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An approximation formula for the variance of positron emission tomography (PET) region-of-interest (ROI) values has been developed, implemented, and evaluated. This formula does not require access to the original projection data and is therefore convenient for routine use. The formula was derived by applying successive approximations to the(More)
When textural features are applied to handwriting identification, the accuracy is not high due to the fact that the textural features fluctuate randomly because of the different contents and positions of the characters. In this paper an approach for the construction of texture images is presented. The features of the texture images are calculated and the(More)
The imaging characteristics of maximum likelihood (ML) reconstruction using the EM algorithm for emission tomography have been extensively evaluated. There has been less study of the precision and accuracy of ML estimates of regional radioactivity concentration. The authors developed a realistic brain slice simulation by segmenting a normal subject's MRI(More)
Printed document examination plays an important role in public security. A printer identification system is presented for the purpose of identifying the printer which created a suspect printed document. It is composed of image acquisition, image preprocessing and character matching. An optical instrument is developed for document image observation and(More)
There are many methods available for printer identification of questioned documents, however most of them need identical contents of the training and testing documents. There is no effective method yet when the contents of the training and testing documents are different. To overcome this obstacle a method based on synthetic texture analysis is proposed in(More)
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