| 摘要 |
Information is encoded manually on a document (2) by making marks (M) at appropriate positions of a marking matrix. The document has a row (TZ) of timing marks (TM) which are recognised (in preprocessor 41) in order to ascertain the column positions. When the document is read by being carried past a scanning unit (10, 11), level shifts and/or oblique positioning thereof can arise due to cutting and printing tolerances or misconveyance. To compensate such possible sources of error, the preprocessor (41) also recognises the vertical position of the timing row (TZ) to ascertain the row positioning relative to the scanning unit. In addition, a code column (CS) with code marks (CM1) is provided on the document and their position is analysed to determine the magnitude and direction of the oblique positioning (if any) of the document. Image data derived from marks (M) is stored in a store and the information derived from the timing row and code column is used to enable the data relative to each mark to be read out correctly by reading data from appropriate columns of the store which are selected in accordance with the amount of obliqueness detected. <IMAGE> |
