An Approach to Real-Time Reflection Tomography Using the Complete Dataset

Broadstone, Steven R.; Arthur, R. Martin

doi:10.1109/ultsym.1986.198850

Cited by 7 publications

(11 citation statements)

References 1 publication

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“…Conventional medical imaging systems are not in focus everywhere because of the complexity of focusing an array at each image location plus the desirability of real-time operation. Recently we have presented a parallel processing approach with an application specific integrated circuit which can produce a 512 x 512 image at a 30 Hz frame rate which is in focus everywhere [18,19].…”

Section: Discussionmentioning

confidence: 99%

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Imaging via inversion of ellipsoidal projections of solutions to the linear acoustic wave equation (medical ultrasound)

Arthur¹,

Broadstone²

1989

IEEE Trans. Med. Imaging

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Backscattered energy from a medium with nearly constant velocity measured by an omnidirectional source-sensor comes from spherical shells centered at the source-sensor location. If source and sensor locations differ, the energy comes from ellipsoidal shells. To image the scattering potential or reflectivity of the medium, backscattered energy must be projected onto ellipsoids with a weighting factor dependent on the eccentricity of the ellipsoid. Eccentricity is the ratio of the separation of source and sensor to the path length from source to scatterer to sensor. Because path length changes with time, this weighting factor is, in general, time-dependent. It is consistent only if the source and sensor location are the same, in which case its value is unity. To estimate scattering potential or reflectivity at a given site, the backscattered signal which could have arisen from that site as measured by a given source-sensor pair is weighted by that pair's time-dependent ellipsoidal factor, then the weighted backscattered signals are averaged over all available source-sensor pairs.

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Section: Discussionmentioning

confidence: 99%

“…where dγ in (18) has been expressed in spherical coordinates. Because the radii are nearly constant over the scattering volume the integral over Γ is just the solid angle Ω V subtended by the scattering volume, i.e.,…”

Section: A Single Scattering Volume Of Known Location and Extentmentioning

confidence: 99%

Imaging via inversion of ellipsoidal projections of solutions to the linear acoustic wave equation (medical ultrasound)

Arthur¹,

Broadstone²

1989

IEEE Trans. Med. Imaging

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“…In its difference form the only arithmetic operation required to synthesize a polynomial with positive-integer powers is addition. The two-dimensional form of (29) can be implemented recursively using the structure we previously described [6]. No multiplications are needed.…”

Section: Analytic Solutions For Time-of-flightmentioning

confidence: 99%

“…We previously reported an approach for generating synthetic-focus images in real time which are in focus at each pixel in the image [6]. Our approach was based on parallel processing with an application-specific integrated circuit that updates estimates of the time of flight in a singleaddition time along an arbitrary contour through the image.…”

Section: Introductionmentioning

confidence: 99%

Determination of time-of-flight surfaces using the method of moments (US imaging)

Broadstone

Arthur

1991

IEEE Trans. Med. Imaging

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To produce an image from backscattered signals requires a knowledge of the time of flight from each source to each sensor in a transducer array. The authors reduced the determination of the rectangular coordinates of a new point on any time-of-flight surface, which requires finding the square root of the sum of squares, to the time of a single addition. To do this, the time-of-flight surface was represented by a two-dimensional, positive-integer-degree polynomial and then that polynomial was implemented in its forward-difference form. Two solutions for such a polynomial were found using the method of moments. A minimum-mean-square-error constraint yields polynomial coefficients from a numeric evaluation of the moments of arbitrary surfaces over rectangular regions, and an analytical solution for moments of time-of-flight surfaces over sector-shaped regions. For a 7x6-cm region at a minimum range of 4 cm centered in a 74 degrees sector, the maximum error for a second-degree polynomial was 0.30% of the average time of flight over the region for the numeric solution and 0.32% for the analytic solution, assuming a 1500-m/s background velocity.

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“…3, 4 Syn thetic-ap erture ac qui si tion time is pro por tional to the num ber of trans duc ers in the ar ray, whereas the time re quired for con ven tional fo cus-and-steer im ag ing is pro por tional to the num ber of focal points in the im age. 5 There fore, be cause the num ber of pix els is typ i cally or ders of magni tude greater than the num ber of trans duc ers, ac quir ing an in-fo cus im age with con ven tional sys tems is im prac ti cal. For a 256-el e ment trans ducer and a tis sue re gion at a max i mum range of 7.5 cm, syn thetic-ap er ture ac qui si tion time for the com plete dataset is about 26 ms, i.e., data sets can be ac quired at a real-time frame rate of ap prox i mately 38 Hz.…”

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confidence: 99%

A Scalable Architecture for Real-Time Synthetic-Focus Imaging

Richard

2003

Ultrason Imaging

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A scalable architecture for forming real-time synthetic focus images is described and the design of a 256-channel system using currently-available technology is presented as an example implementation of the architecture. The parallelism of the system scales directly with the number of array elements and the image computation rate for a given image size (in pixels) stays constant as the number of array elements is increased. The system leverages earlier work in the real-time generation of the required time-of-flight surfaces and allows either real-time image generation or iterative adaptive image generation from a single complete data set.

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An Approach to Real-Time Reflection Tomography Using the Complete Dataset

Cited by 7 publications

References 1 publication

Imaging via inversion of ellipsoidal projections of solutions to the linear acoustic wave equation (medical ultrasound)

Imaging via inversion of ellipsoidal projections of solutions to the linear acoustic wave equation (medical ultrasound)

Determination of time-of-flight surfaces using the method of moments (US imaging)

A Scalable Architecture for Real-Time Synthetic-Focus Imaging

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