A laser profilometer based on adaptive photo-EMF detector that can find application for testing o... more A laser profilometer based on adaptive photo-EMF detector that can find application for testing optically rough surfaces is described. Depth resolution of the configuration is shown to depend on not only the coherence length of the wide-spectrum light source used, but also the interelectrode spacing of the detector and crossing angle of interfering beams. Experimental demonstration of the device having an approximately 10 mm resolution and using a GaAs photo-EMF detector and a superluminescent diode was performed in tests of multisurface reflecting object.
Computer Methods in Biomechanics and Biomedical Engineering, 2010
This work focuses on obtaining realistic human hand models that are suitable for manipulation tas... more This work focuses on obtaining realistic human hand models that are suitable for manipulation tasks. A 24 degrees of freedom (DoF) kinematic model of the human hand is defined. The model reasonably satisfies realism requirements in simulation and movement. To achieve realism, intra- and inter-finger constraints are obtained. The design of the hand model with 24 DoF is based upon a morphological, physiological and anatomical study of the human hand. The model is used to develop a gesture recognition procedure that uses principal components analysis (PCA) and discriminant functions. Two simplified hand descriptions (nine and six DoF) have been developed in accordance with the constraints obtained previously. The accuracy of the simplified models is almost 5% for the nine DoF hand description and 10% for the six DoF hand description. Finally, some criteria are defined by which to select the hand description best suited to the features of the manipulation task.
This work is focused on obtaining efficient human hand models that are suitable for manipulation ... more This work is focused on obtaining efficient human hand models that are suitable for manipulation tasks. A 24 DoF kinematic model of the human hand is defined to realistic movements. This model is based on the human skeleton. Dynamic and static constraints have been included in order to improve the movement realism. Two simplified hand models with 9 and 6 DoF have been developed according to the constraints predefined. These simplified models involve some errors in reconstructing the hand posture. These errors are calculated with respect to the 24 DoF model and evaluated according to the hand gestures. Finally, some criteria are defined to select the hand description best suited to the features of the manipulation task.
Characteristic features of the formation of cylindrical laser-induced thermal steady-state lenses... more Characteristic features of the formation of cylindrical laser-induced thermal steady-state lenses in the dark stripes associated with spatial dark-soliton propagation are analyzed and verified experimentally in an ethanol-dye solution. Positive focusing power perpendicular to the dark stripe is ensured by defocusing along the axis of this stripe and depends strongly on the shape of the light-beam profile and the orientation of the dark stripe within it.
This work is focused on obtaining realistic human hand models that are suitable for manipulation ... more This work is focused on obtaining realistic human hand models that are suitable for manipulation tasks. Firstly, a 24 DOF kinematic model of the human hand is defined. This model is based on the human skeleton. Intra-finger and inter-finger constraints have been included in order to improve the movement realism. Secondly, two simplified hand descriptions (9 and 6 DOF) have been developed according to the constraints predefined. These simplified models involve some errors in reconstructing the hand posture. These errors are calculated with respect to the 24 DOF model and evaluated according to the hand gestures. Finally, some criteria are defined by which to select the hand description best suited to the features of the manipulation task.
The analysis performed shows that in cubic photorefractive crystals (of Bi,,SiO,, and GaAs type i... more The analysis performed shows that in cubic photorefractive crystals (of Bi,,SiO,, and GaAs type in particular) with drift ("quasilocal") mechanism of optical nonlinearity spatial soliton propagation can be observed for reasonable external dc electric fields lo-15 kV/cm. These photorefractive solitons which can be excited at very low cw laser power are stable in a broad region of signal(soliton)/incoherent(spatially uniform) intensity ratio, and allow easy switching from bright to dark type. Original experimental results of self-channeling of submicrowatt HeNe laser beam in a cubic Bir2Ti02,, sample under external dc field are presented.
A laser profilometer based on adaptive photo-EMF detector that can find application for testing o... more A laser profilometer based on adaptive photo-EMF detector that can find application for testing optically rough surfaces is described. Depth resolution of the configuration is shown to depend on not only the coherence length of the wide-spectrum light source used, but also the interelectrode spacing of the detector and crossing angle of interfering beams. Experimental demonstration of the device having an approximately 10 mm resolution and using a GaAs photo-EMF detector and a superluminescent diode was performed in tests of multisurface reflecting object.
Computer Methods in Biomechanics and Biomedical Engineering, 2010
This work focuses on obtaining realistic human hand models that are suitable for manipulation tas... more This work focuses on obtaining realistic human hand models that are suitable for manipulation tasks. A 24 degrees of freedom (DoF) kinematic model of the human hand is defined. The model reasonably satisfies realism requirements in simulation and movement. To achieve realism, intra- and inter-finger constraints are obtained. The design of the hand model with 24 DoF is based upon a morphological, physiological and anatomical study of the human hand. The model is used to develop a gesture recognition procedure that uses principal components analysis (PCA) and discriminant functions. Two simplified hand descriptions (nine and six DoF) have been developed in accordance with the constraints obtained previously. The accuracy of the simplified models is almost 5% for the nine DoF hand description and 10% for the six DoF hand description. Finally, some criteria are defined by which to select the hand description best suited to the features of the manipulation task.
This work is focused on obtaining efficient human hand models that are suitable for manipulation ... more This work is focused on obtaining efficient human hand models that are suitable for manipulation tasks. A 24 DoF kinematic model of the human hand is defined to realistic movements. This model is based on the human skeleton. Dynamic and static constraints have been included in order to improve the movement realism. Two simplified hand models with 9 and 6 DoF have been developed according to the constraints predefined. These simplified models involve some errors in reconstructing the hand posture. These errors are calculated with respect to the 24 DoF model and evaluated according to the hand gestures. Finally, some criteria are defined to select the hand description best suited to the features of the manipulation task.
Characteristic features of the formation of cylindrical laser-induced thermal steady-state lenses... more Characteristic features of the formation of cylindrical laser-induced thermal steady-state lenses in the dark stripes associated with spatial dark-soliton propagation are analyzed and verified experimentally in an ethanol-dye solution. Positive focusing power perpendicular to the dark stripe is ensured by defocusing along the axis of this stripe and depends strongly on the shape of the light-beam profile and the orientation of the dark stripe within it.
This work is focused on obtaining realistic human hand models that are suitable for manipulation ... more This work is focused on obtaining realistic human hand models that are suitable for manipulation tasks. Firstly, a 24 DOF kinematic model of the human hand is defined. This model is based on the human skeleton. Intra-finger and inter-finger constraints have been included in order to improve the movement realism. Secondly, two simplified hand descriptions (9 and 6 DOF) have been developed according to the constraints predefined. These simplified models involve some errors in reconstructing the hand posture. These errors are calculated with respect to the 24 DOF model and evaluated according to the hand gestures. Finally, some criteria are defined by which to select the hand description best suited to the features of the manipulation task.
The analysis performed shows that in cubic photorefractive crystals (of Bi,,SiO,, and GaAs type i... more The analysis performed shows that in cubic photorefractive crystals (of Bi,,SiO,, and GaAs type in particular) with drift ("quasilocal") mechanism of optical nonlinearity spatial soliton propagation can be observed for reasonable external dc electric fields lo-15 kV/cm. These photorefractive solitons which can be excited at very low cw laser power are stable in a broad region of signal(soliton)/incoherent(spatially uniform) intensity ratio, and allow easy switching from bright to dark type. Original experimental results of self-channeling of submicrowatt HeNe laser beam in a cubic Bir2Ti02,, sample under external dc field are presented.
Uploads
Papers by Sanchez Uran