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You searched for subject:(Random Illumination). Showing records 1 – 3 of 3 total matches.

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University of Illinois – Urbana-Champaign

1. Zhou, Zihan. Face recognition under varying illumination, pose and contiguous occlusion.

Degree: MS, 1200, 2010, University of Illinois – Urbana-Champaign

This thesis considers the problem of recognizing human faces despite variations in illumination, pose and contiguous occlusion, using only frontal training images. In particular, we are interested in simultaneously handling multiple modes of variability in automatic face recognition. We first propose a very simple algorithm, called Nearest-Subspace Patch Matching, which combines a local translational model for deformation due to pose with a linear subspace model for lighting variations. This algorithm gives surprisingly competitive performance for moderate variations in both pose and illumination, a domain that encompasses most face recognition applications, such as access control. The results also provide a baseline for justifying the use of more complicated face models or more advanced learning methods to handle more extreme situations. We further develop a more principled and general method for face recognition with contiguous occlusion using tools from sparse representation, which has demonstrated promising results in handling illumination changes and occlusion. While such sparsity-based algorithms achieve their best performance on occlusions that are not spatially correlated (i.e. random pixel corruption), we show that they can be significantly improved by harnessing prior knowledge about the pixel error distribution. We show how a Markov random field model for spatial continuity of the occlusion can be integrated into the computation of a sparse representation of the test image with respect to the training images. Our algorithm efficiently and reliably identifies the corrupted regions and excludes them from the sparse representation. Extensive experiments on publicly available databases verify the efficacy of the proposed methods. Advisors/Committee Members: Ma, Yi (advisor).

Subjects/Keywords: face recognition; illumination; pose; contiguous occlusion; patch matching, Markov random field

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APA (6th Edition):

Zhou, Z. (2010). Face recognition under varying illumination, pose and contiguous occlusion. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/16486

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Zhou, Zihan. “Face recognition under varying illumination, pose and contiguous occlusion.” 2010. Thesis, University of Illinois – Urbana-Champaign. Accessed July 22, 2019. http://hdl.handle.net/2142/16486.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Zhou, Zihan. “Face recognition under varying illumination, pose and contiguous occlusion.” 2010. Web. 22 Jul 2019.

Vancouver:

Zhou Z. Face recognition under varying illumination, pose and contiguous occlusion. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2010. [cited 2019 Jul 22]. Available from: http://hdl.handle.net/2142/16486.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zhou Z. Face recognition under varying illumination, pose and contiguous occlusion. [Thesis]. University of Illinois – Urbana-Champaign; 2010. Available from: http://hdl.handle.net/2142/16486

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Northeastern University

2. Hoffman, Zachary R. Structured illumination microscopy using random intensity incoherent reflectance.

Degree: MS, Department of Electrical and Computer Engineering, 2013, Northeastern University

Depth information is resolved from thick specimens using a modification of structured illumination. By projecting a random projection pattern with varied spatial frequencies that is rotated while capturing images, sectioning can be performed using an incoherent light source in reflectance only. This provides a low cost solution to obtaining information similar to that produced in confocal microscopy and other methods of structured illumination, without the requirement of complex or elaborate equipment, coherent light sources, or fluorescence. The broad line width of the LED minimizes artifacts associated with speckle from the laser, while also increasing the safety of the instrument. Single diffusers and cascaded diffusers are compared to provide the most efficient method for sectioning at depth. By using reflectance only, in-vivo images are produced on a human subject, generating high contrast images and providing depth information about subsurface objects.

Subjects/Keywords: Optical Sectioning; Random Illumination; Reflectance Microscopy; Structured Illumination; Bioimaging and biomedical optics; Electrical and Computer Engineering; Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hoffman, Z. R. (2013). Structured illumination microscopy using random intensity incoherent reflectance. (Masters Thesis). Northeastern University. Retrieved from http://hdl.handle.net/2047/d20003331

Chicago Manual of Style (16th Edition):

Hoffman, Zachary R. “Structured illumination microscopy using random intensity incoherent reflectance.” 2013. Masters Thesis, Northeastern University. Accessed July 22, 2019. http://hdl.handle.net/2047/d20003331.

MLA Handbook (7th Edition):

Hoffman, Zachary R. “Structured illumination microscopy using random intensity incoherent reflectance.” 2013. Web. 22 Jul 2019.

Vancouver:

Hoffman ZR. Structured illumination microscopy using random intensity incoherent reflectance. [Internet] [Masters thesis]. Northeastern University; 2013. [cited 2019 Jul 22]. Available from: http://hdl.handle.net/2047/d20003331.

Council of Science Editors:

Hoffman ZR. Structured illumination microscopy using random intensity incoherent reflectance. [Masters Thesis]. Northeastern University; 2013. Available from: http://hdl.handle.net/2047/d20003331


NSYSU

3. Huang, Sheng-Yao. Study of Physical Mechanisms of Electrical Reliability and Environmental Sensitivity for Advanced InGaZnO Thin Film Transistors.

Degree: PhD, Physics, 2013, NSYSU

In the first part, we investigate the instability of negative bias temperature in the dark and the illumination stresses for the amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (a-IGZO TFTs). During the negative bias temperature illumination stress, properties exhibit an obvious negative threshold voltage shift and a significant degradation of subthreshold swing. The photoelectric heat effect that combined the effects of electric field, illumination, and temperature induces the generation of dangling bonds in the interface, resulting in an apparent degradation. It is related to the presence of light energy. Finally, this work also employs the capacitance-voltage measurement and recovery behavior to further clarify the mechanism of degradation behaviors. In the second part, we investigate oxygen adsorption/desorption to influence on the electrical properties of a-IGZO TFTs during drain or gate-drain stresses. After a drain stress, instable electrical characteristics of device are observed, including a current crowding effect of current-voltage and a stretch-out of capacitance-voltage. These are caused by the oxygen adsorbed on the a-IGZO surface near the drain region. However, for the gate-drain stress, the device exhibits a stable electrical behavior, which could be results from the self-heating effects and desorbed the oxygen by heat energy. In the third part, we investigate behavior of drain bias stress and gate-drain bias stress under illumination for a-IGZO TFTs working as the current-driver. Properties exhibit two-stage degradation behavior during drain bias stress. The photo excites holes non-uniform trapping under illumination inducing drain side barrier lowering and causing an apparent hump phenomenon of the subthreshold swing. However, the positive threshold voltage shift without a hump phenomenon after gate-drain bias stress is different degradation behaviors. It relies on the existing of inversion layer in the channel. In addition, this section also investigates degradation behavior of AC drain-bias stress under illumination. We observe different degradation behavior after the AC drain-bias stress, which the hump phenomenon disappeared but the Vth shift is observed. Significantly, the degradation behavior during the AC drain-bias stress is related with the duty-ratio and frequency of the AC pulse waveform. The experiment results indicate the pulse-width (PW) time during the drain bias makes the holes trapping at interface defect between insulator/active layer, and on the other hand during the pulse-base (PB) time the hole trapping induces surface band banding make electron inject into the interface defect, Resulting in the electron and hole recombine within the interface defect. In the fourth part, we investigate the effects of ambient atmosphere on electrical characteristics of Al2O3 passivated a-IGZO TFTs during positive bias temperature stress. Under H2O vapor environment, the Al2O3 passivated device exhibited a stable electrical behaviors (ÎVth < 0.5V), while the unpassivated device… Advisors/Committee Members: Jeng-Tzong Sheu (chair), Ya-Hsiang Tai (chair), james jung (chair), Ping-Hung Yeh (chair), Ting-Chang Chang (committee member), Tsung-Ming Tsai (chair).

Subjects/Keywords: gate bias induced instability; UV photo sensor; passivation layer of Al2O3; resistive random access memory on three-terminal operation; drain bias induced instability; indium-gallium-zinc oxide thin film transistor (a-IGZO TFT); illumination induced instability

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Huang, S. (2013). Study of Physical Mechanisms of Electrical Reliability and Environmental Sensitivity for Advanced InGaZnO Thin Film Transistors. (Doctoral Dissertation). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0630113-211228

Chicago Manual of Style (16th Edition):

Huang, Sheng-Yao. “Study of Physical Mechanisms of Electrical Reliability and Environmental Sensitivity for Advanced InGaZnO Thin Film Transistors.” 2013. Doctoral Dissertation, NSYSU. Accessed July 22, 2019. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0630113-211228.

MLA Handbook (7th Edition):

Huang, Sheng-Yao. “Study of Physical Mechanisms of Electrical Reliability and Environmental Sensitivity for Advanced InGaZnO Thin Film Transistors.” 2013. Web. 22 Jul 2019.

Vancouver:

Huang S. Study of Physical Mechanisms of Electrical Reliability and Environmental Sensitivity for Advanced InGaZnO Thin Film Transistors. [Internet] [Doctoral dissertation]. NSYSU; 2013. [cited 2019 Jul 22]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0630113-211228.

Council of Science Editors:

Huang S. Study of Physical Mechanisms of Electrical Reliability and Environmental Sensitivity for Advanced InGaZnO Thin Film Transistors. [Doctoral Dissertation]. NSYSU; 2013. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0630113-211228

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