FR2542483A1 - Portable optical device for reading a binary information medium and for audibly restoring this information - Google Patents

Abstract

This device is portable and allows acquisition and audible restoration of information contained in a text 3 with the aid of a read head of a speech synthesiser 11. The coding method used relates to a "bar code" inscribed along two straight-line tracks 6, 7, each of these tracks 6, 7 corresponding to one of the two logic states "0" or "1". This device is used especially to aid the blind.

Description

PORTABLE OPTICAL DEVICE FOR READING A MEDIUM
BINARY AND RETURN INFORMATION
SOUND OF THIS INFORMATION.

 The invention relates to a portable optical device for reading a binary information medium and for sound reproduction of this information, useful in particular for the blind.

 Various studies have been carried out, tending to the production of apparatus capable of reading texts written in block letters, taking into account the various possible formats and the various layouts, and of restoring the content thereof in the form of a summary. vocal.

 These devices are extremely complex, bulky and expensive, because, on the one hand, the problem of pattern recognition by optical means has not yet found an industrially exploitable solution and, on the other hand, the necessary speech synthesizers are very advanced devices which must ensure satisfactory throughput and intelligibility (acoustic, phonetic and prosodic synthesis).

 Another type of device, intended for the educational toy market and not for that of assistive devices for the blind, is currently available; it uses texts coded in "bars", optical readers and speech synthesizers.

 In this type of device, it should be noted, firstly, that speech synthesizers contain only a limited number of words, specific to the intended application, and therefore unusable for reading any text. Second, taking into account the type of "barcode" used and the need to skim the words to form sentences, the spatial density of information is low and it is not comparable to that of a written text. in standard block letters. Finally, the quality of the printing of the bars and their support must be high, and therefore expensive, to ensure correct reading.

 Indeed, all the reading systems of "2 bar codes" currently proposed must be able to distinguish not only the bars of the spaces (spatial information) but also, their respective thicknesses, taking into account the duration of passage of the reader. on a bar or a space (information of a temporal nature). As a result, there are maximum and minimum speeds for scanning texts encoded by optical readers.

 It therefore seems difficult to adapt these systems to the needs of the blind, without making substantial modifications to them.

 In order to offer the blind a suitable device, less complex, portable and economically viable, the device of the invention uses a coding process called "double barcode". According to this method, two separate tracks of bars are written on an information medium, the bars of the first track corresponding to the logic state "1" and the bars of the second track corresponding to the logic state "0", these tracks being arranged in such a way that they can be read simultaneously. By using a speech synthesizer, we simply perform a "BRAILLE" type reading.

The portable optical device for reading a binary information medium and for sound reproduction of this information comprises, according to the invention, a read head, a speech synthesizer connected to this head which delivers a sound signal and an information medium binary which consists of a document page on which the information is of the type "double barcode" in the form of two tracks of binary states, represented by bars with different optical coefficients of transmission (or reflection) from those of the spaces between said bars, the first track corresponding to the logic state "1", the second to the logic state "0". Preferably, this device comprises an element, such as a cover, intended to be placed on the document page, this cover comprising windows in front of said information, and guide means making it possible to move the read head along the windows.
The read head comprises two optoelectronic members, each of these relating to one of the two tracks. The guide means preferably comprise a carriage on which the read head is mounted and which moves along the windows.

 In one embodiment, the information medium is in the form of a simple sheet of paper.

Other features and advantages of the invention will become apparent from the following description and the appended figures, among which:
- Figures 1 and 2 illustrate a device according to the invention.

 - Figures 3 and 4 illustrate the coding of information used in the device.

 - Figure 5 illustrates another device according to the invention.

 The invention relates to a portable device enabling the blind to acquire the information contained in coded text.

 The coding of the text as shown in FIGS. 1 and 2 is carried out using a "double bar code", the reading of which is carried out by a reader 1 comprising two identical optical sensors 4 and 5 moving in a straight line, thanks to a system of mechanical guidance 2.

 The acquisition of information from a blind person is then carried out thanks to a speech synthesizer controlled by a microprocessor managing the data coming from the reader.

 In a simple "barcode"; a character is represented by a succession of lines and spaces perpendicular to the direction of inscription, these lines and these spaces being able to be of different thicknesses. Each character thus has its own code which does not directly correspond to its binary equivalent.

 However, for the reading of such a "bar code", the reading speed can be variable (from cm / s to m / s) and the software necessary for processing the information is complex and often unreliable. Indeed, to make a correct reading, it is not only necessary to distinguish the bars from the spaces, but also, it is necessary to be able to distinguish their respective thicknesses. The information to be processed is therefore simultaneously spatial (bars or spaces) and temporal (duration of passage of the reader over a bar or space). To these difficulties, it should be added that the acquisition of information is highly dependent on the quality of printing, because any "smudge" on a bar will cause a reading error.

One of the essential characteristics of the device of the invention consists in using the so-called "double barcode" method, which makes it possible to eliminate these difficulties and has the following advantages:
- The number of symbols available depends only on the needs of the user and the admissible spatial density of information.

 - The reading speed is only limited by the characteristics of the optical drive and not by the signal processing.

 - Signal processing is carried out in an extremely simple and reliable manner.

 Such a "bar code" is presented on two separate lines: one of these lines, 6, is a line of "1" and the other, 7, a line of "O".

 In FIG. 3, the binary word 110100-10 has been represented according to the method of the invention on an information medium 5. Each "zero" or "one" represents an elementary space made opaque. Each gap between bars is also equal to this elementary space. Distance 8 therefore represents 15 elementary spaces.

 Any "information" (line) on line 6 represents a logical "1" and any "information" on line 7 represents a logic.

 The spatial density of information can be increased by reducing to zero the differences between the bars of line 6 and those of line 7 as shown in Figure 4. The - distance 9 therefore represents 10 elementary spaces, two successive bars representing two 1, a "being separated by a gap 10, to be distinguished.

Under these conditions, the space required to represent a symbol varies from
(2 x No. of bits) - 1 to 1 x No. of bits elementary spaces.

 The number of available symbols can be chosen according to the needs of the user and the permissible spatial density.

For assistive devices for the blind using optical readers, it is necessary, by the very nature of the users, to ensure mechanical guidance of these readers, and, in this case, we can exploit all the advantages of " double barcode ", namely:
- Choice of the number of symbols available and therefore great flexibility of use.

- Identification of these symbols by binary words
- Simple and reliable data processing, because the information is only spatial in nature and its acquisition is carried out by interruption on the appropriate inputs of a microprocessor.

 - Scanning speed limited only by the response time of the optical sensors and not by the data processing.

 - Secondary influence of the print quality of the bars and their support.

 In the device of the invention it is not really a speech synthesis, but rather the restitution of the actual coded speech in the form of a set of control signals, since the input of the synthesizer is composed of single words chosen from a limited repertoire. To this end, simple and reliable integrated speech synthesis circuits are currently available, offering a restricted vocabulary of a few hundred words with perfect intelligibility.

 The choice of the words appearing in these directories being at the discretion of the user, one can choose the restitution of the letters of the alphabet, numbers, punctuation symbols as well as a certain number of the most usual words.

 The coding of the text being carried out with a "double bar code", the system associating the reader and the microprocessor supplies, for each symbol, the corresponding binary word which makes it possible to address directly the memory of the speech synthesizer. It is thus possible to restore the coded text by voice, either by spelling the letters of a word not appearing in the basic directory, or by directly restoring the word which appears there.

 In FIG. 5, the device of the invention is shown with a coded text page 3 on which a cover 2 has been positioned. The movement of the reader 1 makes it possible to perform an optical reading of the information which has been previously written or printed. This reader has its two outputs which are linked to a control console or speech synthesizer 11, itself connected to a loudspeaker 12 and / or to an earpiece 13.

 This process does not present any particular problem for blind people who are used to using the "BRAîLLE" system. It allows the acquisition of all the data contained in a line of coded text and at one time, and this, whatever the scanning speed of the reader on the part of the user. The vocal restitution of this data can take place with a variable bit rate which depends on the adaptation of the users to this type of device.

 Having a high number of symbols and therefore a large number of common words possible, taking into account the memory capacity of the synthesizer, the identification of each common word by its own symbol allows a significant compression of information in coded text which, therefore, presents a spatial density of information practically equal to that of a text written in usual block letters.

 This device of the invention is subject to change as a function of the capacity of the memories of the synthesizers available and of the time necessary to identify a word and to restore it in vocal form.

Claims (7)

AND CLAIMS  1. Portable optical device for reading a binary information medium comprising a read head (1) and a binary information medium (3), characterized in that it comprises a speech synthesizer (I1) connected to this head (1) and in that the support (3) is a page of a document on which the information is of the "barcode" type in the form of a sequence of binary states represented by two tracks distinct (6, 7) of bars forming zones with optical coefficients of transmission (or reflection) different from those of the spaces between said bars, the bars of the first track (6) corresponding to the logic state "1", the bars of the second (7) in the logic "O" state, these tracks being arranged in such a way that they can be read simultaneously.  2. Device according to claim 1, characterized in that it comprises an element intended to be deposited on the document page, this element comprising windows in front of said information, and guide means making it possible to move this read head along windows, the read head comprising two optoelectronic members (4,5), each of these being associated with one of the two tracks.  3. Device according to claim 2, characterized in that the guide means comprise a carriage on which is mounted the read head (1) moving along the windows.  4. Device according to one of claims 1 to 3, characterized in that the information medium is in the form of a sheet of paper.  5. Device according to one of claims 1 to 4, characterized in that an earphone (13) is connected to the speech synthesizer (11)  6. Device according to one of claims 1 to 5, characterized in that a loudspeaker (12) is connected to the speech synthesizer (II).  7. Device according to claim 2, characterized in that the element (2) is a cover.