Segmentação de imagens por agrupamento de regiões: uma comparação entre a abordagem funcional e por grafos.

Carolina Toledo Ferraz and Sergio F. da Silva and Odemir Martinez Bruno

Workshop de Visão Computacional,46-51,2007

Vibro-acoustography (VA) is an imaging modality that produces a map (image) of the mechanical response of an object to a localized dynamic radiation force of an ultrasound field. This technique has been studied for clinical applications such as calcifications in breast tissue and arteries. In this method, images are degraded in its formation process and by the acquisition system. The deterministic component of the degradation can be described by means of the point-spread function of the system, which is a threedimensional complex function defined in terms of the acoustic emission of a point-target in response to a dynamic radiation stress of ultrasound. This paper presents some results of the application of restoration algorithms in VA images. We use a digital phantom to simulate a breast with lesionlike inclusions. The phantom image is convolved with the system PSF to form a degraded image taking into account the depth-of-field effects. Three restoration filters (Wiener, Regularized Least Squares and Geometric Mean) are applied to the degraded images with additive Gaussian noise and their results are compared visually and quantitatively.