Two-Dimensional Spatial Frequency Content And Confusions Among Dot Matrix Characters

Michael E. Maddox

doi:10.1117/12.958048

2 November 1979 Two-Dimensional Spatial Frequency Content And Confusions Among Dot Matrix Characters

Michael E. Maddox

Proceedings Volume 0199, Advances in Display Technology; (1979) https://doi.org/10.1117/12.958048
Event: 23rd Annual Technical Symposium, 1979, San Diego, United States

Abstract

A two-phase study was conducted which related the confusions among dot matrix characters to the two-dimensional spatial frequency similarity of these characters. During the first phase of the study, subjects were shown single alphanumeric characters from four different dot matrix fonts and five matrix size/character subtense combinations. Data from this phase of the research were analyzed in terms of both correctness and character confusion frequencies. The second phase of the study consisted of digitizing and analyzing all characters from two of the fonts used in the first phase. The fonts chosen represent the most and least confusable of the four, based on the performance data obtained. These characters were scanned photometrically using a computer-controlled X-Y stage and subjected to a 512 X 512 point fast Fourier transform (FFT). The Fourier coefficients were correlated for all possible character pairs within each font-matrix/character size cell. These correlations provided an objective similarity measure among characters based upon their 2-D spatial frequency spectra. In addition to the spatial frequency similarity measure, a simple digital Phi coefficient was calculated for each character pair. The final analysis performed in this study was the correlation of observed performance (confusions) with objective similarity measures (2-D spectra and Phi coefficients).

Citation Download Citation

Michael E. Maddox "Two-Dimensional Spatial Frequency Content And Confusions Among Dot Matrix Characters", Proc. SPIE 0199, Advances in Display Technology, (2 November 1979); https://doi.org/10.1117/12.958048

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available