Estimation and Modeling of the Full Well Capacity in Pinned Photodiode CMOS Image Sensors

This letter presents a simple analytical model for the evaluation of the full well capacity (FWC) of pinned photodiode (PPD) CMOS image sensors depending on the operating conditions and on the pixel parameters. While in the literature and technical documentations FWC values are generally presented as fixed values independent of the operating conditions, this letter demonstrates that the PPD charge handling capability is strongly dependent on the photon flu

Estimation and Modeling of Key Design Parameters of Pinned Photodiode CMOS Image Sensors for High Temporal Resolution Applications

Ph.D Defence Alice Pelamatt

Implicit Associations and Alcohol: What Grabs Our Attention?

The Incentive Sensitization Theory of Addiction claims that drug induced sensitization of the mesocorticolymbic system increases the salience of the drug related stimuli. In so doing, drug related stimuli become attention grabbing for an addictive person. We tried to understand the socio-cognitive underpinnings of this process in case of alcohol addiction. The present study involves a group of participants that had alcohol related problems and a non clinical sample. We suggest that two implicit automatic mechanisms could predict the attention towards alcohol related stimuli: the self relevance of the alcohol related stimuli and the evaluation attributed to the same stimuli. The Implicit Association Task was used to determine the strength of these mechanisms (i.e., self-relevance and alcohol evaluation). The attention toward alcohol related stimuli was assessed with the Visual Dot Probe Task. Results showed that the two groups significantly differed on the IAT scores, indicating stronger associations between self and alcohol, and between alcohol and positive words for participants that had alcohol related problems. Moreover a stronger association between the self and the alcohol was a significant and positive predictor of the attentional salience of the alcohol stimuli for the clinical sample, but not for the control group

Effect of Transcranial Magnetic Stimulation (TMS) on Parietal and Premotor Cortex during Planning of Reaching Movements

The activation of the superior parietal lobule (SPL) and premotor cortex (PM) has been investigated using transcranial magnetic stimulation (TMS) during planning of reaching movements under visual guidance. A facilitory effect was found when TMS was delivered on the parietal cortex at about half of the time from sight of the target to hand movement, independently of target location in space. Furthermore, at the same stimulation time, a similar facilitory effect was found in PM, which is probably related to movement preparation. This data contributes to the understanding of cortical dynamics in the parieto-frontal network, and suggests that it is possible to interfere with the planning of reaching movements at different cortical points within a particular time window. Since similar effects may be produced at similar times on both the SPL and PM, parallel processing of visuomotor information is likely to take place in these regions

Charge Transfer Inefficiency in Pinned Photodiode CMOS image sensors: Simple Montecarlo modeling and experimental measurement based on a pulsed storage-gate method

The charge transfer time represents the bottleneck in terms of temporal resolution in Pinned Photodiode (PPD) CMOS image sensors. This work focuses on the modeling and estimation of this key parameter. A simple numerical model of charge transfer in PPDs is presented. The model is based on a Montecarlo simulation and takes into account both charge diffusion in the PPD and the effect of potential obstacles along the charge transfer path. This work also presents a new experimental approach for the estimation of the charge transfer time, called pulsed Storage Gate (SG) method. This method, which allows reproduction of a “worst-case” transfer condition, is based on dedicated SG pixel structures and is particularly suitable to compare transfer efficiency performances for different pixel geometries

On The Pixel Level Estimation of Pinning Voltage, Pinned Photodiode Capacitance and Transfer Gate Channel Potential

The pinning voltage extraction method proposed by Tan et al. is analyzed to clarify its benefits and limitations. It is demonstrated that this simple measurement can bring much more useful information than the pinning voltage, such as the pinned photodiode capacitance and the transfer gate channel potential. Objective criteria to compare the pinning voltage on different devices are also discussed

Temperature dependence and dynamic behaviour of full well capacity in pinned photodiode CMOS image sensors

This study presents an analytical model of the Full Well Capacity(FWC) in Pinned Photodiode (PPD) CMOS image sensors. By introducing the temperature dependence of the PPD pinning voltage, the existing model is extended (with respect to previous works) to take into account the effect of temperature on the FWC. It is shown, with the support of experimental data, that whereas in dark conditions the FWC increases with temperature, a decrease is observed if FWC measurements are performed under illumination. This study also shows that after a light pulse, the charge stored in the PPD drops as the PPD tends toward equilibrium. On the base of these observations, an analytical model of the dynamic behaviour of the FWC in non-continuous illumination conditions is proposed. The model is able to reproduce experimental data over six orders of magnitude of time. Both the static and dynamic models can be useful tools to correctly interpret FWC changes following design variations and to accurately define the operating conditions during device characterizations

Adolescents' Appraisal of Homophobic Epithets: The Role of Individual and Situational Factors

Homophobic epithets have become commonly-used insults among adolescents. However, evidence suggests that there are differences in how these homophobic epithets are evaluated based on beliefs held by the observer, and by the context in which they are used. In order to examine this, Italian high school students were asked to rate the offensiveness of homophic epithets, as well as to consider how they or others would react to homophobic epithets across various situations. Homophobic beliefs and beliefs about the social acceptability of homophobic epithets were also examined. It was found that greater perceived social acceptability of homophobic epithets was related to dismissive reactions to their use, whereas homophobic beliefs were predictive of negative emotional reactions, but in varying ways depending on the specific context. The results indicate that homophobic epithets may not always be perceived as homophobic by adolescents, and that attempts to alter the social acceptability of these insults may be an effective manner of reducing their use

Bayesian optimization of variable-size design space problems

Within the framework of complex system design, it is often necessary to solve mixed variable optimization problems, in which the objective and constraint functions can depend simultaneously on continuous and discrete variables. Additionally, complex system design problems occasionally present a variable-size design space. This results in an optimization problem for which the search space varies dynamically (with respect to both number and type of variables) along the optimization process as a function of the values of specific discrete decision variables. Similarly, the number and type of constraints can vary as well. In this paper, two alternative Bayesian Optimization-based approaches are proposed in order to solve this type of optimization problems. The first one consists in a budget allocation strategy allowing to focus the computational budget on the most promising design sub-spaces. The second approach, instead, is based on the definition of a kernel function allowing to compute the covariance between samples characterized by partially different sets of variables. The results obtained on analytical and engineering related test-cases show a faster and more consistent convergence of both proposed methods with respect to the standard approaches