The Role of Constant Curvature in 2-D Contour Shape Representations

Perception ◽  
10.1068/p6970 ◽  
2011 ◽  
Vol 40 (11) ◽  
pp. 1290-1308 ◽  
Author(s):  
Patrick Garrigan ◽  
Philip J Kellman
Keyword(s):  
Retention Interval ◽  
Constant Curvature ◽  
Visual Information ◽  
Recognition Performance ◽  
Shape Representations ◽  
Contour Shape ◽  
Position And Orientation ◽  
Retention Intervals ◽  
Invariant Shape

In early cortex, visual information is encoded by retinotopic orientation-selective units. Higher-level representations of abstract properties, such as shape, require encodings that are invariant to changes in size, position, and orientation. Within the domain of open, 2-D contours, we consider how an economical representation that supports viewpoint-invariant shape comparisons can be derived from early encodings. We explore the idea that 2-D contour shapes are encoded as joined segments of constant curvature. We report three experiments in which participants compared sequentially presented 2-D contour shapes comprised of constant curvature (CC) or non-constant curvature (NCC) segments. We show that, when shapes are compared across viewpoint or for a retention interval of 1000 ms, performance is better for CC shapes. Similar recognition performance is observed for both shape types, however, if they are compared at the same viewpoint and the retention interval is reduced to 500 ms. These findings are consistent with a symbolic encoding of 2-D contour shapes into CC parts when the retention intervals over which shapes must be stored exceed the duration of initial, transient, visual representations.

Proactive Interference and Intertrial Interval in Short-Term Retention of Temporal Visual Information

1986 ◽  
Vol 63 (2) ◽  
pp. 839-846 ◽  
Author(s):  
Michel Guay
Keyword(s):  
Proactive Interference ◽  
Visual Information ◽  
Short Term Memory ◽  
Time Estimation ◽  
Short Term ◽  
Term Memory ◽  
Term Retention ◽  
Retention Intervals ◽  
Variable Errors

The main purpose was to examine the role of proactive interference in temporal short-term memory when subjects experienced time under a conscious cognitive strategy for time estimation, made without time-aiding techniques. Visual durations of 1, 4, and 8 sec. were estimated by 18 subjects under the method of reproduction. Three retention intervals were used: immediate reproduction, 15, and 30 sec. of rest. The three intertrial intervals were immediate, 15, and 30 sec. Constant error was used as an index of bias. The constant errors provided no indication that proactive interference was operating in temporal short-term memory. The lack of proactive interference was not associated with intertrial intervals; even when the intertrial intervals were shortened to 1 sec. no proactive interference was observed. Variable error was used to evaluate effects of forgetting. The variable errors for the 4- and 8-sec. durations seemed amenable to a trace-decay explanation.

scholarly journals Inclusive digital finance: the industry of equity crowdfunding

2021 ◽  
Author(s):  
Vincenzo Butticè ◽  
Silvio Vismara
Keyword(s):  
Visual Information ◽  
Entrepreneurial Finance ◽  
Industrial Dynamics ◽  
Relevant Research ◽  
Research Directions ◽  
Entrepreneurial Ventures ◽  
Equity Crowdfunding ◽  
Recent Developments

AbstractNowadays equity crowdfunding plays an important role in the entrepreneurial finance markets. To better understand the functioning of the industry, it is important to consider the entire equity crowdfunding process and all the actors involved. Equity crowdfunding platforms match indeed the demand of capital from entrepreneurial ventures with the supply of capital by investors. This manuscript is a first step in this direction, by (1) comparing equity crowdfunding with traditional sources of entrepreneurial finance; (2) discussing the potential and the perils of equity crowdfunding for inclusivity and democratization; (3) highlighting the role of visual information in digital finance; and (4) providing first insights on the industrial dynamics in equity crowdfunding. The paper gives researchers and practitioners orientation about recent developments in equity crowdfunding literature and provides relevant research directions.

scholarly journals Interphotoreceptor coupling: an evolutionary perspective

2021 ◽  
Author(s):  
Lorenzo Cangiano ◽  
Sabrina Asteriti
Keyword(s):  
Visual Information ◽  
Signal To Noise Ratio ◽  
Electrical Coupling ◽  
Physiological Role ◽  
Cellular Processes ◽  
Contact Points ◽  
Highly Sensitive ◽  
The Many ◽  
The Impact

AbstractIn the vertebrate retina, signals generated by cones of different spectral preference and by highly sensitive rod photoreceptors interact at various levels to extract salient visual information. The first opportunity for such interaction is offered by electrical coupling of the photoreceptors themselves, which is mediated by gap junctions located at the contact points of specialised cellular processes: synaptic terminals, telodendria and radial fins. Here, we examine the evolutionary pressures for and against interphotoreceptor coupling, which are likely to have shaped how coupling is deployed in different species. The impact of coupling on signal to noise ratio, spatial acuity, contrast sensitivity, absolute and increment threshold, retinal signal flow and colour discrimination is discussed while emphasising available data from a variety of vertebrate models spanning from lampreys to primates. We highlight the many gaps in our knowledge, persisting discrepancies in the literature, as well as some major unanswered questions on the actual extent and physiological role of cone-cone, rod-cone and rod-rod communication. Lastly, we point toward limited but intriguing evidence suggestive of the ancestral form of coupling among ciliary photoreceptors.

scholarly journals A Method of Defect Depth Recognition in Active Infrared Thermography Based on GRU Networks

2021 ◽  
Vol 11 (14) ◽  
pp. 6387
Author(s):  
Li Xu ◽  
Jianzhong Hu
Keyword(s):  
Infrared Thermography ◽  
Visual Information ◽  
Evaluation Method ◽  
Recognition Performance ◽  
Principal Component ◽  
Defect Depth ◽  
Model Learning ◽  
Flat Bottom ◽  
Bp Network ◽  
Active Infrared Thermography

Active infrared thermography (AIRT) is a significant defect detection and evaluation method in the field of non-destructive testing, on account of the fact that it promptly provides visual information and that the results could be used for quantitative research of defects. At present, the quantitative evaluation of defects is an urgent problem to be solved in this field. In this work, a defect depth recognition method based on gated recurrent unit (GRU) networks is proposed to solve the problem of insufficient accuracy in defect depth recognition. AIRT is applied to obtain the raw thermal sequences of the surface temperature field distribution of the defect specimen. Before training the GRU model, principal component analysis (PCA) is used to reduce the dimension and to eliminate the correlation of the raw datasets. Then, the GRU model is employed to automatically recognize the depth of the defect. The defect depth recognition performance of the proposed method is evaluated through an experiment on polymethyl methacrylate (PMMA) with flat bottom holes. The results indicate that the PCA-processed datasets outperform the raw temperature datasets in model learning when assessing defect depth characteristics. A comparison with the BP network shows that the proposed method has better performance in defect depth recognition.

A New View on Grasping

Motor Control ◽  
1999 ◽  
Vol 3 (3) ◽  
pp. 237-271 ◽  
Author(s):  
Jeroen B.J. Smeets ◽  
Eli Brenner
Keyword(s):  
Surface Roughness ◽  
Visual Information ◽  
Experimental Studies ◽  
Movement Speed ◽  
Object Size ◽  
Extensive Review ◽  
Minimum Jerk ◽  
Alternative Description ◽  
Position And Orientation ◽  
Shape And Size

Reaching out for an object is often described as consisting of two components that are based on different visual information. Information about the object's position and orientation guides the hand to the object, while information about the object's shape and size determines how the fingers move relative to the thumb to grasp it. We propose an alternative description, which consists of determining suitable positions on the object—on the basis of its shape, surface roughness, and so on—and then moving one's thumb and fingers more or less independently to these positions. We modeled this description using a minimum-jerk approach, whereby the finger and thumb approach their respective target positions approximately orthogonally to the surface. Our model predicts how experimental variables such as object size, movement speed, fragility, and required accuracy will influence the timing and size of the maximum aperture of the hand. An extensive review of experimental studies on grasping showed that the predicted influences correspond to human behavior.

scholarly journals How much do visual cues help listeners in perceiving accented speech?

2018 ◽  
Vol 40 (1) ◽  
pp. 93-109
Author(s):  
YI ZHENG ◽  
ARTHUR G. SAMUEL
Keyword(s):  
Visual Information ◽  
Visual Cues ◽  
Nonnative Speakers ◽  
Apparent Distance ◽  
Native English Speakers ◽  
English Speakers ◽  
Accented Speech ◽  
Compressed Speech ◽  
Degraded Speech

AbstractIt has been documented that lipreading facilitates the understanding of difficult speech, such as noisy speech and time-compressed speech. However, relatively little work has addressed the role of visual information in perceiving accented speech, another type of difficult speech. In this study, we specifically focus on accented word recognition. One hundred forty-two native English speakers made lexical decision judgments on English words or nonwords produced by speakers with Mandarin Chinese accents. The stimuli were presented as either as videos that were of a relatively far speaker or as videos in which we zoomed in on the speaker’s head. Consistent with studies of degraded speech, listeners were more accurate at recognizing accented words when they saw lip movements from the closer apparent distance. The effect of apparent distance tended to be larger under nonoptimal conditions: when stimuli were nonwords than words, and when stimuli were produced by a speaker who had a relatively strong accent. However, we did not find any influence of listeners’ prior experience with Chinese accented speech, suggesting that cross-talker generalization is limited. The current study provides practical suggestions for effective communication between native and nonnative speakers: visual information is useful, and it is more useful in some circumstances than others.

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