AUDITORY DISPLAY FOR THE BLIND

• US 3,800,082 A
• Filed: 10/27/1972
• Issued: 03/26/1974
• Est. Priority Date: 10/27/1972
• Status: Expired due to Term

• Current Assignee: Raymond M. Fish
• Original Assignee: Raymond M. Fish
• Inventors: Fish, Raymond M.
• Primary Examiner(s): Richardson, Robert L.
• Application Number:
  US05/301,417
• Time in Patent Office: 515 Days
• Field of Search: 178/5.6,5.8R,6,6.8,DIG.32 35/35A 340/407
• US Class Current: 348/62
• CPC Class Codes: A61F 9/08 Devices or methods enabling eye-patients to replace direct visual perception by another kind of perception
• CPC Class Codes: G09B 21/006 using audible presentation of the information

Abstract

A system for providing an auditory display of two-dimensional patterns as an aid to the blind includes a scanning device, such as a slow scan television camera, for producing first and second voltages respectively indicative of the vertical and horizontal positions of the scan and a further voltage indicative of the intensity at each point of the scan and hence of the presence or absence of the pattern at that point. The vertical position of the scan is represented aurally by the frequency of the tone heard, the first voltage being used to control the frequency output of a VCO. The horizontal position of the scan is represented aurally by the interaural difference between two tones presented so that a point on the left side of a pattern is indicated by a relatively loud sound in the left ear. The voltage related to scan intensity controls transmission of the sounds to the subject so that the subject knows that a portion of the pattern is being encountered by the scan when a tone is heard, the subject determining the position of this portion of the pattern in space by the frequency and interaural difference information contained in the tone.

Claims

1. A system for producing a two-dimensional auditory representation of an image pattern, said system comprising scanning means for scanning the image pattern;

means for generating a variable frequency signal the frequency of which varies in accordance with the vertical position of the scan;

means for generating separate electrical signals for each ear of a user which vary in amplitude in accordance with the horizontal position of said scan;

means for combining said variable frequency signal and said separate electrical signals into corresponding auditory signals for each ear of a user representative of the vertical and horizontal position of the scan;

means for generating a control signal related to the image pattern scanned by said scanning means; and

means for controlling the auditory signals heard by the user in accordance with said control signal.

2. A system as claimed in claim 1 further Comprising headphones connected to the output of said combining means and including left and right earphones, said means for generating separate electrical signals including means for producing a first variable amplitude signal and means for generating a second variable amplitude signal, said first variable signal being connected to said left earphone and said second variable amplitude signal being connected to said right earphone through said combining means.

3. A system as claimed in claim 2 wherein said combining means comprises analog multiplier means.

4. A system as claimed in claim 2 wherein said first and second variable amplitude signal generating means respectively comprise first and second function generator means for generating a signal whose amplitude varies approximately exponentially with the horizontal position of the scan, one of said first and second variable amplitude signals being the inverse of the other.

5. A system as claimed in claim 4 wherein said function generator means each comprise a variable diode function generator.

6. A system as claimed in claim 4 wherein said variable frequency signal generating means includes a voltage controlled oscillator.

7. A system as claimed in claim 6 wherein said variable frequency signal generating means further comprises further function generator means for generating an output signal the amplitude of which varies approximately exponentially with the vertical position of the scan and which is connected to the input of said voltage controlled oscillator.

8. A system as claimed in claim 7 wherein said first and second function generator means and said further function generator means each comprise variable diode function generators.

9. A system as claimed in claim 7 wherein said scanning means comprises a television camera including means for generating a first D.C. voltage whose amplitude varies in accordance with the vertical position of the scan, means for generating a second D.C. voltage whose amplitude varies in accordance with the horizontal position of the scan and a third D.C. voltage whose amplitude varies in accordance with the intensity of the scan, said system further comprising means for processing said third D.C. voltage to produce said control signal.

10. A system as claimed in claim 9 wherein said signal processing means comprises differentiator means, said means for controlling the auditory signals heard by the user comprising an electronic switch controlled by said control signal and connected to the output of said variable frequency oscillator.

11. A system as claimed in claim 7 wherein said scanning means comprises an oscilloscope, a vertical sawtooth generator for generating a vertical control voltage for controlling the vertical scan position of said oscilloscope, a horizontal sawtooth generator for generating a horizontal control voltage for controlling the horizontal scan position of said oscilloscope, the output of said horizontal sawtooth generator being connected to the inputs of said first and second function generator means and the output of said vertical sawtooth generator being connected to the input of said further function generator;

photomultiplier tube means for receiving light from said oscilloscope as modulated by the image pattern; and

level sensor means connected to the output of said photomultiplier tube means for producing said control signal.

12. A system as claimed in claim 11 wherein said means for controlling the auditory signals heard by the user comprises electronic switch connected to the output of said level sensor meand and to the output of said voltage controlled oscillator.

13. A system as claimed in claim 11 further comprising means for connecting the output of said level sensor means back to the inputs of said vertical and horizontal sawtooth generators for controlling the scanning rate of said oscilloscope in accordance with the output of the level sensor means.

14. A system as claimed in claim 1 wherein said combining Means comprises first and second analog multiplier means, said means for controlling the auditory signals heard by the user comprising electronic switch means responsive to said control signal for controlling connection of said variable frequency signal to the input of said analog multiplier means.

15. A system for producing a two-dimensional auditory representation of an image pattern, said system comprising scanning means for scanning the image pattern;

means for generating a variable frequency signal the frequency of which varies in accordance with the vertical position of the scan;

means for generating separate electrical signals for each ear of a user which vary in phase in accordance with the horizontal position of said scan;

means for combining said variable frequency signal and said separate electrical signals into corresponding auditory signals for each ear of a user representative of the vertical and horizontal position of the scan;

means for generating a control signal related to the image pattern scanned by said scanning means; and

means for controlling the auditory signals heard by the user in accordance with said control signal.