1 / 24

Visual Search for Traffic Signs: The Effects of Clutter, Luminance, and Aging

Visual Search for Traffic Signs: The Effects of Clutter, Luminance, and Aging. Professor: Liu Student: Ruby. References. The driver needed a greater number of fixations to see the target when the scenes were very confusion. Boersema, Zwaga, and Adams (1988)

kim-hinton
Download Presentation

Visual Search for Traffic Signs: The Effects of Clutter, Luminance, and Aging

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Visual Search for Traffic Signs: The Effects of Clutter, Luminance, and Aging Professor: Liu Student: Ruby

  2. References • The driver needed a greater number of fixations to see the target when the scenes were very confusion. Boersema, Zwaga, and Adams (1988) • The elderly experience change their visual very often when they were effected by the clutter. Kline & Scialfa (1997)

  3. References • The elderly drivers reduced useful field of view, therefore they make a larger number of eye movements to search a scene. Owsley et al. (1991); Scialfa, Thomas, & Joffe (1994) • The elderly showed cognitive declines that may affect sign obtaining, including problems with working memory and attention. (Caird & Chugh, 1997; Fisk & Warr, 1998; Kidder, Park, Hertzog, & Morrell, 1997; Parasuraman & Nestor, 1991; Plude & Doussard-Roosevelt, 1989; Ponds, Brouwer, & van Wolffelaar, 1988; Stine & Wingfield, 1990)

  4. References • Older adults are difficulties in low luminance (Chrysler, Danielson, & Kirby, 1996; Kline et al., 1992; Sivak, Olson, & Pastalan, 1981), perhaps because the reductions in retinal illuminance. (Weale, 1961) • The older drive had long response times (RT) in the clutter and different inversely with luminance. Schieber and Goodspeed (1997)

  5. Experiment1 • Objective • The clutter were rated by subjective and allowed for the top-down influences to determine clutter. • Participants • 14 older adults (M = 64.71, range = 56–71 years). • 14 younger adults (M = 23.43, range = 20–27 years). • Daytime was composed of 5 women (4 younger, 1 older) and 9 men (3 younger, 6 older) • Nighttime was composed of 10 women (5 younger, 5 older) and 4 men (2 younger, 2 older).

  6. Experiment1 • The practice trials was composed of 2scenes for each high-clutter and low-clutter. • Participants were instructed to press the “High” key (the q key) if they judged the scene to be high clutter and to press the “Low” key (the p key) if they judged the scene to be low clutter.

  7. Results • The 37 images initially presented: • 21 were rated as low clutter. (scores between 0 to 8) • 5 as intermediate clutter. (scores between 8 to 19) • 11 as high clutter. (scores between 19 to 28) • The reliability of the ratings was 0.97. • Divided reliabilities were 0.97 for the nighttime ratings and 0.91 for the daytime ratings.

  8. Experiment 2 • Objective • Participants search for a target sign which inserted to traffic scenes and related to clutter and luminance. • Participants • 14 older adults (M = 63.93, range = 54–79 years). • 14 younger adults (M = 24.07, range = 18–30 years).

  9. Experiment 2

  10. Procedure • 10 practice trials that contained both target present and target-absent scenes. (5 were daytime scenes and 5 were nighttime scenes.) • There were two blocks of 25 trials, half the participants searched the 25 daytime scenes first and the 25 nighttime scenes second.

  11. Results • The analysis of five dependent measures is reported: (a) errors (b) reaction time (c) fixation number (d) average fixation duration (e) fixation duration.

  12. Results - Errors • Errors Figure 2. Errors for target-present (top) and target-absent trials (bottom) as a function of clutter and luminance.

  13. Results - Errors • Older adults were less accurate than younger ones, F(1, 26) = 5.99, p =0.021. • Errors were more common in high-clutter scenes than in low clutter scenes, F(1, 26) = 32.48, p < 0.001 and on target-present trials compared with target absent trials, F(1, 26) = 6.16, p = 0.020.

  14. Results - Errors • Interaction • Clutter × Presence effect, F(1, 26) = 6.77, p = .015. because more errors were made on target-present trials involving greater clutter. • Luminance × Presence effect, F(1, 26) = 5.67, p = .025. because accuracy for daytime scenes was independent of target presence. • Clutter × Luminance interaction, F(1, 26) = 10.95, p = .003.because in daytime scenes the errors were more common in high clutter than in low clutter. • Clutter × Presence × Luminance interaction, F(1, 26) = 10.79, p = .003. Errors were relatively high in three of the four high-clutter conditions.

  15. Results - Reaction times

  16. Results - Reaction times • The main effects of age, F(1, 23) = 27.97, p < .001; clutter, F(1, 23) = 570.07, p < .001; and presence, F(1, 23) = 49.49, p < .001, were all significant. • The Age × Presence interaction was also significant, F(1, 23) = 7.80, p = .01. • because age differences were greater on target-absent trials than on target present trials. • Older adults had even slower RTs in the target absent condition than did their younger counterparts, F(1, 23) = 10.66, p = .003.

  17. Results - Fixation number

  18. Results - Fixation number • Older adults made more fixations, F(1, 23) = 31.89, p < .001. • Need more fixations for high-clutter, F(1, 23) = 60.40, p < .001, and for target-absent scenes, F(1, 23) = 74.40, p < .001. • Age × Presence interaction was significant, F(1, 23) = 11.53, p = .002. • Clutter × Presence, F(1, 23) = 12.76, p = .002. • Nighttime scenes with high clutter also required more fixations, F(1, 23) = 9.39, p = .005.

  19. Results - Last fixation duration

  20. Results - Last fixation duration • The last fixation duration means the last fixated object with the target representation and the terminal decision (in our case, a key press) regarding target presence. • The main effect of age was significant, F(1, 23) = 13.87, p = .001. • The main effect of presence, F(1, 23) = 23.41, p < .001. • The Age × Presence interaction was significant, F(1, 23) = 8.71, p = .007. In contrast with the RT data, age differences were greater on target-present trials than on target absent trials.

  21. Results - Average fixation duration

  22. Results - Average fixation duration • There was a main effect of age, F(1, 23) = 11.11, p = .003; clutter, F(1, 23) = 130.08, p = .001; and presence, F(1, 23) = 49.43, p < .001, in the expected direction. • Age × Clutter interaction, F(1, 23) = 5.76, p = .025. because younger participants showed longer fixations in high-clutter scenes. • A Clutter × Presence × Luminance interaction, F(1, 23) = 9.85, p = .005. because daytime scenes and high-clutter nighttime scenes including a target resulted in longer average fixation durations.

  23. Discussion • In Experiment 1 found that observers were able to classify images reliably on the basis of clutter. • High clutter needed longer fixations to get the sign, which had more errors, and had longer fixation durations. • Older adults used the visual cues that decided targets and distracters to quickly isolate the target on target-present trials.

  24. Discussion • The age effects on RT and fixation number were more cleared on target-absent trials. • Older adults in the present study were not more badly affected when the clutter was increased. because the definition of clutter. • The different age groups had differences result in searching daytime and nighttime scenes.

More Related