Gazing the screensUsing eye-tracking for evaluating visually complex TV programming

Author: Amund BergSupervisor: Frode Volden

Gjøvik University College © 2007

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Outline

• Introduction and background

• Experiment

• Results

• Questions

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Introduction and background

• Gazing the screens - a part of TiDE-project

• Television is traditionally produced as a single stream of images

• New digital equipment enables the producers to create more complex TV graphics

• There is little knowledge of how complex TV graphics affects the viewers behavior

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Introduction and background

• Eye tracking has proven to be a useful tool in a variety of areas

• Despite this, few have used it for studies on television

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Research questions

• Is eye tracking suited for studies of viewer behavior? Er eyetracking egnet for studier av seeratferd?

• Does the amount of graphics in television affect viewer behavior?Påvirkes seeratferden av mengden grafikk på TV?

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Outline

• Introduction and background

• Experiment

• Results

• Questions

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Experimental setup

• 21 participants

• 3 different videos

• Total of 15 minutes

• Questionnaire with 37 questions

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Stimuli material

• Three different videos used as stimuli material

• Increasing amount of graphics1. Static banner

2. SMS chat

3. Stock and exchange tickers

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Outline

• Introduction and background

• Experiment

• Results

• Questions

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Results

• Out of 21 participants, up to 50% was excluded because of faulty data (poor calibration etc)

• 10 participants with valid data for all sets, were used in most of the following tests

  Included Excluded

  N % N %

Set 1 11 52,4 10 47,6

Set 2 13 61,9 8 38,1

Set 3 14 66,7 7 33,3

All sets ok 10 47,6 11 52,4

One set ok 16 76,2 5 23,8

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Fixations, saccades and blink

• Three different types of events:» Fixation – Pause over informative regions» Saccade – Rapid movement between fixations» Blink – A special case of fixations where the

horizontal and vertical position of the gaze is zero

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Fixations, saccades and blinks

• Number of fixations, saccades and blinks per second:– Fixations: 2,2– Saccades: 1,7– Blink: 1,0

• No significant difference between the conditions

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Fixations, saccades and blinks

• Average time spent on fixations, saccades and blinks:– Fixations: 265 ms– Saccades: 56 ms– Blink: 265 ms

• No significant difference between the conditions

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Saccadic vector

• A saccadic vector is calculated using Euclidean distance

• This vector describes how far the eye moves in a saccade

• An average vector is calculated based on the total vector divided by total number of saccades

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Saccade vector

• The average length of an saccade in pixels

• Average:1. 74,9

2. 78,6

3. 91,9

• The difference between conditions are significant

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Fixation frequency

• Divided the screen into different Area Of Interest (AOI)

• Count the fixations in each separate area and divide by the total number of fixations

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Fixation frequency

• The amount of fixation on graphics versus fixations on the program

• Average:1. 48,2 %2. 43,8 %3. 30,7 %

• The difference between conditions are significant

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Scanpath and heatmap

Set 1

Set 2

Set 3

Questions?