Raised Line Drawings are Spontaneously Explored with a Single Finger

Symmons, Mark; Richardson, Barry Lund

doi:10.1068/p2964

Cited by 36 publications

(38 citation statements)

References 4 publications

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“…Our conclusion that searching with one Wnger is more eYcient than searching with more Wngers is largely in line with the results of Symmons and Richardson (2000). In their experiment participants could freely explore tactile line drawings.…”

Section: Discussionsupporting

confidence: 78%

Haptic search with finger movements: using more fingers does not necessarily reduce search times

2007

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Two haptic serial search tasks were used to investigate how the separations between items, and the number of Wngers used to scan them, inXuence the search time and search strategy. In both tasks participants had to search for a target (cross) between a Wxed number of nontargets (circles). The items were placed in a straight line. The target's position was varied within blocks, and interitem separation was varied between blocks. In the Wrst experiment participants used their index Wnger to scan the display. As expected, search time depended on target position as well as on item separation. For larger separations participants' movements were jerky, resembling 'saccades' and 'Wxations', while for the shortest separation the movements were smooth. When only considering time in contact with an item, search times were the same for all separation conditions. Furthermore, participants never continued their movement after they encountered the target. These results suggest that participants did not use the time during which they were moving between the items to process information about the items. The search times were a little shorter than those in a static search experiment (Overvliet et al. in Percept Psychophys, 2007a), where multiple items were presented to the Wngertips simultaneously. To investigate whether this is because the Wnger was moving or because only one Wnger was stimulated, we conducted a second experiment in which we asked participants to put three Wngers in line and use them together to scan the items. Doing so increased the time in contact with the items for all separations, so search times were presumably longer in the static search experiment because multiple Wngers were involved. This may be caused by the time that it takes to switch from one Wnger to the other.

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Section: Discussionsupporting

confidence: 78%

Haptic search with finger movements: using more fingers does not necessarily reduce search times

2007

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“…Some of the sighted subjects in the research reported here opted to feel both the targets and the choices with one hand. This is a normal strategy for sighted individuals (Symmons and Green 2000), but will slow haptic exploration. Sighted subjects often spontaneously explore tangible pictures with the index finger of one hand.…”

Section: Discussionmentioning

confidence: 99%

Superior Haptic Perceptual Selectivity in Late-Blind and Very-Low-Vision Subjects

et al. 2003

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Abstract. Blindfolded sighted, congenitally blind, late-blind, and very-low-vision subjects were tested on a tangible version of the embedded-figures test. The results of ANOVAs on accuracy measures yielded superior performance by the very-low-vision and late-blind subjects compared with the blindfolded sighted and congenitally blind participants. Accuracy of the congenitally blind subjects was similar to that of the blindfolded sighted participants. However, all groups of blind subjects were significantly faster than the blindfolded sighted subjects. It is suggested that experience with pictures combined with haptic skill aid perceptual selectivity in touch.

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“…Collecting data from both one-and five-finger conditions, which was done in alternating order, allowed us to assess the performance of our algorithm for extracting index fingertip position in both one-and five-finger applications. Although using all five fingers may appear to be the most natural for haptic exploration, many participants in haptics studies will spontaneously use only their index finger (Symmons & Richardson, 2000).…”

Section: Data Collectionmentioning

confidence: 99%

Determining the bias and variance of a deterministic finger-tracking algorithm

Morash

Velden

2015

Behav Res

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Finger tracking has the potential to expand haptic research and applications, as eye tracking has done in vision research. In research applications, it is desirable to know the bias and variance associated with a finger-tracking method. However, assessing the bias and variance of a deterministic method is not straightforward. Multiple measurements of the same finger position data will not produce different results, implying zero variance. Here, we present a method of assessing deterministic finger-tracking variance and bias through comparison to a non-deterministic measure. A proof-of-concept is presented using a videobased finger-tracking algorithm developed for the specific purpose of tracking participant fingers during a psychological research study. The algorithm uses ridge detection on videos of the participant's hand, and estimates the location of the right index fingertip. The algorithm was evaluated using data from four participants, who explored tactile maps using only their right index finger and all right-hand fingers. The algorithm identified the index fingertip in 99.78 % of one-finger video frames and 97.55 % of five-finger video frames. Although the algorithm produced slightly biased Image Sciences Institute, University Medical Center Utrecht, Utrecht, the Netherlands and more dispersed estimates relative to a human coder, these differences (x = 0.08 cm, y = 0.04 cm) and standard deviations (σ x = 0.16 cm, σ y = 0.21 cm) were small compared to the size of a fingertip (1.5-2.0 cm). Some example finger-tracking results are provided where corrections are made using the bias and variance estimates.

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Raised Line Drawings are Spontaneously Explored with a Single Finger

Cited by 36 publications

References 4 publications

Haptic search with finger movements: using more fingers does not necessarily reduce search times

Haptic search with finger movements: using more fingers does not necessarily reduce search times

Superior Haptic Perceptual Selectivity in Late-Blind and Very-Low-Vision Subjects

Determining the bias and variance of a deterministic finger-tracking algorithm

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