An image header is associated with every image captured by the scanner. Following is a list of information available in the image header.
Image length size of the image data in bytes.
Image identifier indicates whether the image is front bi-tonal, rear bi-tonal, front color, rear color, front grayscale or rear grayscale.
Resolution the scanner records the selected scanner image resolution in dots per inch.
X-axis upper left pixel horizontal offset to upper left corner of the image. For more information, see the next section entitled “Zone processing”.
Y-axis upper left pixel vertical offset to upper left corner of the image. For more information, see the next section entitled “Zone processing”.
Width the scanner records the number of pixels-per-line in the image. Width is also referred to as line length.
Length the scanner records the lines-per-page in the image. Length is also referred to as page length.
Bits-per-pixel bits-per-pixel can equal 1 for bi-tonal imaging, 8 for grayscale, 24 for compressed color imaging or 64 for uncompressed color. Bits-per-pixel is also referred to as pixel depth.
Compression type the scanner records the compression type used. Values for bi-tonal images are: No Compression or Group IV. The value for grayscale or color images is None or JPEG.
Polarity the scanner records image polarity. White pixels can be indicated as 0 or 1.
Multi-Feed indicates whether or not a multi-feed was detected when the image was scanned. This information could be used by the host to assist operators during error recovery.
