Method to remove edge artifacts from skewed originals

Details Method to remove edge artifacts from skewed originals Method to remove edge artifacts from skewed originals

1998-09-23

2001-08-07

Rogers, Scott (Department: 2624)

Facsimile and static presentation processing

Static presentation processing

Attribute control

C358S001180, C358S488000, C358S453000, C358S464000, C382S282000, C382S286000, C382S289000, C382S319000

Reexamination Certificate

active

06271935

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to imaging devices, such as printers and copiers, and more particularly to a system and method for removing paper edge and platen background artifacts from images to be printed of documents which were copied skewed relative to a platen in a digital copier. The invention allows a user to blank the surrounding regions of an image of the original document if it is skewed in the full image area by using a line-by-line and pixel-by-pixel replacing of each pixel value to a predetermined value along an edge of the image of the original document at any arbitrary angle.
BACKGROUND OF THE INVENTION
In the present invention, a user may place an original document onto the platen of a digital copier where the placement is at a large angle to the platen, which would normally be noticed and corrected by this user before copying the document. In contrast, the placement could be at a slight angle to the platen, which is unnoticed, or the user could be in a rush and non-observant, and this can result in a skewed image of the original document being saved in the copier memory for printing. Further, the cover of a digital copier can become dirty forming a non-white area around the image of the original document, reducing the quality of the printed document. To overcome these problems, a user will desire to blank out all of the unwanted platen and cover artifacts that would surround the image of the skewed original document without causing any of the original document's data to be lost.
Traditionally, the blanked region is orthogonal to the scanner array on all four sides of the full image area. The drawback for the traditional approach is that by using known orthogonal blanking techniques to remove the artifacts in severely skewed originals, part of the original's content may be removed and the artifacts, e.g., platen show through and copier top dirt, may not be completely eliminated. As can be clearly seen in prior art
FIG. 1
, the original document was scanned into the digital copier at a severely skewed angle. Using a conventional blanking technique, the original document
2
is blanked orthogonally, as is shown as
6
, which clearly cutoff parts of the original document
4
and its data, and left artifacts
8
, e.g., platen show through and copier top dirt, reducing the quality of the image and resulting print. The conventional way of blanking around a document is by raster scanning around a margin of the document which replaces pixels with a predetermined pixel value using a set size of the margin. Unfortunately, this usually results in the cutting off of parts of the original document containing important data and leaving of the background artifacts.
It would be advantageous if the background of the image of the original document could be completely blanked, regardless of that fact that the document was placed on the platen at a small or severely skewed angle, without any loss of data. It also would be advantageous if the blanking technique ensured that a user could completely blank the regions surrounding the document so that no data of the document was lost and all of the background artifacts, caused by the platen show through and a dirty top of a digital copier, were removed thus leaving a more accurate and more perfect image of the original document to be printed than conventional blanking techniques.
Unfortunately, known systems do not provide for blanking out regions surrounding the document where they only blank out horizontal and vertical regions on the edges of the image. In doing this, the blanking will remove desired data from the image from the original document, and will leave behind background artifacts of platen show through and copier top dirt which reduces the quality of the image to be printed.
The present invention contemplates a new skew blanking technique which achieves the above-referenced advantages, and others, and resolves appurtenant difficulties.
SUMMARY OF THE INVENTION
In the subject invention, a system and method provide a user with the ability to blank regions surrounding the image of the original document in a full image area of a digital copier. This is done so that no data from the original document is lost and all areas which may contain background artifacts, either from platen show through or dirt of the top cover of a copier, are removed. The technique allows this to be done regardless if the original was placed in a slightly skewed or severely skewed direction on the platen.
In accordance with the present invention, the user may first reduce the image size of the image of the original document in the full image area so that the entire image of the original document shows up in the full image area before the blanking initiates. In this way, although the image is skewed of the original document, a user can blank out all artifacts that are unwanted and have the entire original document show up in the printed image without losing any data from the original document.
In accordance with a primary aspect of the present invention, there is a system and method for removing artifacts from an image of a skewed original document comprising the steps of performing a pre-scan of the original document and storing certain predetermined parameters, of the original document storing parameters of the digital copier, determining if the image of the original document is skewed in a full image area, wherein if the image of the original document is skewed in the full image area, performing the further steps of, recalling the stored parameters of the original document and the digital copier, i.e., platen parameters, setting selected regions, preferably a first through sixth region, with the background artifacts in this selected region, preferably surrounding the image of the original document in the full image area, and scanning the original document, wherein the predetermined parameters of the original document before the scanning are correlated with the scanned image of the original document, and, performing a skew blanking technique to replace the pixel values in the first through sixth regions surrounding the image of the original document in the full image area with a predetermined pixel value.
In accordance with another aspect of the present invention, the first through sixth regions are defined as being from first through sixth lead-edge lines of the image of the original document, wherein the lead-edge lines are at least one of the predetermined parameters correlated to the image of the original document, to first through fourth edges of the full image area wherein the first through fourth edges are defined as being the top edge, right edge, bottom edge, and left edge, respectively, of the full image area.
In accordance with another aspect of the present invention, defining the first region as being from a horizontal top lead-edge line of the image of the original document to the first edge of the full image area. Defining the second region as being from the horizontal top lead-edge line of the image of the original document, down to where the image of the original document intersects with the fourth edge of the full image area. Defining the third region as being from the horizontal top lead-edge line of the image of the original document down to where the original document intersects with the second edge of the full image area. Defining the fourth region as being from an intersection of the image of the original document with the fourth edge of the full image area to a bottom horizontal lead-edge line of the image of the original document. Defining the fifth region as being from an intersection of the image of the original document with the second edge of the image down to the bottom horizontal lead-edge line of the image of the original document. Finally, defining the sixth region as being from the bottom horizontal lead-edge line of the image of the original document to the third edge of the full image area.
In accordance with a still further aspect of the present invention, the skewed blanking is done using

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