Properties of specific image processing settings

Image processing in eVRS always begins with page detection. Even if deskew to page or content, and crop are not requested, page detection is performed. This is to know where the page is to detect content like punch holes within it; decide whether the page is blank or analyze the image only inside the page while determining how better to binarize it. It is recommended to specify the range of scanner background colors in the scanner XML file that contains all the relevant non-defaults for the corresponding parameter settings. The following table describes the properties and the parameter range.

This keyword indicates that the incoming image is already deskewed and cropped, so no page detection is necessary – the whole image is the page.

Health analysis, if requested, is performed when the image of the Kofax Health Target Sheet is detected. The target sheet has bar codes along the sides to detect the orientation and the type of target sheet scanned. The sheet also includes two wide diagonal lines and white space in between. The analysis detects image streaks, problems with illumination uniformity, and straightness and stretching of the lines indicating roller wear. The returned data includes parameters indicating the health of each of the three items on a percent of excellence, 100% being the best.

The following parameters control this module:

Ignores the request to convert the output image to grayscale when the incoming image is binary.

The index image uses an 8-bit encoding of the content found within the processed image to exchange this information among image processing settings. Beginning with eVRS 2.2, index images are created automatically as necessary. Below eVRS 2.2, it is necessary to explicitly request the creation of the index image.

This capability is used to simplify data extraction from a known document type by removing everything other than several specified zones. The information regarding the zones of interest is communicated using _LoadSetting_ or loaded from an external file. For example, the following parameters can be used to extract the driver's license number and name of the holder from one of the license types in Arkansas:

<Property Name="CZoneExtract.Enable" Value="1" Comment="DEFAULT   0" />
	<Property Name="CZoneExtract.UseExactBB" Value="1" Comment="DEFAULT   0" />
	<Property Name="CZoneExtract.NumZones" Value="2" />

	######## Zone 0: DLNumber printed in RED
	<Property Name="CZoneExtract.Color.00.Int" Value="3" Comment="RED_ZONE=3"/>
	<Property Name="CZoneExtract.bbX1.00.Int" Value="1151" />
	<Property Name="CZoneExtract.bbY1.00.Int" Value="260" />
	<Property Name="CZoneExtract.bbX2.00.Int" Value="1484" />
	<Property Name="CZoneExtract.bbY2.00.Int" Value="311" />
	<Property Name="CZoneExtract.LineLabels.00.00.String" Value="DLNumber" />

	######## Zone 1: Name printed in Black
	<Property Name="CZoneExtract.bbX1.01.Int" Value="675" />
	<Property Name="CZoneExtract.bbY1.01.Int" Value="361" />
	<Property Name="CZoneExtract.bbX2.01.Int" Value="1600" />
	<Property Name="CZoneExtract.bbY2.01.Int" Value="408" />
	<Property Name="CZoneExtract.LineLabels.01.00.String" Value="Name" />

In this version of eVRS SDK, Zone Masking expects a color or gray image. The outgoing masked image is binarized by default. To change the bit-depth of the outgoing image, you must specify an appropriate value for the CZoneExtract.Bitdepth.int property. For example:

<Property Name="CZoneExtract.Bitdepth.int" Value="2" Comment="Gray" /> or
	<Property Name="CZoneExtract.Bitdepth.int" Value="3" Comment="Color" />

Performs smoothing of page background for color and grayscale images.

This keyword triggers the analysis of the document determining the color of the main background of the page and the most numerous of the foreground colors. This is assumed to be the color of the form that should be dropped out. See the following table for the most important modifiable parameters.

These keywords trigger the detection of content skew. They activate the processing module which corrects the skew of the original image. If the page is chopped by image frame, skew correction performed on scanned images must fill these missing areas, and in the absence of real data, they are filled with the median color of the image background (the background of the scanner). However, some of the areas of the image resulting from skew correction are still undefined if the angle of skew correction is different from the page skew. For example, if a page with skewed text is deskewed to content or a corner of the page was chopped by the image frame. By default, this color matches the average color of the scanner background. You can modify and provide the desired color by configuring the following settings.

This string activates the processing module which fills all image background areas left around the page that is connected to the outside of the image frame with a color or gray level defined by the settings.

This string activates the processing module which cuts a small frame around the final image to clean the fringes of the detected page. By default, this frame is 8 pixels thick regardless of image resolution but can be adjusted and prorated for DPI.

This string activates a branch in the Edge Cleanup processing module which allows the user to clip a region of interest from the processed image. This branch is triggered if the operations string includes the _DoRegionClip_ token followed by the desired x-offset, width, y-offset, and height in pixels in this order, all separated by blanks. Example: _DoRegionClip_15 350 25 780.

You can achieve the same result by setting the value of the VRS.ManualClip.Enable parameter to 1, and values of VRS.ManualClip.Top, VRS.ManualClip.Width, VRS.ManualClip.Left and VRS.ManualClip.Height parameters to 15, 350, 25, and 780 respectively.

The FINAL_IMAGE_SMALLER_PIXEL_DIM, FINAL_IMAGE_LARGER_PIXEL_DIM, and/or FINAL_IMAGE_DPI strings trigger a new module that allows the user to differentiate the final image from the processed image. This module works at the very end of the image processing chain in eVRS and affects both sides of an image if scanned in a duplex.

This functionality is useful in scenarios such as the following:

• In a case when the resolution of the image necessary for reliable processing and extraction of metadata is higher than the one sufficient for archival or desired for transmission from a device.

• If the final image is used as an input to another application with precise requirements for its height or width in pixels.

The overall logic guiding the internal behavior of this module is as follows:

1. The module is activated if at least one of the parameters (FINAL_IMAGE_SMALLER_PIXEL_DIM, FINAL_IMAGE_LARGER_PIXEL_DIM, or FINAL_IMAGE_DPI) is specified and is different from the corresponding parameter of the processed image.

2. Once a parameter is specified, this module determines the coefficient of the proportional scaling of the processed image. For example, if the processed image is in landscape and its width, height and resolution are 2009 pixels, 1237 pixels, and 400 DPI respectively, and the value of FINAL_IMAGE_LARGER_PIXEL_DIM is 1000, then the scaling coefficient is the ratio of 1000 over 2009 resulting in 0.49776. The final image turns out to be 1000-pixel width, 615-pixel height, and 199 DPI.

3. If both FINAL_IMAGE_SMALLER_PIXEL_DIM and FINAL_IMAGE_LARGER_PIXEL_DIM are specified, the horizontal and vertical scaling are done separately, and with potentially different coefficients. In the example above, if additionally, the specified value of FINAL_IMAGE_ SMALLER _PIXEL_DIM is 600, then the horizontal scaling coefficient is the ratio of 1000 over 2009 resulting in 0.49776 and the vertical scaling coefficient is the ratio of 600 over 1237 resulting in 0.48504. The final image turns out to be 1000-pixel width, 600-pixel height, 199 horizontal DPI, and 194 vertical DPI.

4. If the value of FINAL_IMAGE_DPI is specified in addition to one or both pixel dimensions, the scaling is based on pixel dimension(s) as described above, but both horizontal and vertical DPI values are set to the specified value. In the example above, if additionally, the specified value of FINAL_IMAGE_DPI is 200, then both horizontal and vertical DPI values (calculated as 199 and 194 respectively) are replaced by 200.

The keyword IMAGING_DEVICE_TYPE (actual string: _DeviceType_) followed by an integer 2, as in "_DeviceType_2" can be used with PC-based systems to set the best processing environment for camera images. This mode activates DPI estimation, rectangularization, correction for illumination, the use of auto-contrast, auto-brightness, and Intelligent cleanup during binarization, and several other settings to produce an optimal resulting image. If processing a scanner image, use "_DeviceType_0". This setting is included by default.