@article{(Open Science Index):https://publications.waset.org/pdf/9999907,
	  title     = {Preferred Character Size for Oblique Angles},
	  author    = {Photjanat Phimnom and  Haruetai Lohasiriwat},
	  country	= {},
	  institution	= {},
	  abstract     = {In today’s world, the LED display has been used for
presenting visual information under various circumstances. Such
information is an important intermediary in the human information
processing. Researchers have been investigated diverse factors that
influence this process effectiveness. The letter size is undoubtedly
one major factor that has been tested and recommended by many
standards and guidelines. However, viewing information on the
display from direct perpendicular position is a typical assumption
whereas many actual events are required viewing from the angles.
This current research aims to study the effect of oblique viewing
angle and viewing distance on ability to recognize alphabet, number,
and English word. The total of ten participants was volunteered to our
3 x 4 x 4 within subject study. Independent variables include three
distance levels (2, 6, and 12 m), four oblique angles (0, 45, 60, 75
degree), and four target types (alphabet, number, short word, and
long word). Following the method of constant stimuli our study
suggests that the larger oblique angle, ranging from 0 to 75 degree
from the line of sight, results in significant higher legibility threshold
or larger font size required (p-value < 0.05). Viewing distance factor
also shows to have significant effect on the threshold (p-value <
0.05). However, the effect from distance factor is expected to be
confounded by the quality of the screen used in our experiment.
Lastly, our results show that single alphabet as well as single number
are recognized at significant lower threshold (smaller font size) as
compared to both short and long words (p-value < 0.05). Therefore, it
is recommended that when designs information to be presented on
LED display, understanding of all possible ranges of oblique angle
should be taken into account in order to specify the preferred letter
size. Additionally, the recommendation of letter size for 100%
legibility in our tested conditions is provided in the paper.
	    journal   = {International Journal of Industrial and Manufacturing Engineering},
	  volume    = {8},
	  number    = {12},
	  year      = {2014},
	  pages     = {2007 - 2012},
	  ee        = {https://publications.waset.org/pdf/9999907},
	  url   	= {https://publications.waset.org/vol/96},
	  bibsource = {https://publications.waset.org/},
	  issn  	= {eISSN: 1307-6892},
	  publisher = {World Academy of Science, Engineering and Technology},
	  index 	= {Open Science Index 96, 2014},