ECDL 2006

An Exploration of Space-Time Constraints on Contextual

Information in Image-based Testing Interfaces

Unmil Karadkar, Marlo Nordt

Richard Furuta

Cody Lee

Christopher Quick

Texas A&M University

Center for the Study of Digital Libraries

The Department of Computer Science

Michael E. DeBakey Institute

Veterinary Physiology & Pharmacology

ECDL 2006

Digital Image Collections• Collections

– Museums• The Louvre

– Historical image archives• New York Times

• Supported tasks– Searching and browsing

• Typical interfaces– Table/grid

ECDL 2006

Specialized Tasks• Analytical tasks

– Examine image content– Interpret visible detail

• Assessment tasks– Estimate dimensions of

objects within images

• Associative tasks – Compare and contrast

multiple images

ECDL 2006

Images in Cardiovascular Research

• Artery / Vein recognition– Analytical task

• Estimate order of blood vessels– Assessment task

• Identification of Lymphatic vessels– Associative task

ECDL 2006

Montage Layout

• Spatial Dimensions (0)

• Context (user dependent)

• Temporal Dimension (used)

• Slowed down video

ECDL 2006

Scrolling Layout

• Spatial Dimensions (1)

• Context (4 images)

• Temporal Dimension (used)

• Smooth scrolling

ECDL 2006

Thumbnail Layout• Spatial Dimensions (2)

• Context (all images in set)

• Temporal Dimension (unused)

ECDL 2006

Properties of Image Layouts Montage ThumbnailScrolling

Spatial Dim.

Temporal Dim.

Context

0

Used

User-dependent

1

Used

4 images

2

Unused

16 images

ECDL 2006

Experimental Design• 3 image layouts

– Thumbnail, Scrolling, Montage

• 16 images per set

• 3 tasks– Artery/Vein recognition– Size Estimation– Lymphatic vessel wall identification

• Balanced across subjects – Ordering of tasks (AEL, ELA, LAE)– Ordering of image layouts (TMS, MST, STM)

ECDL 2006

Subjects

• Trained researchers in the bat lab– Available subject pool of 30

• 9 experts– Research experience of more than 2 semesters

• 6 novices– Research experience of 1 semester only

• Age group 18 to 35

• 4 female, 11 male

ECDL 2006

Data Collection• Responses to image-based

questions– Verbal and drawn– Validated by experts– Instrumental measurements

• Demographic questionnaire– Self evaluation of expertise

• Task reflection questionnaire– For each task

• Preferred layout• Perceived best performance

ECDL 2006

• Did not improve between sets

• Performance constrained by knowledge

• Improved between sets (p=0.0004)

• Performance constrained by layout

Artery/Vein RecognitionExperts

0%

20%

40%

60%

80%

100%

T M S

Layout

Per

form

ance

Round 1

Round 2

Novices

0%

20%

40%

60%

80%

100%

T M S

Layout

Pe

rfo

rma

nc

e

Round 1

Round 289.6%

91.4

%

• Performance differed significantly between groups• Both groups preferred the Thumbnail layout

(p=0.005)

ECDL 2006

Size EstimationExperts

0%

20%

40%

60%

80%

M1 M2 S1 S2 T1 T2

Round

Pe

rfo

rma

nc

e +/- 40%

+/- 30%

+/- 20%

+/- 10%

Novices

0%

10%

20%

30%

40%

M1 M2 S1 S2 T1 T2

Round

Pe

rfo

rma

nce +/- 40%

+/- 30%

+/- 20%

+/- 10%

General understanding of the order of blood vessels does not translate into accurate estimation of size

(p<0.002)

(p<0.002)

• Judged at various levels of accuracy (10% - 40%)• Performance differed between groups at all levels• Both groups preferred the Thumbnail layout

ECDL 2006

Lymphatic Vessel Wall Identification

Experts

0%

20%

40%

60%

80%

100%

M S T

Layout

Per

form

ance

Novices

0%

20%

40%

60%

M S T

Layout

Per

form

ance

• Preferred the Montage layout

• Also worked best with the Montage layout (p=0.035)

(p=0.03)87%

55%

Experts and Novices use different strategies for applying contextual information

• Preferred the Montage layout

• But worked best with the Thumbnail layout

ECDL 2006

Continuing Work

• User studies with Summer research students– 21 novices (9 male, 12 female)

• Comparison of training strategies– 10-week intensive vs. 14-week sporadic training

• Results– Consistent with those of the 6 novices presented

here (not statistically different)– Differences in training style did not affect

performance

ECDL 2006

Lessons Learned

• Digital Image Collections enable discipline-specific scholarly tasks– Typical collections provide only a thumbnail

layout view

• Performance on these tasks is affected by– Image layout properties– Task characteristics– User experience and expertise

Collections should provide different layouts

ECDL 2006

Future Work

• Investigate mechanisms for conveying dimensions of objects within images

• Explore other image layouts– Static and dynamic collages

• Train subjects on new interfaces– Improve learning time– Increase productivity

ECDL 2006

http://ebat.tamu.edu

Center for the Study of Digital Libraries

Michael E. DeBakey Institute

Further Information

Unmil Karadkar

Marlo Nordt

Richard Furuta

unmil@csdl.tamu.edu

mnordt@csdl.tamu.edu

furuta@csdl.tamu.edu

Christopher Quick cquick@tamu.edu