Constancy factors in visual perceptionSHAPE CONSTANCY (2) DICo • In shape constancy effect we have a major role of high level brain activity: mental rotations! • We assume that

Constancy factors in visual perception

Raffaella FolgieriDICo – Digital Information & Communication Departiment

Gjovik, Norway

Why interest in visual perception?

• to investigate main factors in VR• to understand boundaries between

perception and cognitive processes• to find instruments and methods to

analyse human reaction to VR stimuli• to understand emotional and cognitive

involvement

MOTIVATION

DICo

Aims: investigate emotions in VR

What are potentially influencing factors?

• Investigating emotions in VR

Virthualis project

Operators virtually immersed in production plant and in control room felt emotionally provenas immersed in real physical situation

AIMS: reduce hazards in production plants and storage sites by addressing end-users’ practical safety issues through merging Human Factors (HF) knowledge and Virtual Reality(VR) technologies

VR AS A COMMUNICATION PROCESS

A coding whose purpose is to bring the observer to the conclusion that the VR set is verisimile, i.e. “similar-to-the-real-thing” (or involves similar sensation?)

DICo

• between human beings• mediated by computer systems

– interaction, visualization and other sensory stimuli to convey information

• Reality – is not a intrinsic characteristic of VR– is the result of a conventional way of coding

information.

VISUAL PERCEPTION RELEVANCE

DICo

• Vision is the main sensorial system• We need to focus on visual perception key factors

– Colors

– Immersivity:

• is the emotional stimulus key factor

• needs all the visual field

– Observer needs to explore actively all the visual fiels moving head and eyes

• The space and the depth perceptions become foundamental

DICo

Eat me, Drink me…What are key factors in spatial perception?

SPACE, SIZE AND SHAPE

DICo

• Spatial perception depends on multiple aspects• We focus on three:

•Relative distances•Size•Shape

• We experiment some constancy effects, what are their origin? Perceptual? Cognitive?

SPATIAL CONSTANCY

DICo

Perception viewpoint:• understand relative

distances and dimensions

• Interaction: foundamental role

SHAPE CONSTANCY (1)

DICo

Cognitive viewpoint:

• mental rotation or translation

SHAPE CONSTANCY (2)

DICo

• In shape constancy effect we have a major role

of high level brain activity: mental rotations!• We assume that this activity can be detected in

different brain areas, producing strong signals,

to be identified and classified

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EXPERIMENTS AND OBSERVATIONS

• To detect above activity we need to devise specific experiments

• To observe brain activity we could use:

– fMRI– Experiments on primate

• Both are invasive/difficult to use in VR environment

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INVESTIGATION OBJECTIVES

In a VR context:• fMRI not enough• Need: uninvasive and portable instrument to

investigate brain activity– to identify brain areas activated in space and depth

perception processes– to correlate brain areas to active interactive exploration

of spaces

• This will allows us to– understand if in VR similarity to phisical reality is

necessary– find boundaries between perception and cognitive

processes

EEG in VR: WHAT AND HOW

DICo

• Experiments setup• VR similar to physical reality

• Reproducing stimuli through VR far from reality

MODELS AND METHODS

DICo

• Computational models to analyse data from

brain-motion and emotion sensors:

– Brain activity, cardio frequency, sweat, eye,

arms and legs activities

• Data-fusion problem:

– Machine learning methods

MACHINE LEARNING

DICo

Area of Artificial Intelligence concerned with the development of techniques which allow computers to "learn".

Machine Learning:design and development of algorithms that allow computers to evolve behaviors based on empirical data (sensor data or databases).

We want VR reacting to human perception!

EXPECTED RESULTS

DICo

Indications on brain areas involved in

• VR perception:

• relative distances and dimensions

• interaction

• Cognitive viewpoint:

• objects (mental) recognition

FINAL OBJECTIVE

DICo

Experiments with EEG foundamental for the

realization of algorithms allowing VR to

adapt to human and vice-versa

DICo

Thank you!