TIEBitmapHelper.OrbDetectAndDeskew
Declaration
function OrbDetectAndDeskew(InImage: TIEBitmap; ReferenceImage: TIEBitmap; OutImage: TIEBitmap = nil; MaxFeatures: Integer = 500; GoodMatchPercentage: Double = 0.15; HomographyMethod: TIEVisionHomographyMethod = ievRANSAC): BooleanDescription
A shortcut method that creates a TIEVisionORBFeaturesDetector object, calls findHomography to determine the homography and then uses warpPerspective to deskew the image.
| Parameter | Description |
|---|---|
| Self | The input image to be deskewed |
| ReferenceImage | The image to use as a reference for optimal alignment |
| OutImage | Destination image for the result (needs to be created before calling method). If nil, then current image is updated |
| MaxFeatures | Maximum number of points to detect. The higher the value specified the more accurate the result is likely to be |
| GoodMatchPercentage | Percentage (0..1) of "good-match" to choose which points to take |
| HomographyMethod | Method to compute the homography matrix |
Result is true, unless an error occured. Typically errors occur because the homography matrix cannot be calculated (you should try increasing MaxFeatures).
Note:
◼You must add the iexHelperFunctions unit to your uses clause
◼You can draw the rects to a canvas using DrawRects
◼If attached to a TImageEnView, it will automatically call Update
◼Object detection requires IEVision. You will need to register it before calling the method
Method Behaviour
The following call:ImageEnViewInput.IEBitmap.OrbDetectAndDeskew( ImageEnViewReference.IEBitmap, ImageEnViewResult.IEBitmap, UpDownMaxFeatures.Position );
Is the same as calling:
// detect matching points of the two images
orb := IEVisionLib().createORBFeaturesDetector();
orb.detect( ImageEnViewInput.IEBitmap.GetIEVisionImage(), ImageEnViewReference.IEBitmap.GetIEVisionImage(), 500 );
// find homography matrix (hmat) from matching points
hmat := IEVisionLib().createMath().findHomography(orb.getPoints1(), orb.getPoints2(), ievRANSAC);
// check homography validity
if IEVisionLib().createMath().isValidHomography(hmat) then
begin
// adjust "scanned-form" to the same skew of "form" image
imgres := ImageEnViewInput.IEBitmap.GetIEVisionImage().warpPerspective( hmat, IEVisionSize( ImageEnViewReference.IEBitmap.Width, ImageEnViewReference.IEBitmap.Height ));
ImageEnViewResult.IEBitmap.AssignIEVisionImage( imgres );
ImageEnViewResult.Update();
end;
Examples
// Skewed image is ImageEnViewInput, Reference image is ImageEnViewReference, deskewed result is shown in ImageEnViewResultImageEnViewInput.IEBitmap.OrbDetectAndDeskew( ImageEnViewReference.IEBitmap, ImageEnViewResult.IEBitmap );
// Deskew current image using a reference image
ImageEnViewInput.IEBitmap.OrbDetectAndDeskew( ImageEnViewReference.IEBitmap, nil );