Method and device for reading contrasting characters

摘要

These characters are arranged in one or more data fields in at least one data track each and are combined to form character groups and may contain format control characters which identify the subformat of the in each case subsequent character group. The data field or fields are optically scanned and converted into a corresponding electrical video signal which is decoded. The characters and format control characters read are then serially converted into standard-code binary character signals or format control character signals and are then displayed, printed out or processed further. To indicate or process further the data field or fields read only when certain predeterminable context conditions have been met within the data field or fields, at least one context condition is predetermined which identifies a relationship between several subformats. Then a check is carried out as to whether the relationship demanded by the context condition is satisfied by the subformats read. If the required context relationship is found, the binary signals output by the decoder are processed further or indicated. If, in contrast, the required context relationship is not found, an error signal can be output which either triggers a new read process or indicates an error.