In optical reading systems(OMR,OCR),the recording surface (paper) considered with respect to its contrast to the characters or marks to be read.

• 在光学阅读(输入)系统(例如光标志阅读器,光代码读出器)中,指从与准备原阅读的光(字)符或光标志形成的反差出发考虑的记录表面(或纸面)的状况。