PT Journal AU Sergio Escalera Ana Puig Oscar Amoros Maria Salamo TI Intelligent GPGPU Classification in Volume Visualization: a framework based on Error-Correcting Output Codes SO Computer Graphics Forum JI CGF PY 2011 BP 2107 EP 2115 VL 30 IS 7 DI 10.1111/j.1467-8659.2011.02043.x AB IF JCR 1.455 2010 25/99In volume visualization, the definition of the regions of interest is inherently an iterative trial-and-error process finding out the best parameters to classify and render the final image. Generally, the user requires a lot of expertise to analyze and edit these parameters through multi-dimensional transfer functions. In this paper, we present a framework of intelligent methods to label on-demand multiple regions of interest. These methods can be split into a two-level GPU-based labelling algorithm that computes in time of rendering a set of labelled structures using the Machine Learning Error-Correcting Output Codes (ECOC) framework. In a pre-processing step, ECOC trains a set of Adaboost binary classifiers from a reduced pre-labelled data set. Then, at the testing stage, each classifier is independently applied on the features of a set of unlabelled samples and combined to perform multi-class labelling. We also propose an alternative representation of these classifiers that allows to highly parallelize the testing stage. To exploit that parallelism we implemented the testing stage in GPU-OpenCL. The empirical results on different data sets for several volume structures shows high computational performance and classification accuracy. ER