This is a very informative article on color drop-out by the Document Doctor. : Fujitsu PANTONE Dropout Confirmation Listing) for printing the forms. Therefore it is essential to use the recommended color pantone ( e.g. Only selected colors (shades of red, blue and green) can be dropped, which depends from scanner to scanner. Color drop out accuracy directly depends on the printing quality of the forms. This technique requires planning for color dropout in the early stages of the project, because it requires that the original forms be printed with the portions that are intended to be dropped out colored differently than the data to be captured. Now this has been improved and is achieved by software. ( eg : Blue Imaging Color Drop-Out Element for Kodak 9520/9500). Earlier scanners used specific colored lamps to achieve this. This will increase the recognition rate of OCR. The idea is to discard the text boxes and lines of a scanned image. (Illustration : noise removal)Ĭolour dropout is a proven useful technique for large-scale forms processing applications such as census projects. De-speckling (also known as noise reduction) is the process of removing such unwanted speckles from the image background. Whatever the form, this affects the image compression and increases the file size. (This is an example of an image with salt and pepper noise) This is also known as Salt and pepper noise. This could be in two forms black speckles in a white background as well as white speckles in a black background. When scanning old documents we usually get unwanted dots ( speckles) in the background. Unlike cropping this does not reduce the image size. The other technique is to replace the black coloured pixels in the borders with white colour pixels which is called black border removal. (This is an illustration of border cropping). However this does not reduce the resolution of the image. Border cropping removes black borders from the image completely also resulting in the reduction of image height and width. In document scanning, black border cropping is one technique that is used to remove the unnecessary black colour borders from an image. Here is a nice illustration called “The Effects of Deskewing a Document” in Ĭropping refers to the removal of the outer parts of an image. VRS can analyze the content of the image and correct the orientation accordingly. The De-skew process can straighten pages which were misaligned during the document feeding process, within a specified range of degrees.Ī more advanced feature is available with Kofax VRS called content based rotation. The De-skew facility in production capture applications helps to reduce this effort by automatically de-skewing misaligned images.
One objective of this step is to arrange the documents correctly by rotating (incorrectly filed documents) and aligning them together. In a production scanning set up, document pre-processing is the most time consuming step.
Described below are 8 such image processing techniques. There are number of image enhancement techniques available today. This is especially important for forms processing / OCR applications in order to improve character recognition. The purpose of image enhancement (image cleanup / image processing) is to make the images more readable, and also to remove unwanted noise reducing the storage requirements. Thus image enhancement has become an essential step in a well-defined capture workflow. Anyone will need to get the best possible image quality while keeping the file size to a minimum for obvious reasons. Two main concerns for any document imaging exercise are the image quality and the file size.
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