that combats the loss of lateral resolution due to beam spreading by using a novel processing algorithm. This gives a factor of two improvement in the picture resolution. (The details of this processing are the subject of a patent application).  The wideband pulses replace the short burst sinusoid by a comparatively long frequency sweep. This allows more energy to be carried by the pulse without increasing the peak level. The effect of the processing is equivalent to filtering the return signal into a lot of individual sinusoids and then stacking them on top of each other to mimic a short pulse with a much-increased amplitude. 
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