Event-based camera refractory period characterization and initial clock drift evaluation

Event-based camera (EBC) technology provides high-dynamic range operation and shows promise for efficient capture of spatio-temporal information, producing a sparse data stream and enabling consideration of nontraditional data processing solutions (e.g., new algorithms, neuromorphic processors, etc.). Given the fundamental difference in camera architecture, the EBC response and noise behavior differ considerably compared to standard CCD/CMOS framing sensors. These differences necessitate the development of new characterization techniques and sensor models to evaluate hardware performance and elucidate the trade-space between the two camera architectures. Laboratory characterization techniques reported previously include noise level as a function of static scene light level (background activity) and contrast responses referred to as S-curves. Here we present further progress on development of basic characterization methods and test capabilities for commercial-off-the-shelf (COTS) visible EBCs, with a focus on measurement of pixel deadtime (refractory period) including results for the 4th-generation sensor from Prophesee and Sony. Refractory period is empirically determined from analysis of the interspike intervals (ISIs), and results visualized using log-histograms of the minimum per-pixel ISI values for a subset of pixels activated by a controlled dynamic scene. Our tests of the Prophesee gen4 EVKv2 yield refractory period estimates ranging from 6.1 msec to 6.8 μsec going from the slowest (20) to fastest (100) settings of the relevant bias parameter, bias_refr. We also introduce and demonstrate the concept of pixel bandwidth measurement from data captured while viewing a static scene – based on recording data at a range of refractory period setting and then analyzing noise-event statistics. Finally, we present initial results for estimating and correcting EBC clock drift using a GPS PPS signal to generate special timing events in the event-list data streams generated by the DAVIS346 and DVXplorer EBCs from iniVation

Falcon Neuro: an event-based sensor on the International Space Station

We report on the Falcon neuro event-based sensor (EBS) instrument that is designed to acquire data from lightning and sprite phenomena and is currently operating on the International Space Station. The instrument consists of two independent, identical EBS cameras pointing in two fixed directions, toward the nominal forward direction of flight and toward the nominal Nadir direction. The payload employs stock DAVIS 240C focal plane arrays along with custom-built control and readout electronics to remotely interface with the cameras. To predict the sensor’s ability to effectively record sprites and lightning, we explore temporal response characteristics of the DAVIS 240C and use lab measurements along with reported limitations to model the expected response to a characteristic sprite illumination time-series. These simulations indicate that with appropriate camera settings the instrument will be capable of capturing these transient luminous events when they occur. Finally, we include initial results from the instrument, representing the first reported EBS recordings successfully collected aboard a space-based platform and demonstrating proof of concept that a neuromorphic camera is capable of operating in the space environment

The Feasibility of Mandating School Breakfast in California's Severe Need Schools: Costs, Challenges, and Recommendations

Research has shown that students who regularly eat a nourishing breakfast perform better in school, get along better with their peers, are generally happier, and are at a reduced risk of obesity. Eating a healthy breakfast daily is especially important for children from low-income families.California has been gradually increasing the proportion of students who are participating in the School Breakfast Program (SBP). However, progress has slowed compared to many other states.To accelerate growth, the California Legislature authorized the California Department of Education to conduct a study to evaluate the feasibility of mandating that all severe need schools in California offer the SBP.Prepared by WestEd and the California Department of Education, this is the final report of that study

Modeling and decoding event-based sensor lightning response

Neuromorphic cameras, or Event-based Vision Sensors (EVS), operate in a fundamentally different way than conventional frame-based cameras. Their unique operational paradigm results in a sparse stream of high temporal resolution output events which encode pixel-level brightness changes with low-latency and wide dynamic range. Recently, interest has grown in exploiting these capabilities for scientific studies; however, accurately reconstructing signals from the output event stream presents a challenge due to physical limitations of the analog circuits that implement logarithmic change detection. In this paper, we present simultaneous recordings of lightning strikes using both an event camera and frame-based high-speed camera. To our knowledge, this is the first side-by-side recording using these two sensor types in a real-world scene with challenging dynamics that include very fast and bright illumination changes. Our goal in this work is to accurately map the illumination to EVS output in order to better inform modeling and reconstruction of events from a real-scene. We first combine lab measurements of key performance metrics to inform an existing pixel model. We then use the high-speed frames as signal ground truth to simulate an event stream and refine parameter estimates to optimally match the event-based sensor response for several dozen pixels representing different regions of the scene. These results will be used to predict sensor response and develop methods to more precisely reconstruct lightning and sprite signals for Falcon ODIN, our upcoming International Space Station neuromorphic sensing mission

Falcon Neuro: an event-based sensor on the International Space Station

We report on the Falcon neuro event-based sensor (EBS) instrument that is designed to acquire data from lightning and sprite phenomena and is currently operating on the International Space Station. The instrument consists of two independent, identical EBS cameras pointing in two fixed directions, toward the nominal forward direction of flight and toward the nominal Nadir direction. The payload employs stock DAVIS 240C focal plane arrays along with custom-built control and readout electronics to remotely interface with the cameras. To predict the sensor’s ability to effectively record sprites and lightning, we explore temporal response characteristics of the DAVIS 240C and use lab measurements along with reported limitations to model the expected response to a characteristic sprite illumination time-series. These simulations indicate that with appropriate camera settings the instrument will be capable of capturing these transient luminous events when they occur. Finally, we include initial results from the instrument, representing the first reported EBS recordings successfully collected aboard a space-based platform and demonstrating proof of concept that a neuromorphic camera is capable of operating in the space environment.ISSN:0091-3286ISSN:1560-230

Draft Genome of the Filarial Nematode Parasite Brugia malayi

Parasitic nematodes that cause elephantiasis and river blindness threaten hundreds of millions of people in the developing world. We have sequenced the ∼90 megabase (Mb) genome of the human filarial parasite Brugia malayi and predict ∼11,500 protein coding genes in 71 Mb of robustly assembled sequence. Comparative analysis with the free-living, model nematode Caenorhabditis elegans revealed that, despite these genes having maintained little conservation of local synteny during ∼350 million years of evolution, they largely remain in linkage on chromosomal units. More than 100 conserved operons were identified. Analysis of the predicted proteome provides evidence for adaptations of B. malayi to niches in its human and vector hosts and insights into the molecular basis of a mutualistic relationship with its Wolbachia endosymbiont. These findings offer a foundation for rational drug design

Common sequence variants on 2p15 and Xp11.22 confer susceptibility to prostate cancer.

Contains fulltext : 70723.pdf (publisher's version ) (Closed access)We conducted a genome-wide SNP association study on prostate cancer on over 23,000 Icelanders, followed by a replication study including over 15,500 individuals from Europe and the United States. Two newly identified variants were shown to be associated with prostate cancer: rs5945572 on Xp11.22 and rs721048 on 2p15 (odds ratios (OR) = 1.23 and 1.15; P = 3.9 x 10(-13) and 7.7 x 10(-9), respectively). The 2p15 variant shows a significantly stronger association with more aggressive, rather than less aggressive, forms of the disease