TIEVisionImage.removeLines

Declaration

function removeLines(directions: TIEVisionLineDirections = ievLinesBoth; minLength: int32_t = 0; maxThickness: int32_t = 0; repairText: bool32 = True): TIEVisionImage; safecall;

Description

Removes the straight horizontal and vertical lines of a document image, such as the lines of forms and tables, boxes around fields and underlines. Lines that touch or cross the text are a common cause of OCR errors.
The lines are painted with the background color. Text, and filled areas such as logos or bold headings, are kept.
Returns a new 8-bit gray image (a black and white image stays black and white). The current image is not changed.

Parameter	Description
directions	Remove horizontal lines, vertical lines or both
minLength	Shortest line to remove, in pixels. Must be longer than any character. 0 (default) chooses it automatically from the text height and image size
maxThickness	Thickest line to remove (its average thickness), in pixels. 0 (default) uses a quarter of the text height (at least 3)
repairText	Reconnects characters that were cut where they crossed or touched a removed line

Note:
◼The image should be dark text on a light background
◼Lines must be horizontal or vertical, so deskew the image first if needed
◼This is also available as a step of prepareForOCR (ievOCRPrepRemoveLines)

Demo

Demos\ImageEditing\EveryMethod\EveryMethod.dpr

Examples

Also see: Automated Samples

// Remove the lines of a form before OCR
img := ImageEnView1.IEBitmap.GetIEVisionImage().removeLines();
ImageEnView1.IEBitmap.AssignIEVisionImage( img );
ImageEnView1.Update();

// Remove only underlines at least 100 pixels long
img := ImageEnView1.IEBitmap.GetIEVisionImage().removeLines( ievLinesHorizontal, 100 );

// Remove the form and table lines, and underlines of a document
ImageEnView1.IEBitmap.AssignIEVisionImage( ImageEnView1.IEBitmap.GetIEVisionImage().removeLines( ievLinesBoth, 0, 0, True ));
ImageEnView1.Update(); // Show changes in our viewer

TIEVisionImage.removeLines