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Ultrasound imaging techniques are widely applied for medical diagnosis. However its main disadvantage compared with other techniques are low resolution and speckle artifacts. Therefore, improving the spatial resolution of ultrasound images has been a very active research area. System parameters that affect resolution include the size of the active transducer aperture, the center frequency and the...
Color flow imaging in medical ultrasound color codes pixels in blood vessels according to its estimated velocity, which is calculated at every pixel within a user selected region of interest regardless of whether the pixel came from tissue or blood flow. Hence, a tissue/flow detector is required to color code only flow pixels. Scanning conditions and scenarios, available output parameters from the...
Signal-to-noise ratio (SNR) can be improved by chirp excitation signal in ultrasound color flow imaging. However, the performance of autocorrelation estimator, which relies on a narrowband approximation, will be degraded by the broadband characteristics of compressed chirp signals. Frequency splitting (FS) method has been proposed to deal with this problem, where broadband signal is divided into several...
Many automatic time gain compensations are proposed, but most of them depart from the assumption that ultrasound signals are homogenous attenuated across examined tissues, which is often violated. In real ultrasound system, the large attenuation variation between different types of tissues confused the attenuation compensation. In this paper, considering the frequency shift effect, we propose the...
The segmentation and analysis of the carotid artery is useful for the diagnosis of serious cardiovascular disease. Several methods have been presented for the segmentation of ultrasound carotid artery images, but almost all need a certain degree of user interaction. In this paper, we present an automatic segmentation method for detecting the intimal and adventitial layers. The method firstly uses...
This paper presents a novel method for motion estimation and visualization of cardiac ultrasound images. The motion vectors are derived from an adaptive curve region based matching algorithm. The size of curve regions can be adjusted adaptively based on ultrasound system parameters and position information of the region's center which is located on the scan lines as sampling points. Then the Curve...
Accurate measurement of intima-media thickness (IMT) in ultrasound images is clinically meaningful but also difficult because of low resolution. This paper proposes an approach to reconstruct a resolution-enhanced intima from a sequence of acquired images using a maximum a-posteriori framework. Anisotropic diffusion is used to reduce speckle with edge enhancement during reconstruction. For real time...
Modern medical ultrasound scanners estimate blood velocity distribution by computing the spectrogram of a temporal data sequence, typically using periodogram methods which require long observation windows. Furthermore, an additional B-mode image is often displayed, resulting in gaps in the data at B-mode emissions. We propose a data-adaptive velocity estimator for periodically gapped (PG) data that...
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