Image recording system performing error correction repeatedly with the same check fields

摘要

According to a first aspect of the invention, digital image data are recorded in the form of compressed codewords with check information and flags. The flags indicate codewords containing uncorrected errors. Each time the data are copied, error detection and correction are performed and the flags are updated to indicate any new uncorrectable errors that are detected. The flags can be used for error concealment, to avoid error miscorrection, and to permit the check information to be regenerated each time the data are copied. According to a second aspect of the invention, when image data are copied, the same check information is used to perform error detection and correction twice. Flags identifying uncorrected errors can be transferred from the first error-detecting-and-correcting process to the second.