scholarly journals Infants’ prospective control during object manipulation in an uncertain environment

2018 ◽  
Author(s):  
Janna M. Gottwald ◽  
Gustaf Gredebäck
Keyword(s):  
Motion Capture ◽  
Visual Information ◽  
Color Condition ◽  
Significant Interaction Effect ◽  
Prospective Control ◽  
Object Weight ◽  
Sensorimotor Memory ◽  
Sensorimotor Information ◽  
Different Color ◽  
Movement Unit

This study investigates how infants use visual and sensorimotor information to prospectively control their actions. We gave 14-month-olds two objects of different weight and observed how high they were lifted, using a Qualisys Motion Capture System. In one condition, the two objects were visually distinct (different color condition) in another they were visually identical (same color condition). Lifting amplitudes of the first movement unit were analyzed in order to assess prospective control. Results demonstrate that infants lifted a light object higher than a heavy object, especially when vision could be used to assess weight (different color condition). When being confronted with two visually identical objects of different weight (same color condition), infants showed a different lifting pattern than what could be observed in the different color condition, expressed by a significant interaction effect between object weight and color condition on lifting amplitude. These results indicate that (a) visual information about object weight can be used to prospectively control lifting actions and that (b) infants are able to prospectively control their lifting actions even without visual information about object weight. We argue that infants, in the absence of reliable visual information about object weight, heighten their dependence on non-visual information (tactile, sensorimotor memory) in order to estimate weight and pre-adjust their lifting actions in a prospective manner.

Material evidence: interaction of well-learned priors and sensorimotor memory when lifting objects

2012 ◽  
Vol 108 (5) ◽  
pp. 1262-1269 ◽  
Author(s):  
Lee A. Baugh ◽  
Michelle Kao ◽  
Roland S. Johansson ◽  
J. Randall Flanagan
Keyword(s):  
Rate Of Change ◽  
Core Material ◽  
Load Force ◽  
Small Object ◽  
Surface Material ◽  
Phase Duration ◽  
Material Density ◽  
Small Cube ◽  
Object Weight ◽  
Sensorimotor Memory

Skilled object lifting requires the prediction of object weight. When lifting new objects, such prediction is based on well-learned size-weight and material-density correlations, or priors. However, if the prediction is erroneous, people quickly learn the weight of the particular object and can use this knowledge, referred to as sensorimotor memory, when lifting the object again. In the present study, we explored how sensorimotor memory, gained when lifting a given object, interacts with well-learned material-density priors when predicting the weight of a larger but otherwise similar-looking object. Different groups of participants 1st lifted 1 of 4 small objects 10 times. These included a pair of wood-filled objects and a pair of brass-filled objects where 1 of each pair was covered in a wood veneer and the other was covered in a brass veneer. All groups then lifted a larger, brass-filled object with the same covering as the small object they had lifted. For each lift, we determined the initial peak rate of change of vertical load-force rate and the load-phase duration, which provide estimates of predicted object weight. Analysis of the 10th lift of the small cube revealed no effects of surface material, indicating participants learned the appropriate forces required to lift the small cube regardless of object appearance. However, both surface material and core material of the small cube affected the 1st lift of the large block. We conclude that sensorimotor memory related to object density can contribute to weight prediction when lifting novel objects but also that long-term priors related to material properties can influence the prediction.

scholarly journals Differences in adults’ spatial scaling based on visual or haptic information

2021 ◽  
Author(s):  
Magdalena Szubielska ◽  
Marta Szewczyk ◽  
Wenke Möhring
Keyword(s):  
Visual Information ◽  
Linear Increase ◽  
Scaling Factor ◽  
Haptic Information ◽  
Spatial Scaling ◽  
Significant Interaction Effect ◽  
Perceptual Condition ◽  
Mental Transformation ◽  
Entire Experiment ◽  
Scaling Process

AbstractThe present study examined differences in adults’ spatial-scaling abilities across three perceptual conditions: (1) visual, (2) haptic, and (3) visual and haptic. Participants were instructed to encode the position of a convex target presented in a simple map without a time limit. Immediately after encoding the map, participants were presented with a referent space and asked to place a disc at the same location from memory. All spaces were designed as tactile graphics. Positions of targets varied along the horizontal dimension. The referent space was constant in size while sizes of maps were systematically varied, resulting in three scaling factor conditions: 1:4, 1:2, 1:1. Sixty adults participated in the study (M = 21.18; SD = 1.05). One-third of them was blindfolded throughout the entire experiment (haptic condition). The second group of participants was allowed to see the graphics (visual condition); the third group were instructed to see and touch the graphics (bimodal condition). An analysis of participants’ absolute errors showed that participants produced larger errors in the haptic condition as opposed to the visual and bimodal conditions. There was also a significant interaction effect between scaling factor and perceptual condition. In the visual and bimodal conditions, results showed a linear increase in errors with higher scaling factors (which may suggest that adults adopted mental transformation strategies during the spatial scaling process), whereas, in the haptic condition, this relation was quadratic. Findings imply that adults’ spatial-scaling performance decreases when visual information is not available.

scholarly journals Sensorimotor Memory for Object Weight is Based on Previous Experience During Lifting, Not Holding

2018 ◽  
Author(s):  
Vonne van Polanen ◽  
Marco Davare
Keyword(s):  
Motor Command ◽  
Object Manipulation ◽  
Recent Experience ◽  
List Type ◽  
Holding Period ◽  
Object Weight ◽  
Object Lifting ◽  
Time Period ◽  
Sensorimotor Memory ◽  
Force Planning

ABSTRACTTo allow skilled object manipulation, the brain must generate a motor command specifically tailored to the object properties. For instance, in object lifting, the forces applied by the fingertips must be scaled to the object’s weight. When lifting a series of objects, forces are usually scaled according to recent experience from previously lifted objects, an effect often referred to as sensorimotor memory. In this study, we investigated the specific time period during which stored information from previous object manipulation is used to mediate sensorimotor memory. More specifically, we examined whether sensorimotor memory was based on weight information obtained between object contact and lift completion (lifting phase) or during stable holding (holding phase). Participants lifted objects in virtual reality that could increase or decrease in weight after the object was lifted and held in the air. In this way, we could distinguish whether the force planning in the next lift was scaled depending on weight information gathered from either the dynamic lifting or static holding period. We found that force planning was based on the previous object weight experienced during the lifting, but not holding, phase. This suggest that the lifting phase, while merely lasting a few hundred milliseconds, is a key time period for building up internal object representations used for planning future hand-object interactions.HIGHLIGHTSWhen lifting objects, fingertip force scaling is based on the most recent liftWe investigated what time period is critical for acquiring sensorimotor memorySensorimotor memory is based on weight experienced during previous lift, not holdThe lifting phase is a key period for building up internal models of object lifting

Sensorimotor memory of object weight distribution during multidigit grasp

2009 ◽  
Vol 463 (3) ◽  
pp. 188-193 ◽  
Author(s):  
Frederic Albert ◽  
Marco Santello ◽  
Andrew M. Gordon
Keyword(s):  
Weight Distribution ◽  
Object Weight ◽  
Sensorimotor Memory

Prospective Control in Catching by Infants

Perception ◽  
1994 ◽  
Vol 23 (3) ◽  
pp. 287-302 ◽  
Author(s):  
Audrey L H van der Meer ◽  
F R Ruud van der Weel ◽  
David N Lee
Keyword(s):  
Visual Information ◽  
Hand Movement ◽  
Moving Object ◽  
Movement Duration ◽  
Exit Side ◽  
Prospective Control ◽  
The Future

Catching a moving object requires the ability to predict the future trajectory of the object. To test whether infants can use visual information predictively, reaching for a toy moving at different speeds was investigated in six infants around 11 months of age. The toy was occluded from view by a screen during the last part of its approach. Gaze arrived at the exit side of the screen and the hand started to move forward before the toy had disappeared behind the occluder; these actions were prospectively geared to certain times before the toy would reappear. In addition, hand-movement duration was found to be related to the time of reappearance of the toy—the information used to regulate duration of hand movement being picked up before the toy disappeared behind the occluder. In a longitudinal experiment, the development of predictive reaching was investigated in two infants between the ages of 20 and 48 weeks. At all ages studied, gaze anticipated the reappearance of the moving toy. However, anticipation with hand movement of the disappearance of the toy and the ability to gear actions prospectively to the time (instead of distance) the toy was away from certain points on the track developed relatively late and marked the transition to successfully catching faster-moving toys.

scholarly journals Performance Evaluation of Color Descriptors under Illumination Variation

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Danyu Sun ◽  
Xixuan Zhao ◽  
Jiangming Kan
Keyword(s):  
Image Retrieval ◽  
Visual Information ◽  
Theoretical Basis ◽  
Recognition Rate ◽  
Evaluation Criteria ◽  
Surface Characteristics ◽  
Illumination Variation ◽  
Color Descriptors ◽  
Different Color ◽  
Indoor And Outdoor

Color descriptors, which involve the extraction of color information that is robust to illumination variation, are indispensable for accessing reliable visual information as illumination variation is inevitable in many practical cases. There has been many color descriptors proposed in literature, but the performance of different color descriptors in different scenes under illumination variation and the influence of the surface characteristics have not been investigated. In this paper, we first systematically introduced the theoretical basis of color descriptors, categorized the existing color descriptors according to the theoretical basis, and then compared the performance of different color descriptors utilized for image recognition and image retrieval tasks on both the indoor and outdoor image datasets. We adopted the recognition rate and normalized average rank as the evaluation criteria to measure the performance of color descriptors. Experiment results show that the color moment invariants (CMI) provide the optimal balance between the performance and dimensions in most tests, and color descriptors derived from physical reflectance models are more suitable for object recognition and image retrieval. We also concluded the best color descriptors for each kind of scene and surface characteristics.

scholarly journals Development of a Versatile Modular Platform for Aerial Manipulators

2020 ◽  
Author(s):  
Nikolaos Evangeliou ◽  
Athanasios Tsoukalas ◽  
Nikolaos Giakoumidis ◽  
Steffen Holter ◽  
Anthony Tzes
Keyword(s):  
Motion Capture ◽  
Visual Information ◽  
Visual Servoing ◽  
Vision System ◽  
Experimental Studies ◽  
Camera System ◽  
Outdoor Spaces ◽  
Aerial Manipulator ◽  
Manipulation System ◽  
Modular Platform

The scope of this chapter is the development of an aerial manipulator platform using an octarotor drone with an attached manipulator. An on-board spherical camera provides visual information for the drone’s surroundings, while a Pan-Tilt-Zoom camera system is used to track targets. A powerful computer with a GPU offers significant on-board computational power for the visual servoing of the aerial manipulator system. This vision system, along with the Inertial Management Unit based controller provides exemplary guidance in confined and outdoor spaces. Coupled with the manipulator’s force sensing capabilities the system can interact with the environment. This aerial manipulation system is modular as far as attaching various payloads depending on the application (i.e., environmental sensing, facade cleaning and others, aerial netting for evader-drone geofencing, and others). Experimental studies using a motion capture system are offered to validate the system’s efficiency.

scholarly journals Temporal integration and attentional selection of color and contrast target pairs in rapid serial visual presentation

2019 ◽  
Author(s):  
Aytaç Karabay ◽  
Elkan G. Akyurek
Keyword(s):  
Rapid Serial Visual Presentation ◽  
Temporal Integration ◽  
Visual Presentation ◽  
Identification Accuracy ◽  
Color Condition ◽  
Temporal Attention ◽  
Contrast Condition ◽  
Different Color ◽  
Dual Target ◽  
Selection Of

Performance in a dual target rapid serial visual presentation task was investigated, dependent on whether the color or the contrast of the targets was the same or different. Both identification accuracy on the second target, as a measure of temporal attention, and the frequency of temporal integration were measured. When targets had a different color (red or blue), overall identification accuracy of the second target and identification accuracy of the second target at Lag 1 were both higher than when targets had the same color. At the same time, increased temporal integration of the targets at Lag 1 was observed in the different color condition, even though actual (non-integrated) single targets never consisted of multiple colors. When the color pairs were made more similar, so that they all fell within the range of a single nominal hue (blue), these effects were not observed. Different findings were obtained when contrast was manipulated. Identification accuracy of the second target was higher in the same contrast condition than in the different contrast condition. Higher identification accuracy of both targets was furthermore observed when they were presented with high contrast, while target contrast did not influence temporal integration at all. Temporal attention and integration were thus influenced differently by target contrast pairing than by (categorical) color pairing. Categorically different color pairs, or more generally, categorical feature pairs, may thus afford a reduction in temporal competition between successive targets that eventually enhances attention and integration.

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