ATL attacks image speckle problem with ultrasound parallel processing

April 21, 1993

ATL was scheduled to roll out the red carpet for 140 physicianson Monday to introduce what the ultrasound vendor considers itsmost significant product upgrade since the advent of high-definitionimaging two years ago (SCAN 4/24/91). Over the next month,

ATL was scheduled to roll out the red carpet for 140 physicianson Monday to introduce what the ultrasound vendor considers itsmost significant product upgrade since the advent of high-definitionimaging two years ago (SCAN 4/24/91). Over the next month, ATLwill display its new technology around the world, with physicianmeetings scheduled in Hong Kong, Sydney, London, Berlin, Milanand Paris.

HDI combined broadband transducers with ATL's digital beamformerto increase the amount of image information acquired by the Ultramark9 scanner over a range of frequencies. Extended signal processing(ESP), the central feature of ATL's level four upgrade, boostsHDI's power further by applying parallel processing techniquesas the signal moves further through the ultrasound machine.

Most important to diagnostic imagers is ATL's claim that ESPsubstantially reduces image speckle, thus boosting contrast resolutionand the ability to visualize tissue borders. The vendor does notmake tissue differentiation claims but instead maintains thatphysicians will have a better view of lesions aid in making theirown diagnostic judgments about possible malignancies.

"The ability to see structures as small as possible iscertainly a goal that we want to achieve with level four; notonly to detect but also to assess the lesion and clearly seeits margins," said David M. Perozek, president.

ESP opens the door to further improvements in functionality,since the ultrasound system can now perform many different processingfunctions simultaneously, avoiding limitations inherent in sequentialprocessing. This could take ultrasound a step closer to incorporatingcomplex postacquisition functions, such as three-dimensional imageprocessing, into the real-time scanning procedure, according toJacques Souquet, vice president for product generation.

"We have the computing power in this system to processin parallel, using different algorithms, the data that comes tothat portion of our ultrasound machine," he told SCAN.

Current techniques to smooth out speckle, the intersperseddark and light zones common in ultrasound images, involve smoothingtechniques, such as frame averaging or filtering, which also decreasespatial resolution detail in the image, Souquet said.

"Our strategy is different," he said. "Insteadof looking at the data already in memory and processing that data,we look at the data that comes from the transducer before it hasreached memory."

As with HDI acquisition functions, ATL development of ESP wasassisted by breakthroughs in technology for the creation of complexcustomized microprocessor chips, application-specific integratedcircuits (ASICs).

ATL took signal processing technology already used in somefields, particularly in military applications, and designed itsown ASICs for applications in medical image processing, Souquetsaid.

"This (chip making) technology has enabled us to crammore function on the same chip," he said.

All ultrasound phased-array and dynamic focus front-end technologyinvolves parallel processing in the sense that multiple channelsof image data are handled simultaneously, Perozek noted. ESP bringsparallel processing further along in the imaging chain.

This process will continue when ATL introduces its DigitalLaboratory ultrasound image management and display technology.The pipeline of image information must be widened from acquisitionto display, as ultrasound competitor Acuson noted when it introducedthe Aegis digital image handling system last year.

"This happens to be a case in which we agree with Acuson,"Perozek said. "We would like to preserve the original fidelityof the acquired image through every link in the image chain."