2-12 A-61504 April 2007
Image header
information
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.
Image identifier indicates whether the image is front black and
white, rear black and white, front color or rear color.
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 black and white
imaging. 8 for grayscale or 24 for color imaging. Bits-per-pixel is also
referred to as pixel depth.
Compression type the scanner records the compression type used.
Values for black and white images are: No Compression, Group III,
Group III 2D or Group IV. The values for grayscale or color images are
No Compression or JPEG.
Polarity the scanner records image polarity. White pixels can be
indicated as 0 or 1.
Multifeed — indicates whether or not a multifeed was detected when
the image was scanned. This information can be used by the host to
assist operators during error recovery.
Deskew enabled — a flag in the image header reflects whether the
scanner was asked to perform deskew. If deskew is enabled, the image
header also indicates whether or not the document was deskewed.
Deskewed a flag the image header indicates whether or not the
image was deskewed.
Skew angle image header records the skew angle which was
determined for the scanned image. A severe skew angle may result in
no deskew being performed. If the scanner is unable to determine a
skew angle, the image will not be deskewed. The skew angle field of
the image header will be set to 0.
Print string the actual character string printed on the document is
returned in the image header. This string may be up to 40 characters in
length. Print strings are defined in the host application.
Sequential counter the scanner assigns a unique Sequential ID
Number to each document which is returned in the image header. The
host application controls the setting of the starting value for this counter.