RESUMO
The joint source-channel coding system proposed in this paper has two aims: lossless compression with a progressive mode and the integrity of medical data, which takes into account the priorities of the image and the properties of a network with no guaranteed quality of service. In this context, the use of scalable coding, locally adapted resolution (LAR) and a discrete and exact Radon transform, known as the Mojette transform, meets this twofold requirement. In this paper, details of this joint coding implementation are provided as well as a performance evaluation with respect to the reference CALIC coding and to unequal error protection using Reed-Solomon codes.
Assuntos
Compressão de Dados/métodos , Diagnóstico por Imagem , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Internet , Algoritmos , Segurança Computacional , Humanos , Análise Numérica Assistida por Computador , Processamento de Sinais Assistido por ComputadorRESUMO
An evaluation of two software tools dedicated to an automatic analysis of the CT scanner image spatial resolution is presented in this paper. The methods evaluated consist of calculating the Modulation Transfer Function (MTF) of the CT scanners; the first uses an image of an impulse source, while the second method proposed by Droege and Morin uses an image of cyclic bar patterns. Two Digital Test Objects (DTO) are created to this purpose. These DTOs are then blurred by doing a convolution with a two-dimensional Gaussian Point Spread Function (PSF(Ref)), which has a well known Full Width at Half Maximum (FWHM). The evaluation process consists then of comparing the Fourier transform of the PSF on the one hand, and the two mentioned methods on the other hand.
