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1.
IEEE Trans Pattern Anal Mach Intell ; 34(1): 66-78, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21576750

ABSTRACT

SIFT-like local feature descriptors are ubiquitously employed in computer vision applications such as content-based retrieval, video analysis, copy detection, object recognition, photo tourism, and 3D reconstruction. Feature descriptors can be designed to be invariant to certain classes of photometric and geometric transformations, in particular, affine and intensity scale transformations. However, real transformations that an image can undergo can only be approximately modeled in this way, and thus most descriptors are only approximately invariant in practice. Second, descriptors are usually high dimensional (e.g., SIFT is represented as a 128-dimensional vector). In large-scale retrieval and matching problems, this can pose challenges in storing and retrieving descriptor data. We map the descriptor vectors into the Hamming space in which the Hamming metric is used to compare the resulting representations. This way, we reduce the size of the descriptors by representing them as short binary strings and learn descriptor invariance from examples. We show extensive experimental validation, demonstrating the advantage of the proposed approach.

2.
Hum Mov Sci ; 20(3): 313-41, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11517674

ABSTRACT

Optical motion capture provides an impressive ability to replicate gestures. However, even with a highly professional system there are many instances where crucial markers are occluded or when the algorithm confuses the trajectory of one marker with that of another. This requires much editing work on the user's part before the complete animation is ready for use. In this paper, we present an approach to increasing the robustness of a motion capture system by using an anatomical human model. It includes a reasonably precise description of the skeleton's mobility and an approximated envelope. It allows us to accurately predict the 3-D location and visibility of markers, thus significantly increasing the robustness of the marker tracking and assignment, and drastically reducing--or even eliminating--the need for human intervention during the 3-D reconstruction process.


Subject(s)
Hip/physiology , Knee/physiology , Motion Perception/physiology , Videotape Recording , Algorithms , Biomechanical Phenomena , Gestures , Humans , Imitative Behavior , Movement/physiology , Reproducibility of Results , Signal Detection, Psychological
3.
Monogr Neural Sci ; 5: 258-64, 1980.
Article in English | MEDLINE | ID: mdl-7322163

ABSTRACT

Twenty-six patients, suffering from various forms of epilepsy (2 with simple partial, 14 with complex partial, and 10 with generalized seizures) and treated with different drugs (10 with DPH, 10 with PB, and 6 with CBZ), underwent neuropsychological tests in order to evaluate: 1) Vigilance; 2) attention; 3) motor, sensory and adaptive (visuomotor) performances; 4) memory span, short-term and long-term memory, considering verbal as well as spatial aspects. The battery of tests was administered prior to treatment and when the drug plasmatic levels were within the ranges considered therapeutic. The results show that in the case of DPH there is an improvement of vigilance and adaptive performances but a worsening of attention and memory functions. With PB, only motor and adaptive performances improve; all other functions worsen. Finally, with CBZ, vigilance, attention, sensory performances and memory functions are unmodified while only motor and adaptive performances appear to improve.


Subject(s)
Anticonvulsants/therapeutic use , Epilepsy/physiopathology , Adult , Cognition/drug effects , Epilepsy/drug therapy , Epilepsy/psychology , Female , Humans , Learning/drug effects , Male , Memory/drug effects , Motor Skills/drug effects , Sensation/drug effects
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