Method for gaze-controlled text size control, and methods for gaze-based measuring of a text reading speed and of a number of visual saccades per text line

• US 9,256,285 B2
• Filed: 08/10/2012
• Issued: 02/09/2016
• Est. Priority Date: 08/19/2011
• Status: Expired due to Fees

• Current Assignee: Thomson Licensing SA (Vantiva SA)
• Original Assignee: Thomson Licensing SA (Vantiva SA)
• Inventors: Leroy, Arnaud, Fleureau, Julien, Guillotel, Philippe
• Primary Examiner(s): Patel, Sanjiv D
• Application Number:
  US14/239,360
• Publication Number:
  US 20140327609A1
• Time in Patent Office: 1,278 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: G06F 17/148 Wavelet transforms
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G06F 3/015 Input arrangements based on nervous system activity detection, e.g. brain waves [EEG] detection, electromyograms [EMG] detection, electrodermal response detection
• CPC Class Codes: G06F 40/109 Font handling; Temporal or kinetic typography

Abstract

For gaze-controlled text size control of a display, the invention proposes to probe, sample and record a user'"'"'s horizontal gaze Signal; to subject the gaze Signal to a subband filterbank or wavelet transform; to detect line delimiters in the gaze Signal; to derive a reading speed; to determine, as a number of saccades per text line the number of locations where the gaze Signal has sudden high slope portions surrounded on both sides by portions of markedly smaller slope; to detect, based on the reading speed and the number of saccades, a too small font size Status or a too big font size Status; and to initiate a corresponding font size change. Parts of this method can be used for gaze-based measuring of text reading speed and for gaze-based measuring of number of saccades.

Claims

1. A method for gaze-controlled text size control, comprising:

probing, sampling and recording a user'"'"'s horizontal gaze signal at a predefined sampling frequency;

subjecting the horizontal gaze signal to a frequency or wavelet transform on several levels;

detecting, in the transformed horizontal gaze signal, line delimiters;

deriving, for each pair of consecutive line delimiters enclosing the transformed horizontal gaze signal of a current line, a reading speed from the distance in samples of the pair of line delimiters, in relation to the sampling frequency of the horizontal gaze signal;

determining, from the transformed horizontal gaze signal of the current line, a number of saccades in the current line, by counting those locations, where the horizontal gaze signal has a sudden high slope portion surrounded on both sides by portions of markedly smaller slope, and wherein the number of the saccades is determined by determining a positive saccade count, determining a negative saccade count, and calculating the number of saccades as a difference between the positive saccade count and the negative saccade count;

wherein

an increase of the font size is initiated if the number of saccades is above a first threshold or if the reading speed is below a second threshold, and a decrease of the font size is initiated if the number of saccades is less than a third threshold.

2. A method for gaze-controlled text size control, comprising:

probing, sampling and recording a user'"'"'s horizontal gaze signal at a predefined sampling frequency;

subjecting the horizontal gaze signal to a transform;

detecting, in the transformed horizontal gaze signal, line delimiters;

deriving, for each pair of consecutive line delimiters enclosing the transformed horizontal gaze signal of a current line, a reading speed from the distance in samples of the pair of line delimiters, in relation to the sampling frequency of the horizontal gaze signal;

determining, from the transformed horizontal gaze signal of the current line, a number of saccades in the current line, by counting those locations, where the horizontal gaze signal has a sudden high slope portion surrounded on both sides by portions of markedly smaller slope;

wherein

an increase of the font size is initiated if the number of saccades is above a first threshold or if the reading speed is below a second threshold, and a decrease of the font size is initiated if the number of saccades is less than a third threshold; and

wherein the horizontal gaze signal, before the detecting of the line delimiters, is calibrated in such a way that an amplitude difference of 1 in the calibrated signal matches width of text being read.

3. The method of claim 2 wherein the transform subjected to by the horizontal gaze signal is a frequency transform.

4. The method of claim 2 wherein the transform subjected to by the horizontal gaze signal is a wavelet transform.

5. The method of claim 3 wherein line delimiters are detected by locating pieces of the transformed horizontal gaze signal where selected ones of frequency bands are below a threshold.

6. The method of claim 4 wherein line delimiters are detected by locating pieces of the transformed horizontal gaze signal where selected ones of wavelet levels of detail are below a threshold.