Victor Sanchez

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We present an automatic system for planar 3D modeling of building interiors from point cloud data generated by range scanners. This is motivated by the observation that most building interiors may be modeled as a collection of planes representing ceilings, floors, walls and staircases. Our proposed system, which employs model-fitting and RANSAC, is capable(More)
OBJECTIVE This study compared two methods of booking elective surgery - booking from wait lists and pre-booking surgery dates at the time of decision to operate - in terms of cancellations of elective procedures and time to surgery. METHODS The authors conducted simulation experiments with group randomized design, in which the unit of allocation was the(More)
We propose a novel symmetry-based technique for scalable lossless compression of 3D medical image data. The proposed method employs the 2D integer wavelet transform to decorrelate the data and an intraband prediction method to reduce the energy of the sub-bands by exploiting the anatomical symmetries typically present in structural medical images. A(More)
Computer simulation has been employed to evaluate proposed changes in the delivery of health care. However, little is known about the utility of simulation approaches for analysis of changes in the delivery of surgical care. We searched eight bibliographic databases for this comprehensive review of the literature published over the past five decades, and(More)
We recently proposed a symmetry-based scalable lossless compression method for 3D medical images using the 2D integer wavelet transform and the embedded block coder with optimized truncation (EBCOT). In this paper, we present two major contributions that enhance our early work: 1) a new block-based intra-band prediction method that exploits the global and(More)
This paper presents an efficient lossless compression method for 4-D medical images based on the advanced video coding scheme (H.264/AVC). The proposed method efficiently reduces data redundancies in all four dimensions by recursively applying multiframe motion compensation. Performance evaluations on real 4-D medical images of varying modalities including(More)
Four dimensional (4D) medical data are sequences of volumetric images captured in time. These data sets are typically very large in size and demand a great amount of resources for storage and transmission. In this paper, we present a lossless compression technique for 4D medical images which is based on the H.264/AVC video coding standard. Our lossless(More)
The recent introduction of the High Efficiency Video Coding (HEVC) standard provides opportunities to improve medical image compression in picture archiving and communications systems. In this paper, we propose improvements to the HEVC intra coding process for lossless compression of grayscale anatomical medical images, which are characterized by their(More)
X-ray angiography (angio) images are widely used to identify irregularities in the vascular system. Because of their high spatial resolution and the increasing amount of X-ray angio images generated, compression of these images is becoming paramount. In this paper, we propose a diagnostically lossless compression method based on automatic segmentation using(More)
Harnessing the latent knowledge present in geospatial trajectories allows for the potential to revolutionise our understanding of behaviour. This paper discusses one component of such analysis, namely the extraction of significant locations. Specifically, we: (i) present the Gradient-based Visit Extractor (GVE) algorithm capable of extracting periods of low(More)