FOUR-POINT CORRESPONDENCE TYPE INDIVIDUAL INFORMATION MARK SHEET

Abstract: A mark sheet is constituted by a combination of four sections which are separately smeared and denote by numbers (I-X). This is done either by hand or by printing. In order to read information from such a sheet, a mask sheet with four light transmitting holes is used. For the size of a section of the mark (a) and the diameter of the hole (b) the maximum positioning error of (a-b) is allowed. Whilst a conventional bar-code sheet having a combination of longitudinal black and white margins is susceptible to error in positioning and marking. The mark sheet of this invention provides correct information reading in the presence of overflow or incompleteness of handwriting.

Description: The present invention relates to a shaded code system including a marked sheet, to a method of coding and reading such a sheet, and to a printed information sheet marked in accordance with the code. Examples of codes can be found from Japanese Patent Publication No. 57-191788 by Takeo Tada and French Patent No. 1115882 by Decrulle. In the first reference, a shaded code is disclosed for enabling data entry to a computer to be simplified and quickened. In the second reference, a code using a perforated card is described for enabling a numerical value to be more quickly entered. U.S. Patent No. 3898434 discloses an automatic coding system in which a machine prints a shaded code onto a sheet which can then be scanned by fiber optics through an apertured masking sheet. Each square unit of the code has four square regions which may be printed or not printed in accordance with a binary representation of a number. This disclosure corresponds to the pre-characterizing portion of Claim 1. Conventional bar codes have also been used for printing a code onto various products. The code depends on the variation of widths of bars to provide the coded information. Accordingly very high accuracy of the widths of the written bars is required in the order of microns. Regardless of whether the bars are written manually or printed, this imposes many technical limitations, resulting in high cost. The present invention seeks to provide a shaded code which may be accurately read by a sensor even in the presence of comparatively large errors in the manual writing of the code. According to the present invention there is provided a shaded code system as defined in the appended claims 1 and 4. Preferred embodiments of the present invention are defined in other appended claims. By way of example only, the preferred embodiment of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a plan view of a unit being divided into four regions; Figure 2 illustrates a plan view of 10 possible units of the code showing how the numerals are represented by four-point correspondence type individual information mark shaded regions; Figure 3 is a schematic diagram of a unit showing the sides of a fourfold unit; Figure 4 is an exploded perspective view of a mastersheet; Figure 5 is a plan view of an information sheet on which the code has not yet been printed; Figure 6 is a plan view of an information sheet having a code according to the preferred embodiment of the present invention; and Figure 7 is a plan view of a unit and associated sites for printing the equivalent character. The preferred embodiment of the present invention comprises a number of units 6 each of which is divided into four regions 1-4. Each region 1-4 is either completely shaded or remains blank. Each character of the code is represented by a particular combination of shaded regions 1-4. In this embodiment, each region 1-4 is shown as a square. Referring to Figure 2, each of the unique units represents one of the characters one to ten. For example numeral five is represented by a unit 6 having regions 1 and 3 shaded or printed. Figure 4 illustrates an information sheet having the information extracted therefrom. The masking sheet 10 is positioned between the mastersheet containing the code and a sensor sheet 11. The present invention enables the shaded code to be manually written or printed, without making the regions 1-4 large, whilst enabling the code to be read accurately. If one side 8 of the unit 6 has a dimension of A millimetres and the diameter of the light passage holes 9 of the mastersheet 10 has a dimension of B millimetres (in this case A is greater than B), then an accurate reading is possible within an error margin of (A-B)/2 millimetres in the vertical or horizontal directions. Therefore even if there is an overflow of shading or printing, so long as the overflow does not affect the other regions 1-4, accurate reading of the code is possible. In some applications only a small quantity of information is required and so an information sheet as shown in Figure 5 may be simply marked with the required information and results in an information sheet having the manually marked code as shown in Figure 6. Also, in cases where a large number of identical information sheets are required, a printing negative plate may be prepared on which the required quantity of information following the rules of Fig. 2 is arranged in the requisite sequence, sheets being used that are printed from this negative. In this case, in order to minimise information errors especially in proof reading, at the sites 20 indicated by a "O" in Fig. 7 the equivalent characters associated with the corresponding units 6 may be provided. Accordingly the present invention enables the shaded code to be read in the same manner as bar codes but has a greater degree of flexibility for over-flow or errors in marking, so that the shaded code can be read more accurately, and simpler reading methods may be used. Additionally simpler printing techniques may also be used for preparing the information sheets which have hitherto been unavailable to preparation of bar codes. The present invention has a number of applications which includes communications, massmedia publications, data processing, industrial and service applications, and electrical equipment and devices. The foregoing description of the preferred embodiment of the present invention has been given by way of example only and it will be appreciated by persons skilled in the art that modifications may be made without departing from the scope of the claims.

Claims: A shaded code system comprising: a sheet marked in accordance with a predetermined shading code having a plurality of characteristics, comprising at least one unit (6), each unit (6) being divided into four square regions (1, 2, 3, 4) having substantially similar dimensions, each characteristic of the code being represented by a respective unit (6) having a particular arrangement of shaded and blank regions; and means cooperating with the marked sheet for defining four discrete sensed regions of the plane of the sheet which are smaller (9) than the said square regions (1, 2, 3, 4) and which are capable of registering in one-to-one correspondence with respective square regions with correct relative positioning of the code, characterized in that the sheet is a manually marked sheet showing the unit (6) divided into its square regions (1,2,3,4) and in which the means for defining the discrete sensed regions comprises a masking sheet with four discrete regions (9) for defining the sensed regions whereby the masking sheet is interposed between the shaded code sheet and a sensor sheet. A shaded code system as claimed in claim 1, characterised in that said plurality of characteristics comprise the decimal notation 0 to 9. A method of coding and reading a shaded code using the marked sheet of the system of Claim 1 or 2 comprising manually marking the pre-printed marking sheet to represent characteristics as shaded units (6) and then using a sensor sheet to sense light from four discrete sensed regions of the plane of each code which are smaller (9) than the said square regions (1, 2, 3, 4) and which are placed in register in one-to-one correspondence with respective square regions, including positioning the code for accurate sensing of the code such that none of the sensed regions (9) comes into register with any part of any of the square regions (e.g. 2, 3, 4) adjacent to its unique square region (1). A printed information sheet marked in accordance with a predetermined shading code having a plurality of characteristics, comprising at least one unit (6), each unit (6) being divided into four square regions (1, 2, 3, 4) having substantially similar dimensions, each characteristic of the code being represented by a respective unit (6) having a particular arrangement of shaded and blank regions; means cooperating with the sheet for defining four discrete sensed regions of the plane of the sheet which are smaller (9) than the said square regions (1, 2, 3, 4) and which are capable of registering in one-to-one correspondence with respective square regions with correct relative positioning of the code, characterized in that the sheet is pre-printed from a negative printing plate and in that the sheet includes a plurality of such units (6) each marked with a character, equivalent to the respective one of said characteristics represented by shading in that unit (6), the characters being provided in specific portions (20, Fig. 7) of the sheet around the units (6) and adjacent their edges and in which the means for defining the discrete sensed regions comprises a masking sheet with four discrete regions (9) for defining the sensed regions whereby the masking sheet is interposed between the shaded code sheet and a sensor sheet. A method of coding and reading a sheet in accordance with Claim 4, in which the sheet is encoded with marks representing characteristics as shaded units (6) and additionally as corresponding characters at the specific portions (20, Fig. 7), and in which the sheet is read using a sensor to sense light from four discrete sensed regions of the plane of each code which are smaller (9) than the said square regions (1, 2, 3, 4) and which are placed in register in one-to-one correspondence with respective square regions, including positioning the code for accurate sensing of the code such that none of the sensed regions (9) comes into register with any part of any of the square regions (e.g. 2, 3, 4) adjacent to its unique square region (1) and in which the sheet is proof-read.

Inventors: TOMIOKA MAKOTO, TOMIOKA, MAKOTO
Applicants: TOMIOKA MAKOTO, TOMIOKA, MAKOTO
Application year: 1987
Main classification: B42D15
IPC codes: G06K19