GB2266395A

GB2266395A - Reading information from a medium

Info

Publication number: GB2266395A
Application number: GB9208538A
Authority: GB
Inventors: Paul Yiu Shum Ko; Chung To Leung
Original assignee: APIC TECHNOLOGIES Ltd
Current assignee: APIC TECHNOLOGIES Ltd
Priority date: 1992-04-21
Filing date: 1992-04-21
Publication date: 1993-10-27
Anticipated expiration: 2012-04-21
Also published as: AU3693293A; GB9208538D0; GB2266395B

Abstract

An encoded pattern has a plurality of cells 100-116, each of cells 100-112 including an outline of an alphabet letter. Processing means senses when the outline has been inked in by sensing the extent of light and dark areas of each cell and the cells 100-112 in combination define a 7-digit binary number in dependence on whether each cell has been marked or not. Wholly dark cells 114, 116 act as locators for the cell array 100-112. <IMAGE>

Description

AN INFORMATION BEARING MEDIUM AND A METHOD OF AND APPARATUS FOR READING INFORMATION TEERSFROM This invention relates to an information bearing medium and a method of and apparatus for reading information from the information bearing medium.

Information bearing media from which encoded information can be optically derived by digital processing apparatus are known. Such apparatus may take the form of an optical character reader, which reads a typed character on the medium and recognizes this as an alphabet letter rather than a pattern of dots. Furthermore, bar codes and bar code readers are known in which a pattern of pre-printed dark bands is optically read and information derived designating, for example, a product with which the bar code is associated.

It is a disadvantage of these encoding techniques that they require an accurate representation of the encoded information, for example characters generated from specific fonts and accurately printed bar codes, to be provided for recognition to take place.

It is an object of the invention to provide an encoding method and information bearing medium which enables information to be decoded accurately without requiring the same degree of accuracy of representation of the encoded matter.

According to the invention there is provided a method of reading information from an information bearing medium, the medium having a plurality of cells arranged in pre-determined relative positions, comprising the steps of optically scanning each cell to determine the presence or absence of a mark, deriving said information from the combination of the presence of one or more marks and the position of the cell in which the or each mark is disposed, the determination of presence of a said mark being a function of the extent of light and dark areas of the cell.

The invention further comprises an information recording medium having a plurality of optically readable cells arranged in pre-determined relative positions, the cells being markable in an optically identifiable manner, information being derivable from the combination of the presence and position of one or more marks and determination of the presence of a said mark being a function of the extent of light and dark areas of the cell.

The invention further provides an apparatus for reading information from an information bearing medium comprising optical scanning means for scanning the medium and recognition means for determining the location of a plurality of cells arranged in pre-determined relative positions, for determining the presence or absence of a mark in each cell and for deriving said information from the combination of the presence of one or more marks and the position of the cell in which the or each mark is disposed, determination of the presence of a said mark being a function of the extent of light and dark areas of the cell.

With the invention as claimed, the recognition of information relies on the extent of light and dark areas in each cell, and preferably a threshold of percentage dark area is used to indicate the presence of a mark. The invention allows a degree of imprecision in the representation of the encoded matter and allows a mark to be manually applied to a cell to provide the required encoding.

Preferably, the cells are arranged in line and an outline of an alphabet character is disposed in each cell, the outline being insufficient to provide the necessary mark.

Inking in of pre-determined ones of the alphabet characters will then mark those cells and at the same time will spell a particular pneumonic which can provide a visual interpretation of the information conveyed by the cells Preferably, the information derived from the cells defines at least one set in which the information bearing medium, for example a medical record or report, is classified.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a schematic drawing of an embodiment of the invention.

Figure 2 is a flow diagram illustrating operation of the scanner and information processor for reading the information encoded in the embodiment of figure 1.

Figure 3 is a flow diagram illustrating the operation of block 1.3 of figure 2.

Figure 4 is a diagram illustrating a skewed block cell.

Figure 5 is a flow diagram illustrating in more detail the operation of block 1.4 of figure 2.

With reference to figure 1, an embodiment of the invention is illustrated which comprises a cell array having a plurality of cells 100-112 which are arranged side by side in a line between two wholly dark cell locators 114, 116.

The cells 100-112 have the outline of an alphabet character disposed therein which can be inked in by a user as shown, for example, inbcells 102, 106 and 108. The cell array 100-116 is pre-printed onto a sheet paper record or document to be stored in and classified by a computer by being optically scanned and stored as a pixel map in memory.

As will be described in detail below, the cell array is used to provide classification information for the record which is being scanned and this is achieved by the computer interpreting which cells 100-112 have the alphabet characters inked in. The alphabet characters in turn spell a pneumonic which indicates to the user in which category or categories the record has been classified.

The computer does not sense the identification of the alphabet characters but merely counts the number of dark pixels for each cell and compares these with a threshold.

If the number of pixels is above the threshold, this indicates that the alphabet letter outline has been inked in. The cells with inked in characters are then assigned a binary 1 whereas the others are assigned a binary 0 thus forming a binary word, in the case of that shown in figure 1 of value 44 in decimal which will indicate classification of the record in one or more categories.

The mode of operation of the embodiment of the invention is illustrated in figure 2. Firstly, the document is scanned and then the analysis routine is started at step 1.1.

At step 1.2, the paper orientation position is entered into the computer and in step 1.3, the cell locators 114, 116 are located. The routine for performing this is illustrated in more detail in figure 3 in which the pixel map of the scanned document is interrogated to determine the cell locators 114, 116. A start location for interrogating across the pixel map (which is continually adjusted until the locators are found) is chosen at step 2.2, a grid corresponding to the shape of cell locators 114, 116 is notionally taken and the number of horizontally orientated (H) dark pixels is counted. If the number of pixels is equalled to a number M indicating that the horizontal line region being tested is wholly dark, the number of vertically orientated (V) pixels is then counted and if equal to a number N, vertical and horizontal correspondence is verified and the cell locator is taken to be identified. This procedure is performed for both cell locators 114, 116 and serves to indicate the position of the cells 100-112. In order to compensate for some degree of skew of the paper relative to the scanner, the numbers M and N are preferably thresholds set at 80-90% of the full locator area, with a number of dark pixels above these thresholds providing verification.

Having determined this, at step 1.4 the precise coordinates of each cell are calculated. This is illustrated in more detail in figure 5.

Based on the position of the cell locators 114, 116, notional start and end points for the cell array are calculated in steps 3.2 and 3.3. At step 3.4, it is determined whether the start and end points are in horizontal line indicating that the page was scanned accurately and that the cell pattern is not slightly skewed as, for example, illustrated in figure 4. If the pattern is skewed to a limited extent ( < 30 ), compensation for the angle of skew 8 is provided at step 3.6 by dividing the difference in locator positions by the number of cells to calculate the positional offset of each cell, with the positions of the cells 100-112 then being calculated using the offset information in relation to the pixel map at steps 3.7 and 3.8.

At step 1.5, the areas in the pixel map corresponding to the located cells are examined and the number of dark pixels counted.

At steps 1.6, 1.7 and 1.8, the total number of dark pixels as compared to a threshold which is calculated to indicate when an alphabet character has been inked in. If the number of pixels is greater than the threshold, the bit value 1 is assigned to the cell and otherwise the bit value O is assigned to the cell. This procedure is calculated for all the cells and the relevant combined value stored as a binary word, in this case of 7-digits. This number is used to catalogue the scanned document.

While the embodiment of the invention described illustrates an encoding method using a plurality of cells in which an alphabet character is placed, as the scanning and interpreting method relies on the extend of light and dark areas within the cell, any mark, pattern or shape may be used within the boundaries of the cell, provided it is of sufficient dark area to be greater than the threshold measured in step 1.6 of the flow chart of figure 2.

Although the alphabet characters in the cells can be marked by hand, these can be pre-printed if forms or documents for particular applications are pre-printed in advance.

The encoding method is particularly useful for medical records, application forms and accounting documents which often need to be classified into various categories within an electronic data storage system.

Although the scanning method has been described as using dark or light to categorize the value of the cell, grey scales or colours may be used to increase the information content. For colours, these could be applied with highlighting pens, for example.

Claims

1. A method of reading information from an information bearing medium, the medium having a plurality of cells arranged in pre-determined relative positions comprising the steps of optically scanning each cell to determine the presence or absence of a mark, deriving said information from the combination of the presence and position of one or more marks and wherein the determination of the presence of a said mark is a function of the extent of light and dark areas of the cell.

2. A method as claimed in claim 1 wherein the presence of the said mark is determined when the dark area of a said cell exceeds a threshold.

3. A method as claimed in claim 1 or claim 2 further comprising the step of recognizing at least one cell locator defining the location of said cells.

4. A method as claimed in claim 3 wherein the or each cell locator comprises a wholly dark cell.

5. A method as claimed in claim 3 or claim 4 wherein the cells are arranged in a line between two said cell locators.

6. A method as claimed in any one of the preceding claims wherein each mark is in the form of an alphabet character.

7. A method as claimed in any one of the preceding claims wherein each cell includes the outline of said mark, the outline being insufficient for the presence of a mark to be determined thereby.

8. A method as claimed in claim 6 wherein a marked combination of alphabet characters spells a pneumonic associated with the derivable information.

9. A method as claimed in any one of the preceding claims wherein the information derived from the cells defines at least one category in which said information bearing medium is classified.

10. A method as claimed in claim 9 wherein said information bearing medium comprises a medical report or record.

11. An information bearing medium for use in the method as claimed in any one of the preceding claims.

12. An information bearing medium comprising a plurality of optically readable cells arranged in pre-determined relative positions, the cells being markable in an optically identifiable manner whereby information from combination of the presence of one or more marks and the position of the cell in which the or each mark is disposed is derivable, and wherein the presence or absence of a said mark is a function of the extent of light and dark areas of the cell.

13. A medium as claimed in claim 12 further comprising at least one cell locator defining the location of said cells.

14. A medium as claimed in claim 13 wherein the or each cell locator comprises a wholly dark cell.

15. A medium as claimed in claim 13 or claim 14 wherein the cells are arranged in a line between two said cell locators.

16. A medium as claimed in any one of claims 12 to 15 wherein each mark is in the form of an alphabet character.

17. A medium as claimed in any one of claims 12 to 16 wherein each cell includes the outline of said mark, the outline being insufficient for the presence of a mark to be determined thereby.

18. A medium as claimed in claim 16 or claim 17 wherein a marked combination of alphabet characters spells a pneumonic associated with the derivable information.

19. A medium as claimed in any one of claims 12 to 18 wherein the information derived from the cells defines at least one category in which said information bearing medium is classified.

20. A medium as claimed in claim 19 wherein said information bearing medium comprises a medical report or record.

21. An information bearing medium comprising a plurality of optically readable cells arranged in pre-determined relative positions, the cells being markable in an optically identifiable manner whereby information from the combination of the presence and position of one or more marks is derivable, each cell including an outline of said mark, the outline being insufficient for the presence of a mark to be determined thereby.

22. An information bearing medium as claimed in claim 21 whereby each mark is in the form of an alphabet character.

23. A medium as claimed in claim 21 or claim 22 wherein a marked combination of alphabet characters spells a pneumonic associated with the derivable information.

24. Apparatus for reading information from an information bearing medium having a plurality of cells arranged in pre-determined relative positions comprising optical scanning means for scanning the information bearing medium, storage means for storing the scanned image; and processing means for determining the presence or absence of a mark in each cell and deriving said information from the combination of the presence of one or more marks and the position of the cells in which the or each mark is disposed, the presence of a said mark being a function of the extent of light and dark areas of the cell.

25. Apparatus for performing the method as claimed in any one of claims 1 to 10.

26. A method of reading information substantially as hereinbefore described with reference to the accompanying drawings.

27. An information bearing medium substantially as hereinbefore described with reference to the accompanying drawings.

28. Apparatus for reading information from an information recording medium substantially as hereinbefore described with reference to the accompanying drawings.