GB2194092A - Machine readable characters - Google Patents

Abstract

Characters representing hexadecimal numbers in a machine readable form are each formed by a first line 5 and one or more of a plurality of lines 1, 2, 3 and 4 which represent the values, 1, 2, 4 and 8 respectively. By scanning each character vertically and horizontally at two spaced positions it is possible to determine precisely which lines are present and to read the value of the character. <IMAGE>

Description

SPECIFICATION Machine readable characters The present invention relates to the provision of machine readable characters, and in particular to the provision of a set of characters for representing numerals of the hexadecimal system. The characters may also be used to represent letters or another numeral system.

The invention also provides a method of entering information in a computer by means of such characters.

One known system of machine readable characters, a bar code system, adopts a binary system in which values are represented in a succession of lines read by a machine.

These are practically illegible to people who are not well versed in computer science.

Another system is a punch tape system in which holes are punched in a tape, the information being put on the tape via a keyboard.

However, this requires the use of the punch tape machine and such tapes can only be read by an operator with considerable experience.

A first aspect of the invention provides a character system in which a character comprises a first line and a line or lines from a set of lines, each line of the set being non-parallel to the first line.

Preferably the lines of the set surround the first line. Preferably the set of lines comprises four lines arranged in a quadrilateral around the first line, preferably the lines are arranged in two pairs of substantially parallel lines, preferably in a substantially square or rectangular shape.

The characters of the system may be readily drawn by hand and easily identified by eye as well as by machine, thus overcoming the drawbacks of existing systems such as bar code systems.

The characters of the system may be read electronically by, for example, present day bar code readers which are passed across the character and detect changes in reflectivity of the surface on which the character is printed or written, thus detecting the lines which make up the character. By detecting the relative orientation of the lines the presence of particular lines may be detected and so the value of the character represented may be determined.

A second aspect of the invention provides a character system in which a character is represented by drawing one or more sides of a quadrilateral, each side of the quadrilateral having a different value or meaning and each representing a particular character, the sides being combined to represent further characters.

A third aspect of the invention provides a method of inputting information to a computer, comprising forming a printed or written code from a character system as hereinbefore defined and scanning the code with the aid of a machine such as an electrooptic device.

The invention will be further described by way of example with reference to the accompanying drawings, in which: Figure 1 illustrates the lines which make up a character set according to the invention; Figure 2 to 4 illustrate particular numbers of the set of Figure 1, and Figure 5 shows another arrangement of lines for a character set according to the invention.

Referring to figure 1, a character set for representing the numbers 0 to 15 of the hexadecimal system comprises a set of four lines 1, 2, 3, 4 forming the sides of a square, and a diagonal 5 of the square. The diagonal 5 represents the number 0, and the sides 1, 2, 3, 4 represent the numbers 1, 2, 4 and 8 respectively. The diagonal 5, number 0, is present in every character. Subsequent numerals are represented by incorporation of the appropriate sides of the square. Hence the number 9 is represented by sides 1 and 4 (1 + 8 = 9), number 13 by sides 1, 3 and 4 (1 + 4 + 8).

The numbers can of course be readily identified visually by a reader after only a short period of familiarisation.

The numbers can be read by a electrooptic wand or the like as generally known in the art, which detects the number of lines, by passing the wand sideways across the number, to detect the presence of any of lines 4, 5, 2 and from top to bottom, to detect lines 1, 5, 3.

Considering the number 13 illustrated in Figure 2b, the wand will detect the lines 1, 5, 3 in its vertical path, thus giving the sum 1 + O + 4. In the sideways path the wand will detect two lines but it is necessary to determine whether lines 4 and 5 or lines 5 and 2 have been detected.

If the wand is passed across the character above the median line A-A then it can be seen that the space between lines 4, 5 will be greater than that between lines 5, 2. Hence if the wand can be consistently passed across the character and at known speed it would be possible to determine automatically the spacing between the detected lines and hence which two lines are present. However, in practice this is difficult when the wand is drawn across the character manually in view of the variation in the speed at which wand is drawn across the character.

In a particularly preferred aspect of the invention, the wand is arranged to detect a line at two positions, for example by being provided with two reading heads. Because the lines 4, 2 are non-parallel to the diagonal line 5 it will then be possible to detect the relative slope of the lines, or the angle they make with the diagonal, by comparing the sp-acing of the lines at the two positions.

This is explained more fully by reference to figures 3a and 3b which show the characters for the numbers 8 and 2 respectively.

In Figure 3a, the spacing b' detected by a reading head passing along line B' is greater than the spacing c' detected by a reading head passing along line C', whereas in Figure 3b the spacing c" is greater along line C" than that spacing b" along line B". Hence it is possible to deduce which of the lines 4, 2 is present with the diagonal 5. Of course, if only the diagonal 5, or if both lines 4, 2 are present the comparison does not need to be made. Similarly the presence of the horizontal lines 1 or 3 can be detected.

The character lends itself to being written manually since it is necessary for the writer to ensure only that the line 1, 2, 3 or 4 converges with the diagonal line 5 in the correct direction. This is illustrated in Figures 4a and 4b which show the characters for numbers 1 and 4 respectively. In the Example of Figures 4a and 4b, care must be taken that both reading heads do not cross both lines in making a horizontal pass across the characters. If one head only crosses both lines then an error can be indicated.

The character set shown is particularly useful for the hexadecimal system which is commonly used for input to computers, but is of course equally useful with systems having less than 16 characters, such as the decimal system. Pairs of characters may of course be used if a set larger than 16 is required.

The characters may be embossed or raised above the paper or other support surface so that they can be read easily by blind persons.

The character system of the invention may be used to draw up order forms, enquiry forms, identification sheets, surveys and other public relations services, servo-mechanism check sheets, and for marking objects for mechanical sorting.

The characters may be written on paper carrying a feint outline of the complete set of lines and the diagonal line to assist writing of the characters manually.

The outline may be printed on the paper in a feint coloured ink, such as yellow, which will be invisible in light of that colour, or invisible to the wand used for reading the characters.

In another arrangement, the diagonal line, which is always present, may be printed on the paper, to help with writing the characters.

The invention also provides paper printed, marked or embossed in this way.

Figure 5 shows a character set similar to that illustrated in Figures 1 to 4, but with the top and bottom lines representing 2 and 4 respectively, and the left and right lines representing 8 and 1 respectively.

Various modifications are envisaged. For example, the other diagonal of the square may be used or the diagonal may be replaced by a line joining mid points of the sides or the top and bottom. The number value attached to the different sides may be varied.

Aside from inputting information into a computer the system finds particular utility a game, for example for teaching hexadecimal mathematics. The game may comprise four sets of sixteen cards, each card having a numeral represented on it. The cards may be used to perform simple mathematical calculations or to input questions and answers to a computer by means of a wand as aforesaid.

Various other modifications will be apparent to those in the art and it is desired to include all such modifications as fall within the scope of the accompanying claims.

Claims (20)

1. A system of machine readable characters, wherein each character is represented by one or more lines from a set of four lines which form a substantially quadrilateral shape when they are all present.

2. A system as claimed in claim 1, wherein each line of the set represents a respective power of 2.

3. A system as claimed in claim 2, wherein the powers represented are the zero, first, second and third powers of 2.

4. A system as claimed in claim 3, wherein the value of a character is determined by summing the value of the individual lines which are present.

5. A system as claimed in claim 1, 2, 3 or 4, wherein a fifth line is provided to represent zero.

6. A system as claimed in claim 5, in which the fifth line is always present.

7. A system machine readable characters, in which a character comprises a first line and a line or lines from a set of lines which are ncnparallel to the first line.

8. A system as claimed in claim 7, wherein the first line represents zero.

9. A system as claimed in claims 7 or 8, wherein each line of the set of lines represents a power of 2.

10. A system as claimed in claim 9, wherein the set of lines comprises two pairs of substantially parallel lines arranged in a quadrilateral around the first line.

11. A system as claimed in any one of claims 7 to 10, for representing numbers of the decimal or hexadecimal system.

12. A method of inputting information into a computer, comprising writing or printing characters according to the system defined in any one of claims 1 to 11, and reading the characters by means of a machine.

13. A method as claimed in claim 12, wherein an electrooptic wand is passed across the characters.

14. A method of inputting information into a computer by representing the information by a numeral or numerals of a set of numerals, the numerals of the set being represented by a first line, which is always present, and option- ally one or more lines from a set of lines, the lines of the set being non-parallel to the first line.

15. A method as claimed in claim 14, wherein the first line represents zero and the lines of the set each represent a respective power of two.

16. A method as claimed in claim 15 wherein the set of lines comprises two pairs of substantially parallel lines arranged in a quadrilateral around the first line.

17. A method as claimed in claim 16, wherein the presence of a particular line of a pair of parallel lines is detected by determining the spacing between the particular line and the first line at two positions, thus indicating the relative orientation of the line.

18. Paper or card having markings which indicate positions for the lines of claims 1 to 7.

19. A system of machine readable characters, substantially as hereinbefore described with reference to the accompanying drawings.

20. A method of inputting information into a computer by means of machine readable characters, substantially as hereinbefore described with reference to the accompanying drawings.