CIS file format

CIS stands for Contact Image Sensor. CIS files are 1-bit image files using run-length encoding for data compression.

Structure of CIS files

Byte offset	Byte size	Data type	Field	Description
0	40	char	description	ASCII characters describing roll. Unused trailing bytes filled with spaces (0x20). Nul (0x00) might be used to terminate string.
40	2	LE ushort	scanner width	Number of bytes in one scan line.
42	2		reserved	Unused field.
44	2	LE ushort	tempo	Tempo of the roll (beats per minute format). Default value is 90 if value is 0.
46	2	LE ushort	LPI	Lines per inch along the vertical axis (length of roll). The default for this value is 182.
48	4	LE ulong	line count	Number of scan lines in the file.
52			data	Compressed version of the scanned data