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Official Journal of the Japan Wood Research Society

Quantification of visual inducement of knots by eye-tracking

A Correction to this article was published on 23 November 2018


Knots have been considered an undesirable visual feature of lumber. To clarify the essence of this visual undesirability, eye-tracking data from 20 subjects, who freely observed 55 images of wood wall panels, were recorded and distribution maps of eye-fixation pauses were composed. These maps were compared with the arrangement of knots on each knotty wall panel image and the visual inducement of knots was evaluated using a new numerical index of pausing probability. The present study is the first to objectively quantify the visual inducement of knots. In addition, the subjective noticeability of knots and ten visual impressions of each wood panel image were investigated by a sensory evaluation. There was a very clear linear relationship between the visual inducement of knots and the subjective noticeability of knots. A correlation analysis suggested that many visual impressions of wood wall panels were influenced by a complementary effect between the subjective noticeability of knots and the visual inducement of knots. The visual impact of knots was masked to some extent by special visual stimuli such as deep red grooves on the wood wall panels.


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Correspondence to Masashi Nakamura.

Additional information

This study was presented at the 56th and 57th Annual Meetings of the Japan Wood Research Society, Akita and Hiroshima, August 2006 and August 2007, respectively

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Nakamura, M., Kondo, T. Quantification of visual inducement of knots by eye-tracking. J Wood Sci 54, 22–27 (2008).

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Key words

  • Knot
  • Visual inducement
  • Masking effect
  • Eye mark
  • Sugi