scholarly journals Brightness exponent as a function of flash duration and retinal eccentricity

1981 ◽  
Vol 30 (2) ◽  
pp. 144-148
Author(s):  
Naoyuki Osaka
Keyword(s):  
Retinal Eccentricity ◽  
Flash Duration

scholarly journals ERG signals driven by chromatic and luminance processing: Variation as a function of retinal eccentricity

2009 ◽  
Vol 9 (14) ◽  
pp. 65-65
Author(s):  
D. J. McKeefry ◽  
N. Parry ◽  
N. Challa ◽  
J. Kremers ◽  
I. Murray ◽  
...  
Keyword(s):  
Retinal Eccentricity

scholarly journals The temporal evolution of three-dimensional lightning parameters and their suitability for thunderstorm tracking and nowcasting

2013 ◽  
Vol 13 (1) ◽  
pp. 2217-2242
Author(s):  
V. K. Meyer ◽  
H. Höller ◽  
H. D. Betz
Keyword(s):  
Case Studies ◽  
Temporal Evolution ◽  
Discharge Rate ◽  
Single Cells ◽  
Life Cycles ◽  
Mature Stage ◽  
Cell Area ◽  
Flash Duration ◽  
Discharge Characteristics ◽  
Storm Cells

Abstract. Total lightning (TL) data has been found to provide valuable information about the internal dynamics of a thunderstorm allowing conclusions about its further development as well as indicating potential of thunderstorm-related severe weather at the ground. This paper investigates electrical discharge correlations of strokes and flashes with respect to the temporal evolution of thunderstorms in case studies as well as by statistical means. The recently developed algorithm li-TRAM (tracking and monitoring of lightning-cells, Meyer et al., 2012) has been employed to track and monitor thunderstorms based on three-dimensionally resolved TL lightning data provided as stroke events by the European lightning location network LINET. From statistical investigation of 863 suited thunderstorm life-cycles the cell area turned out to correlate well with (a) the total discharge rate, (b) the in-cloud (IC) discharge rate, and (c) the mean IC discharge height per lightning-cell as identified by li-TRAM. All three parameter correlations consistently show an abrupt change in discharge characteristics around a cell area of 170 km2. Statistical investigations supported by the comparison of three case studies – selected to represent a single storm, a multi-cell and a supercell – strongly suggest that the correlation functions include the temporal evolution as well as the storm type. With the help of volumetric radar data, it can also be suggested that the well defined break observed at 170 km2 marks the region, where the transition occurs from short-lived and rather simple structured single storm cells to better organized, more persistent, and more complex structured thunderstorm forms, e.g. multi-cells and super-cells. All three storm-types experience similar discharge characteristics during their growing and dissipating phases. However, while the poorly organized and short-lived cells preferentially remain small during a short mature phase, mainly the more persistent thunderstorm types develop to sizes above 170 km2 during a pronounced mature stage. At that stage they exhibit on average higher discharge rates at higher altitudes as compared with matured single-cells. With the maximum stroke distance set to 10 km and a flash duration set to 1 s the parameterisation functions found for the stroke rate as function of the cell area has been transformed to a flash rate. The presented study suggests that, with respect to the storm type, stroke and flash correlations can be parameterized. There is also strong evidence, that parameterization functions include the time parameter, so that altogether TL stroke information has good potential to pre-estimate the further evolution (nowcast) of a currently observed storm in an object-oriented thunderstorm nowcasting approach.

scholarly journals Image content is more important than Bouma’s Law for scene metamers

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Thomas SA Wallis ◽  
Christina M Funke ◽  
Alexander S Ecker ◽  
Leon A Gatys ◽  
Felix A Wichmann ◽  
...  
Keyword(s):  
Perceptual Experience ◽  
Receptive Fields ◽  
Natural Images ◽  
Retinal Eccentricity ◽  
High Fidelity ◽  
Prior Work ◽  
Visual Stream ◽  
Area V2 ◽  
Ventral Visual Stream ◽  
Stream Model

We subjectively perceive our visual field with high fidelity, yet peripheral distortions can go unnoticed and peripheral objects can be difficult to identify (crowding). Prior work showed that humans could not discriminate images synthesised to match the responses of a mid-level ventral visual stream model when information was averaged in receptive fields with a scaling of about half their retinal eccentricity. This result implicated ventral visual area V2, approximated ‘Bouma’s Law’ of crowding, and has subsequently been interpreted as a link between crowding zones, receptive field scaling, and our perceptual experience. However, this experiment never assessed natural images. We find that humans can easily discriminate real and model-generated images at V2 scaling, requiring scales at least as small as V1 receptive fields to generate metamers. We speculate that explaining why scenes look as they do may require incorporating segmentation and global organisational constraints in addition to local pooling.

Auditory facilitation of visual-target detection persists regardless of retinal eccentricity and despite wide audiovisual misalignments

2011 ◽  
Vol 213 (2-3) ◽  
pp. 167-174 ◽  
Author(s):  
Ian C. Fiebelkorn ◽  
John J. Foxe ◽  
John S. Butler ◽  
Sophie Molholm
Keyword(s):  
Target Detection ◽  
Visual Target ◽  
Retinal Eccentricity
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