In this paper, we propose a fully automatic system for analyzing ecographic movies of flow-mediated dilation.
Our approach uses a spline-based active contour (deformable template) to follow artery boundaries during the
FMD procedure. A number of preprocessing steps (grayscale conversion, contrast enhancing, sharpening) are
used to improve the visual quality of frames coming from the echographic acquisition. Our system can be used
in real-time environments due to the high speed of edge recognition which iteratively minimizes fitting errors on
endothelium boundaries. We also implemented a fully functional GUI which permits to interactively follow the
whole recognition process as well as to reshape the results. The system accuracy and reproducibility has been
validated with extensive in vivo experiments.
In this paper, we propose a compression scheme that is tailored for stereo-laparoscope sequences. The inter-frame correlation
is modeled by the deformation field obtained by elastic registration between two subsequent frames and exploited
for prediction of the left sequence. The right sequence is lossy encoded by prediction from the corresponding left images.
Wavelet-based coding is applied to both the deformation vector fields and residual images. The resulting system supports
spatio temporal scalability, while providing lossless performance. The implementation of the wavelet transform by integer
lifting ensures a low computational complexity, thus reducing the required run-time memory allocation and on line implementation.
Extensive psychovisual tests were performed for system validation and characterization with respect to the
MPEG4 standard for video coding. Results are very encouraging: the PSVC system features the functionalities making it
suitable for PACS while providing a good trade-off between usability and performance in lossy mode.
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