Correct Inverse Text

Finds and corrects areas of a 1-bit image containing inverse text.

InverseBefore2 → Description: Description: Description: InverseAfter2

The uncompressed image to be processed must reside in the Get Queue prior to REQ_EXEC. Typically, the image will be fully contained in the Get Queue, but that is not a requirement. The output image will be placed into the Put Queue during REQ_EXEC.

Padding pixels present at the end of each line may be modified by this operation.

This operation relies primarily on three parameters to select the areas to remove: minimum area width, minimum area height, and maximum dot size. All three criteria must be true of an area for it to be removed.

Subcode is set to SF_SUBCODE_CORRECT_INVERSE_TEXT (18).
u.SC18.MinimumAreaHeight is set to the height of the smallest inverse area that the opcode processes. Valid values are from 0 to 20,000, with 50 being a good default value.
u.SC18.MinimumAreaWidth is set to the width of the smallest inverse area that the opcode processes. Valid values are from 0 to 20,000, with 300 being a good default value.
u.SC18.MinimumBlackOnEdges is set to the smallest horizontal distance between the edges of an inverse text zone and the inverse text itself. Use a lower value if inverse zones are missed. Use a higher value if normal text is being treated as inverse. Valid values are from 0 to 100, with 10 being a good default.
u.SC18.Density is set to the maximum number of white pixels per 100 black pixels within a given area. Valid values are from 0 to 20,000, with 200 being a good default. You should use a higher value to detect lighter zones.
Stride is set to the image line width in bytes including padding at the end of the line width or to 0. If Stride is 0 and PF_NoDibPad is set in PicFlags, the operation will compute the stride using: [ (PixelWidth*BitCount)/8 ]. If Stride is 0 and PF_NoDibPad is not set in PicFlags, the operation will compute the stride using: [ (((PixelWidth*BitCount)+31)&(~31))/8 ].

In addition to placing an output image into the Put Queue, this operation stores some output information into the PIC_PARM structure in the following locations.

CountOfFeaturesDetected is set, during REQ_EXEC, to the number of areas removed.

OutputStride is set, during REQ_INIT and REQ_EXEC, to the image line width in bytes including padding at the end of the line.

BiOut is set, during REQ_INIT and REQ_EXEC, to the attributes of the output image. Since this operation does not adjust the size of the image, BiOut will be set to a copy of the Head structure within PIC_PARM.