GB2153576A

GB2153576A - Electronic reading aid for the blind

Info

Publication number: GB2153576A
Application number: GB08402123A
Authority: GB
Inventors: Shizuo Ishiguro
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-01-26
Filing date: 1984-01-26
Publication date: 1985-08-21
Also published as: GB8402123D0

Abstract

The aid, for "reading" ordinary printed letters or symbols, comprises an opto-electronic letter-image sensor 9, a rotating daisy-shaped wheel 3 having a pin 14 on each of its "petals" in a one-turn spiral pattern, and an electronic synchronizing system consisting of a marked optical disc 2 between the sensor and the wheel. When an element in the image sensor is activated, its output lifts a "petal" momentarily by electro-magnetic means so that the top of the pin goes above a threshold level 15, the synthesized position of the pins above the threshold forming the shape of the letter which is detected by the blind person's finger. The apparatus can contain a monitor (LED 17 and holes 18) for a sighted person to monitor the image of a letter. The apparatus can be made pocket-size including batteries. <IMAGE>

Description

SPECIFICATION Electronic reading aid for the blind This invention relates to an electronic apparatus for aiding the blind to read ordinary printed letters.

Braille characters, which have been used successfully for some 140 years, show thatthe replacement of the sense of signt of the blind by the sense of touch is the most practical way to aid their 'reading'.

However, the transferring of an ordinary document to a braille document is very time consuming task in addition to a delay in communications. The instantanious conversion of ordinary printed letters into a form which can be felt, will solve this problem.

According to the present invention, an apparatus is provided which consists of an opto-electronic sensor to detect a printed letter, and an electromechanical transducer to produce the shape of the letter, so that the blind can detect the letter by touching it. The sensor consists of an array of opto-electronic elements (e.g. photo transistors or diodes), and its electric output is obtained by scanning the elements in order. The electromechanical transducer consists of a daisy-shaped wheel which is rotated horizontally by a motor. The wheel has 'petals' evenly separated, each of which has a pin pointing upwards. The position of the pins in the wheel forms one turn of the spiral (or an effectively equivalent pattern).Each petal of the daisy wheel is lifted upwards momentarily, by electro-magnetic means, in synchronization with the scanning of the opto-electronic sensing array, when each of its elements is activated. Quansequently, the combined positions of pins in a lifted state during every turn of the wheel forms the shape of a letter.

This can be felt by the blind.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 shows a scheme of the whole apparatus; Figure 2 shows the movement of a petal with a pin during a rotation of the wheel; Figure 3 shows a section of a pin array which improves the blind person's feeling ofthe lifted pins on the wheel; Figure 4 is similar to the previous Figure, but shows another example of the pin array; Figure 5 shows an example of the electronic circuit for this apparatus; and Figure 6 shows an example of the physical construction of the whole apparatus.

Referring to Figure 1, a motor 1 drives the optical disk 2 and a 'spiral daisy wheel' 3, at a certain speed.

The optical disk has two types of optical marks (e.g.

both black-and-white stripes) on it. The first mark 4 has one stripe, and the second mark 5 has 100 stripes along the circumference of the disk for example. When the disk rotates, these marks are converted into two types of electronic pulses, through the opto-electronic pulse generators 6 and 7 (each of which consists of a LED and a phototransistor for example). Both the types of pulses are fed into the array-scanning circuit 8. The latter-image sensor 9 (e.g. an array of phototransistors) with its lens system 10 has an optical image of a printed letter to be read 11. The size of the image is adjusted for the array by the lens system. Each of the elements in the array is activated in order (one at a time), through its scanning circuit, by each strip of the optical mark 5. The starting position of the scanning is identified at every single cycle of scanning by the optical mark 4.The output signal of the array afterthe output circuit 12 is a series of pulses representing the image of the letter with logic high or logic low. The output signal drives the electromagnet 13, which lifts one of the petals of the spiral daisy wheel, at the moment when a particular element in the array is activated. The synchronization between the wheel and the scanning of the array is always kept independent of their speeds. The petals of the wheel can be lifted, either by direct contact of the armature of the electro-magnetto a petal; or by driving each petal with an on-or-off magnetic field produced by the magnet, providing each petal has a magnetic-sensitive part (e.g. an iron part). The petals of the wheel are evenly separated, each having a pin 14 pointing upwards.The position of the pins on the wheel forms one turn of the spiral.

When a petal is lifted upwards, its pin goes through the threshold level 15, so that the pins above the level form the shape of the letter 11. This is touched by a finger of the blind person, directly or through a pin array shown in Figures 3 and 4.

It is convenient for a sighted person (a tutor to train blind at the beginning of use of the apparatus, or an engineer to service it) to monitor the function of the apparatus, through a visual image of the letter under conversion. For this purpose, a part of the output from the output circuit 12 is fed to a LED 17, and a synthesized image of a letter can be seen through holes 18 which are situated in a spiral shape on the optical disk 2.

Referring to Figure 2, a pin 14 on a petal of the daisy wheel, in a normal position 19 and a lifted position 20 are illustrated together with the threshold level 15 (which is determined by a plate with slots 21) and the track of the petal 22. An alternative to the threshold plate is a pin array shown in Figure 3. This consists of a fixed plate 23 with many holes (their position in the array corresponds to the elements in the array for the letterimage sensor 9). Each of the holes has a vertically moveable pin which normally rest on the plate surface, since there is a gap between the bottom of each pin and the top of the pin on a petal. When a petal is lifted, a pin is also lifted upwards. Another type of pin array is shown in Figure 4. This is similar to that in Figure 3, but each pin is held near its top by an elastic material 25 (e.g. a rubber sheet) on a plate 26.The pin swings momentarily when a petal is lifted during its rotation, providing each pin hole is slightly greater than the diameter of the pin. Both the methods shown in Figures 3 and 4 improve the detection of activated pins by a finger of the blind person.

An example of the electronic circuit for this apparatus is shown in Figure 5. The two types of optical mark 4 and 5 on the optical disk 2 are converted into electronic signals by two sets of opto-electronic detector 6 and 7 and two comparators 27 and 28. These signals drive a binary-coded counter 29 which produce a cycling binary coded signal. The output of the counter is fed into two multiplexers 30 and 31. The former scans the letter-image sensor array 9 in its X direction and the latter in its Y direction. The output of the array 32 drives the electro-magnet 13 and the monitor LED 17, through another comparator 33 and a power transistor 34. The circuit can be adjusted for a dark letter on a bright background, or a bright letter on a dark background, by a reversing switch 35. Parts 27, 28,29,30 and 31 can be constructed by only four commercially available intergated-circuit packages for example. The whole circuit can be operated by batteries 36.

An example of the physical construction of the whole apparatus is shown in Figure 6. The apparatus is divided into two boxes 37 and 38. The first box contains the spiral daisy wheel 3, the optical disk 2 with the motor, the pin array 39, the electronic circuit 40, and batteries 36. The second box contains the letter-image sensor 9 and its lens system 10. The two boxes are linked with a cable 41. The apparatus is used normally by touching the pin array in the first box with a finger of one hand, and by adjusting the position of the second box on the printed document 42 with the other hand.

Claims

1. An electronic reading aid for printed letters (including symbols and and simple diagrams) for the blind comprising of: an array of opto-electronic elements for the letterimage sensor; a rotating 'spiral daisy wheel' defined by a daisyshaped wheel having evenly separated petals each of which has a pin, and the positions of all the pins on the wheel from a one-turn spiral (or an equivalent pattern); an electronic synchronizing system, between the rotation of the spiral daisy wheel and the scanning of the letter-image sensor, by means of on optical disk which rotates with the spiral daisy wheel and produces a set of opto-electronic signals;; an electro-magnet system which moves (push or pulls) a part of a petal of the spiral daisy wheel, at a moment when an opto-electronic element in the letter-image sensor is activated, so that the pin on the petal corresponding to the element goes through a certain threshold level; and the means of forming a letter shape by the positions of pins which go through the threshold level, and allow the letter shape to be felt bythe blind person's finger (or another part of his body).

2. An electronic reading aid for the blind as claimed in Claim 1 wherein an array of pins is inserted between the pins on the spiral daisy wheel (which go through a certain theshold level) and the blind person's finger, so that his detection of the letter is improved by clearly separating the pin above and below the threshold level.

3. An electronic reading aid for the blind as claimed in Claimes 1 and 2 wherein the array of pins consists of a plate with many holes; in each, a pin is vertically moveable when its bottom is pushed up by a pin on the spiral daisy wheel, and its top hits the blind person's finger.

4. An electronic reading aid for the blind as claimed in Claim 3 wherein the array of pins is similar to that in Claim 3, but the diameter of each hole in the plate is considerably greater than that of each pin, and each pin is held near its top with an elastic material (or an equivalent means). The pin swings when this is hit by the top of a pin on a petal of the spiral daisy wheel when the petal is lifted momentarily during its rotation.

5. An electronic reading aid for the blind as claimed in Claim 1 wherein a monitorfora sighted person (e.g. a tutor to the blind at the beginning of use of the apparatus) to monitor the image of the letter under conversion is constructed by the following means:- a part of the output from the output circuit is fed to a LED (or an equivalent light source), and a synthesized image of a letter can be seen through holes which are situated in a spiral shape (or an equivalent shape) on the part of the optical disk (used in the above-mentioned synchronization system) or on another disk which rotates with the optical disk.

6. An electronic reading aid for the blind substantially described herein with reference to Figures 1-6 of the accompanying drawing.