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, back black and white, front color or back color.
Resolution the scanner records the selected scanner image resolution in dots per inch.
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
Length the scanner records the
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.
Deskew the image header reflects whether or not the scanner was asked to perform deskew. If deskew is enabled, the image header also indicates whether or not the document was deskewed. The maximum angle the scanner will deskew is 44.9 degrees.
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.