TIEVisionImage.getConnectedComponents

Declaration

function getConnectedComponents(connectivity: int32_t = 8; minWidth: int32_t = 0; minHeight: int32_t = 0; maxWidth: int32_t = 0; maxHeight: int32_t = 0): TIEVisionVectorRect; safecall;

Description

Finds every group of touching dark pixels (via Leptonica) and returns their bounding rectangles.
The image is binarized with Otsu first (black and white images are unchanged by this), so it should contain dark objects on a light background.
Useful for finding characters, blobs and lines, measuring text size, and locating noise or borders.

Parameter	Description
connectivity	4 (pixels touch horizontally or vertically) or 8 (diagonals also count)
minWidth, minHeight	Skip components smaller than this
maxWidth, maxHeight	Skip components larger than this. 0 means no limit

Examples

// Outline every character-sized component
rects := ImageEnView1.IEBitmap.GetIEVisionImage().getConnectedComponents( 8, 3, 5, 100, 100 );
for i := 0 to rects.size - 1 do
  with rects.getRect( i ) do
    ImageEnView1.IEBitmap.Canvas.Rectangle( x, y, x + width, y + height );
ImageEnView1.Update();

// Outline the dark connected components of a document (e.g. characters)
rects := ImageEnView1.IEBitmap.GetIEVisionImage().getConnectedComponents( 8, 3, 3, 100, 100 );
ImageEnView1.IEBitmap.IECanvas.Pen.Width   := 1;
ImageEnView1.IEBitmap.IECanvas.Pen.Color   := clRed;
ImageEnView1.IEBitmap.IECanvas.Brush.Style := bsClear;
for i := 0 to rects.size() - 1 do
begin
  r := rects.getRect( i );
  ImageEnView1.IEBitmap.IECanvas.Rectangle( r.x, r.y, r.x + r.width, r.y + r.height );
end;
ImageEnView1.Update();

TIEVisionImage.getConnectedComponents