METHOD AND DEVICE FOR READING OPTICAL INFORMATION

PURPOSE:To provide a method and device for reading optical information by which information recorded optically can be read exactly, and also, in a short time. CONSTITUTION:Bars and spaces of plural kinds of width dimensions are combined so as to be an arrangement corresponding to prescribed information, optical information recorded in a photographic film is read, and as shown in (A), a waveform of a read signal is subjected to sampling in a period T and converted to digital data. Whenever parts (for instance, sections 94, 95) in which a value of a bit of the optical information is varied are detected, CPU calculates an average value of the maximum value and the minimum value extracted as a peak corresponding to the space and the bar of the same width in the section, converts the result of operation to an analog signal and sets it in a comparator, and updates a threshold level of the comparator. As shown in (B), the comparator compares the set threshold level with the read signal, and as shown in (C), the result of comparison is outputted as data.